Helochelydridae Temporal range:
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Helochelydra nopcsai skull | |
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Shell of Naomichelys | |
Scientific classification
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Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Pantestudines |
Clade: | Testudinata |
Clade: | Perichelydia |
Family: | †
Helochelydridae Nopsca, 1928 |
Genera | |
See text | |
Synonyms [1] | |
Solemydidae Lapparent and Murelaga 1997 |
The Helochelydridae are an extinct family of stem-turtles known from fossils found in North America and Europe spanning the Early to Late Cretaceous. [1] [2]
The skull, shell and osteoderms of helochelydrids are covered in small, cylindrical protuberances, which are a distinctive characteristic of the group. [3] They are thought to be terrestrial, based on the presence of limb osteoderms (granicones) and bone histology. [4] Their skull morphology is dissimilar to that of extant tortoises, suggesting an omnivorous habit similar to that of box turtles. [5]
Helochelydridae includes all turtles that are more closely related to Helochelydra than Sichuanchelys, Meiolania, or extant turtles. [6] Although referred to as Solemydidae in recent literature on extinct turtles, Helochelydridae has priority over Solemydidae. They are placed as part of the clade Perichelydia. [7] Some recent studies have recovered them as paracryptodires, [8] [9] though other studies have found them to be more basal than paracryptodires. [10] [11]
Indeterminate remains most similar to “Helochelydra” anglica and “Helochelydra” bakewelli have been reported from the Berriasian aged Angeac-Charente bonebed of France. [14]
Helochelydridae Temporal range:
| |
---|---|
![]() | |
Helochelydra nopcsai skull | |
![]() | |
Shell of Naomichelys | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Pantestudines |
Clade: | Testudinata |
Clade: | Perichelydia |
Family: | †
Helochelydridae Nopsca, 1928 |
Genera | |
See text | |
Synonyms [1] | |
Solemydidae Lapparent and Murelaga 1997 |
The Helochelydridae are an extinct family of stem-turtles known from fossils found in North America and Europe spanning the Early to Late Cretaceous. [1] [2]
The skull, shell and osteoderms of helochelydrids are covered in small, cylindrical protuberances, which are a distinctive characteristic of the group. [3] They are thought to be terrestrial, based on the presence of limb osteoderms (granicones) and bone histology. [4] Their skull morphology is dissimilar to that of extant tortoises, suggesting an omnivorous habit similar to that of box turtles. [5]
Helochelydridae includes all turtles that are more closely related to Helochelydra than Sichuanchelys, Meiolania, or extant turtles. [6] Although referred to as Solemydidae in recent literature on extinct turtles, Helochelydridae has priority over Solemydidae. They are placed as part of the clade Perichelydia. [7] Some recent studies have recovered them as paracryptodires, [8] [9] though other studies have found them to be more basal than paracryptodires. [10] [11]
Indeterminate remains most similar to “Helochelydra” anglica and “Helochelydra” bakewelli have been reported from the Berriasian aged Angeac-Charente bonebed of France. [14]