PBDB Taxon

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Echmatemys

Osteichthyes - Testudines - Geoemydidae

Taxonomy

Echmatemys was named by Hay (1906). It is not extant. Its type is Emys septarius.

It was assigned to Emydidae by Hay (1906), Gilmore (1915), Hay (1930), Carroll (1988), Hutchison (1992); to Bataguridae by Hutchison (1996), Holroyd et al. (2001); to Ptychogasteridae by Hervet (2004); to Geoemydidae by Lichtig and Lucas (2015); and to Geoemydidae by Claude et al. (2012), Lichtig and Lucas (2015), Vlachos (2018), Vlachos (2020).

Species

E. arethusa, E. callopyge, E. cibollensis, E. depressa, E. haydeni, E. jeanesi, E. lativertebralis (syn. Emys shaughnessiana, Chrysemys inornata, E. hollandi, E. douglassi, E. rivalis, Graptemys cordifera), E. naomi (syn. E. obscura), E. stevensoniana (syn. E. aegle, Emys septarius, E. ocyrrhoe, E. cyane), E. wyomingensis (syn. E. uintensis), Palaeotheca polycypha, Palaeotheca terrestris

Synonyms

Echmatemys depressa was named by Gilmore (1915). Its type specimen is CM 2936, a partial shell, and it is not a trace fossil. Its type locality is East of Myton, which is in an Uintan terrestrial horizon in Utah.

It was considered a nomen dubium by Vlachos (2018).
Palaeotheca polycypha was named by Cope (1872). Its type specimen is USNM 4097 (holotype), a partial shell (two neurals and a peripheral), and it is a 3D body fossil. Its type locality is Cottonwood Creek badlands (Bridger B), which is in a Bridgerian terrestrial horizon in Wyoming. It is the type species of Palaeotheca.

It was recombined as Emys polycypha by Cope (1873), Cope (1884), Hay (1902); it was considered a nomen dubium by Vlachos (2018).
Palaeotheca terrestris was named by Cope (1872). Its type specimen is USNM 2107 (holotype), a partial shell (neural, costal, and epiplastron), and it is a 3D body fossil. Its type locality is Cottonwood Creek badlands (Bridger B), which is in a Bridgerian terrestrial horizon in Wyoming.

It was recombined as Emys terrestris by Cope (1873), Cope (1884), Hay (1902); it was considered a nomen dubium by Vlachos (2018).

Synonymy list

Year	Name and author
1872	Palaeotheca polycypha Cope p. 463
1872	Palaeotheca terrestris Cope p. 464
1873	Emys polycypha Cope
1873	Emys terrestris Cope
1884	Emys polycypha Cope
1884	Emys terrestris Cope
1902	Emys polycypha Hay p. 448
1902	Emys terrestris Hay p. 448
1906	Echmatemys Hay p. 27
1915	Echmatemys Gilmore p. 123
1915	Echmatemys depressa Gilmore p. 139 figs. 2; 16
1930	Echmatemys Hay p. 95
1930	Echmatemys depressa Hay p. 95
1930	Palaeotheca polycypha Hay p. 96
1930	Palaeotheca terrestris Hay p. 96
1988	Echmatemys Carroll
1992	Echmatemys Hutchison
1996	Echmatemys Hutchison p. 340
2001	Echmatemys Holroyd et al.
2004	Echmatemys Hervet
2012	Echmatemys Claude et al.
2015	Echmatemys Lichtig and Lucas
2018	Echmatemys Vlachos
2020	Echmatemys Vlachos p. 13

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
class	Osteichthyes
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha

Rank	Name	Author
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
—	Testudinata	(Oppel 1811)
order	Testudines	Batsch 1788
suborder	Cryptodira
—	Pantestudinoidea
superfamily	Testudinoidea
family	Geoemydidae	Theobald 1868
genus	Echmatemys

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

G. †Echmatemys Hay 1906

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†Echmatemys arethusa Hay 1908

†Echmatemys callopyge Hay 1908

†Echmatemys cibollensis Cope 1877

†Echmatemys haydeni Leidy 1870

†Echmatemys jeanesi Leidy 1870

†Echmatemys lativertebralis Cope 1877

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Invalid names: Chrysemys inornata Loomis 1904 [synonym], Echmatemys douglassi Gilmore 1915 [synonym], Echmatemys hollandi Gilmore 1915 [synonym], Echmatemys rivalis Hay 1909 [synonym], Emys shaughnessiana Cope 1882 [synonym], Graptemys cordifera Clark 1937 [synonym]

†Echmatemys naomi Hay 1908

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Invalid names: Echmatemys obscura Gilmore 1915 [synonym]

†Echmatemys stevensoniana Leidy 1870

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Invalid names: Echmatemys aegle Hay 1908 [synonym], Echmatemys cyane Hay 1908 [synonym], Echmatemys ocyrrhoe Hay 1908 [synonym], Emys septarius Cope 1873 [synonym]

†Echmatemys wyomingensis Leidy 1870

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Invalid names: Echmatemys uintensis Hay 1908 [synonym]

Invalid names: Echmatemys depressa Gilmore 1915 [nomen dubium], Palaeotheca polycypha Cope 1872 [nomen dubium], Palaeotheca terrestris Cope 1872 [nomen dubium]

Diagnosis

Reference	Diagnosis
E. Vlachos 2018	Echmatemys can be diagnosed as a member of Geoemydidae based on by the presence of musk ducts and associated musk duct foramina, wide rib heads, a narrow costo-vertebral tunnel, and paired marginals XII that expand on the suprapygal II. Echmatemys differs from other Geoemydidae based on the presence of narrow triturating surfaces, a short cervical scute, mostly hexagonal neurals II–VIII with short antero-lateral sides, a posteriorly flared carapace margin, anals that are shorter medially than the femorals, and well-developed axillary and inguinal buttresses.