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Spring: A boy named Pliny Moody uncovered a piece of
sandstone with mysterious three-toed tracks about 30 cm (1 foot) long while plowing in his father's fields near
South Hadley,
Massachusetts. The local clergy thought the tracks had been left by the
ravenNoah sent out from the
ark to look for dry land during the
Biblical Flood.[1]
A slab of
Permian sandstone preserving 24 small footprints came into the possession of the
Scottish Reverend
Henry Duncan. Duncan visited the quarry where his slab was originally excavated in
Corncockle Muir to see if he could find more of the fascinating impressions and successfully recovered more of them. He notified leading paleontologist
William Buckland of
Oxford University about his discovery.[2]
Buckland published the first scientific description of fossil footprints about the tracks discovered at Corncockle Muir. He attributed the footprints to ancient
tortoises because after having various modern reptiles walk over stretches of
pie crust
dough, the tracks left by tortoises most closely resembled those from the Permian sandstone.[4]
A man named
Helmut Barth was building a garden house in
Hildburghausen,
Germany when he discovered strange, hand-shaped tracks in the sandstone he was using in the construction.[5] Barth's discovery would be named Chirotherium by
Johan Jacob Kaup.[6]
While the streets of
Greenfield, Massachusetts were being paved, locals noticed footprints impressed in the stone. The townspeople thought the tracks were left by
turkeys.[1] They informed
James Deane, a local doctor and naturalist about the footprints. Deane found the tracks intriguing and wrote to another local scholar,
Edward B. Hitchcock about the find.[7] Hitchcock spent the rest of the summer investigating the local footprints fossils.[8]
A man surnamed Cotta wrote a letter including the first documented mention of the many Permian tracks perserved in the "
Rotliegendes" of central Germany's
Thuringian forest.[12] "Rotliegendes" is German for "red layers" referring to a Permian sandstone layer rich in
rustedironminerals known elsewhere as the "New Red Sandstone".[13] The tracks Cotta reported were later named Saurichnites cottae in his honor.[12]
Sir William Jardine argued against Owen's referral of the Corncockle Muir "tortoise" footprints to Testudo because the name applied to a specific group of modern
turtles rather than to footprints. He coined the name Chelichnus, meaning "turtle track" to replace Owen's use of Testudo, but preserved the specific epithet "duncani".[4]
Beckles continued to publish research on the dinosaur footprints from the Wealden, referring to them as Ornithoidichnites following the nomenclature devised by Edward Hitchcock for some American tracks. Despite his use of a term implying an avian trackmaker, Beckles admitted that he did not know what kind of animals made the tracks.[16]
Edward Hitchcock published a summary of his research into the fossil footprints of the
Connecticut Valley area. He continued to attribute the tracks to large flightless birds that he named their footprints "ornithichnites", meaning "stone bird footprints". He divided the trackmakers into two groups, the leptodactylous birds with narrow toes and the pachydactylous birds with thick toes. He also described seven new ichnospecies for the tracks he studied.[9] He also described the ichnogenus Grallator.[17]
A posthumous "supplement" to Hitchcock's monograph on the Connecticut Valley tracks was published.[20]
1860: Some English dinosaur footprints were recognzed as Iguanodon tracks. They were the first dinosaur tracks to be recognized as belonging to and individual genus.[11]
Thomas Henry Huxley argued against Buckland and Owen's attribution of Chelichnus duncani to ancient tortoises, instead concluding that it was impossible to identify the trackmaker with the knowledge of time.[15]
Some
Welsh dinosaur tracks that had been previously displayed in front of the Jolly Sailor Pub in
Newton Nottage were acquired by the
Cardiff Museum.[21]
T. H. Thomas reported the Welsh dinosaur footprints to the scientific literature and noted their similarity to the "Ornithichnites" of Connecticut.[21]
W. J. Sollas independently published a report of the Welsh dinosaur footprints.[21]
1880s
Early: Inmates of
Nevada's
State Prison uncovered a large
Pleistocene fossil tracksite while excavating sandstone. The track sites was a
lakeshore 50,000 years ago where familiar
Ice Age animals like birds,
deer,
mammoths, and
wolves left behind their footprints. However, ten of the roughly 50 trails seemed to have been left by an even stranger trackmaker; a sandaled
giant.~NA277~
Large
theropod footprints were reported in
Late Jurassic rocks at
Cabo Mondego,
Portugal. These may have been the first European Late Jurassic dinosaur footprints to be documented in the scientific literature.~152~
W. P. Blake reported the fossil footprints discovered at the prison in
Carson City, Nevada to the scientific literature.~NA321~
Mark Twain wrote the satirical "The Carson Fossil Footprints" attributing the purported giant tracks discovered there to primitive members of the
territorial legislature.~NA279~
A geology professor named
James A. Mitchell discovered some small Grallator tracks in the Late Triassic
Gettysburg Formation of
Maryland. These are the first and only known dinosaur tracks in the state.[26]
Luis Dollo matched the foot of Iguanodon bernissartensis with a purported Iguanodon footprint in "the first attempt to match these tracks with a particular species of the genus".[29]
Harold Broderick described the three-toed Middle Jurassic dinosaur footprints that had first been discovered during the 1890s at England's Yorkshire coast.[25]
A deluxe editions of Sir Arthur Conan Doyle's The Lost World was issued whose cover featured an illustration of the Iguanodon tracks recently discovered at Crowborough, Sussex.[16]
90 million year old Cretaceous dinosaur footprints were discovered in New Jersey but were accidentally destroyed during an attempt at excavating them.[24]
Charles Whitney Gilmore began collecting and studying the Carboniferous and Permian-aged footprint fossils of the Grand Canyon area on behalf of the
Smithsonian. He also constructed an outdoor exhibit about the tracks at
Hermit Trail.~NA34~
Renovations to
Oak Hill, the historical home of
US PresidentJames Monroe, led to the discovery of fossil dinosaur footprints when workers repaved the properties walkways with
Lower Jurassic stone. The preserved tracks included Grallator and Eubrontes prints ranging in length from 13 to 33 cm (5–13 inches).[24] Other local footprints included the tracks of a crocodilian-like animal, Batrachopus. The tracks originated in the
Midland Formation.[32]
Baron Franz von Nopsca published a "seminal" work on fossil amphibian and reptile tracks.[33] He hypothesized that Plateosaurus was the Chirotherium trackmaker. Although Plateosaurus has only four hind toes and Chirotherium tracks have five impressions, Nopsca followed
Willruth's argument that the "thumb" of Chirotherium was composed only of
soft tissue and would have left no skeletal record.[34] He also named the large Late Jurassic theropod fossils discovered at Cabo Mondego, Portugal Eutynichnium lusitanicum. However, this name lacks validity because Nopsca did not formally describe it or designate a
type specimen.~154~
Wolfgang Soergel interpreted the Chirotherium trackmaker as a
pseudosuchian related to, but much larger than, Euparkeria.[34] He noted that the bulk of the animal's weight was born by its hindlimbs.[35]
German geologist
Adolf Bachofen-Echt reported the first scientifically recognized dinosaur tracks from
Croatia. These three-toed tracks were preserved on the
Brioni Islands and
Bachofen-Echt thought they were made by Iguanodon.~218~
Charles Gilmore described the Paleocene amphibian tracks from the Fort Union Formation of Montana. He named the new ichnospecies Ammobatrachus montanensis for the tracks. He observed that these were the first Paleocene fossil footprints to be documented in the scientific literature.~NA246~
Potential Paleocene mammal footprints were reported from
Alberta.~NA247~
Charles Whitney Gilmore published his third report on fossil footprints from the Grand Canyon area.~NA313~
Bradford Willard discovered a new ichnogenus
Devonian-aged trace fossils in Pennsylvania that he named Paramphibius because he thought the trackmaker was a transitional form between
fishes and
tetrapods. He named a new taxon, the
Ichthyopoda to classify this creature.~NA37-38~
Roland T. Bird discovered a new Early Jurassic dinosaur tracksite in the
Moenave Formation of northwestern
Arizona. Although the site's location would be lost, Bird's photographs would help
Dinosaur National Monument paleontologist Scott Madsen relocate the site decades later.~NA118~
Late: An expansion of the Nevada State Prison was built over the Pleistocene fossil footprints that had been discovered there. However, some specimens had been collected before and are now curated by the
Nevada State Museum.~NA280~
1930: Amateur paleontologist
Charles Strevell privately published a description of various Cretaceous dinosaur footprints he collected from the coal mines of Carbon County, Utah. Strevell named the tracks "Dinosauropodes" at the advice of
Earl Douglass after Strevell had failed to interest Richard Swann Lull or
Walter Granger in studying the tracks themselves. Strevell named many ichnospecies of "Dinosauropodes" in this publication, but none are considered valid because he published outside of the traditional scientific literature, failed to cite any other ichnological works, and referred too wide variety of dissimilar tracks to "Dinosauropodes".~NA217-219~
More Cretaceous dinosaur footprints were discovered at the Hampton Cutter Clay Works quarry at Woodbridge, New Jersey. The largest tracks discovered in the quarry were 19 inches long.[24]
Maurice Mehl erected the new ichnogenus Ignotornis for some bird tracks preserved in the Dakota Group near
Golden, Colorado. These were the first scientifically documented
Mesozoic bird footprints.~NA194-195~ The bird in question as interpreted as a "small
shorebird or
wader".~NA211~ The site would eventually be heavily collected and all of its tracks were presumed removed.~NA194-195~
Edward Branson and Maurice Mehl reported the presence of Carboniferous-aged fossil footprints of a new ichnospecies in the
Tensleep Formation of
Wyoming.~NA34~ They named the tracks Steganoposaurus belli and attributed them to an amphibian nearly three feet in length.~NA34-35~
Edward Branson and Maurice Mehl named a new kind of Late Triassic dinosaur footprint discovered in the
Popo Agie Formation of western Wyoming. The new ichnogenus and species was named Agialopus wyomingensis.~NA93-94~
Toepelman and
Rodeck made the first report on fossil
arthropod trackways in the Lyons Sandstone and fossil vertebrate footprints preserved in the
Fountain Formation.~NA314~
The
Dinosaur Ridge dinosaur tracksite was discovered near
Denver, Colorado. Tracks include those made by ornithopods and theropods. Some of the ornithopod tracks seem to have been left by individuals traveling together and are thus evidence for social behavior.~NA196-197~ Further, these ornithopods seem to have traveled predominately on all fours, unlike most ornithopod tracks, which were made by bipeds.~NA197~
The
New York Times reported that
Barnum Brown had discovered the fossil footprints of a huge and unknown kind of dinosaur in a Wyoming coal mine. Brown's claim was simply a "publicity stunt" aimed at attracting funding.~NA219-220~ However, Brown's report attracted the attention of a coal mine operator from the
Cedaredge, Colorado area named Charlie States, who reported large dinosaur footprints spaced five meters apart in his mine, the Red Mountain Mine.~NA220~ Brown and his assistant Roland Bird oversaw an "ambitious" excavation of the purported giant's tracks. After three weeks of 24 hour labor on the part of the miners and the development of specialized equipment to extract the specimen, a 17 foot long slab of track-bearing rock was taken from the mine and shipped to the
American Museum of Natural History in
New York.~NA220-221~
More Late Triassic dinosaur footprints were discovered near Gettysburg. These tracks ranged from chicken-sized to 15 cm (6 inches) in length.[38]
Kenneth Caster conclusively demonstrated that unusual fossil tracks from the Solnhofen lithographic limestone variously attributed to creatures like Archaeopteryx, little dinosaurs, or pterosaurs were actually made by
horsehoe crabs, as specimens had been found literally "dead in their tracks".[19] Similar fossils in the United States had been attributed to a transitional form between fishes and tetrapods by Bradford Willard earlier in the 1930s.~NA37-38~
Brown published a description of the dinosaur tracks with the purported giant stride length. He tried to keep up his charade of there being an undiscovered mystery dinosaur by downplaying "the obvious
hadrosaurian affinity of the tracks".~???NA220-221~
Nash bought the Massachusetts property where he discovered dinosaur footprints. He would begin excavating and selling the dinosaur footprints on his land and the property would come to be known as
Nash Dinosaur Land.[39]
Lionel F. Brady began experimenting with living arthropods to help determine which sorts of arthropods may have produced various ancient trace fossils.~NA43~
Sumner Anderson reported the presence of small carnivorous dinosaur footprints between 15 and 20 cm in length preserved in the Early Cretaceous
Lakota Formation at two different sites in
South Dakota.~NA184-185~
Earl L. Poole of the
Public Museum and Art Gallery discovered a new Late Triassic dinosaur track site at a quarry near
Schwenksville, Pennsylvania.[38] The dozens of tracks preserved there were mostly left by
chicken-sized dinosaurs, but about a "half dozen" of them were left by turkey-sized trackmakers.[40] Poole ascribed these tracks to the ichnogenus Anchisauripus. One footprint was left by a dinosaur with about the same body mass as a
horse.[39] This site is now known as the
Squirrel Hill Quarry.[38]
1940s
Frank Peabody performed "extensive" research on Early Triassic fossil footprints.~NA71-72~
Roland T. Bird oversaw the excavation of sauropod and theropod tracks from the
Paluxy River in Texas. This was the first large-scale dinosaur track excavation in history.~NA199~
Frank Peabody studied the early
Pliocene fossil amphibian footprints of the
Sierra Nevada Mountains of
California. He found them to be almost identical to the tracks of their descendants. This was his first major contribution to ichnology.~NA274~
Robert Chaffee reported the presence of a tracksite from Wyoming preserving the footprints of a
camel-like
even-toed ungulate and a
rhinoceros-like odd-toed ungulate in the Oligocene-aged
White River Beds. He noted that only two other Oligocene fossil tracks were known and neither had been described.~NA257~ Chaffee attributed one of these, a partial print preserved in the
Yale Peabody Museum, to a
brontothere.~NA257-258~
Casteret reported the presence of Pleistocene hyena tracks in the
Aldene cave of France.[42]
F. E. Peabody published a study of the amphibian and reptile tracks preserved in the Triassic Moenkopi Formation. Lockley and Hunt would later regard this paper as "a classic" in the field.~NA316~
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
1950s
Oligocene to Miocene-aged bird tracks were first reported from the "
Molasse" rocks of
Switzerland.[43]
Frank Peabody performed "extensive" research on Early Triassic fossil footprints.~NA71-72~
A rock hound named Al Look "embellished" Barnum Brown's mystery dinosaur hoax, informally naming the creature "Xosaurus". He also reported having encountered another dinosaur trackway with a similarly long stride as Brown's original specimen. This trackway supposedly recorded the huge mystery dinosaur stepping on a crocodile-like reptile.~NA221~
Albert de Lapparent and others restudied the large Late Jurassic theropod tracks of Cabo Mondego.[31] They thought the tracks were made by Megalosaurus.[44]
Henry Faul and
Wayne Roberts reported the presence of Early Jurassic fossil footprints in Colorado's
Navajo Sandstone. These tracks were probably left by an evolutionary precursor to mammals.~NA144~
Wilhelm Bock reinterpreted the footprints discovered in the Squirrel Hill Quarry as Grallator and non-dinosaurian
archosaur tracks. He also described the ichnospecies Anchisauripus gwynnedensis for a dinosaur track discovered in the
North Pennsylvania Railroad tunnel near
Gwynned. These tracks are now thought to belong to Atreipus, however.[39]
A French ichnologist named
Lessertisseur erected the ichnogenus Megalosauripus. He attributed the Cabo Mondego tracks to a
megalosaurid.[45] He also named the ichnogenus Tyrannosauripus, but as both ichnogenera lacked type species and type specimens these taxonomic names were invalid.[46]
M. F. Farmer published the locations of many track sites in northern Arizona.~NA312~
Lee Stokes erected the new ichnogenus Pteraichnus for fossil footprints discovered in the Morrison Formation of Utah that he thought were left by pterosaurs.~NA144~
Oskar Kuhn named the new Early Cretaceous theropod ichnogenus and species Buckeburgichnus maximus from Germany. It is notable in its preservation of a large
hallux impression.[47]
August 3rd:Albert de Lapparent and
Robert Lafitte stumbled on some fossil footprints left by a large bipedal dinosaur at
Isfjorden, Spitzbergen.[49] The researchers suspected that the tracks were made by a
carnosaur. At 78 degrees of latitude north, these were the highest latitude dinosaur tracks known in the world, up from the previous record of 56 degrees.[50]
A
geologist named
H. D. Curry working for the
Shell Oil Company discovered a slab of rock preserving high quality three-toed mammal footprints in Utah's
Strawberry Canyon. The trackmakers were probably Eocene relatives of modern
tapirs and
horses. Curry donated the so-called "Strawberry Slab" to the Smithsonian Institution.~NA252-253~
Albert de Lapparent reinterpreted the dinosaur tracks from Spitzbergen. Although mentioning their initial impression that the tracks were carnosaurian, he concluded that the tracks were probably left by Iguanodon instead, due to their lack of claw marks, rounded toe prints, and general similairty to the feet of Iguanodon bernissartensis.[50]
Panin and
Avram published research on
Miocene fossil bird and mammal tracks from the vicinity of the
Carpathian Mountains of
Romania. They attributed the local bird footprints to four different families, the
anatids,
ardeids,
charadriids, and
gruids. Contemporary mammalian trackmakers included
artiodactyls,
cats,
dogs, and
relatives of modern elephants. The latter of these left behind one thoroughly trampled site with an area of more than 100 sq m. The researchers erected several new ichnotaxa for the tracks they studied and similar tracks would later be discovered elsewhere in Europe.[51]
Natasha Heintz documented the return expedition to Spitzbergen to make plaster casts of the Spitzbergen dinosaur tracks. Although the casts were made, the effort was frought with difficulty because the intense cold and high humidity hindered the plaster's ability to set.[50]
A large pseudosuchian named Tichinosuchus was named for remains found in Swiss Triassic rocks. It had the right size and anatomy to account for the Chirotherium tracks of Europe and is considered the most likely trackmaker.[55]
Panin published more research on the fossil bird footprints from the Carpathian vicinity.[56]
de Raaf,
Beets, and
Kortenbout van der Sluijs reported the presence of a large number of well-preserved web-footed bird tracks from
Oligocene rocks in Spain.[57] The high percentage of the fossil trails being oriented in the same direction suggests that this deposit records evidence for flocking in these ancient birds. This is extraordinary because evidence for social behavior in fossil bird footprints is very uncommon.[37]
Albert de Lapparent and
Christian Montenat published the results of their research on the dinosaur tracks reported from western France in 1963.[52] They identified the rocks preserving the tracks as part of a geologic formation called the
Infralias and track sites were found in at least seven different positions in the local stratigraphy. The changing paleoenvironments implied by the local geology led the researchers to conclude that this series of dinosaur track beds spanned the Triassic-Jurassic boundary.[58]
March: A coal miner working near
Hayden, Colorado hit his head on the natural cast of a dinosaur footprint while in pursuit of a run-away coal cart. The impact injured his spinal cord, leading to his death 10 days later.~NA227~
1970s
Mid: Dinosaur tracks of the ichnogenera Atreipus and Grallator were discovered in a quarry that straddles the Virginia-
North Carolina border. These may be the oldest dinosaur tracks known in the eastern United States.[60]
Late: The publication of a formula capable of inferring the life speeds of dinosaurs from their fossil trackways brought further attention to Barnum Brown's claim of having discovered the tracks of a mystery dinosaur with an abnormally long stride length. Scientists instantly recognized the footprints as belonging to a duck-billed hadrosaur rather than some completely unknown dinosaur, but the validity of the trackway's stride length proved controversial.
