Pleurodira Temporal range: Late Jurassic to present 163–present Ma PreꞒ Ꞓ O S D C P T J K Pg N

Eastern long-necked turtle Chelodina longicollis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Clade:	Pan-Pleurodira
Suborder:	Pleurodira Cope, 1865^[1]
Synonyms^[2]
Pleuroderes - Duméril and Bibron 1834:354^[3] Pleurodera - Lichtenstein 1856:2^[4] Pleurodera - Cope 1864:181^[5] Pleurodira - Cope 1865:186^[1]

The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. The division between these two suborders represents a very deep evolutionary divide between two very different types of turtles. The physical differences between them, although anatomical and largely internal, are nonetheless significant, and the zoogeographic implications of them are substantial. The Pleurodira are known more commonly as the side-necked turtles and the name Pleurodira quite literally translates to side neck, whereas the Cryptodira are known as hidden-necked turtles.^[6] The Pleurodira turtles are currently restricted to freshwater habitats in the Southern Hemisphere, largely to Australia, South America, and Africa. Within the Pleurodira, three living families are represented: Chelidae, also known as the Austro-South American side-necked turtles, the Pelomedusidae, also known as the African mud terrapins, and the Podocnemididae, also known as the American side-neck river turtles.^[6]^[7] However, they were cosmopolitan clade during the Cretaceous and most of the Cenozoic, and even occurred in marine environments around the world.^[8]^[9]

Definition and description

The Pleurodira are identified by the method with which they withdraw their heads into their shells. In these turtles, the neck is bent in the horizontal plane, drawing the head into a space in front of one of the front legs. A larger overhang of the carapace helps to protect the neck, which remains partially exposed after retraction. This differs from the method employed by a cryptodiran, which tucks its head and neck between its forelegs, within the shell.

The different methods of bending the neck require completely different anatomies of the cervical vertebrae. All extant turtles studied so far have eight vertebrae in the neck.^[10] In the Pleurodira, these vertebrae are narrow in cross-section and spool-shaped with biconvex centra on one or more of the cervicals.^[10] These centra act as a double joint, allowing a large degree of sideways movement and providing a means of folding the neck onto itself in the lateral plane. Conversely, in the Cryptodira, the neck bones are wide and flat. The biconvex centra in some of the cryptodiran cervicals allow the neck to fold onto itself in the vertical plane.^[10]

Pleurodirans also differ from cryptodirans in the emarginations of their skulls. Skull emargination provides room and anchorage for the jaw muscles. The connection points and the position of the emarginations relate to different bones of the skull.

Another difference is in the arrangement of the bones of the shell and the scutes overlaying them. Pleurodiran turtles have 13 scutes on the plastron of the shell, whereas cryptodiran turtles have only 12. The extra scute is called the intergular and is at the front of the plastron between the gular scutes. Pelomedusid turtles also possess mesoplastra, further differentiating this group.

Suction feeding

One of the three extant families in this suborder is the family Chelidae, which have a specially adapted strategy for catching prey. While the majority of the family Chelidae are omnivores there are 17 species that are carnivores;^[7] Chelus fimbriatus and species of the Chelodina genus.^[7] This special strategy is referred to as a gape-suck mechanism.^[7]^[11] The turtle first opens its mouth little by little. Then, when the turtle is within striking range of the prey, it will open its mouth completely sucking in water at such a rate that the current into its mouth is too strong for prey to escape and it engulfs the prey within 0.004 seconds.^[11] This strategy also circumvents issues to quick capture of underwater prey, such as resistance to rapid movement in water, pressure waves due to a rapid strike, and rapid water intake when feeding.^[11]

Taxonomy

^[12]^[13]^[14]

After Ferreria, et al. 2018.^[15]

Panpleurodira
- †Dortokidae (extinct) (Early Cretaceous-Paleocene)
- †Platychelyidae (extinct) (Late Jurassic-Early Cretaceous)
- Pleurodira
  - Chelidae
  - Pan-Pelomedusoides
    - †Araripemydidae (extinct) (Early Cretaceous)
    - †Euraxemydidae (extinct)
    - Pelomedusoides
      - Pelomedusidae
      - †Atolchelys (extinct) (Early Cretaceous)
      - †Francemys (extinct) (Early Cretaceous)
      - †Sahonachelyidae (extinct) (Late Cretaceous)
      - †Bothremydidae (extinct) (Early Cretaceous-Miocene)
      - Podocnemidoidae
        †Peiropemydidae (extinct)
        
