Nichollsemys Temporal range: Late Cretaceous 84.9–70.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N

Skull, Royal Tyrrell Museum in Alberta, Canada
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Superfamily:	Chelonioidea
Genus:	†Nichollsemys Brinkman, 2006^[1]
Species
†N. baieri (Brinkman, 2006)

Nichollsemys is a genus of extinct sea turtles. The only known species is Nichollsemys baieri.^[2]

Taxonomy

Fossils of the Nichollsemys have been found in Alberta, Canada, by Donald Brinkman.^[3] The fossils found are all skulls.

The name of Nichollsemys is a tribute to Elizabeth Nicholls, a paleontologist from Canada who studied marine reptiles from the Triassic period. She had previously done work with Brinkman when they found the ichthyosaur genus Parvinatator.^[4]

Evolution

Panchelonioidea

†Toxochelys

†Protostegidae

Chelonioidea

†Corsochelys

Dermochelyidae

†Nichollsemys

†Allopleuron

Cheloniidae

†Argillochelys

†Procolpochelys

	†Eochelone

	†Puppigerus

	†Ctenochelys

	†Peritresius

	†Cabindachelys

Description

The full length of the Nichollsemys is unknown, but Brinkman made a chart of the length of some parts of the specimen. The length from the basioccipital to the premaxilla measures 11.4 cm, the width of all the quadrates measures 9.8 cm, the depth at level of the quadrates measures 7.1 cm, the intraorbital width measures 2 cm, and the length measures 3.6 cm.^[5] The cranium has many things in common with that of Toxochelys: for example, they both have a rostrum basisphenoidale shaped like a rod.

References

^ Brinkman, D. (2006), A primitive chelonioid turtle from the late Campanian of North America
^ Global Biodiversity Information Facility, 2019: Nichollsemys (Brinkman, Hart, Jamniczky & Colbert, 2006)
^ Fossilworks, 2013: Nichollsemys (Behrensmeyer, A. K., and Turner, A.)
^ Paleofile: Nichollsemys. Accessed 16 June 2020
^ Brinkman, Donald B, et al.: "Measurements of the Skull of Nichollsemys Baieri." Research Gate, Sept. 2006

Cheloniidae family

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Subclass: Anapsida
Order: Testudines
Suborder: Cryptodira
Superfamily: Sea turtles
Family: Cheloniidae

Genera

Species of the Cheloniidae family

†Allopleuron

†Allopleuron hofmanni

†Argillochelys

†Argillochelys africana

Caretta

Loggerhead sea turtle

†Carolinochelys

†Carolinochelys wilsoni

Chelonia

Green sea turtle

†Eochelone

†Eochelone brabantica
†Eochelone voltregana

Eretmochelys

Hawksbill sea turtle

†Gigantatypus

†Gigantatypus salahi

†Glarichelys

†Glarichelys knorri

†Itilochelys

†Itilochelys rasstrigin

Lepidochelys

Kemp's ridley sea turtle
Olive ridley sea turtle
†Lepidochelys waikatoica

†Mexichelys

†Mexichelys coahuilaensis

†Miocaretta

†Miocaretta lankae

Natator

Flatback sea turtle

†Pacifichelys

†Pacifichelys hutchisoni
†Pacifichelys urbinai

†Syllomus

†Syllomus aegyptiacus
†Syllomus crispatus

†Tasbacka

†Tasbacka aldabergeni
†Tasbacka danica
†Tasbacka ouledabdounensis
†Tasbacka ruhoffi
†Tasbacka salisburgensis

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

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