Dale Russell and
Pierre Beland accepted Brown's measurement and calculated the trackmaker as moving at 27 kilometers and hour.
Tony Thulborn argued that a footprint left by another dinosaur obscured a track left by the original trackmaker roughly halfway between the prints composing the supposedly enormous stride. This implied that the trackmaker's stride was only half the claimed size and it was probably only traveling at about 8.5 kilometers and hour.~NA221~
Leonard Wills and
Bill Sarjeant reported potential dinosaur footprints from Triassic rocks in
Nottinghamshire and
Worcestershire. Ichnotaxa reported included Coelurosaurichnus, Otozoum, and Swinertonichnus. The rocks were of uncertain age at the time of the authors writing and are now known to have been Lower Triassic.[61] Dinosaur tracks dating to the Early Triassic would be anomalous as their skeletal remains are not known until later in the period.[62] Not suprisingly, the dinosaurian status of the tracks reported by Wills and Sarjeant have been disputed.[61]
Sarjeant found the three-toed Middle Jurassic dinosaur footprints comparable to the Cretaceous ichnogenus Saltapliasaurus from
Russia.[63]
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
de Clercq and
Holst published on the Upper Oligocene bird tracks of
Lucerne, Switzerland. The tracks, which the researchers concluded were left by
rails, were left in the fine-grained sediments at the top of a 15 roughly stratigraphic interval characterized by gradually decreasing particle size.[43]
Hartmut Haubold erected several new ichnogenera for fossil footprints discovered in Colorado. The proto-mammal tracks that Faul and Roberts reported he named Bipedopus coloradensis and Semibipedopus meekerensis.~NA144-145~ He also named the new ichnogenus Lacertipus for the small tracks in the formation that were apparently left by a lizard-like animal.~NA145~
Vialov classified fossil bird footprints as members of the ichno order Avipedia.[56]
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
David Webb studied the fossil footprints left by ancient camels and determined that even these ancient forms shared modern camels' "pacing gait", where the animal moves both legs on one side of the body at the same time, unlike most mammals which move hindlimbs and forelimbs from the opposite sides of the body in each step. Webb argued that the energetic efficiency of the pacing gait enabled camels' success in desert and prairie environments where significant distances may separate food and water sources.~NA267~
Paul Olsen and
Robert F. Salvia discovered dinosaur Late Triassic footprints in the
Stockton Formation of
Nyack Beach State Park, New York. The tracks included 12–15 cm (5–6 inch) long Grallator tracks. Possible Atreipus tracks were also found there. The regions's non-dinosaurian tracks included Apatopus, Brachychirotherium, Chirotherium, and Rhynchosauroides.[65]
Justin Delair and
A. B. Lander reported the presence of three parallel dinosaur trackways in the Roach Stone of Herston, England.
A significant Permian-aged fossil tracksite in the
Cedar Mesa Sandstone of Utah was inundated following the creation of the
Glen Canyon Dam. This tracksite preserved an apparent predator-prey interaction wherein the trail left by a small amphibian or reptile vanished at the point where it intersected with the trail left by a large carnivorous proto-mammal. Fortunately for ichnologists, plaster casts of the trackways and photographs remain available for study.~NA55-56~
W. J. Breed reported fossil
goose footprints from the Pliocene
Bidahochi Formation of Arizona.~NA321~
Kaever and de Lapparent named the new ichnogenus and species Elephanotpides barkhausensis for the poorly preserved tracks of a large quadrupedal dinosaur discovered near Barkhausen, Germany. The trackmaker was probably a sauropod.[66]
Bill Sarjeant described the five-toed Middle Jurassic footprints discovered by C. Pooley and named it Pooleyichnus burfordensis in his honor.[22] Sarjeant proposed that this unusual track may have been made by a mammal.[68]
A large tracksite preserved in the late Eocene
Vieja Group of Texas was first studied in a
University of Texas research program.
Robert E. Weems was informed of, and began researching, a Late Triassic reptile track site in a quarry near
Culpeper, Virginia.[69]
Leon Pales described the Pleistocene human footprints of France's Niaux cave complex. This paper has been considered "one of the most comprehensive studies of cave footprints ever published."[30]
R. McNeil Alexander published a formula for inferring the speeds of dinosaurs from their fossil trackways.~NA312~
Russell and Beland examined Brown's claim to have discovered the tracks of a running dinosaur.~NA320~
Weems continued to excavate and study the Late Triassic reptile track site near Culpeper, Virginia.[69]
Several hundred Late Triassic dinosaur footprints were reported from the vicinity of Cardiff, Wales.[72] This report was made by
M. E. Tucker and
T. P. Burchette.[73]
By this point, Weems found the Late Triassic reptile track site near Culpeper, Virginia to be roughly an acre in size and preserving 32 different reptile trackways, including those left by dinosaurs.[69]
Marc Edwards and others reported the dinosaur footprints discovered in Spitzbergen in 1978. Only two footprints were discovered at the site, which was an exposure of the Helvetiafjellet Formation. The researchers interpreted the tracks as carnosaur footprints, but now they are thought to have been left by
iguanodontids.[71]
Stokes observed that tracks left by close evolutionary relatives of mammals were common and widespread in the Navajo Sandstone. He found such tracksites in Colorado,
Idaho, and Utah.~NA145~ He reported many new sites in the Navajo formation.~NA318~
Carme Lompart reported the presence of Late Cretaceous dinosaur tracks in the
Ager Valley of Spain, near the country's border with France.[75]
Marc Weidmann and
Manfred Reichel published a "lengthy" review of the Oligocene to Miocene aged bird tracks found in Switzerland's "Molasse" rock.[43] They reported the presence of tracks left by one kind of
duck, two kinds of
herons, one kind of
perching bird, and four kinds of
waders.[76] Weidmann and Reichel devoted intense effort to classifying these tracks based on previous schemes devised by scholars like Avram, Panin, and Vialov for other bird track sites.[56] They also worked diligently to discern the tracks' positions within the stratigraphic column.[77]
Stokes and Madsen published more on the purported pterosaur footprints from the Jurassic Navajo Sandstone of Utah.~NA318~
1980s
Researchers interpreted large vertical burrows in the sediments of the Lower Triassic
Chinle Formation as having been made by
lungfish. Now, however, the burrows are attributed to arthropods similar to modern
crayfish.~NA77-80~
Hasiotis and
Mitchell '89~NA315~
Lockley and
Hunt returned to the Late Triassic dinosaur tracksite discovered northeast of Dinosaur National Monument to collect specimens for the University of Colorado and
United States Geological Survey.~NA93-94~
Lockley and Hunt studied a coal mine near
Gunnison, Colorado. They found many hadrosaur trackways, apparently left by a herd traveling in a southerly direction.~NA221-223~
Mid: A new dinosaur track site in the
Dakota Group was discovered just outside of
Roxborough State Park. The park was later to acquire the land where the specimens were preserved.~NA200-201~
Mid: Dinosaur footprints were first reported from the
Laramie Formation.~NA229~
Donald Baird attributed the ichnogenus Navahopus of Arizona's Navajo Formation to a prosauropod trackmaker.~NA89~ He also describedit.~NA316~
Gerard de Beaumont and
Georges Demathieu hypothesized that sauropods walked on the knuckles of their forelimb, and this explains why so many sauropod foreprints lack any impression left by the large claws born on the first toe in many species.~E141~
Don Baird erected the ichnogenus Navahopus for footprints preserved in the Early Jurassic Navajo Formation. He thought these tracks were left behind by a small prosauropod.~NA145~
A nine meter long Pleistocene
bear trackway was reported from
Lake County, Oregon. The tracks themselves were about 40 cm long, suggesting a trackmaker roughly the size of a large modern bear. These tracks may have been left by an Arctotherium.~NA275-276~
Olsen argued that the ichnogenera Grallator, Anchisauripus, and Eubrontes actually represent a growth series.~NA317~
Walter P. Coombs, Jr. interpreted some unusual Eubrontes tracks from Dinosaur State Park of
Rocky Hill, Connecticut as traces left by a swimming theropod because the tracks only preserved impressions from the tips of the animal's toes as if the rest of its body weight was supported by water.[80]
Giuseppe Leonardi erected the new ichnogenus and species Brasilichnium elusivum to classify the Early Jurassic proto-mammal tracks from the Botucatu Sandstone of Brazil. This work has since been praised as "very thorough" by Martin Lockley and Adrian Hunt.~NA145~
Thulborn criticized the the idea that the hadrosaur tracks reported by Brown in 1938 were left by a running animal.~NA320~
Demathieu and Haubold described the new Early Triassic ichnogenus and species Isochirotherium archaem from Germany. As only the hind prints are preserved in this trackway it may represent the oldest evidence in the world for the existence of animals with bipedal gaits. However, while intriguing, their remains the possibility that the track maker was a quadruped and its foreprints eroded away before the trail was discovered.[82]
Demathieu and
Marc Weidmann described a new Triassic fossil tracksite from Swtizerland called the
Vieux Emosson tracksite.[83] The authors named nine ichnospecies and several new ichnogenera, although none of these new ichnotaxa would be subequently observed at other sites. The poor preservation, anomalously high ichnodiversity, and lack of corroboration at other sites cast doubts on he legitimacy of the researchers' ichnotaxa, however.[84]
Bernier and others erected the ichnogenus Chelonichnium and interpreted it as the tracks of a large turtle.[85]
Edwin McKee reported the presence of apparent
horseshoe-shaped trace fossils in the Carboniferous
Esplanade Sandstone that he attributed to a tetrapod. However, these tracks are more likely to have been invertebrate traces or artifacts of erosion.~NA36~
Geology student Jeff Pittman recognized that the "potholes" hindering excavation equipment traffic through a gypsum mine in southeastern Arkansas were actually sauropod dinosaur footprint.~NA191-192~
Hartmut Haubold published the
Saurierfahrten.~E50~ Haubold was a German ichnologist,and the Saurierfahrten a specialist's handbook for identifying Carboniferous and Permian fossil footprints. It was the only publication of its type in the world at the time and only available in German.~E33-34~
Paul Olsen and
Peter Galton argued that Ellenberger had oversplit the Late Triassic and Early Jurassic ichnotaxa he studied and that many of the kinds of tracks he regarded as distinct were actually the same as tracks previously described in eastern North America.[86]
J. E. Andrews and J. D. Hudson reported the first dinosaur tracks to be scientifically documented in Scotland. The tracks are three-toed and preserved in the Middle Jurassic
Leate Shale.~144~
Hans Mensink and
Dorothee Mertmann described the new ichnogenus and species Gigantosauropus asturiensis from Jurassic near
Asturias, Spain. The researchers attributed the tracks to a theropod. At 1.35 m in length, these tracks were actually twice as long as those of a more typical length for a large theropod.[66]
Bernier and others named the new ichnogenus and species Saltosauropus latus for strange widely spaced tracks discovered in France. They interpreted the traces as those left by a hopping dinosaur.~173–174~
Lompart erected two new ichnogenera and species for the three-toed Late Cretaceous dinosaur footprints she reported from Spain. The new ichnotaxa were Ornithopodichnites magna and Orcauichnites garumeniensis. Lompart thought both were made by ornithopods, but they are now thought attributable to theropods. Also, because these footprints were poorly preserved and the ichnotaxa not properly named, the names are regarded as being of dubious scientific utility.[87] Sauropod tracks were also reported from the site.[88]
George Demathieu and others described an Oligocene bird and mammal track site from southeastern France. Three different mammalian ichnotaxa were present. One was an artiodactyl track they named Bifidipes velox. The second was the largest of the three, Ronzotherichnus, was apparently left by the rhinoceros Ronzotherium. A
creodont or early carnivoran left behind the third kind of tracks, which the researchers named Sarcotherichnus enigmaticus. They named the bird tracks at the site Pulchravipes magnificus.[59]
Kevin Padian and Paul Olsen reinterpreted the supposed pterosaur tracks named Pteraichnus from the Morrison Formation of Utah as crocodilian tracks.~NA145~
L. D. Agenbroad published an interpretation of the preservation of mammoth remains and footprints at Hot Springs, South Dakota.~NA320~
Luis Aguirrezabala reported the presence of nine parallel trails left by Hypsilophodon or one of its close relatives in Lower Cretaceous rocks of
La Rioja, Spain. This tracksite is now known as the Valdevajes site.[89]
An international symposium for paleontologists performing research on "Dinosaur Tracks and Traces" was held in New Mexico.[90] The gathering was a success and "led to the rejuvenation and maturing of the discipline of dinosaur ichnology".[91]
