Podocnemididae Temporal range: Late Cretaceous to present, 84.9–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N

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
Erymnochelys Peltocephalus Podocnemis 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]

Taxonomy and systematics

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:

Podocnemidae (Baur, 1893) is an alternate but less commonly-used name for the same biological group as family Podocnemididae (Cope, 1868).^[5]
Epifamily Podocnemidinura: The family Podocnemididae has two sister families (Hamadachelys and Brasilemys); the relationship of these three families is sometimes recognized by grouping them as the epifamily Podocnemidinura.^[6]
Superfamily Podocnemidoidea: At a higher level yet, the epifamily Podocnemidinura is grouped with the family Bothremydidae to form the superfamily Podocnemidoidea.^[6]
Podocnemidinae: An earlier classification, rejected by Gaffney, treated Podocnemididae as a subfamily (Podocnemidinae) within the closely related family Pelomedusidae.^[7])

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:

Erymnochelys – Madagascan big-headed turtle
Peltocephalus
- Peltocephalus dumerilianus – Big-headed Amazon River turtle
- †Peltocephalus maturin^[9]
Podocnemis – South American side-necked river turtles

Taxonomy

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:

Stem group taxa (Podocnemidoidae)
- †Brasilemys^[15] Romualdo Formation, Brazil, Early Cretaceous (Albian)
- †Amabilis^[16] São José do Rio Preto Formation, Brazil, Late Cretaceous (Santonian)
- †Hamadachelys Kem Kem Group, Morocco, Late Cretaceous (Cenomanian)
- †Portezueloemys Portezuelo Formation, Argentina, Late Cretaceous (Turonian)
- †Cambaremys Marília Formation, Brazil, Late Cretaceous (Maastrichtian)
- †Bauruemys Presidente Prudente Formation, Brazil, Late Cretaceous (Campanian)
- †Roxochelys Adamantina Formation, Brazil, Campanian
- Family †Peiropemydidae
  - †Peiropemys Marília Formation, Brazil, Maastrichtian
  - †Pricemys Marília Formation, Brazil, Maastrichtian
  - †Lapparentemys Santa Lucía Formation, Bolivia, Paleocene
  - †Yuraramirim^[17] Adamantina Formation, Brazil, Campanian
- Family Podocnemididae (crown group)
- †Caninemys Northern South America, Miocene
  - Subfamily Podocnemidinae
    - †Cerrejonemys Cerrejón Formation, Colombia, Paleocene
    - Podocnemis South America, Miocene-Recent
  - Subfamily Erymnochelyinae
    - †Gestemys Geste Formation, Argentina, Eocene
    - †Stupendemys^[8] Northern South America, Miocene
    - †Carbonemys Cerrejón Formation, Colombia, Paleocene
    - Peltocephalus Northern South America, Late Pleistocene-Recent
    - †Ragechelus^[18] Farin-Doutchi Formation, Niger, Maastrichtian
    - Erymnochelyini (formerly the "Erymnochelys group")
      - †Apeshemys^[19] (formerly "Podocnemis" aegyptiaca) Egypt, Early Miocene
      - †Eocenochelus Eocene, Europe
      - Erymnochelys Madagascar, Recent
      - †Shetwemys^[19] (formerly "Podocnemis" fajumensis) Jebel Qatrani Formation, Egypt, Oligocene Shumaysi Formation, Saudi Arabia, Oligocene
      - †Turkanemys Kenya, Miocene-Pliocene
      - †Kenyemys Kenya, Miocene-Pliocene
      - †Mokelemys Democratic Republic of the Congo, Pliocene
    - Stereogenyina
      - †Stereogenys cromeri Qasr el Sagha Formation, Egypt, Late Eocene
      - †Andrewsemys^[20] (formerly "Stereogenys" libyca) Egypt, Late Eocene-Early Oligocene
      - †Cordichelys Egypt, Late Eocene
      - †Lemurchelys Moghara Formation, Egypt, Early Miocene
      - †"Podocnemis" bramlyi Moghara Formation, Egypt, Early Miocene
      - †Latentemys Egypt, Miocene
      - †Bairdemys Late Oligocene-Miocene, Americas
      - †Brontochelys Bugti Hills, Pakistan Early Miocene
      - †Shweboemys Pliocene-Pleistocene, Myanmar
      - †Piramys^[21] India, Late Miocene
    - Incertae sedis
      - †Neochelys Eocene, Europe
      - †"Stereogenys" podocnemoides Qasr el Sagha Formation, Egypt, Late Eocene
      - †Dacquemys Birket Qarun Formation, Egypt, Late Eocene, Jebel Qatrani Formation, Egypt, Early Oligocene
      - †Albertwoodemys Jebel Qatrani Formation, Egypt, Oligocene
      - †Mogharemys Moghara Formation, Egypt, Early Miocene

