Coloradisaurus | |
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![]() | |
Diagram showing known skull elements; shaded parts represent missing bones | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Family: | † Massospondylidae |
Genus: | †
Coloradisaurus Galton, 1990 [2] [3] |
Type species | |
†Coloradisaurus brevis | |
Synonyms | |
|
Coloradisaurus (meaning "Los Colorados lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period ( Norian stage) in what is now La Rioja Province, Argentina. It is known from two specimens collected from the Los Colorados Formation of the Ischigualasto-Villa Unión Basin.
Coloradisaurus brevis was originally named Coloradia brevis by José Bonaparte in 1978, [4] but that genus name was preoccupied by the pine moth Coloradia, [5] so it needed a replacement name. In 1983, David Lambert used the name Coloradisaurus for the genus, but did not indicate it was a replacement or diagnose it. [6] Lambert had gotten the name from Bonaparte in a personal communication and mistakenly thought that Bonaparte had already published it. [3] Peter Galton was the next to use the name Coloradisaurus in 1990, which he credited to Lambert, when he gave the taxon a diagnosis in his review of prosauropods in The Dinosauria. [2] [3] Authorship of Coloradisaurus has traditionally been attributed to Lambert, but in 2020, Greenfield et al. judged Lambert's use of the name to be a nomen nudum. They concluded that authorship should be attributed to Galton, who was the first to use the name Coloradisaurus in a way that met the requirements of the ICZN. [3]
The holotype of Coloradisaurus (PVL 3967) is a mostly complete skull found associated with an undescribed partial skeleton. [4] While the right side of the skull is well-preserved with almost all bones intact, the left side is distorted and missing more bones. [7] The holotype individual has been estimated to have been 3 m (10 ft) long with a mass of 70 kg (150 lb). [8] A referred specimen (PVL 5904) is a partial skeleton including most of the dorsal vertebrae and parts of the pectoral and pelvic girdles and limbs. [9] Like Lufengosaurus, it have the angle between the pterygoid and quadratojugal rami nearly 90°. There is also a possibility that the postorbital bones of Coloradisaurus and Sarahsaurus are similar, but due to the deformation of the skull this is difficult to say. [10]
All material of Coloradisaurus was discovered in 1971 at the La Esquina locality in the upper section of the Los Colorados Formation near Pagancillo, La Rioja Province, Argentina. [4] [7] [9] The top of the Los Colorados Formation has been dated to 213 Ma, [1] which would place Coloradisaurus in the Norian stage of the Late Triassic.
Coloradisaurus was classified as a plateosaurid in the original description by Bonaparte, [4] but this pre-dated the use of phylogenetic analyses in paleontology. He later became opposed to cladistics [11] and continued to consider Coloradisaurus a plateosaurid without testing its phylogenetic position. [12] The analyses of Galton (1990), Galton & Upchurch (2004), and Upchurch et al. (2007) found it to be a plateosaurid, supporting Bonaparte's placement. [2] [13] [14] However, the analyses of Benton et al. (2000) and Yates (2003) recovered it in a polytomy with other basal sauropodomorphs or as a massospondylid, respectively. [15] [16] Subsequent analyses such as Yates et al. (2010), Apaldetti et al. (2013; 2014), Wang et al. (2017), and Müller (2020) have reached the consensus that Coloradisaurus is a massospondylid most closely related to Lufengosaurus and Glacialisaurus. [7] [9] [17] [18] [10] [19] These three taxa share four synapomorphies found in the metatarsals and femur. [9]
Below is a simplified cladogram after Galton & Upchurch (2004), reflecting its early placement as a plateosaurid. [13]
Below is a simplified cladogram after Müller (2020), showing its current position as a massospondylid. [19]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
Coloradisaurus | |
---|---|
![]() | |
Diagram showing known skull elements; shaded parts represent missing bones | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Family: | † Massospondylidae |
Genus: | †
Coloradisaurus Galton, 1990 [2] [3] |
Type species | |
†Coloradisaurus brevis | |
Synonyms | |
|
Coloradisaurus (meaning "Los Colorados lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period ( Norian stage) in what is now La Rioja Province, Argentina. It is known from two specimens collected from the Los Colorados Formation of the Ischigualasto-Villa Unión Basin.
Coloradisaurus brevis was originally named Coloradia brevis by José Bonaparte in 1978, [4] but that genus name was preoccupied by the pine moth Coloradia, [5] so it needed a replacement name. In 1983, David Lambert used the name Coloradisaurus for the genus, but did not indicate it was a replacement or diagnose it. [6] Lambert had gotten the name from Bonaparte in a personal communication and mistakenly thought that Bonaparte had already published it. [3] Peter Galton was the next to use the name Coloradisaurus in 1990, which he credited to Lambert, when he gave the taxon a diagnosis in his review of prosauropods in The Dinosauria. [2] [3] Authorship of Coloradisaurus has traditionally been attributed to Lambert, but in 2020, Greenfield et al. judged Lambert's use of the name to be a nomen nudum. They concluded that authorship should be attributed to Galton, who was the first to use the name Coloradisaurus in a way that met the requirements of the ICZN. [3]
The holotype of Coloradisaurus (PVL 3967) is a mostly complete skull found associated with an undescribed partial skeleton. [4] While the right side of the skull is well-preserved with almost all bones intact, the left side is distorted and missing more bones. [7] The holotype individual has been estimated to have been 3 m (10 ft) long with a mass of 70 kg (150 lb). [8] A referred specimen (PVL 5904) is a partial skeleton including most of the dorsal vertebrae and parts of the pectoral and pelvic girdles and limbs. [9] Like Lufengosaurus, it have the angle between the pterygoid and quadratojugal rami nearly 90°. There is also a possibility that the postorbital bones of Coloradisaurus and Sarahsaurus are similar, but due to the deformation of the skull this is difficult to say. [10]
All material of Coloradisaurus was discovered in 1971 at the La Esquina locality in the upper section of the Los Colorados Formation near Pagancillo, La Rioja Province, Argentina. [4] [7] [9] The top of the Los Colorados Formation has been dated to 213 Ma, [1] which would place Coloradisaurus in the Norian stage of the Late Triassic.
Coloradisaurus was classified as a plateosaurid in the original description by Bonaparte, [4] but this pre-dated the use of phylogenetic analyses in paleontology. He later became opposed to cladistics [11] and continued to consider Coloradisaurus a plateosaurid without testing its phylogenetic position. [12] The analyses of Galton (1990), Galton & Upchurch (2004), and Upchurch et al. (2007) found it to be a plateosaurid, supporting Bonaparte's placement. [2] [13] [14] However, the analyses of Benton et al. (2000) and Yates (2003) recovered it in a polytomy with other basal sauropodomorphs or as a massospondylid, respectively. [15] [16] Subsequent analyses such as Yates et al. (2010), Apaldetti et al. (2013; 2014), Wang et al. (2017), and Müller (2020) have reached the consensus that Coloradisaurus is a massospondylid most closely related to Lufengosaurus and Glacialisaurus. [7] [9] [17] [18] [10] [19] These three taxa share four synapomorphies found in the metatarsals and femur. [9]
Below is a simplified cladogram after Galton & Upchurch (2004), reflecting its early placement as a plateosaurid. [13]
Below is a simplified cladogram after Müller (2020), showing its current position as a massospondylid. [19]
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)