Haubold observed that during the Late Triassic, small Grallator tracks become common.[73] Haubold published a discussion of archosaur tracks from near the Triassic-Jurassic boundary and their distribution through the stratigraphic column.~NA315~
Paul Olsen and Kevin Padian reported the presence of the crocodilian ichnogenus Batrachopus in the Early Jurassic Moenave.~NA145~
Paul Olsen and Kevin Padian discovered Batrachopus tracks in the Navajo Formation, but did not publish their findings.~NA145~
Lockley and Martin showed that some of the purported baby dinosaur footprints collected by William Wilson from Utah were "enhanced" by carving.~NA226~
Kirk Johnson discovered a new Paleocene fossil tracksite in the
Fort Union Formation. This site preserved additional amphibian tracks as well as the tracks of two different wading birds and traces of insect activity. The tracks were preserved in what was once the banks of an ancient stream~NA246~
Scrivener and
Bottjer published a census of tracks from the Miocene
Copper Canyon Formation of
Death Valley National Monument, California. Most of these footprints were camel tracks, but bird and horse prints were also common. Less common traces included those of
bear-dogs, cats, deer, and proboscideans.~NA269-270~
Jordan Marche argued that the Pleistocene tracks discovered by prisoners near Carson City, Nevada deserved more scientific attention than they had received.~NA276~
Houck and Lockley published the first illustrations of the foosil footprints preserved in the
Belden Formation.~NA313~
Olsen and Baird published "[a] detailed study of the ichnogenus Atreipus."~NA316~
Paul Ensom reported dinosaur tracks from the Purbeck Limestone of Dorset, England as the latest Jurassic dinosaur footprints known from Europe.[92] Ensom interpreted these trace fossils as sauropod footprints.[93] The tracks were preserved only 2m below the horizon representing the consensus Jurassic-Cretaceous boundary. Since then the tracks have come to be regarded as Early Cretaceous.[92]
David Norman suggested that smaller species of Iguanodon may have walked on their hind legs while larger and heavier species may have preferred to walk on all fours.[89]
Giuseppe Leonardi also referred the Navajo Formation tracks examined by Olsen and Padian to Batrachopus.~NA145~
Lockley disputed
Robert T. Bakker's hypothesis that an Early Cretaceous sauropod trackway from the Davenport Ranch, Texas area preserves evidence that sauropods traveled in herds with the young surrounded by the adults to protect them from predators. Instead, Lockley interpreted this trackway as a herd of sauropods traveling through a narrow area, with the young following the adults.~NA186~
Lockley and Hunt began studying the dinosaur tracks of the Dakota Group at the
Alameda Parkway site, which is now called
Dinosaur Ridge.~NA209~
Lockley and Jennings published the first illustration of the fossil footprints preserved in the Late Triassic rock of Colorado's
Dolores Valley.~NA315~
Lockley described the ichnogenus Caririchnium. This publication was also the first detailed treatment of the Dakota Group's trace fossil record in the scientific literature.~NA319~
Robert E. Weems described the new ichnospecies Gregaripus bairdi from a rock quarry in Virginia. The ichnospecies epithet was chosen to honor Donald Baird. Gregaripus dated back to the Late Triassic and were left by a trackmaker that walked on hind feet less than four inches long, with three toes and blunt nails.[94] This suggests that the Gregaripus trackmaker was a small ornithischian dinosaur about 1.5 meters (five feet) long.[95] Robert E. Weems published the results of his research into the Late Triassic reptile tracksite near
Culpeper, Virginia. Among the fossil footprints he found there were the dinosaur ichnogenera Agrestipus, Grallator, Gregaripus, and Kayentapus.[69]
Weems also describe the new ichnogenus and species Agrestipus hottoni. The species epithet was chosen in honor of
Nicholas Hotton III. Weems attributed these three to four-toed tracks as sauropod footprints, but now they are thought to have been left by the sauropods' slightly more primitive relatives, the prosauropods.[96]
Ensom published further research on the Purbeck Limestone dinosaur tracks from Dorset.[92]
Harald von Walter and
Ralf Werneberg reported the discovery of body impressions left behind by
diplocaulid amphibians in the Rotliegende of the Thuringian Forest area. The assemblage includes the body impression of several individuals, all no more than a few centimeters in length.~46~ The authors named these traces Hermundurichnus fornicatus.[97]
Lockley and Hunt rediscovered fossil bird footprints in the Dakota Group near Golden Colorado.~NA194-196~ Among the specimens recovered was the first in the world to preserve dinosaur and bird footprints together.~NA196~
Lockley and Prince expanded on their previous descriptive work on the Purgatoire Valley dinosaur tracksite.~NA317~
Lockley reported the first observation in the Dakota Group of dinosaur footprints with preserved skin impressions.~NA319~
W. A. S Sargeant and
J. A. Wilson reported the presence of Eocene mammal footprints in Texas.~NA322~
Demathieu reported potential dinosaur footprints from the Middle Triassic of France.[98]
Dana Batory and William Sarjeant proposed that the 1909 discovery of Iguanodon footprints at Crowborough, Sussex was Sir Arthur Conan Doyle's inspiration for writing The Lost World.[16]
R. Santamaria,
G. Lopez, and
M. L. Casanovas-Cladellas reported an Oligocene mammal track site discovered near
Agramunt, Spain. This tracksite preserved four new ichnospecies, three of which were in new ichnogenera. First was a new species of Bothriodontipus, which was made by the pig-like animal Bothriodon or a close relative. The researchers new ichnogenera were Creodontipus and Plagiolophustipus.[59] They classified two of their new ichnospecies in Creodontipus, an ichnogenus they fittingly attributed to creodonts. They attributed Plagiolophustipus to tapir-like animals distantly related to horses.[99]
Jeff Pittman proved that the sauropod tracks he recognized in an Arkansas
gypsum mine were actually at the same level of the geologic column as the Glen Rose Formation sauropod tracks of Texas.~NA192~
A research group headed by Lockley and Hunt, along with a collaborator from
Japan, excavated the co-ocurring dinosaur and bird footprints from Colorado. The three ton specimen was shipped to Japan to star in a traveling museum exhibit about dinosaur footprints.~NA196~
Lee Parker and
John Balsley reported the presence of potential Hesperornis footprints in a coal mine near Price, Utah.~NA223~ They might actually be pterosaur tracks.~NA224~ Lockley, Matsukawa and Hunt described the specimen.~NA320~
Lockley reported the presence of fossil footprints in the Minturn Formation.~NA313~
Prince and Lockley further expanded on their earlier descriptions of the Purgatoire Valley dinosaur track site.~NA317~
Farlow, Pittman, and Hawthorne described the ichnogenus Brontopodus.~NA318~
April: A quarry worker named Robert Clore blasting stone near Culpeper, Virginia uncovered a new Late Triassic reptile tracksite. This site was apparently about 300,000 years older than the first Late Triassic tracksite discovered near Culpeper and had an even greater area of about 6 acres.[100] Weems began studying the site that same year, and reported the presence of 4,000 individual tracks. The local tracks included the dinosaur ichnogenera Grallator and Kayentapus. Other tracks may have been left by
aetosaurs.[101]
Michael J. Szajna and Brian W. Hartline discovered Late Triassic reptile footprints in an excavation for a housing development near Reading, Pennsylvania.[102]
Thulborn disputed the referral of a trace fossil found in a core sample taken from the Early Triassic
Bunter Sandstone to the dinosaur ichnogenus Coelurosaurichnus. He hypothesized that its trackmaker was actually a horeshoe crab.[61] Thulborn also disputed the supposed theropodan origin of the ichnogenus Gigantosauropus of Asturias, Spain. Instead, he concluded, the Gigantosauropus trackmaker was actually a sauropod.[66] Thulborn also disputed the interpretation of Saltosauropus latus put forward by the team of French researchers who first described the ichnogenus as the tracks of a hopping dinosaur. Thulborn found this interpretation inconsistent with the expected morphology and spacing a hopping dinosaur would produced. His own interpretation of Saltosauropus was that it represents marks left by a
sea turtle swimming just above the seafloor.[103]
Ryszard Fuglewicz and others reported fossil trackways from the
Holy Cross Mountains of
Poland that may be the oldest Triassic trackways in Europe. They reported tracksites at six different positions within a stratigraphic series in several distinct paleoenvironments including river channels and floodplains. The ichnogenera they identified in these tracksites included Brachychirotherium, Capitosauroides, Isochirotherium, Rhynchosauroides, and Synaptichnium.[104]
Hunt, Lucas, and
Huber published the first in-depth description of the fossil footprints preserved in the
Sangre de Cristo Formation.~NA313~
Lockley published the "[f]irst map of an Otozoum trackway from the western states." He also noted the presence of tracks resembling Brasilichnium and attributed them to a
tritilodont.~NA317~
Currie,
Nadon, and Lockley described Cretaceous ornithopod tracks that preserved impressions of the trackmakers' skin.~NA318~
Lockley disputed claims that some sauropod tracks were left underwater by swimming trackmakers.~NA319~
Geologists
Anders Ahlberg and
Mikael Siverson reported the discovery of a dinosaur track in a railroad tunnel in southern Sweden. The rocks preserving the print are part of a stratigraphic unit called the
Hoganas Formation which straddles the Triassic-Jurassic boundary.[106]
Gierlinski reported the presence of
Hettangian theropod tracks in the Holy Cross Mountains of Poland.[107]
Lockley disputed Paul Ensom's interpretation of some dinosaur tracks from the Purbeck Limestone of Dorset, England as sauropod footprints and instead suggested that they were probably made by ankylosaurs.[92]
A track site containing more than 250 fossil bird footprints was discovered ear
Villar del Rio, Spain.[109]
Casanovas-Cladellas and others reinterpreted the purported hypsilophodontid tracks of the Valdavajes site in Spain as theropod footprints in a heavily criticized paper.[89]
Robison reported shorebird footprints in the Cretaceous Mesa Verde Group of Utah. He also reported the presence of the oldest known
frog tracks.~NA225-226~
Brand and
Tang published the controversial argument that the fossil footprints of the Permian Coconino Sandstone were made underwater by swimming animals.~NA312~
dos Santos and others observed that at the Portugese Carenque dinosaur tracksite fossil shells and small vertebrate fossils were more common inside dinosaur footprints than untrodden portions of the same rock. Apparently the compression of the sediment under the dinosaur's foot somehow led to more favorable conditions for fossilization than were present elsewhere in the ancient trackmaking environment.~E232~ They also found that the purported South American iguanodont ichnogenus Iguanodonichnus was actually probably made by a sauropod.[11]
C. Lancis and
A. Estevez reported the presence of early Pliocene tracks preseved near
Alicante, Spain. Among the mammals who left their mark here were members of the horse family and bears. The bear that left its track there were probably either a species in the genus Agriotherium or Ursus ruscinensis.[110]
Farlow observed that sauropod trackways could be categorized as either being "narrow-gauge" or "wide-gauge".~NA175~
Mid November: Lockley and Hunt's research group at the University of Colorado undertook one of the few major dinosaur footprint excavations in history in order to expand the exposed track-bearing surface at Dinosaur Ridge for an outdoor interpretive center. To do so they collaborated with the Friends of Dinosaur Ridge and the
Jefferson County Scientific and Cultural District to remove a one meter thick layer of sandstone via "precision blasting".~NA199-200~
July 17th: Another Seattle reported that
Allison Andors and other researchers had determined that the large bird track discovered in Flaming Geyser State Park was a hoax carved into the rock. Other researchers would subsequently conclude that the track was genuine after all.~NA262~
Lockley argued against Brand and Tang's hypothesis that the fossil footprints of the Coconino Sandstone were made underwater.~NA313~
Lockley and Madsen published ichnological evidence for the predation of large reptiles on smaller animals during the Permian period.~NA313-314~
Loope argued against Brand and Tang's hypothesis that the fossil footprints of the Coconino Sandstone were made underwater.~NA314~
Lockley and others published the "[f]irst report of Atreipussensu stricto in the western states."~NA315~
Lockley, Conrad, and Paquette published a summary of Dinosaur National Monument's recently discovered Late Triassic fossil footprints.~NA315~
Lockley and others described a new fossil track site at Cub Creek that preserved the first known instance of the ichnogenus Pseudotetrasauropus in the western US.~NA315-316~
Olsen and others argued that a supposed Otozoum foreprint was actually the hind prints of two small theropods impressed on top of eachother into a single impression.~NA317~
Lockley and others summarized the state of science's knowledge about the fossil footprints preserved in the Dakota Group megatracksite.~NA319-320~
Greben and Lockley published an "[o]verview of the Eocene Green River tracks."