Morphology based cladogram after Ferreira et al. 2024^[22]

Podocnemididae

Podocnemidinae

	†Cerrejonemys

	Podocnemis

Erymnochelyinae

†Caninemys

†Neochelys arenarum

†Neochelys franzeni

	†Turkanemys

	Erymnochelys

†Neochelys fajumensis

†Papoulemys

	†Kenyemys

	†Carbonemys

	†Dacquemys

	†UCMP 42008

	Peltocephalus dumerilianus

	†Peltocephalus maturin

†Stupendemys

Stereogenyini

†Mogharemys

†Cordichelys

†Latentemys

†Bairdemys healeyorum

†Brontochelys

†Lemurchelys

	†Piramys

	†Stereogenys

	†Shweboemys

†Bairdemys spp.

References

External links

Side-necked turtle species

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Testudines
Suborder: Pleurodira

Acanthochelys

	Acanthochelys macrocephala Acanthochelys pallidipectoris Acanthochelys radiolata Acanthochelys spixii

Chelus

	Chelus fimbriata

Mesoclemmys

	Mesoclemmys dahli Mesoclemmys gibba Mesoclemmys jurutiensis Mesoclemmys nasuta Mesoclemmys perplexa Mesoclemmys raniceps Mesoclemmys sabiniparaensis Mesoclemmys tuberculata Mesoclemmys vanderhaegei †Mesoclemmys vanegasorum Mesoclemmys zuliae

Phrynops

	Phrynops geoffroanus Phrynops hilarii †Phrynops paranaensis Phrynops tuberosus Phrynops williamsi

Platemys

	Platemys platycephala

Ranacephala

	Ranacephala hogei

Rhinemys

	Rhinemys rufipes

Chelodininae

Chelodina

Chelodina	Chelodina canni Chelodina gunaleni Chelodina longicollis Chelodina mccordi †Chelodina murrayi Chelodina novaeguineae Chelodina pritchardi Chelodina reimanni Chelodina steindachneri
Chelydera	†Chelodina alanrixi Chelodina burrungandjii Chelodina expansa Chelodina insculpta Chelodina kuchlingi Chelodina kurrichalpongo Chelodina parkeri Chelodina rugosa Chelodina walloyarrina
Macrochelodina	Chelodina oblonga

Elseya

Elseya	Elseya dentata Elseya branderhorsti Elseya flaviventralis
Pelocomastes	Elseya albagula Elseya irwini Elseya lavarackorum †Elseya nadibajagu †Elseya uberrima
Hanwarachelys	Elseya caelatus Elseya novaeguineae Elseya orestiad Elseya rhodini Elseya schultzei

Elusor

	Elusor macrurus

Emydura

	Emydura australis Emydura gunaleni Emydura macquarii Emydura subglobosa Emydura tanybaraga Emydura victoriae

Myuchelys

	Myuchelys belli Myuchelys georgesi Myuchelys latisternum Myuchelys purvisi

Rheodytes

	Rheodytes leukops †Rheodytes devisi

Hydromedusinae

Hydromedusa

	Hydromedusa maximiliani Hydromedusa tectifera

Pseudemydurinae

Pseudemydura

	Pseudemydura umbrina

Pelomedusidae

Pelomedusa

	Pelomedusa subrufa

Pelusios

	Pelusios adansonii Pelusios bechuanicus Pelusios broadleyi Pelusios carinatus Pelusios castaneus Pelusios castanoides Pelusios chapini Pelusios cupulatta Pelusios gabonensis Pelusios marani Pelusios nanus Pelusios niger Pelusios rhodesianus Pelusios sinuatus Pelusios subniger Pelusios upembae Pelusios williamsi

Podocnemididae

Erymnochelys

	Erymnochelys madagascariensis

Peltocephalus

	Peltocephalus dumerilianus

Podocnemis

	Podocnemis erythrocephala Podocnemis expansa Podocnemis lewyana Podocnemis sextuberculata Podocnemis unifilis Podocnemis vogli

Phylogenetic arrangement of turtles based on Turtles of the World 2021 Update: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status. Key: †=extinct.

