Axestemys

Extinct genus of turtles

Axestemys Temporal range: Campanian–Bridgerian PreꞒ Ꞓ O S D C P T J K Pg N

Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Family:	Trionychidae
Subfamily:	Trionychinae
Genus:	†Axestemys Hay, 1899
Species
†A. byssina (Cope, 1872) †A. cerevisia Vitek, 2012 †A. montinsana Vitek, 2012 †A. quinni (Schmidt, 1945) †A. splendida (Hay, 1908) †A. vittata (Pomel, 1847) †A. infernalis (Joyce, Brinkman & Lyson, 2019)
Synonyms
Axestus Cope, 1872 Conchochelys Hay, 1905 Eurycephalochelys Moody & Walker, 1970 Paleotrionyx Schmidt, 1945

Axestemys is an extinct genus of softshell turtle that lived from the Late Cretaceous to the Eocene in western North America and Europe.

Axestemys, like its modern relatives, had no scutes on its carapace, which probably had leathery, pliable skin at the sides. Despite living several million years ago, Axestemys would have looked very similar to its modern relatives, with a long neck, a sharp beak, and three toes on each foot.^[1] All species of Axestemys grew to a large size, especially A. byssina, that could reach a total length of 2 metres (79 in) or more, being larger than any modern day species of softshell turtle.^[2] Based on the diet of modern softshell turtles, it was an omnivore, eating water plants, invertebrates, and perhaps small fish.^[1]

A specimen of A. splendida was identified when a study by Victoria Megan Arbour et al. proposed that the presumed Dakotaraptor furculae in fact represented a part of a turtle’s armor, the entoplastron of Axestemys splendida, a member of Trionychidae.^[3] In 2016, DePalma et al. recognized that none of the referred furculae actually belonged to Dakotaraptor and excluded them from its hypodigm.^[4]

References

^ ^a ^b Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 69. ISBN 1-84028-152-9.
^ Grande, Lance (14 June 2013). The Lost World of Fossil Lake: Snapshots from Deep Time. p. 200. ISBN 9780226922966.
^ Arbour, V.M.; Zanno, L.E.; Larson, D.W.; Evans, D.C.; Sues, H. (2015). "The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra". PeerJ. 3: e1957. doi:10.7717/peerj.1691. PMC 4756751. PMID 26893972.
^ DePalma, R.A.; Burnham, D.A.; Martin, L.D.; Larson, P.L.; Bakker, R.T. (2016). "Corrigendum to: The First Giant Raptor (Theropoda: Dromaeosauridae) from the Hell Creek Formation". Paleontological Contributions. 16. doi:10.17161/1808.22120.

Natasha S. Vitek (2012). "Giant fossil soft-shelled turtles of North America". Palaeontologia Electronica. 15 (16): 1–43. doi:10.26879/299.
Walter G. Joyce, Donald B. Brinkman and Tyler R. Lyson (2019). "A new species of trionychid turtle, Axestemys infernalis sp. nov., from the Late Cretaceous (Maastrichtian) Hell Creek and Lance formations of the Northern Great Plains, USA". Palaeontologia Electronica. 33 (3): 1–28. doi:10.26879/949.

Trionychidae family

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Testudines
Superfamily: Trionychia

Genera

Species of the Trionychidae family

Amyda

Asiatic softshell turtle
†Amyda gregaria
Amyda ornata

Apalone

†Axestemys

†Axestemys byssina
†Axestemys cerevisia
†Axestemys montinsana
†Axestemys quinni
†Axestemys splendida
†Axestemys vittata

Chitra

Cyclanorbis

Cycloderma

Dogania

Malayan softshell turtle

†Gilmoremys

†Gilmoremys gettyspherensis
†Gilmoremys lancensis

†Hutchemys

†Hutchemys arctochelys
†Hutchemys rememdium
†Hutchemys tetanetron
†Hutchemys sterea
†Hutchemys acupictus

†Khunnuchelys

†Khunnuchelys erinhotensis
†Khunnuchelys kizylkumensis
†Khunnuchelys lophorhothon

Lissemys

Nilssonia

†Palaeoamyda

†Palaeoamyda messeliana

Palea

Wattle-necked softshell turtle

Pelochelys

Pelodiscus

Rafetus

Trionyx

Phylogenetic arrangement of turtles based on turtles of the world 2017 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status. †=extinct.

Testudines

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

Suborder

Superfamily

Family

Genus

Cryptodira

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
Axestemys	Wikidata: Q16530309 Wikispecies: Axestemys EoL: 4519336 GBIF: 4965204 Open Tree of Life: 3606189 Paleobiology Database: 67300 Plazi: 7B6F87DE-9A08-FF81-FF2E-FBC2FCF9FB03
Palaeotrionyx	Wikidata: Q1639002 GBIF: 4965202