Demathieu reported the presence of dinosaur tracks the Causses region of France.[105]
Whyte and
Romano argued that the ichnogenus Deltapodus, which they named, was left behind by a sauropod.~135~
Lockley and dos Santos described the
Kimmeridgian-aged
Avelino quarry tracksite near
Lisbon, Portugal, the first scientifically documented sauropod dinosaur tracksite in Europe to contain well-preserved tracks of the animals' front feet. The quarry contained only one track-bearing layer with five intersecting sauropod trails. Although the animals varied in size all had hindprints smaller of 30 cm or less in length, suggesting that they were juveniles.[111] They also argued against the idea that sauropod trackways consisting mainly of foreprints were left by swimming animals.~NA320~
Lockley, Meyer, and dos Santos performed fieldwork mapping the dinosaur tracks at Cabo Espichel, Portugal.[70]
Meyer reported the first scientifically documented Late Jurassic dinosaur footprints from Switzerland. These tracks were discovered near the town of
Lommiswil.[112]
Parkes reported theropod tracks in the Ashdown beds of the Wealden near Hastings, Sussex.[113]
Moratalla first used the name of the theropod ichnospecies Therangospodus oncalensis in the scientific literature, although it had not yet been described. He also informally coined the ichnogenus Filichnites.[114]
Viera and
Torres argued that contrary to the reinterpretation published the previous year by Casanovas-Cladellas and others, the dinosaur footprints of the Spanish Valdavajes site were hypsilophodontid tracks after all.[89]
Martin-Escorza also published a paper arguing for the hypsilophodontid status of the Valdavejes dinosaur tracks.[89]
Scientists began studying the recently discovered fossil footprints at
Las Hoyas, Spain.[115]
Claude Guerin and George Demathieu described the new ichnospecies Dicerotichnus laetoliensis. This ichnospecies was left behind by a late Pliocene rhinoceros of fairly modern build, possibly from the genus Diceros. Its tracks are preserved at the same site known for its ancient
hominid tracks.~E246~
A non-technical article in the Spanish magazine Blanco y Negro discussed the wide variety of Miocene tracks preserved at
Salinas de Anana, Spain.[116]
J. Quintana reported the presence of Quaternary-aged footprints on the
Balearic island of
Menorca. The most conspicuous tracks were those of the extinct goat Myotragus, but tiny footprints left by the
mouse genus Hypnomys were also preserved in places where blocks of fallen sandstone sheltered them from the elements.~264~
Lockley, Hunt, and Meyer synonymized Navahopus with Brasilichnium, and noted that these tracks were common among the Early Jurassic sand dunes of the Western Hemisphere.~NA146~
Lockley and Hunt introduced the idea of ichnofacies to the scientific literature. They described and named the Brontopodus ichnofacies based on sauropod tracksites in Texas.~NA210~[citation needed]
A new tracksite was discovered in
Toadstool Park area of Nebraska's
Oglalla National Grassland.~NA260~ The tracks were left across a kilometer-long stretch of what was once an ancient river valley, but is now part of the
White River Group.~NA260-261~ Eleven different trackmakers have been documented here, including camels, carnivorans, ducks, rhinoceroses, and shorebirds.~NA261~ Some of the mammals seem to have been moving in herds.~NA261-263~ Dixon-LaGarry-Guyon~NA321-322~
Hunt and others described the fossil footprints of the Robledo Mountains.~NA313~
Hunt, Santucci, and Lockley reported the first therapsid tracks to have been discovered in the Moenkopi Formation.~NA315~
Lockley and Hunt described a new fossil tracksite and accompanying ichnotaxa preserved in the Triassic Sloan Canyon Formation of New Mexico.~NA315~
Szajna and
Shaymaria M. Sylvestri described the Late Triassic reptile tracks discovered near Reading, Pennsylvania. They found most of the tracks to belong to ichnogenera like Apatopus, Brachychirotherium, Chirotherium, Gwynnedichnium, and Rhynchosauroides, although dinosaur tracks like Atreipus and Grallator were also present.[102]
[117] At least three different ichnospecies were preserved in the local Lockatong Formation rocks, including the dinosaur tracks Atreipus and Grallator ranging from 9 to 15 cm (3.5–6 inches) long.[118]
Other tracks included possible Gwynnedichnium or Rhynchosauroides tracks up to 2 cm (0.8 inches) long.[69]
Jenkins and others reported the presence of Late Triassic dinosaur tracks from the
Fleming Fjord Formation of eastern
Greenland. Most of the reported footprints were Grallator, but there were some prints apparently left by prosauropods. These tracks may be referable to the ichnogenus Tetrasauropus.
Gierlinski and Ahlberg reported additional Triassic-Jurassic dinosaur footprints from southern Sweden.[106]
Whyte and Romano continued to regard the ichnogenus Deltapodus as being sauropod tracks.~135
Lockley and others argued that Deltapodus was probably not left by a sauropod because the hind prints had only three toes and the tracks themselves were preserved in an environment where sauropod tracks are not generally found.~135~ Instead they concluded it was more likely to be the tracks of a
thyreophoran, possibly a
stegosaur.[119]
A cave enthusiast near
Fatima, Portugal looked down on a quarry from a high ridge and noticed that its floor was covered in sauropod footprints.[120] The site included the longest known dinosaur trails at the time. The individual tracks are the largest sauropod prints known from the Middle Jurassic and include the largest foreprints of any known sauropod track type.[121]
Lockley and others reported that nearly two thirds of sauropod tracksites known to science were located in Europe. One was in Germany, sixteen were in Portugal, two in Spain, and eleven were in Switzerland for a grand total of thirty across the continent overall.[122]
Lockley, Meyer, and dos Santos published the result of their project mapping the tracks of Cabo Espichel, Portugal.[70] They found eight separate track-bearing layers at the site, the second of which preserved evidence of sauropod social behavior. This layer contains seven trails left by an apparent herd of immature sauropods.[123]
Lockley, Hunt, and Meyer defined the Brontopodus ichnofacies.
Moratalla and others observed that at this point in time only 4 Early Cretaceous sauropod track sites were known from the La Rioja Province of Spain.[81]
Dalla Vecchia published futher research on the Croatian dinosaur footprints he reinterpreted as theropod tracks.
Galopim published The Battle of Carenque, a book describing the successful efforts of Portugese conservationists to save the home of the world's longest dinosaur trackway from being destroyed by freeway construction.~E229-230~
A major collaborative research venture between the
US Bureau of Land Management, the
New Mexico Museum of Natural History, the Smithsonian, and the University of Colorado began aimed at studying the Permian-aged tracks of the Abo Formation in New Mexico.~NA57-61~
Terry Logue maintained that there were pterosaur footprints preserved in the Sundance Formation despite the popular opinion that such tracks were left by crocodilians.~NA160~
Bill Sarjeant and Wann Langston published a monograph on the late Eocene track site from the Vieja Group of Texas. The tracks preserved there indicate a fauna including six kinds of bird, two kinds of invertebrate, nineteen mammal species, and two kinds of turtle.~NA256~
Hunt, Lockley, and Lucas reported the existence of a fossil trackway preserving an apparent act of predation of a
pelycosaur upon a small reptile.~NA313~
Lockley, Hunt, and Meyer proposed the idea of vertebrate
ichnofacies.~NA314~
Lockley and Hunt published a review paper summarizing the state of science's knowledge about the Mesozoic fossil tracksites preserved in the western United States.~NA319~
Lockley and Hunt "[d]efine[d] the Brontopodus and Caririchnium ichnofacies."~NA319~
Iwan Stossel reported the oldest known fossil vertebrate footprints in Europe to the scientific literature.~E29~ The tracks were preserved in the
Mid-
Late Devonian
Valentia Slate of
Valentia Island, which lies off the southwestern coast of
Ireland. Roughly 150 tracks were present in an 8 meter long trail left behind by an early tetrapod.~E29-30~
David Scarboro and
Maurice Tucker reported the discovery of a fossil trail probably left by a
temnospondyl amphibian about 1.5 meters long walking through a delta during the Middle Carboniferous. The find is one of the largest Carboniferous fossil trackways in all of Europe. The estimated size of the trackmaker indicates an the presence of an amphibian larger than any known from England's body fossils dating back to the same time period.~E34~
Geoffrey Tresise proposed that Chirotherium tracks exhibit sexual dimorphism. The ichnospecies C. stortonense is slender and Tresise hypothesized was made by a female trackmaker while the ichnospecies C. barthi was thicker and may have been made by the male. This publication was the first to propose sexual dimorphism based on trace fossil morphology rather than just size.[124]
Gerard Gierlinksi reinterpreted the ichnogenus Otozoum, generally regarded as prosauropod tracks, as the footprints of the primitive armored dinosaur Scelidosaurus. However, he would later retract this interpretation and return to the traditional prosauropod interpretation.[125]
Moratalla and others published research on the fossil tracks from Las Hoyas Spain. They attributed some unusual three-toed tracks at the site to turtles.[115]
Lockley and others reinterpreted the supposed turtle tracks from Las Hoyas, Spain as pterosaur footprints based on a recent increase in pterosaur trace fossils being discovered all around the world.[115]
Leonardi and Lockley argued that use Friedrich von Huene's ichnogenus name Coelurosaurichnus should be abandoned because it refers to the same kind of footprint as Grallator.
Avanzini reported the theropod ichnogenus Eubrontes among the fossil dinosaur footprints at the Lavini de Marco track site in Italy. They also reported tracks of the ichnogenus Parabrontopodus which were likely made by a small-to-medium-sized sauropod.[108]
Cyril Ivens and
Geoffrey Watson published Records of Dinosaur Footprints on the North Coast of Yorkshire, documenting the many local dinosaur track discoveries.[63]
Jean-Michel Mazin and others described the first scientifically documented pterosaur fossils from Europe. These tracks were preserved in a Late Jurassic limestone in
Crayssac, France.[126] The pterosaurs that left these footprints seem to have been in the sparrow to sea gull size range. These tracks have played a "pivotal" role in confirming that various unusual and controversial trace fossils reported around the world really were made by pterosaurs after all.[127]
April: Fabio Dalla Vecchia and one of his students were arrested while mapping dinosaur footprints in Croatia and inadvertently following the tracks into a military zone. They were tried and subsequently fined their trial expenses and released.~E217-218~
Koenigswald, Walders, and Sander described a 30,000 to 20,000 year old Pleistocene fossil mammal track site from
Bottrop, Germany. This ste was discovered on the grounds of a sewage treatment plant. Local trackmakers included
bison, horses,
cave lions,
reindeer, and wolves. The cave lion tracks are notably the first to be discovered outside of an actual cave.~E257~
Price argued that scholars generally underestimated how long ago humanity first domesticated horses based on a
Bronze Age tracksite in Sweden.~E265~
Phylis Jackson argued that the pedal anatomy of
Anglo-Saxon and
Celtic peoples are so distinct that these populations can be distinguished based on feet alone going all the way back to the
Neolithic.~E268~ Celtic people have narrower feet while Anglo-Saxon feet are broader.~E269~
King and
Benton[disambiguation needed] disputed Thulborn's attribution of the Early Triassic Bunter Sandstone Coelurosaurichnus to a horsehoe crab because they didn't think the supposed tracks were tracefossils at all instead they interpreted the apparent tracks as sedimentary structures of geological rather than biological origin. They referred Sarjeant's supposed Otozoum and Swinertonichnus to Chirotherium.[61]
Bill Sarjeant reclassified the supposed Early Triassic dinosaur fossils he reported from England in 1970. He originally reported the presence of two Coelurosaurichnus species. However he had since concluded that one of these Coelurosaurichnus species was actually referable to the ichnogenus Batrachopus and the other to Plectoperna.[61] He reclassified his supposed Otozoum specimens as Paratetrasauropus and attributed Swinertonichnus to crocodilians.[98]
Lockley and others reported the presence of the ichnogenera Pseudotetrasauropus and Tetrasauropus among the dinosaur footprints reported from the Cardiff, Wales area by Tucker and Burchette in 1977. These tracks may have been left by a prosauropod.[73]
Brigitte Lange-Badre reported the first Late Jurassic sauropod footprints to have been discovered in France.[128]
Fuentes Vidarte reported the oldest known bird tracks in the world from the Berriasian Wealden Beds of the Villar del Rio, Spain. There were more than 250 individual prints at the track site and Fuentes Vidarte named the new ichnogenus and species Archaeornithopus meijidei for them.[109]
Fabio Dalla Vecchia returned to Croatia and finished mapping the dinosaur footprints with Croatian geologist
Igor Vlahovic.~E218~
Fabio Dalla Vecchia and Marco Rustioni reported a Miocene mammal tracksite in the
Conglomerato di Osoppo in
Udine Province, Italy. Across its 100 square meter area the track site preserved the footprints of three different kinds of large mammal.[51] Dalla Vecchia and Rustioni attributed these tracks to a large bovid,
Hipparion, and what may be a small rhinoceros.[129] The sediments preserving these tracks are coarser than those of most fossil track sites.[51]
The first international workshop on Paleozoic footprint fossils, presided over by Hartmut Haubold was held in Germany. The assembled scholars visited many significant German Paleozoic track sites and museum collections.[90] The symposium was such a success that it is regarded as a turning point in the history of Paleozoic vertebrate ichnology.[91]
Gierlinski reported the presence of possible small sauropod footprints in Early Jurassic rocks fromt the Holy Cross Mountains of Poland.~E122~
Avanzini,
van den Dreissche and
Keppens found that there were no ornithopod prints among the tracks preserved at Lavini de Marco in Italy and the only dinosaur groups to leave behind footprints there were the sauropods and theropods.[108] They concluded that the tracks were cemented through chemical processes trigger by the rapid evaporation of water from the carbonate track-bearing substrate and speculated that similar circumstances may have preserved tracks in carbonates at other sites and different positions in the stratigraphic column.[130]
Meyer reported that the Late Jurassic dinosaur tracks discovered near Lommiswil, Switzerland were actually part of a gigantic megatracksite. This was the first report of a dinosaur megatracksite in Europe.~E171~
Jean-Michel Mazin and others published further research on the pterosaur tracks of Crayssac, France.[126]
Wright and others re-examined the Purbeckopus pentadactylus tracks from Dorset, England and concluded that not only were they pterosaur tracks, but they were among the largest known pterosaur tracks in the fossil record.[53]
Joaquin Moratalla and
Jose Sanz found theropod tracks to compose 80% of the fossil footprints in Spain's Cameros Basin, with the remaining 20% consisting mostly of ornithopods (16%) and sauropods (4%).[131]
Casanovas and others reported that by this point in time 10 Early Cretaceous sauropod track sites had been discovered in La Rioja Province, Spain.[81]
Tuner and
Anton attributed Miocene cat footprints found at Salinas de Anana, Spain to the genus Pseudaelurus. These tracks may in fact be the oldest known cat footprints in the world.[116]
Yuong-Nam Lee erected the new ichnogenus Magnoavipes preserved in the
CenomanianWoodbine Formation of Texas. The trackmaker was aparently a waterbird of great size, with slender-toed feet 19–21 cm long.~NA212~
Phylis Jackson published further research on the use of pedal anatomy and footprints to distinguish different groups of people.~E268~
Sarjeant, Delair, and Lockley named the ichnogenus Iguanodontipus for some English dinosaur tracks probably made by Iguanodon.