        Podocnemididae

References

^ ^a ^b Cope, E. D. (1865). "Third Contribution to the Herpetology of Tropical America". Proceedings of the Academy of Natural Sciences of Philadelphia. 17 (4): 185–198. JSTOR 4624040.
^ Van Dijk, Peter Paul; Iverson, John; Shaffer, H. Bradley; Bour, Roger; Rhodin, Anders (2012). "Turtles of the World, 2012 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution, and Conservation Status". Conservation Biology of Freshwater Turtles and Tortoises. doi:10.3854/crm.5.000.checklist.v5.2012. ISBN 978-0965354097.
^ Duméril, C.; Baird, Spencer Fullerton; Bibron, Gabriel; Duméril, Auguste Henri André (1834). "Erpétologie générale, ou, Histoire naturelle complète des reptiles / Par A.M.C. Duméril et par G. Bibron". doi:10.5962/bhl.title.45973. ((cite journal)): Cite journal requires |journal= (help)
^ Lichtenstein, Heinrich. (1856). "Nomenclator reptilium et amphibiorum musei zoologici Berolinensis : Namenverzeichnis der in der zoologischen Sammlung der Koeniglichen Universität zu Berlin aufgestellten Arten von Reptilien und Amphibien nach ihren Ordnungen, Familien und Gattungen / (Mit Vorrede von H. Lichtenstein)". doi:10.5962/bhl.title.45245. ((cite journal)): Cite journal requires |journal= (help)
^ Cope, E. D. (1864). "On the Limits and Relations of the Raniformes". Proceedings of the Academy of Natural Sciences of Philadelphia. 16 (4): 181–183. JSTOR 4623931.
^ ^a ^b Pritchard, Peter Charles Howard; Trebbau, Pedro (1984). The Turtles of Venezuela. Society for the Study of Amphibians and Reptiles. p. 403. ISBN 9780916984113.
^ ^a ^b ^c ^d Vitt, L. and Caldwell, J. (2014). Herpetology: An Introductory Biology of Amphibians and Reptiles. Academic Press. pp. 523–543.((cite book)): CS1 maint: multiple names: authors list (link)
^ Gaffney, Eugene S.; Tong, Haiyan; Meylan, Peter A. (2006). "Evolution of the Side-Necked Turtles: The Families Bothremydidae, Euraxemydidae, and Araripemydidae" (PDF). Bulletin of the American Museum of Natural History. 300: 1–698. doi:10.1206/0003-0090(2006)300[1:EOTSTT]2.0.CO;2. ISSN 0003-0090. S2CID 85790134.
^ Pérez-García, Adán (2016). "A new turtle confirms the presence of Bothremydidae (Pleurodira) in the Cenozoic of Europe and expands the biostratigraphic range of Foxemydina". The Science of Nature. 103 (7–8): 50. Bibcode:2016SciNa.103...50P. doi:10.1007/s00114-016-1375-y. PMID 27262289. S2CID 15652309.
^ ^a ^b ^c Romer, Alfred (1956). Osteology of the Reptiles. Chicago: University of Chicago Press. p. 772.
^ ^a ^b ^c Lemell, P., Lemell, C., Snelderwaard, P., Gumpenberger, M., Wocheslander, R., and Weisgram, J. (2002). "Feeding patterns of Chelus fimbriatus (Pleurodira: Childae)". The Journal of Experimental Biology. 205 (Pt 10): 1495–1506. doi:10.1242/jeb.205.10.1495. PMID 11976360.((cite journal)): CS1 maint: multiple names: authors list (link)
^ "The Paleobiology Database". Paleodb.org. Retrieved 2012-09-24.
^ Joyce, Walter G.; Anquetin, Jérémy; Cadena, Edwin-Alberto; Claude, Julien; Danilov, Igor G.; Evers, Serjoscha W.; Ferreira, Gabriel S.; Gentry, Andrew D.; Georgalis, Georgios L.; Lyson, Tyler R.; Pérez-García, Adán (2021-02-09). "A nomenclature for fossil and living turtles using phylogenetically defined clade names". Swiss Journal of Palaeontology. 140 (1): 5. Bibcode:2021SwJP..140....5J. doi:10.1186/s13358-020-00211-x. hdl:11336/155192. ISSN 1664-2384.
^ Joyce, Walter G.; Rollot, Yann; Evers, Serjoscha W.; Lyson, Tyler R.; Rahantarisoa, Lydia J.; Krause, David W. (2021). "A new pelomedusoid turtle, Sahonachelys mailakavava, from the Late Cretaceous of Madagascar provides evidence for convergent evolution of specialized suction feeding among pleurodires". Royal Society Open Science. 8 (5): 210098. Bibcode:2021RSOS....810098J. doi:10.1098/rsos.210098. PMC 8097199. PMID 34035950.
^ Ferreira, Gabriel S.; Bronzati, Mario; Langer, Max C.; Sterli, Juliana (2018). "Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira)". Royal Society Open Science. 5 (3): 171773. Bibcode:2018RSOS....571773F. doi:10.1098/rsos.171773. PMC 5882704. PMID 29657780.

Wikispecies has information related to Pleurodira.

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

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.