Testudines

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Diapsida
Order: Testudines

Genus

Chelonioidea
(Sea turtles)

Cheloniidae	†Allopleuron Caretta †Carolinochelys Chelonia †Eochelone Eretmochelys †Gigantatypus †Glarichelys †Itilochelys Lepidochelys †Mexichelys †Miocaretta Natator †Pacifichelys †Syllomus †Tasbacka
Dermochelyidae	†Arabemys †Corsochelys †Cosmochelys Dermochelys †Eosphargis †Mesodermochelys †Psephophorus
	†Euclastes †Peritresius †Procolpochelys †Protosphargis †Puppigerus

Kinosternoidea

Dermatemydidae	Dermatemys
Kinosternidae	Claudius †Hoplochelys Kinosternon Staurotypus Sternotherus

Testudinoidea

Emydidae	†Acherontemys Chrysemys Clemmys Deirochelys Emys Actinemys Emydoidea Glyptemys Graptemys Malaclemys Pseudemys Terrapene Trachemys †Wilburemys
Geoemydidae	Batagur †Banhxeochelys Cuora Cyclemys Geoclemys Geoemyda Hardella Heosemys Leucocephalon Malayemys Mauremys Melanochelys Morenia Notochelys Orlitia Pangshura Rhinoclemmys Sacalia Siebenrockiella Vijayachelys
Platysternidae	Platysternon
Testudinidae	Aldabrachelys Astrochelys Centrochelys Chelonoidis Chersina Cylindraspis †Cymatholcus †Floridemys Geochelone Gopherus †Hadrianus †Hesperotestudo Homopus Indotestudo Kinixys Malacochersus Manouria †Megalochelys †Oligopherus Psammobates Pyxis †Solitudo Stigmochelys †Stylemys Testudo

Trionychia

Carettochelyidae	†Allaeochelys †Anosteira Carettochelys
Trionychidae	Amyda Apalone †Axestemys Chitra Cyclanorbis Cycloderma †Drazinderetes Dogania †Gilmoremys †Hutchemys †Khunnuchelys Lissemys Nilssonia Palea †Palaeoamyda Pelochelys Pelodiscus Rafetus Trionyx
	†Basilochelys †Sinaspideretes

Chelydridae	Chelydra †Chelydrops †Chelydropsis †Emarginachelys †Macrocephalochelys Macrochelys †Planiplastron †Protochelydra
†Nanhsiungchelyidae	†Anomalochelys †Basilemys †Jiangxichelys
†Protostegidae	†Alienochelys †Archelon †Atlantochelys †Bouliachelys †Calcarichelys †Cratochelone †Desmatochelys †Iserosaurus †Notochelone †Ocepechelon †Pneumatoarthrus †Protostega †Rhinochelys †Santanachelys †Terlinguachelys
	†Adocus †Argillochelys †Bashuchelys †Ctenochelys †Prionochelys †Toxochelys

Pleurodira

†Araripemydidae	†Araripemys
†Bothremydidae	†Araiochelys †Arenila †Azabbaremys †Bothremys †Cearachelys †Chedighaii †Chupacabrachelys †Eotaphrosphys †Foxemys †Galianemys †Ilatardia †Inaechelys †Itapecuruemys †Jainemys †Kinkonychelys †Kurmademys †Labrostochelys †Nigeremys †Phosphatochelys †Polysternon †Puentemys †Rosasia †Rhothonemys †Sankuchemys †Taphrosphys †Ummulisani †Zolhafah
Chelidae	Acanthochelys Chelodina Chelus Elseya Elusor Emydura Hydromedusa †Lomalatachelys Mesoclemmys Myuchelys Phrynops Platemys †Prochelidella Pseudemydura Rheodytes Rhinemys †Yaminuechelys
Pelomedusidae	Pelomedusa Pelusios
Podocnemididae	†Albertwoodemys †Bauruemys †Brontochelys †Caninemys †Carbonemys †Cerrejonemys †Cordichelys Erymnochelys †Lapparentemys †Latentemys Peltocephalus Podocnemis †Stupendemys
†Sahonachelyidae	†Sahonachelys †Sokatra

	†Caribemys †Caririemys †Tacuarembemys

Phylogenetic arrangement of turtles based on Turtles of the World 2017 Update: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status. † = extinct.

See also List of Testudines families

Taxon identifiers

Taxon identifiers
Podocnemididae	Wikidata: Q133885 Wikispecies: Podocnemididae BOLD: 171533 CoL: 627HH EoL: 8131 Fossilworks: 58161 GBIF: 5721 iNaturalist: 40142 IRMNG: 105532 ITIS: 948954 NCBI: 329146 Open Tree of Life: 540331 WoRMS: 1339074

Authority control databases: National