Lockley, dos Santos, and Hunt found the purported hypsilophodont tracks of the Spanish Valdavajes tracksite similar to the Late Jurassic ichnogenus Dinehichnus that has been attributed to
dryosaurids.[89]
Lopez-Martinez and others noted the presence of sauropod and ornithopod tracks near the
K-T Boundary in the
Tremp Formation of northeastern Spain. The presence of tracks so close to the Cretaceous-Tertiary suggests that the dinosaur died out rapidly rather than gradually.~E239~
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Spring: A boy named Pliny Moody uncovered a piece of
sandstone with mysterious three-toed tracks about 30 cm (1 foot) long while plowing in his father's fields near
South Hadley,
Massachusetts. The local clergy thought the tracks had been left by the
ravenNoah sent out from the
ark to look for dry land during the
Biblical Flood.[1]
A slab of
Permian sandstone preserving 24 small footprints came into the possession of the
Scottish Reverend
Henry Duncan. Duncan visited the quarry where his slab was originally excavated in
Corncockle Muir to see if he could find more of the fascinating impressions and successfully recovered more of them. He notified leading paleontologist
William Buckland of
Oxford University about his discovery.[2]
Buckland published the first scientific description of fossil footprints about the tracks discovered at Corncockle Muir. He attributed the footprints to ancient
tortoises because after having various modern reptiles walk over stretches of
pie crust
dough, the tracks left by tortoises most closely resembled those from the Permian sandstone.[4]
A man named
Helmut Barth was building a garden house in
Hildburghausen,
Germany when he discovered strange, hand-shaped tracks in the sandstone he was using in the construction.[5] Barth's discovery would be named Chirotherium by
Johan Jacob Kaup.[6]
While the streets of
Greenfield, Massachusetts were being paved, locals noticed footprints impressed in the stone. The townspeople thought the tracks were left by
turkeys.[1] They informed
James Deane, a local doctor and naturalist about the footprints. Deane found the tracks intriguing and wrote to another local scholar,
Edward B. Hitchcock about the find.[7] Hitchcock spent the rest of the summer investigating the local footprints fossils.[8]
A man surnamed Cotta wrote a letter including the first documented mention of the many Permian tracks perserved in the "
Rotliegendes" of central Germany's
Thuringian forest.[12] "Rotliegendes" is German for "red layers" referring to a Permian sandstone layer rich in
rustedironminerals known elsewhere as the "New Red Sandstone".[13] The tracks Cotta reported were later named Saurichnites cottae in his honor.[12]
Sir William Jardine argued against Owen's referral of the Corncockle Muir "tortoise" footprints to Testudo because the name applied to a specific group of modern
turtles rather than to footprints. He coined the name Chelichnus, meaning "turtle track" to replace Owen's use of Testudo, but preserved the specific epithet "duncani".[4]
Beckles continued to publish research on the dinosaur footprints from the Wealden, referring to them as Ornithoidichnites following the nomenclature devised by Edward Hitchcock for some American tracks. Despite his use of a term implying an avian trackmaker, Beckles admitted that he did not know what kind of animals made the tracks.[16]
Edward Hitchcock published a summary of his research into the fossil footprints of the
Connecticut Valley area. He continued to attribute the tracks to large flightless birds that he named their footprints "ornithichnites", meaning "stone bird footprints". He divided the trackmakers into two groups, the leptodactylous birds with narrow toes and the pachydactylous birds with thick toes. He also described seven new ichnospecies for the tracks he studied.[9] He also described the ichnogenus Grallator.[17]
A posthumous "supplement" to Hitchcock's monograph on the Connecticut Valley tracks was published.[20]
1860: Some English dinosaur footprints were recognzed as Iguanodon tracks. They were the first dinosaur tracks to be recognized as belonging to and individual genus.[11]
Thomas Henry Huxley argued against Buckland and Owen's attribution of Chelichnus duncani to ancient tortoises, instead concluding that it was impossible to identify the trackmaker with the knowledge of time.[15]
Some
Welsh dinosaur tracks that had been previously displayed in front of the Jolly Sailor Pub in
Newton Nottage were acquired by the
Cardiff Museum.[21]
T. H. Thomas reported the Welsh dinosaur footprints to the scientific literature and noted their similarity to the "Ornithichnites" of Connecticut.[21]
W. J. Sollas independently published a report of the Welsh dinosaur footprints.[21]
1880s
Early: Inmates of
Nevada's
State Prison uncovered a large
Pleistocene fossil tracksite while excavating sandstone. The track sites was a
lakeshore 50,000 years ago where familiar
Ice Age animals like birds,
deer,
mammoths, and
wolves left behind their footprints. However, ten of the roughly 50 trails seemed to have been left by an even stranger trackmaker; a sandaled
giant.~NA277~
Large
theropod footprints were reported in
Late Jurassic rocks at
Cabo Mondego,
Portugal. These may have been the first European Late Jurassic dinosaur footprints to be documented in the scientific literature.~152~
W. P. Blake reported the fossil footprints discovered at the prison in
Carson City, Nevada to the scientific literature.~NA321~
Mark Twain wrote the satirical "The Carson Fossil Footprints" attributing the purported giant tracks discovered there to primitive members of the
territorial legislature.~NA279~
A geology professor named
James A. Mitchell discovered some small Grallator tracks in the Late Triassic
Gettysburg Formation of
Maryland. These are the first and only known dinosaur tracks in the state.[26]
Luis Dollo matched the foot of Iguanodon bernissartensis with a purported Iguanodon footprint in "the first attempt to match these tracks with a particular species of the genus".[29]
Harold Broderick described the three-toed Middle Jurassic dinosaur footprints that had first been discovered during the 1890s at England's Yorkshire coast.[25]
A deluxe editions of Sir Arthur Conan Doyle's The Lost World was issued whose cover featured an illustration of the Iguanodon tracks recently discovered at Crowborough, Sussex.[16]
90 million year old Cretaceous dinosaur footprints were discovered in New Jersey but were accidentally destroyed during an attempt at excavating them.[24]
Charles Whitney Gilmore began collecting and studying the Carboniferous and Permian-aged footprint fossils of the Grand Canyon area on behalf of the
Smithsonian. He also constructed an outdoor exhibit about the tracks at
Hermit Trail.~NA34~
Renovations to
Oak Hill, the historical home of
US PresidentJames Monroe, led to the discovery of fossil dinosaur footprints when workers repaved the properties walkways with
Lower Jurassic stone. The preserved tracks included Grallator and Eubrontes prints ranging in length from 13 to 33 cm (5–13 inches).[24] Other local footprints included the tracks of a crocodilian-like animal, Batrachopus. The tracks originated in the
Midland Formation.[32]
Baron Franz von Nopsca published a "seminal" work on fossil amphibian and reptile tracks.[33] He hypothesized that Plateosaurus was the Chirotherium trackmaker. Although Plateosaurus has only four hind toes and Chirotherium tracks have five impressions, Nopsca followed
Willruth's argument that the "thumb" of Chirotherium was composed only of
soft tissue and would have left no skeletal record.[34] He also named the large Late Jurassic theropod fossils discovered at Cabo Mondego, Portugal Eutynichnium lusitanicum. However, this name lacks validity because Nopsca did not formally describe it or designate a
type specimen.~154~
Wolfgang Soergel interpreted the Chirotherium trackmaker as a
pseudosuchian related to, but much larger than, Euparkeria.[34] He noted that the bulk of the animal's weight was born by its hindlimbs.[35]
German geologist
Adolf Bachofen-Echt reported the first scientifically recognized dinosaur tracks from
Croatia. These three-toed tracks were preserved on the
Brioni Islands and
Bachofen-Echt thought they were made by Iguanodon.~218~
Charles Gilmore described the Paleocene amphibian tracks from the Fort Union Formation of Montana. He named the new ichnospecies Ammobatrachus montanensis for the tracks. He observed that these were the first Paleocene fossil footprints to be documented in the scientific literature.~NA246~
Potential Paleocene mammal footprints were reported from
Alberta.~NA247~
Charles Whitney Gilmore published his third report on fossil footprints from the Grand Canyon area.~NA313~
Bradford Willard discovered a new ichnogenus
Devonian-aged trace fossils in Pennsylvania that he named Paramphibius because he thought the trackmaker was a transitional form between
fishes and
tetrapods. He named a new taxon, the
Ichthyopoda to classify this creature.~NA37-38~
Roland T. Bird discovered a new Early Jurassic dinosaur tracksite in the
Moenave Formation of northwestern
Arizona. Although the site's location would be lost, Bird's photographs would help
Dinosaur National Monument paleontologist Scott Madsen relocate the site decades later.~NA118~
Late: An expansion of the Nevada State Prison was built over the Pleistocene fossil footprints that had been discovered there. However, some specimens had been collected before and are now curated by the
Nevada State Museum.~NA280~
1930: Amateur paleontologist
Charles Strevell privately published a description of various Cretaceous dinosaur footprints he collected from the coal mines of Carbon County, Utah. Strevell named the tracks "Dinosauropodes" at the advice of
Earl Douglass after Strevell had failed to interest Richard Swann Lull or
Walter Granger in studying the tracks themselves. Strevell named many ichnospecies of "Dinosauropodes" in this publication, but none are considered valid because he published outside of the traditional scientific literature, failed to cite any other ichnological works, and referred too wide variety of dissimilar tracks to "Dinosauropodes".~NA217-219~
More Cretaceous dinosaur footprints were discovered at the Hampton Cutter Clay Works quarry at Woodbridge, New Jersey. The largest tracks discovered in the quarry were 19 inches long.[24]
Maurice Mehl erected the new ichnogenus Ignotornis for some bird tracks preserved in the Dakota Group near
Golden, Colorado. These were the first scientifically documented
Mesozoic bird footprints.~NA194-195~ The bird in question as interpreted as a "small
shorebird or
wader".~NA211~ The site would eventually be heavily collected and all of its tracks were presumed removed.~NA194-195~
Edward Branson and Maurice Mehl reported the presence of Carboniferous-aged fossil footprints of a new ichnospecies in the
Tensleep Formation of
Wyoming.~NA34~ They named the tracks Steganoposaurus belli and attributed them to an amphibian nearly three feet in length.~NA34-35~
Edward Branson and Maurice Mehl named a new kind of Late Triassic dinosaur footprint discovered in the
Popo Agie Formation of western Wyoming. The new ichnogenus and species was named Agialopus wyomingensis.~NA93-94~
Toepelman and
Rodeck made the first report on fossil
arthropod trackways in the Lyons Sandstone and fossil vertebrate footprints preserved in the
Fountain Formation.~NA314~
The
Dinosaur Ridge dinosaur tracksite was discovered near
Denver, Colorado. Tracks include those made by ornithopods and theropods. Some of the ornithopod tracks seem to have been left by individuals traveling together and are thus evidence for social behavior.~NA196-197~ Further, these ornithopods seem to have traveled predominately on all fours, unlike most ornithopod tracks, which were made by bipeds.~NA197~
The
New York Times reported that
Barnum Brown had discovered the fossil footprints of a huge and unknown kind of dinosaur in a Wyoming coal mine. Brown's claim was simply a "publicity stunt" aimed at attracting funding.~NA219-220~ However, Brown's report attracted the attention of a coal mine operator from the
Cedaredge, Colorado area named Charlie States, who reported large dinosaur footprints spaced five meters apart in his mine, the Red Mountain Mine.~NA220~ Brown and his assistant Roland Bird oversaw an "ambitious" excavation of the purported giant's tracks. After three weeks of 24 hour labor on the part of the miners and the development of specialized equipment to extract the specimen, a 17 foot long slab of track-bearing rock was taken from the mine and shipped to the
American Museum of Natural History in
New York.~NA220-221~
More Late Triassic dinosaur footprints were discovered near Gettysburg. These tracks ranged from chicken-sized to 15 cm (6 inches) in length.[38]
Kenneth Caster conclusively demonstrated that unusual fossil tracks from the Solnhofen lithographic limestone variously attributed to creatures like Archaeopteryx, little dinosaurs, or pterosaurs were actually made by
horsehoe crabs, as specimens had been found literally "dead in their tracks".[19] Similar fossils in the United States had been attributed to a transitional form between fishes and tetrapods by Bradford Willard earlier in the 1930s.~NA37-38~
Brown published a description of the dinosaur tracks with the purported giant stride length. He tried to keep up his charade of there being an undiscovered mystery dinosaur by downplaying "the obvious
hadrosaurian affinity of the tracks".~???NA220-221~
Nash bought the Massachusetts property where he discovered dinosaur footprints. He would begin excavating and selling the dinosaur footprints on his land and the property would come to be known as
Nash Dinosaur Land.[39]
Lionel F. Brady began experimenting with living arthropods to help determine which sorts of arthropods may have produced various ancient trace fossils.~NA43~
Sumner Anderson reported the presence of small carnivorous dinosaur footprints between 15 and 20 cm in length preserved in the Early Cretaceous
Lakota Formation at two different sites in
South Dakota.~NA184-185~
Earl L. Poole of the
Public Museum and Art Gallery discovered a new Late Triassic dinosaur track site at a quarry near
Schwenksville, Pennsylvania.[38] The dozens of tracks preserved there were mostly left by
chicken-sized dinosaurs, but about a "half dozen" of them were left by turkey-sized trackmakers.[40] Poole ascribed these tracks to the ichnogenus Anchisauripus. One footprint was left by a dinosaur with about the same body mass as a
horse.[39] This site is now known as the
Squirrel Hill Quarry.[38]
1940s
Frank Peabody performed "extensive" research on Early Triassic fossil footprints.~NA71-72~
Roland T. Bird oversaw the excavation of sauropod and theropod tracks from the
Paluxy River in Texas. This was the first large-scale dinosaur track excavation in history.~NA199~
Frank Peabody studied the early
Pliocene fossil amphibian footprints of the
Sierra Nevada Mountains of
California. He found them to be almost identical to the tracks of their descendants. This was his first major contribution to ichnology.~NA274~
Robert Chaffee reported the presence of a tracksite from Wyoming preserving the footprints of a
camel-like
even-toed ungulate and a
rhinoceros-like odd-toed ungulate in the Oligocene-aged
White River Beds. He noted that only two other Oligocene fossil tracks were known and neither had been described.~NA257~ Chaffee attributed one of these, a partial print preserved in the
Yale Peabody Museum, to a
brontothere.~NA257-258~
Casteret reported the presence of Pleistocene hyena tracks in the
Aldene cave of France.[42]
F. E. Peabody published a study of the amphibian and reptile tracks preserved in the Triassic Moenkopi Formation. Lockley and Hunt would later regard this paper as "a classic" in the field.~NA316~
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
1950s
Oligocene to Miocene-aged bird tracks were first reported from the "
Molasse" rocks of
Switzerland.[43]
Frank Peabody performed "extensive" research on Early Triassic fossil footprints.~NA71-72~
A rock hound named Al Look "embellished" Barnum Brown's mystery dinosaur hoax, informally naming the creature "Xosaurus". He also reported having encountered another dinosaur trackway with a similarly long stride as Brown's original specimen. This trackway supposedly recorded the huge mystery dinosaur stepping on a crocodile-like reptile.~NA221~
Albert de Lapparent and others restudied the large Late Jurassic theropod tracks of Cabo Mondego.[31] They thought the tracks were made by Megalosaurus.[44]
Henry Faul and
Wayne Roberts reported the presence of Early Jurassic fossil footprints in Colorado's
Navajo Sandstone. These tracks were probably left by an evolutionary precursor to mammals.~NA144~
Wilhelm Bock reinterpreted the footprints discovered in the Squirrel Hill Quarry as Grallator and non-dinosaurian
archosaur tracks. He also described the ichnospecies Anchisauripus gwynnedensis for a dinosaur track discovered in the
North Pennsylvania Railroad tunnel near
Gwynned. These tracks are now thought to belong to Atreipus, however.[39]
A French ichnologist named
Lessertisseur erected the ichnogenus Megalosauripus. He attributed the Cabo Mondego tracks to a
megalosaurid.[45] He also named the ichnogenus Tyrannosauripus, but as both ichnogenera lacked type species and type specimens these taxonomic names were invalid.[46]
M. F. Farmer published the locations of many track sites in northern Arizona.~NA312~
Lee Stokes erected the new ichnogenus Pteraichnus for fossil footprints discovered in the Morrison Formation of Utah that he thought were left by pterosaurs.~NA144~
Oskar Kuhn named the new Early Cretaceous theropod ichnogenus and species Buckeburgichnus maximus from Germany. It is notable in its preservation of a large
hallux impression.[47]
August 3rd:Albert de Lapparent and
Robert Lafitte stumbled on some fossil footprints left by a large bipedal dinosaur at
Isfjorden, Spitzbergen.[49] The researchers suspected that the tracks were made by a
carnosaur. At 78 degrees of latitude north, these were the highest latitude dinosaur tracks known in the world, up from the previous record of 56 degrees.[50]
A
geologist named
H. D. Curry working for the
Shell Oil Company discovered a slab of rock preserving high quality three-toed mammal footprints in Utah's
Strawberry Canyon. The trackmakers were probably Eocene relatives of modern
tapirs and
horses. Curry donated the so-called "Strawberry Slab" to the Smithsonian Institution.~NA252-253~
Albert de Lapparent reinterpreted the dinosaur tracks from Spitzbergen. Although mentioning their initial impression that the tracks were carnosaurian, he concluded that the tracks were probably left by Iguanodon instead, due to their lack of claw marks, rounded toe prints, and general similairty to the feet of Iguanodon bernissartensis.[50]
Panin and
Avram published research on
Miocene fossil bird and mammal tracks from the vicinity of the
Carpathian Mountains of
Romania. They attributed the local bird footprints to four different families, the
anatids,
ardeids,
charadriids, and
gruids. Contemporary mammalian trackmakers included
artiodactyls,
cats,
dogs, and
relatives of modern elephants. The latter of these left behind one thoroughly trampled site with an area of more than 100 sq m. The researchers erected several new ichnotaxa for the tracks they studied and similar tracks would later be discovered elsewhere in Europe.[51]
Natasha Heintz documented the return expedition to Spitzbergen to make plaster casts of the Spitzbergen dinosaur tracks. Although the casts were made, the effort was frought with difficulty because the intense cold and high humidity hindered the plaster's ability to set.[50]
A large pseudosuchian named Tichinosuchus was named for remains found in Swiss Triassic rocks. It had the right size and anatomy to account for the Chirotherium tracks of Europe and is considered the most likely trackmaker.[55]
Panin published more research on the fossil bird footprints from the Carpathian vicinity.[56]
de Raaf,
Beets, and
Kortenbout van der Sluijs reported the presence of a large number of well-preserved web-footed bird tracks from
Oligocene rocks in Spain.[57] The high percentage of the fossil trails being oriented in the same direction suggests that this deposit records evidence for flocking in these ancient birds. This is extraordinary because evidence for social behavior in fossil bird footprints is very uncommon.[37]
Albert de Lapparent and
Christian Montenat published the results of their research on the dinosaur tracks reported from western France in 1963.[52] They identified the rocks preserving the tracks as part of a geologic formation called the
Infralias and track sites were found in at least seven different positions in the local stratigraphy. The changing paleoenvironments implied by the local geology led the researchers to conclude that this series of dinosaur track beds spanned the Triassic-Jurassic boundary.[58]
March: A coal miner working near
Hayden, Colorado hit his head on the natural cast of a dinosaur footprint while in pursuit of a run-away coal cart. The impact injured his spinal cord, leading to his death 10 days later.~NA227~
1970s
Mid: Dinosaur tracks of the ichnogenera Atreipus and Grallator were discovered in a quarry that straddles the Virginia-
North Carolina border. These may be the oldest dinosaur tracks known in the eastern United States.[60]
Late: The publication of a formula capable of inferring the life speeds of dinosaurs from their fossil trackways brought further attention to Barnum Brown's claim of having discovered the tracks of a mystery dinosaur with an abnormally long stride length. Scientists instantly recognized the footprints as belonging to a duck-billed hadrosaur rather than some completely unknown dinosaur, but the validity of the trackway's stride length proved controversial.
