Nichollsemys

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
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 from Alberta [Alberta]], Canada, were discovered in 1997 by Ron Baier^[3] while prospecting near Chin Lake. Baier, who grew up in southeastern Alberta, contacted the Royal Terrell Museum which then performed a CT scan and identified it as the skull of a marine turtle dating to the Cretaceous Period and the first of its kind found. The fossils have been described by Donald Brinkman who named it in 2006.^[4] The fossils found so far 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.^[5] The species name of baieri is in honor of Baier, who found the first fossil.

Evolution

†Toxochelys

†Corsochelys

†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.^[6] The cranium has many things in common with that of Toxochelys: for example, they both have a rostrum basisphenoidale shaped like a rod.

Nichollsemys Baieri front view Photo taken at Royal Tyrrell Museum (4 May 2025 Susan Gerbic)
Nichollsemys Baieri side view Photo taken at Royal Tyrrell Museum (4 May 2025 Susan Gerbic)
Display for Nichollsemys Baieri Photo taken at Royal Tyrrell Museum (4 May 2025 Susan Gerbic)

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)
^ Rob, Baier. "Stories of discovery: life under the sea". RETROactive Eploring Alberta's Past. Historic Resources Management Branch of Alberta Arts, Culture and Status of Women. Retrieved 11 May 2025.
^ 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

[1] Brinkman, D. (2006), A primitive chelonioid turtle from the late Campanian of North America

[2] Global Biodiversity Information Facility, 2019: Nichollsemys (Brinkman, Hart, Jamniczky & Colbert, 2006)

[3] Rob, Baier. "Stories of discovery: life under the sea". RETROactive Eploring Alberta's Past. Historic Resources Management Branch of Alberta Arts, Culture and Status of Women. Retrieved 11 May 2025.

[4] Fossilworks, 2013: Nichollsemys (Behrensmeyer, A. K., and Turner, A.)

[5] Paleofile: Nichollsemys. Accessed 16 June 2020

[6] Brinkman, Donald B, et al.: "Measurements of the Skull of Nichollsemys Baieri." Research Gate, Sept. 2006

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