Podocnemididae Temporal range:
Late Cretaceous to present,
| |
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Yellow-spotted river turtle (Podocnemis unifilis) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Pleurodira |
Clade: | Podocnemidoidae |
Family: |
Podocnemididae Cope, 1868 [1] |
Extant genera | |
For fossil genera see text | |
Synonyms | |
Podocnemidinae |
Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant (P. dumerilianus, the Big-headed Amazon River turtle); and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.
Like other pleurodire turtles, podocs have a "side-necked" defensive posture, turning the head sideways to hide it under the shell. Another characteristic of pleurodires is that the pelvis is fused to the shell which prevents pelvic motion, making it difficult to walk on land. [2] [3] Podocnemididae turtles live in aquatic environments and have shells streamlined to aid in swimming. [4]
According to Ferreira et al. (2015), the family name derives from two Greek words: "podos" (foot) and "cnemis" (leg armor worn by Roman soldiers.) [5]
To clarify some closely related names:
According to Gaffney et al. (2011), the family Podocnemididae can be diagnosed from its cranial traits including "the unique possession of a cavum pterygoidei formed by the basisphenoid, pterygoid, prootic, and quadrate [bones], underlain by the pterygoid and basisphenoid." [8]
The pocnemid family dates to the late Cretaceous; it includes 20 genera and 30 species. Only three genera (and eight species) survive. [8]
The three living genera of Podocnemididae (one of which is monotypic) are:
Fossils show that Podocnemidids were once found in Europe, Asia, North America, and Africa. Stupendemys lived around 5.5 million years ago in northern South America, and was the largest freshwater turtle with a carapace length of 2.4 metres (7.9 ft), the largest of any known turtle and is the largest pleurodire known. [10] While Peltocephalus and Erymnochelys have often been recovered as more closely related to each other than to Podocnemis in morphological analyses, [11] [12] [9] genetic studies have found Erymochelys to be more closely related to Podocnemis than to Peltocephalus. [13] [14]
Genera:
Morphology based cladogram after Ferreira et al. 2024 [22]
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Three phalanges on most digits; Zygomatic arch; no parieto-mastoid .. Podocnemididae. Temporal fossa overroofed by parietal.. Podocnemis.
The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily Podocnemidinura is the sister group to the family Bothremydidae, and together they form the superfamily Podocnemidoidea.
The family Podocnemididae consists of 20 genera and 30 species considered here as valid and diagnosable by cranial characters. Three of these genera and eight species persist into the Recent fauna, barely reflecting the evolutionary diversity and distribution of the group. The family extends from the late Cretaceous to the Recent and occurs in North and South America, Europe, Asia, and Africa.
In the Podocnemidoidea, Brasilemys n.g. represents the earliest known specimen of the Podocnemidoidae, immediately after the divergence of the Bothremydidae. It is part of the formidable radiation in the Pelomedusoides which occurs during the early Cretaceous when South America separated from Africa.
Podocnemididae Temporal range:
Late Cretaceous to present,
| |
---|---|
Yellow-spotted river turtle (Podocnemis unifilis) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Pleurodira |
Clade: | Podocnemidoidae |
Family: |
Podocnemididae Cope, 1868 [1] |
Extant genera | |
For fossil genera see text | |
Synonyms | |
Podocnemidinae |
Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant (P. dumerilianus, the Big-headed Amazon River turtle); and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.
Like other pleurodire turtles, podocs have a "side-necked" defensive posture, turning the head sideways to hide it under the shell. Another characteristic of pleurodires is that the pelvis is fused to the shell which prevents pelvic motion, making it difficult to walk on land. [2] [3] Podocnemididae turtles live in aquatic environments and have shells streamlined to aid in swimming. [4]
According to Ferreira et al. (2015), the family name derives from two Greek words: "podos" (foot) and "cnemis" (leg armor worn by Roman soldiers.) [5]
To clarify some closely related names:
According to Gaffney et al. (2011), the family Podocnemididae can be diagnosed from its cranial traits including "the unique possession of a cavum pterygoidei formed by the basisphenoid, pterygoid, prootic, and quadrate [bones], underlain by the pterygoid and basisphenoid." [8]
The pocnemid family dates to the late Cretaceous; it includes 20 genera and 30 species. Only three genera (and eight species) survive. [8]
The three living genera of Podocnemididae (one of which is monotypic) are:
Fossils show that Podocnemidids were once found in Europe, Asia, North America, and Africa. Stupendemys lived around 5.5 million years ago in northern South America, and was the largest freshwater turtle with a carapace length of 2.4 metres (7.9 ft), the largest of any known turtle and is the largest pleurodire known. [10] While Peltocephalus and Erymnochelys have often been recovered as more closely related to each other than to Podocnemis in morphological analyses, [11] [12] [9] genetic studies have found Erymochelys to be more closely related to Podocnemis than to Peltocephalus. [13] [14]
Genera:
Morphology based cladogram after Ferreira et al. 2024 [22]
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Three phalanges on most digits; Zygomatic arch; no parieto-mastoid .. Podocnemididae. Temporal fossa overroofed by parietal.. Podocnemis.
The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily Podocnemidinura is the sister group to the family Bothremydidae, and together they form the superfamily Podocnemidoidea.
The family Podocnemididae consists of 20 genera and 30 species considered here as valid and diagnosable by cranial characters. Three of these genera and eight species persist into the Recent fauna, barely reflecting the evolutionary diversity and distribution of the group. The family extends from the late Cretaceous to the Recent and occurs in North and South America, Europe, Asia, and Africa.
In the Podocnemidoidea, Brasilemys n.g. represents the earliest known specimen of the Podocnemidoidae, immediately after the divergence of the Bothremydidae. It is part of the formidable radiation in the Pelomedusoides which occurs during the early Cretaceous when South America separated from Africa.