Dale Russell and
Pierre Beland accepted Brown's measurement and calculated the trackmaker as moving at 27 kilometers and hour.
Tony Thulborn argued that a footprint left by another dinosaur obscured a track left by the original trackmaker roughly halfway between the prints composing the supposedly enormous stride. This implied that the trackmaker's stride was only half the claimed size and it was probably only traveling at about 8.5 kilometers and hour.~NA221~
Leonard Wills and
Bill Sarjeant reported potential dinosaur footprints from Triassic rocks in
Nottinghamshire and
Worcestershire. Ichnotaxa reported included Coelurosaurichnus, Otozoum, and Swinertonichnus. The rocks were of uncertain age at the time of the authors writing and are now known to have been Lower Triassic.[61] Dinosaur tracks dating to the Early Triassic would be anomalous as their skeletal remains are not known until later in the period.[62] Not suprisingly, the dinosaurian status of the tracks reported by Wills and Sarjeant have been disputed.[61]
Sarjeant found the three-toed Middle Jurassic dinosaur footprints comparable to the Cretaceous ichnogenus Saltapliasaurus from
Russia.[63]
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
de Clercq and
Holst published on the Upper Oligocene bird tracks of
Lucerne, Switzerland. The tracks, which the researchers concluded were left by
rails, were left in the fine-grained sediments at the top of a 15 roughly stratigraphic interval characterized by gradually decreasing particle size.[43]
Hartmut Haubold erected several new ichnogenera for fossil footprints discovered in Colorado. The proto-mammal tracks that Faul and Roberts reported he named Bipedopus coloradensis and Semibipedopus meekerensis.~NA144-145~ He also named the new ichnogenus Lacertipus for the small tracks in the formation that were apparently left by a lizard-like animal.~NA145~
Vialov classified fossil bird footprints as members of the ichno order Avipedia.[56]
Pleistocene human footprints were discovered in the Niaux cave complex of France.[30]
David Webb studied the fossil footprints left by ancient camels and determined that even these ancient forms shared modern camels' "pacing gait", where the animal moves both legs on one side of the body at the same time, unlike most mammals which move hindlimbs and forelimbs from the opposite sides of the body in each step. Webb argued that the energetic efficiency of the pacing gait enabled camels' success in desert and prairie environments where significant distances may separate food and water sources.~NA267~
Paul Olsen and
Robert F. Salvia discovered dinosaur Late Triassic footprints in the
Stockton Formation of
Nyack Beach State Park, New York. The tracks included 12–15 cm (5–6 inch) long Grallator tracks. Possible Atreipus tracks were also found there. The regions's non-dinosaurian tracks included Apatopus, Brachychirotherium, Chirotherium, and Rhynchosauroides.[65]
Justin Delair and
A. B. Lander reported the presence of three parallel dinosaur trackways in the Roach Stone of Herston, England.
A significant Permian-aged fossil tracksite in the
Cedar Mesa Sandstone of Utah was inundated following the creation of the
Glen Canyon Dam. This tracksite preserved an apparent predator-prey interaction wherein the trail left by a small amphibian or reptile vanished at the point where it intersected with the trail left by a large carnivorous proto-mammal. Fortunately for ichnologists, plaster casts of the trackways and photographs remain available for study.~NA55-56~
W. J. Breed reported fossil
goose footprints from the Pliocene
Bidahochi Formation of Arizona.~NA321~
Kaever and de Lapparent named the new ichnogenus and species Elephanotpides barkhausensis for the poorly preserved tracks of a large quadrupedal dinosaur discovered near Barkhausen, Germany. The trackmaker was probably a sauropod.[66]
Bill Sarjeant described the five-toed Middle Jurassic footprints discovered by C. Pooley and named it Pooleyichnus burfordensis in his honor.[22] Sarjeant proposed that this unusual track may have been made by a mammal.[68]
A large tracksite preserved in the late Eocene
Vieja Group of Texas was first studied in a
University of Texas research program.
Robert E. Weems was informed of, and began researching, a Late Triassic reptile track site in a quarry near
Culpeper, Virginia.[69]
Leon Pales described the Pleistocene human footprints of France's Niaux cave complex. This paper has been considered "one of the most comprehensive studies of cave footprints ever published."[30]
R. McNeil Alexander published a formula for inferring the speeds of dinosaurs from their fossil trackways.~NA312~
Russell and Beland examined Brown's claim to have discovered the tracks of a running dinosaur.~NA320~
Weems continued to excavate and study the Late Triassic reptile track site near Culpeper, Virginia.[69]
Several hundred Late Triassic dinosaur footprints were reported from the vicinity of Cardiff, Wales.[72] This report was made by
M. E. Tucker and
T. P. Burchette.[73]
By this point, Weems found the Late Triassic reptile track site near Culpeper, Virginia to be roughly an acre in size and preserving 32 different reptile trackways, including those left by dinosaurs.[69]
Marc Edwards and others reported the dinosaur footprints discovered in Spitzbergen in 1978. Only two footprints were discovered at the site, which was an exposure of the Helvetiafjellet Formation. The researchers interpreted the tracks as carnosaur footprints, but now they are thought to have been left by
iguanodontids.[71]
Stokes observed that tracks left by close evolutionary relatives of mammals were common and widespread in the Navajo Sandstone. He found such tracksites in Colorado,
Idaho, and Utah.~NA145~ He reported many new sites in the Navajo formation.~NA318~
Carme Lompart reported the presence of Late Cretaceous dinosaur tracks in the
Ager Valley of Spain, near the country's border with France.[75]
Marc Weidmann and
Manfred Reichel published a "lengthy" review of the Oligocene to Miocene aged bird tracks found in Switzerland's "Molasse" rock.[43] They reported the presence of tracks left by one kind of
duck, two kinds of
herons, one kind of
perching bird, and four kinds of
waders.[76] Weidmann and Reichel devoted intense effort to classifying these tracks based on previous schemes devised by scholars like Avram, Panin, and Vialov for other bird track sites.[56] They also worked diligently to discern the tracks' positions within the stratigraphic column.[77]
Stokes and Madsen published more on the purported pterosaur footprints from the Jurassic Navajo Sandstone of Utah.~NA318~
1980s
Researchers interpreted large vertical burrows in the sediments of the Lower Triassic
Chinle Formation as having been made by
lungfish. Now, however, the burrows are attributed to arthropods similar to modern
crayfish.~NA77-80~
Hasiotis and
Mitchell '89~NA315~
Lockley and
Hunt returned to the Late Triassic dinosaur tracksite discovered northeast of Dinosaur National Monument to collect specimens for the University of Colorado and
United States Geological Survey.~NA93-94~
Lockley and Hunt studied a coal mine near
Gunnison, Colorado. They found many hadrosaur trackways, apparently left by a herd traveling in a southerly direction.~NA221-223~
Mid: A new dinosaur track site in the
Dakota Group was discovered just outside of
Roxborough State Park. The park was later to acquire the land where the specimens were preserved.~NA200-201~
Mid: Dinosaur footprints were first reported from the
Laramie Formation.~NA229~
Donald Baird attributed the ichnogenus Navahopus of Arizona's Navajo Formation to a prosauropod trackmaker.~NA89~ He also describedit.~NA316~
Gerard de Beaumont and
Georges Demathieu hypothesized that sauropods walked on the knuckles of their forelimb, and this explains why so many sauropod foreprints lack any impression left by the large claws born on the first toe in many species.~E141~
Don Baird erected the ichnogenus Navahopus for footprints preserved in the Early Jurassic Navajo Formation. He thought these tracks were left behind by a small prosauropod.~NA145~
A nine meter long Pleistocene
bear trackway was reported from
Lake County, Oregon. The tracks themselves were about 40 cm long, suggesting a trackmaker roughly the size of a large modern bear. These tracks may have been left by an Arctotherium.~NA275-276~
Olsen argued that the ichnogenera Grallator, Anchisauripus, and Eubrontes actually represent a growth series.~NA317~
Walter P. Coombs, Jr. interpreted some unusual Eubrontes tracks from Dinosaur State Park of
Rocky Hill, Connecticut as traces left by a swimming theropod because the tracks only preserved impressions from the tips of the animal's toes as if the rest of its body weight was supported by water.[80]
Giuseppe Leonardi erected the new ichnogenus and species Brasilichnium elusivum to classify the Early Jurassic proto-mammal tracks from the Botucatu Sandstone of Brazil. This work has since been praised as "very thorough" by Martin Lockley and Adrian Hunt.~NA145~
Thulborn criticized the the idea that the hadrosaur tracks reported by Brown in 1938 were left by a running animal.~NA320~
Demathieu and Haubold described the new Early Triassic ichnogenus and species Isochirotherium archaem from Germany. As only the hind prints are preserved in this trackway it may represent the oldest evidence in the world for the existence of animals with bipedal gaits. However, while intriguing, their remains the possibility that the track maker was a quadruped and its foreprints eroded away before the trail was discovered.[82]
Demathieu and
Marc Weidmann described a new Triassic fossil tracksite from Swtizerland called the
Vieux Emosson tracksite.[83] The authors named nine ichnospecies and several new ichnogenera, although none of these new ichnotaxa would be subequently observed at other sites. The poor preservation, anomalously high ichnodiversity, and lack of corroboration at other sites cast doubts on he legitimacy of the researchers' ichnotaxa, however.[84]
Bernier and others erected the ichnogenus Chelonichnium and interpreted it as the tracks of a large turtle.[85]
Edwin McKee reported the presence of apparent
horseshoe-shaped trace fossils in the Carboniferous
Esplanade Sandstone that he attributed to a tetrapod. However, these tracks are more likely to have been invertebrate traces or artifacts of erosion.~NA36~
Geology student Jeff Pittman recognized that the "potholes" hindering excavation equipment traffic through a gypsum mine in southeastern Arkansas were actually sauropod dinosaur footprint.~NA191-192~
Hartmut Haubold published the
Saurierfahrten.~E50~ Haubold was a German ichnologist,and the Saurierfahrten a specialist's handbook for identifying Carboniferous and Permian fossil footprints. It was the only publication of its type in the world at the time and only available in German.~E33-34~
Paul Olsen and
Peter Galton argued that Ellenberger had oversplit the Late Triassic and Early Jurassic ichnotaxa he studied and that many of the kinds of tracks he regarded as distinct were actually the same as tracks previously described in eastern North America.[86]
J. E. Andrews and J. D. Hudson reported the first dinosaur tracks to be scientifically documented in Scotland. The tracks are three-toed and preserved in the Middle Jurassic
Leate Shale.~144~
Hans Mensink and
Dorothee Mertmann described the new ichnogenus and species Gigantosauropus asturiensis from Jurassic near
Asturias, Spain. The researchers attributed the tracks to a theropod. At 1.35 m in length, these tracks were actually twice as long as those of a more typical length for a large theropod.[66]
Bernier and others named the new ichnogenus and species Saltosauropus latus for strange widely spaced tracks discovered in France. They interpreted the traces as those left by a hopping dinosaur.~173–174~
Lompart erected two new ichnogenera and species for the three-toed Late Cretaceous dinosaur footprints she reported from Spain. The new ichnotaxa were Ornithopodichnites magna and Orcauichnites garumeniensis. Lompart thought both were made by ornithopods, but they are now thought attributable to theropods. Also, because these footprints were poorly preserved and the ichnotaxa not properly named, the names are regarded as being of dubious scientific utility.[87] Sauropod tracks were also reported from the site.[88]
George Demathieu and others described an Oligocene bird and mammal track site from southeastern France. Three different mammalian ichnotaxa were present. One was an artiodactyl track they named Bifidipes velox. The second was the largest of the three, Ronzotherichnus, was apparently left by the rhinoceros Ronzotherium. A
creodont or early carnivoran left behind the third kind of tracks, which the researchers named Sarcotherichnus enigmaticus. They named the bird tracks at the site Pulchravipes magnificus.[59]
Kevin Padian and Paul Olsen reinterpreted the supposed pterosaur tracks named Pteraichnus from the Morrison Formation of Utah as crocodilian tracks.~NA145~
L. D. Agenbroad published an interpretation of the preservation of mammoth remains and footprints at Hot Springs, South Dakota.~NA320~
Luis Aguirrezabala reported the presence of nine parallel trails left by Hypsilophodon or one of its close relatives in Lower Cretaceous rocks of
La Rioja, Spain. This tracksite is now known as the Valdevajes site.[89]
An international symposium for paleontologists performing research on "Dinosaur Tracks and Traces" was held in New Mexico.[90] The gathering was a success and "led to the rejuvenation and maturing of the discipline of dinosaur ichnology".[91]
