PBDB Taxon

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Echmatemys stevensoniana

Reptilia - Testudines - Geoemydidae

Taxonomy

Emys stevensonianus was named by Leidy (1870). Its type specimen is USNM 963+965+967 (syntypes), a partial shell, and it is a 3D body fossil. Its type locality is A few miles from Fort Bridger, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was synonymized subjectively with Emys wyomingensis by Leidy (1873); it was recombined as Echmatemys stevensoniana by Hay (1930) and Vlachos (2018).

Synonyms

Emys septarius was named by Cope (1873). Its type specimen is USNM 4088+4114 (syntype series), a partial shell (mostly complete plastron and partial carapace), and it is a 3D body fossil. Its type locality is Badlands of South Bitter Creek (Cope Collection), which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming. It is the type species of Echmatemys.

It was corrected as Emys septaria by Cope (1882), Cope (1884) and Hay (1902); it was recombined as Echmatemys septaria by Hay (1906), Hay (1908), Hay (1930), Roberts (1962) and Zonneveld et al. (2000); it was synonymized subjectively with Echmatemys stevensoniana by Vlachos (2018).
Echmatemys aegle was named by Hay (1908). Its type specimen is AMNH 5909 (holotype), a partial shell (complete plastron and some carapacial bones), and it is a 3D body fossil. Its type locality is Grizzly Buttes, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was synonymized subjectively with Echmatemys stevensoniana by Vlachos (2018).
Echmatemys cyane was named by Hay (1908). Its type specimen is AMNH 5924 (holotype), a partial shell, and it is a 3D body fossil. Its type locality is Grizzly Buttes, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was synonymized subjectively with Echmatemys stevensoniana by Vlachos (2018).
Echmatemys ocyrrhoe was named by Hay (1908). Its type specimen is AMNH 5933 (holotype), a shell, and it is a 3D body fossil. Its type locality is Church Buttes, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was synonymized subjectively with Echmatemys stevensoniana by Vlachos (2018).

Synonymy list

Year	Name and author
1870	Emys stevensonianus Leidy p. 6
1873	Emys septarius Cope p. 625
1875	Emys stevensonianus Cope p. 36
1882	Emys septaria Cope p. 992
1884	Emys septaria Cope p. 139
1902	Emys septaria Hay p. 448
1906	Echmatemys septaria Hay p. 27
1908	Echmatemys ocyrrhoe Hay
1908	Echmatemys septaria Hay p. 319
1908	Echmatemys aegle Hay p. 346
1908	Echmatemys cyane Hay p. 346
1908	Echmatemys ocyrrhoe Hay p. 346
1930	Echmatemys aegle Hay p. 95
1930	Echmatemys cyane Hay p. 95
1930	Echmatemys ocyrrhoe Hay p. 95
1930	Echmatemys septaria Hay p. 95
1930	Echmatemys stevensoniana Hay p. 96
1962	Echmatemys septaria Roberts p. 386
2000	Echmatemys septaria Zonneveld et al.
2018	Echmatemys stevensoniana Vlachos

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

Rank	Name	Author
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
species	stevensoniana	()

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.

†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]

Diagnosis

Reference	Diagnosis
E. Vlachos 2018	Echmatemys stevensoniana can be diagnosed as a member of Echmatemys based on the characters listed for that clade above. Echmatemys stevensoniana differs from other Echmatemys based on the following combination of characters: neurals II–VIII hexagonal, suprapygal longer than wide and with narrow anterior border, contact of marginal II with vertebral I, and vertebral IV/V sulcus crossing suprapygal I.

Measurements

No measurements are available

Composition:

phosphaticsubp

Entire body:

yesg

Adult length:

100 to < 1000g

Environment:

freshwaterg

Locomotion:

actively mobilec

Life habit:

aquaticg

Diet:

herbivoreg

Reproduction:

oviparoussubo

Created:

2006-04-19 14:59:48

Modified:

2006-04-19 17:05:43

Source: g = genus, subo = suborder, c = class, subp = subphylum

References: Hendy et al. 2009, Uetz 2005, Carroll 1988, Holroyd et al. 2001

Age range: base of the Lysitean to the top of the Uintan or 55.80000 to 39.70000 Ma

Collections (17 total)

Time interval	Ma	Country or state	Original ID and collection number
Lysitean	55.8 - 50.3	USA (Colorado)	Echmatemys stevensoniana (15654)
Bridgerian	50.3 - 46.2	USA (Wyoming)	Echmatemys aegle, Echmatemys cyane (16228) Echmatemys ocyrrhoe (16201) Echmatemys septaria (15837 16261 16262 16265 16267 16270 16273 16405 55207) Emys septarius (191004) Emys stevensonianus (type locality: 128447)
Bridgerian	50.3 - 46.2	USA (Colorado)	Echmatemys stevensoniana (16242)
Early/Lower Uintan	46.2 - 39.7	USA (Colorado)	Echmatemys septaria (16623)
Uintan	46.2 - 39.7	USA (Utah)	Echmatemys septaria (74505)