Haubold observed that during the Late Triassic, small Grallator tracks become common.[73] Haubold published a discussion of archosaur tracks from near the Triassic-Jurassic boundary and their distribution through the stratigraphic column.~NA315~
Paul Olsen and Kevin Padian reported the presence of the crocodilian ichnogenus Batrachopus in the Early Jurassic Moenave.~NA145~
Paul Olsen and Kevin Padian discovered Batrachopus tracks in the Navajo Formation, but did not publish their findings.~NA145~
Lockley and Martin showed that some of the purported baby dinosaur footprints collected by William Wilson from Utah were "enhanced" by carving.~NA226~
Kirk Johnson discovered a new Paleocene fossil tracksite in the
Fort Union Formation. This site preserved additional amphibian tracks as well as the tracks of two different wading birds and traces of insect activity. The tracks were preserved in what was once the banks of an ancient stream~NA246~
Scrivener and
Bottjer published a census of tracks from the Miocene
Copper Canyon Formation of
Death Valley National Monument, California. Most of these footprints were camel tracks, but bird and horse prints were also common. Less common traces included those of
bear-dogs, cats, deer, and proboscideans.~NA269-270~
Jordan Marche argued that the Pleistocene tracks discovered by prisoners near Carson City, Nevada deserved more scientific attention than they had received.~NA276~
Houck and Lockley published the first illustrations of the foosil footprints preserved in the
Belden Formation.~NA313~
Olsen and Baird published "[a] detailed study of the ichnogenus Atreipus."~NA316~
Paul Ensom reported dinosaur tracks from the Purbeck Limestone of Dorset, England as the latest Jurassic dinosaur footprints known from Europe.[92] Ensom interpreted these trace fossils as sauropod footprints.[93] The tracks were preserved only 2m below the horizon representing the consensus Jurassic-Cretaceous boundary. Since then the tracks have come to be regarded as Early Cretaceous.[92]
David Norman suggested that smaller species of Iguanodon may have walked on their hind legs while larger and heavier species may have preferred to walk on all fours.[89]
Giuseppe Leonardi also referred the Navajo Formation tracks examined by Olsen and Padian to Batrachopus.~NA145~
Lockley disputed
Robert T. Bakker's hypothesis that an Early Cretaceous sauropod trackway from the Davenport Ranch, Texas area preserves evidence that sauropods traveled in herds with the young surrounded by the adults to protect them from predators. Instead, Lockley interpreted this trackway as a herd of sauropods traveling through a narrow area, with the young following the adults.~NA186~
Lockley and Hunt began studying the dinosaur tracks of the Dakota Group at the
Alameda Parkway site, which is now called
Dinosaur Ridge.~NA209~
Lockley and Jennings published the first illustration of the fossil footprints preserved in the Late Triassic rock of Colorado's
Dolores Valley.~NA315~
Lockley described the ichnogenus Caririchnium. This publication was also the first detailed treatment of the Dakota Group's trace fossil record in the scientific literature.~NA319~
Robert E. Weems described the new ichnospecies Gregaripus bairdi from a rock quarry in Virginia. The ichnospecies epithet was chosen to honor Donald Baird. Gregaripus dated back to the Late Triassic and were left by a trackmaker that walked on hind feet less than four inches long, with three toes and blunt nails.[94] This suggests that the Gregaripus trackmaker was a small ornithischian dinosaur about 1.5 meters (five feet) long.[95] Robert E. Weems published the results of his research into the Late Triassic reptile tracksite near
Culpeper, Virginia. Among the fossil footprints he found there were the dinosaur ichnogenera Agrestipus, Grallator, Gregaripus, and Kayentapus.[69]
Weems also describe the new ichnogenus and species Agrestipus hottoni. The species epithet was chosen in honor of
Nicholas Hotton III. Weems attributed these three to four-toed tracks as sauropod footprints, but now they are thought to have been left by the sauropods' slightly more primitive relatives, the prosauropods.[96]
Ensom published further research on the Purbeck Limestone dinosaur tracks from Dorset.[92]
Harald von Walter and
Ralf Werneberg reported the discovery of body impressions left behind by
diplocaulid amphibians in the Rotliegende of the Thuringian Forest area. The assemblage includes the body impression of several individuals, all no more than a few centimeters in length.~46~ The authors named these traces Hermundurichnus fornicatus.[97]
Lockley and Hunt rediscovered fossil bird footprints in the Dakota Group near Golden Colorado.~NA194-196~ Among the specimens recovered was the first in the world to preserve dinosaur and bird footprints together.~NA196~
Lockley and Prince expanded on their previous descriptive work on the Purgatoire Valley dinosaur tracksite.~NA317~
Lockley reported the first observation in the Dakota Group of dinosaur footprints with preserved skin impressions.~NA319~
W. A. S Sargeant and
J. A. Wilson reported the presence of Eocene mammal footprints in Texas.~NA322~
Demathieu reported potential dinosaur footprints from the Middle Triassic of France.[98]
Dana Batory and William Sarjeant proposed that the 1909 discovery of Iguanodon footprints at Crowborough, Sussex was Sir Arthur Conan Doyle's inspiration for writing The Lost World.[16]
R. Santamaria,
G. Lopez, and
M. L. Casanovas-Cladellas reported an Oligocene mammal track site discovered near
Agramunt, Spain. This tracksite preserved four new ichnospecies, three of which were in new ichnogenera. First was a new species of Bothriodontipus, which was made by the pig-like animal Bothriodon or a close relative. The researchers new ichnogenera were Creodontipus and Plagiolophustipus.[59] They classified two of their new ichnospecies in Creodontipus, an ichnogenus they fittingly attributed to creodonts. They attributed Plagiolophustipus to tapir-like animals distantly related to horses.[99]
Jeff Pittman proved that the sauropod tracks he recognized in an Arkansas
gypsum mine were actually at the same level of the geologic column as the Glen Rose Formation sauropod tracks of Texas.~NA192~
A research group headed by Lockley and Hunt, along with a collaborator from
Japan, excavated the co-ocurring dinosaur and bird footprints from Colorado. The three ton specimen was shipped to Japan to star in a traveling museum exhibit about dinosaur footprints.~NA196~
Lee Parker and
John Balsley reported the presence of potential Hesperornis footprints in a coal mine near Price, Utah.~NA223~ They might actually be pterosaur tracks.~NA224~ Lockley, Matsukawa and Hunt described the specimen.~NA320~
Lockley reported the presence of fossil footprints in the Minturn Formation.~NA313~
Prince and Lockley further expanded on their earlier descriptions of the Purgatoire Valley dinosaur track site.~NA317~
Farlow, Pittman, and Hawthorne described the ichnogenus Brontopodus.~NA318~
April: A quarry worker named Robert Clore blasting stone near Culpeper, Virginia uncovered a new Late Triassic reptile tracksite. This site was apparently about 300,000 years older than the first Late Triassic tracksite discovered near Culpeper and had an even greater area of about 6 acres.[100] Weems began studying the site that same year, and reported the presence of 4,000 individual tracks. The local tracks included the dinosaur ichnogenera Grallator and Kayentapus. Other tracks may have been left by
aetosaurs.[101]
Michael J. Szajna and Brian W. Hartline discovered Late Triassic reptile footprints in an excavation for a housing development near Reading, Pennsylvania.[102]
Thulborn disputed the referral of a trace fossil found in a core sample taken from the Early Triassic
Bunter Sandstone to the dinosaur ichnogenus Coelurosaurichnus. He hypothesized that its trackmaker was actually a horeshoe crab.[61] Thulborn also disputed the supposed theropodan origin of the ichnogenus Gigantosauropus of Asturias, Spain. Instead, he concluded, the Gigantosauropus trackmaker was actually a sauropod.[66] Thulborn also disputed the interpretation of Saltosauropus latus put forward by the team of French researchers who first described the ichnogenus as the tracks of a hopping dinosaur. Thulborn found this interpretation inconsistent with the expected morphology and spacing a hopping dinosaur would produced. His own interpretation of Saltosauropus was that it represents marks left by a
sea turtle swimming just above the seafloor.[103]
Ryszard Fuglewicz and others reported fossil trackways from the
Holy Cross Mountains of
Poland that may be the oldest Triassic trackways in Europe. They reported tracksites at six different positions within a stratigraphic series in several distinct paleoenvironments including river channels and floodplains. The ichnogenera they identified in these tracksites included Brachychirotherium, Capitosauroides, Isochirotherium, Rhynchosauroides, and Synaptichnium.[104]
Hunt, Lucas, and
Huber published the first in-depth description of the fossil footprints preserved in the
Sangre de Cristo Formation.~NA313~
Lockley published the "[f]irst map of an Otozoum trackway from the western states." He also noted the presence of tracks resembling Brasilichnium and attributed them to a
tritilodont.~NA317~
Currie,
Nadon, and Lockley described Cretaceous ornithopod tracks that preserved impressions of the trackmakers' skin.~NA318~
Lockley disputed claims that some sauropod tracks were left underwater by swimming trackmakers.~NA319~
Geologists
Anders Ahlberg and
Mikael Siverson reported the discovery of a dinosaur track in a railroad tunnel in southern Sweden. The rocks preserving the print are part of a stratigraphic unit called the
Hoganas Formation which straddles the Triassic-Jurassic boundary.[106]
Gierlinski reported the presence of
Hettangian theropod tracks in the Holy Cross Mountains of Poland.[107]
Lockley disputed Paul Ensom's interpretation of some dinosaur tracks from the Purbeck Limestone of Dorset, England as sauropod footprints and instead suggested that they were probably made by ankylosaurs.[92]
A track site containing more than 250 fossil bird footprints was discovered ear
Villar del Rio, Spain.[109]
Casanovas-Cladellas and others reinterpreted the purported hypsilophodontid tracks of the Valdavajes site in Spain as theropod footprints in a heavily criticized paper.[89]
Robison reported shorebird footprints in the Cretaceous Mesa Verde Group of Utah. He also reported the presence of the oldest known
frog tracks.~NA225-226~
Brand and
Tang published the controversial argument that the fossil footprints of the Permian Coconino Sandstone were made underwater by swimming animals.~NA312~
dos Santos and others observed that at the Portugese Carenque dinosaur tracksite fossil shells and small vertebrate fossils were more common inside dinosaur footprints than untrodden portions of the same rock. Apparently the compression of the sediment under the dinosaur's foot somehow led to more favorable conditions for fossilization than were present elsewhere in the ancient trackmaking environment.~E232~ They also found that the purported South American iguanodont ichnogenus Iguanodonichnus was actually probably made by a sauropod.[11]
C. Lancis and
A. Estevez reported the presence of early Pliocene tracks preseved near
Alicante, Spain. Among the mammals who left their mark here were members of the horse family and bears. The bear that left its track there were probably either a species in the genus Agriotherium or Ursus ruscinensis.[110]
Farlow observed that sauropod trackways could be categorized as either being "narrow-gauge" or "wide-gauge".~NA175~
Mid November: Lockley and Hunt's research group at the University of Colorado undertook one of the few major dinosaur footprint excavations in history in order to expand the exposed track-bearing surface at Dinosaur Ridge for an outdoor interpretive center. To do so they collaborated with the Friends of Dinosaur Ridge and the
Jefferson County Scientific and Cultural District to remove a one meter thick layer of sandstone via "precision blasting".~NA199-200~
July 17th: Another Seattle reported that
Allison Andors and other researchers had determined that the large bird track discovered in Flaming Geyser State Park was a hoax carved into the rock. Other researchers would subsequently conclude that the track was genuine after all.~NA262~
Lockley argued against Brand and Tang's hypothesis that the fossil footprints of the Coconino Sandstone were made underwater.~NA313~
Lockley and Madsen published ichnological evidence for the predation of large reptiles on smaller animals during the Permian period.~NA313-314~
Loope argued against Brand and Tang's hypothesis that the fossil footprints of the Coconino Sandstone were made underwater.~NA314~
Lockley and others published the "[f]irst report of Atreipussensu stricto in the western states."~NA315~
Lockley, Conrad, and Paquette published a summary of Dinosaur National Monument's recently discovered Late Triassic fossil footprints.~NA315~
Lockley and others described a new fossil track site at Cub Creek that preserved the first known instance of the ichnogenus Pseudotetrasauropus in the western US.~NA315-316~
Olsen and others argued that a supposed Otozoum foreprint was actually the hind prints of two small theropods impressed on top of eachother into a single impression.~NA317~
Lockley and others summarized the state of science's knowledge about the fossil footprints preserved in the Dakota Group megatracksite.~NA319-320~
Greben and Lockley published an "[o]verview of the Eocene Green River tracks."
Demathieu reported the presence of dinosaur tracks the Causses region of France.[105]
Whyte and
Romano argued that the ichnogenus Deltapodus, which they named, was left behind by a sauropod.~135~
Lockley and dos Santos described the
Kimmeridgian-aged
Avelino quarry tracksite near
Lisbon, Portugal, the first scientifically documented sauropod dinosaur tracksite in Europe to contain well-preserved tracks of the animals' front feet. The quarry contained only one track-bearing layer with five intersecting sauropod trails. Although the animals varied in size all had hindprints smaller of 30 cm or less in length, suggesting that they were juveniles.[111] They also argued against the idea that sauropod trackways consisting mainly of foreprints were left by swimming animals.~NA320~
Lockley, Meyer, and dos Santos performed fieldwork mapping the dinosaur tracks at Cabo Espichel, Portugal.[70]
Meyer reported the first scientifically documented Late Jurassic dinosaur footprints from Switzerland. These tracks were discovered near the town of
Lommiswil.[112]
Parkes reported theropod tracks in the Ashdown beds of the Wealden near Hastings, Sussex.[113]
Moratalla first used the name of the theropod ichnospecies Therangospodus oncalensis in the scientific literature, although it had not yet been described. He also informally coined the ichnogenus Filichnites.[114]
Viera and
Torres argued that contrary to the reinterpretation published the previous year by Casanovas-Cladellas and others, the dinosaur footprints of the Spanish Valdavajes site were hypsilophodontid tracks after all.[89]
Martin-Escorza also published a paper arguing for the hypsilophodontid status of the Valdavejes dinosaur tracks.[89]
Scientists began studying the recently discovered fossil footprints at
Las Hoyas, Spain.[115]
Claude Guerin and George Demathieu described the new ichnospecies Dicerotichnus laetoliensis. This ichnospecies was left behind by a late Pliocene rhinoceros of fairly modern build, possibly from the genus Diceros. Its tracks are preserved at the same site known for its ancient
hominid tracks.~E246~
A non-technical article in the Spanish magazine Blanco y Negro discussed the wide variety of Miocene tracks preserved at
Salinas de Anana, Spain.[116]
J. Quintana reported the presence of Quaternary-aged footprints on the
Balearic island of
Menorca. The most conspicuous tracks were those of the extinct goat Myotragus, but tiny footprints left by the
mouse genus Hypnomys were also preserved in places where blocks of fallen sandstone sheltered them from the elements.~264~
Lockley, Hunt, and Meyer synonymized Navahopus with Brasilichnium, and noted that these tracks were common among the Early Jurassic sand dunes of the Western Hemisphere.~NA146~
Lockley and Hunt introduced the idea of ichnofacies to the scientific literature. They described and named the Brontopodus ichnofacies based on sauropod tracksites in Texas.~NA210~[citation needed]
A new tracksite was discovered in
Toadstool Park area of Nebraska's
Oglalla National Grassland.~NA260~ The tracks were left across a kilometer-long stretch of what was once an ancient river valley, but is now part of the
White River Group.~NA260-261~ Eleven different trackmakers have been documented here, including camels, carnivorans, ducks, rhinoceroses, and shorebirds.~NA261~ Some of the mammals seem to have been moving in herds.~NA261-263~ Dixon-LaGarry-Guyon~NA321-322~
Hunt and others described the fossil footprints of the Robledo Mountains.~NA313~
Hunt, Santucci, and Lockley reported the first therapsid tracks to have been discovered in the Moenkopi Formation.~NA315~
Lockley and Hunt described a new fossil tracksite and accompanying ichnotaxa preserved in the Triassic Sloan Canyon Formation of New Mexico.~NA315~
Szajna and
Shaymaria M. Sylvestri described the Late Triassic reptile tracks discovered near Reading, Pennsylvania. They found most of the tracks to belong to ichnogenera like Apatopus, Brachychirotherium, Chirotherium, Gwynnedichnium, and Rhynchosauroides, although dinosaur tracks like Atreipus and Grallator were also present.[102]
[117] At least three different ichnospecies were preserved in the local Lockatong Formation rocks, including the dinosaur tracks Atreipus and Grallator ranging from 9 to 15 cm (3.5–6 inches) long.[118]
Other tracks included possible Gwynnedichnium or Rhynchosauroides tracks up to 2 cm (0.8 inches) long.[69]
Jenkins and others reported the presence of Late Triassic dinosaur tracks from the
Fleming Fjord Formation of eastern
Greenland. Most of the reported footprints were Grallator, but there were some prints apparently left by prosauropods. These tracks may be referable to the ichnogenus Tetrasauropus.
Gierlinski and Ahlberg reported additional Triassic-Jurassic dinosaur footprints from southern Sweden.[106]
Whyte and Romano continued to regard the ichnogenus Deltapodus as being sauropod tracks.~135
Lockley and others argued that Deltapodus was probably not left by a sauropod because the hind prints had only three toes and the tracks themselves were preserved in an environment where sauropod tracks are not generally found.~135~ Instead they concluded it was more likely to be the tracks of a
thyreophoran, possibly a
stegosaur.[119]
A cave enthusiast near
Fatima, Portugal looked down on a quarry from a high ridge and noticed that its floor was covered in sauropod footprints.[120] The site included the longest known dinosaur trails at the time. The individual tracks are the largest sauropod prints known from the Middle Jurassic and include the largest foreprints of any known sauropod track type.[121]
Lockley and others reported that nearly two thirds of sauropod tracksites known to science were located in Europe. One was in Germany, sixteen were in Portugal, two in Spain, and eleven were in Switzerland for a grand total of thirty across the continent overall.[122]
Lockley, Meyer, and dos Santos published the result of their project mapping the tracks of Cabo Espichel, Portugal.[70] They found eight separate track-bearing layers at the site, the second of which preserved evidence of sauropod social behavior. This layer contains seven trails left by an apparent herd of immature sauropods.[123]
Lockley, Hunt, and Meyer defined the Brontopodus ichnofacies.
Moratalla and others observed that at this point in time only 4 Early Cretaceous sauropod track sites were known from the La Rioja Province of Spain.[81]
Dalla Vecchia published futher research on the Croatian dinosaur footprints he reinterpreted as theropod tracks.
Galopim published The Battle of Carenque, a book describing the successful efforts of Portugese conservationists to save the home of the world's longest dinosaur trackway from being destroyed by freeway construction.~E229-230~
A major collaborative research venture between the
US Bureau of Land Management, the
New Mexico Museum of Natural History, the Smithsonian, and the University of Colorado began aimed at studying the Permian-aged tracks of the Abo Formation in New Mexico.~NA57-61~
Terry Logue maintained that there were pterosaur footprints preserved in the Sundance Formation despite the popular opinion that such tracks were left by crocodilians.~NA160~
Bill Sarjeant and Wann Langston published a monograph on the late Eocene track site from the Vieja Group of Texas. The tracks preserved there indicate a fauna including six kinds of bird, two kinds of invertebrate, nineteen mammal species, and two kinds of turtle.~NA256~
Hunt, Lockley, and Lucas reported the existence of a fossil trackway preserving an apparent act of predation of a
pelycosaur upon a small reptile.~NA313~
Lockley, Hunt, and Meyer proposed the idea of vertebrate
ichnofacies.~NA314~
Lockley and Hunt published a review paper summarizing the state of science's knowledge about the Mesozoic fossil tracksites preserved in the western United States.~NA319~
Lockley and Hunt "[d]efine[d] the Brontopodus and Caririchnium ichnofacies."~NA319~
Iwan Stossel reported the oldest known fossil vertebrate footprints in Europe to the scientific literature.~E29~ The tracks were preserved in the
Mid-
Late Devonian
Valentia Slate of
Valentia Island, which lies off the southwestern coast of
Ireland. Roughly 150 tracks were present in an 8 meter long trail left behind by an early tetrapod.~E29-30~
David Scarboro and
Maurice Tucker reported the discovery of a fossil trail probably left by a
temnospondyl amphibian about 1.5 meters long walking through a delta during the Middle Carboniferous. The find is one of the largest Carboniferous fossil trackways in all of Europe. The estimated size of the trackmaker indicates an the presence of an amphibian larger than any known from England's body fossils dating back to the same time period.~E34~
Geoffrey Tresise proposed that Chirotherium tracks exhibit sexual dimorphism. The ichnospecies C. stortonense is slender and Tresise hypothesized was made by a female trackmaker while the ichnospecies C. barthi was thicker and may have been made by the male. This publication was the first to propose sexual dimorphism based on trace fossil morphology rather than just size.[124]
Gerard Gierlinksi reinterpreted the ichnogenus Otozoum, generally regarded as prosauropod tracks, as the footprints of the primitive armored dinosaur Scelidosaurus. However, he would later retract this interpretation and return to the traditional prosauropod interpretation.[125]
Moratalla and others published research on the fossil tracks from Las Hoyas Spain. They attributed some unusual three-toed tracks at the site to turtles.[115]
Lockley and others reinterpreted the supposed turtle tracks from Las Hoyas, Spain as pterosaur footprints based on a recent increase in pterosaur trace fossils being discovered all around the world.[115]
Leonardi and Lockley argued that use Friedrich von Huene's ichnogenus name Coelurosaurichnus should be abandoned because it refers to the same kind of footprint as Grallator.
Avanzini reported the theropod ichnogenus Eubrontes among the fossil dinosaur footprints at the Lavini de Marco track site in Italy. They also reported tracks of the ichnogenus Parabrontopodus which were likely made by a small-to-medium-sized sauropod.[108]
Cyril Ivens and
Geoffrey Watson published Records of Dinosaur Footprints on the North Coast of Yorkshire, documenting the many local dinosaur track discoveries.[63]
Jean-Michel Mazin and others described the first scientifically documented pterosaur fossils from Europe. These tracks were preserved in a Late Jurassic limestone in
Crayssac, France.[126] The pterosaurs that left these footprints seem to have been in the sparrow to sea gull size range. These tracks have played a "pivotal" role in confirming that various unusual and controversial trace fossils reported around the world really were made by pterosaurs after all.[127]
April: Fabio Dalla Vecchia and one of his students were arrested while mapping dinosaur footprints in Croatia and inadvertently following the tracks into a military zone. They were tried and subsequently fined their trial expenses and released.~E217-218~
Koenigswald, Walders, and Sander described a 30,000 to 20,000 year old Pleistocene fossil mammal track site from
Bottrop, Germany. This ste was discovered on the grounds of a sewage treatment plant. Local trackmakers included
bison, horses,
cave lions,
reindeer, and wolves. The cave lion tracks are notably the first to be discovered outside of an actual cave.~E257~
Price argued that scholars generally underestimated how long ago humanity first domesticated horses based on a
Bronze Age tracksite in Sweden.~E265~
Phylis Jackson argued that the pedal anatomy of
Anglo-Saxon and
Celtic peoples are so distinct that these populations can be distinguished based on feet alone going all the way back to the
Neolithic.~E268~ Celtic people have narrower feet while Anglo-Saxon feet are broader.~E269~
King and
Benton[disambiguation needed] disputed Thulborn's attribution of the Early Triassic Bunter Sandstone Coelurosaurichnus to a horsehoe crab because they didn't think the supposed tracks were tracefossils at all instead they interpreted the apparent tracks as sedimentary structures of geological rather than biological origin. They referred Sarjeant's supposed Otozoum and Swinertonichnus to Chirotherium.[61]
Bill Sarjeant reclassified the supposed Early Triassic dinosaur fossils he reported from England in 1970. He originally reported the presence of two Coelurosaurichnus species. However he had since concluded that one of these Coelurosaurichnus species was actually referable to the ichnogenus Batrachopus and the other to Plectoperna.[61] He reclassified his supposed Otozoum specimens as Paratetrasauropus and attributed Swinertonichnus to crocodilians.[98]
Lockley and others reported the presence of the ichnogenera Pseudotetrasauropus and Tetrasauropus among the dinosaur footprints reported from the Cardiff, Wales area by Tucker and Burchette in 1977. These tracks may have been left by a prosauropod.[73]
Brigitte Lange-Badre reported the first Late Jurassic sauropod footprints to have been discovered in France.[128]
Fuentes Vidarte reported the oldest known bird tracks in the world from the Berriasian Wealden Beds of the Villar del Rio, Spain. There were more than 250 individual prints at the track site and Fuentes Vidarte named the new ichnogenus and species Archaeornithopus meijidei for them.[109]
Fabio Dalla Vecchia returned to Croatia and finished mapping the dinosaur footprints with Croatian geologist
Igor Vlahovic.~E218~
Fabio Dalla Vecchia and Marco Rustioni reported a Miocene mammal tracksite in the
Conglomerato di Osoppo in
Udine Province, Italy. Across its 100 square meter area the track site preserved the footprints of three different kinds of large mammal.[51] Dalla Vecchia and Rustioni attributed these tracks to a large bovid,
Hipparion, and what may be a small rhinoceros.[129] The sediments preserving these tracks are coarser than those of most fossil track sites.[51]
The first international workshop on Paleozoic footprint fossils, presided over by Hartmut Haubold was held in Germany. The assembled scholars visited many significant German Paleozoic track sites and museum collections.[90] The symposium was such a success that it is regarded as a turning point in the history of Paleozoic vertebrate ichnology.[91]
Gierlinski reported the presence of possible small sauropod footprints in Early Jurassic rocks fromt the Holy Cross Mountains of Poland.~E122~
Avanzini,
van den Dreissche and
Keppens found that there were no ornithopod prints among the tracks preserved at Lavini de Marco in Italy and the only dinosaur groups to leave behind footprints there were the sauropods and theropods.[108] They concluded that the tracks were cemented through chemical processes trigger by the rapid evaporation of water from the carbonate track-bearing substrate and speculated that similar circumstances may have preserved tracks in carbonates at other sites and different positions in the stratigraphic column.[130]
Meyer reported that the Late Jurassic dinosaur tracks discovered near Lommiswil, Switzerland were actually part of a gigantic megatracksite. This was the first report of a dinosaur megatracksite in Europe.~E171~
Jean-Michel Mazin and others published further research on the pterosaur tracks of Crayssac, France.[126]
Wright and others re-examined the Purbeckopus pentadactylus tracks from Dorset, England and concluded that not only were they pterosaur tracks, but they were among the largest known pterosaur tracks in the fossil record.[53]
Joaquin Moratalla and
Jose Sanz found theropod tracks to compose 80% of the fossil footprints in Spain's Cameros Basin, with the remaining 20% consisting mostly of ornithopods (16%) and sauropods (4%).[131]
Casanovas and others reported that by this point in time 10 Early Cretaceous sauropod track sites had been discovered in La Rioja Province, Spain.[81]
Tuner and
Anton attributed Miocene cat footprints found at Salinas de Anana, Spain to the genus Pseudaelurus. These tracks may in fact be the oldest known cat footprints in the world.[116]
Yuong-Nam Lee erected the new ichnogenus Magnoavipes preserved in the
CenomanianWoodbine Formation of Texas. The trackmaker was aparently a waterbird of great size, with slender-toed feet 19–21 cm long.~NA212~
Phylis Jackson published further research on the use of pedal anatomy and footprints to distinguish different groups of people.~E268~
Sarjeant, Delair, and Lockley named the ichnogenus Iguanodontipus for some English dinosaur tracks probably made by Iguanodon.
Lockley, dos Santos, and Hunt found the purported hypsilophodont tracks of the Spanish Valdavajes tracksite similar to the Late Jurassic ichnogenus Dinehichnus that has been attributed to
dryosaurids.[89]
Lopez-Martinez and others noted the presence of sauropod and ornithopod tracks near the
K-T Boundary in the
Tremp Formation of northeastern Spain. The presence of tracks so close to the Cretaceous-Tertiary suggests that the dinosaur died out rapidly rather than gradually.~E239~