PBDB Taxon

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Stylemys

Reptilia - Testudines - Testudinidae

Taxonomy

Stylemys was named by Leidy (1851). Its type is Stylemys nebrascensis.

It was reranked as Testudo (Stylemys) by Leidy (1858).

It was assigned to Testudo by Leidy (1858); to Chelonia by Leidy (1869); to Testudinata by Cope (1891); to Emydidae by Cope (1884), Case (1936) and Galbreath (1953); to Testudinidae by Lydekker (1889), Hay (1902), Lambe (1908), Hay (1908), Hay (1930), Auffenberg (1971), Carroll (1988), Hutchison (1992), Hutchison (1996), Wall and Maddox (1998), Meylan and Sterrer (2000), Joyce et al. (2004), de la Fuente et al. (2014) and Vlachos (2018); and to Testudininae by Auffenberg (1964) and Vlachos and Rabi (2018).

Species

S. bottii, S. capax (syn. S. conspecta), S. frizaciana, S. gisellae, S. inusitata (syn. S. copei, Testudo primaeva), S. karakolensis, S. nebrascensis (syn. Testudo lata, Emys hemispherica, Gopherus neglectus, Testudo emiliae, Emys culbertsonii, Testudo ligonius, Emys oweni, Testudo amphithorax), S. oregonensis, S. pygmea, Testudo niobrarensis

Synonyms

Stylemys oregonensis was named by Leidy (1872). Its type specimen is unknown, a partial shell (neural plate), and it is a 3D body fossil. Its type locality is Crooked River, which is in a Chattian terrestrial horizon in the John Day Formation of Oregon.

It was recombined as Testudo oregonensis by Leidy (1873); it was considered a nomen dubium by Vlachos (2018).
Testudo (Stylemys) niobrarensis was named by Leidy (1858). Its type specimen is USNM 956 , a partial shell (epiplastron and part of entoplastron), and it is a 3D body fossil. Its type locality is Niobrara River (coll. Hayden 1857), which is in a Barstovian/Clarendonian terrestrial horizon in the Loup Fork Formation of Nebraska.

It was recombined as Testudo niobrarensis by Leidy (1873) and Hay (1930); it was recombined as Stylemys niobrarensis by Hay (1902); it was recombined as Geochelone (Hesperotestudo) niobrarensis by Auffenberg (1974); it was considered a nomen dubium by Vlachos (2018).

Synonymy list

Year	Name and author
1851	Stylemys Leidy p. 29
1858	Testudo (Stylemys) Leidy p. 29
1858	Testudo (Stylemys) niobrarensis Leidy p. 29
1869	Stylemys Leidy p. 275
1872	Stylemys oregonensis Leidy p. 248
1873	Testudo niobrarensis Leidy p. 340
1873	Testudo oregonensis Leidy p. 340
1884	Stylemys Cope
1889	Stylemys Lydekker p. 93
1891	Stylemys Cope p. 5
1902	Stylemys Hay p. 450
1902	Stylemys niobrarensis Hay p. 450
1902	Stylemys oregonensis Hay p. 451
1908	Stylemys Hay
1908	Stylemys Lambe
1930	Stylemys Hay p. 100
1930	Stylemys oregonensis Hay p. 101
1930	Testudo niobrarensis Hay p. 104
1936	Stylemys Case p. 71
1953	Stylemys Galbreath p. 38
1956	Testudo (Stylemys) niobrarensis Green p. 150
1964	Stylemys Auffenberg p. 323
1964	Stylemys oregonensis Auffenberg p. 323
1971	Stylemys Auffenberg p. 116
1974	Geochelone (Hesperotestudo) niobrarensis Auffenberg p. 164
1988	Stylemys Carroll
1992	Stylemys Hutchison
1996	Stylemys Hutchison p. 346
1998	Stylemys Wall and Maddox p. 11
2000	Stylemys Meylan and Sterrer
2004	Stylemys Joyce et al.
2014	Stylemys de la Fuente et al.
2018	Stylemys Vlachos
2018	Stylemys Vlachos and Rabi p. 663

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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	Testudinidae	Batsch 1788
subfamily	Testudininae
genus	Stylemys

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. †Stylemys Leidy 1851

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†Stylemys bottii de Stefano 1902

†Stylemys capax Hay 1908

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Invalid names: Stylemys conspecta Hay 1908 [synonym]

†Stylemys frizaciana Lartet 1851

†Stylemys gisellae Carbot-Chanona et al. 2022

†Stylemys inusitata Hay 1906

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Invalid names: Stylemys copei Koerner 1940 [synonym], Testudo primaeva Oelrich 1950 [synonym]

†Stylemys karakolensis Riabinin 1927

†Stylemys nebrascensis Leidy 1851

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Invalid names: Emys culbertsonii Leidy 1852 [synonym], Emys hemispherica Leidy 1851 [synonym], Emys oweni Leidy 1851 [synonym], Gopherus neglectus Brattstrom 1961 [synonym], Testudo amphithorax Cope 1873 [synonym], Testudo emiliae Hay 1908 [synonym], Testudo lata Leidy 1851 [synonym], Testudo ligonius Cope 1873 [synonym]

†Stylemys pygmea Lartet 1851

Invalid names: Stylemys oregonensis Leidy 1872 [nomen dubium], Testudo niobrarensis Leidy 1858 [nomen dubium]

Diagnosis

Reference	Diagnosis
E. Vlachos 2018	Stylemys can be diagnosed as a member of Testudinidae based on the full list of characters listed for that clade above. Stylemys can be differentiated from other testudinids by the presence of a premaxillae ridge with a corresponding dentary symphyseal groove, a neural pattern of 4>6A/8>6A/4>6A>6A>6A>6A>6A, the absence of epiplastral excavation, and placement of the medially straight and anterolaterally convex humero-pectoral sulcus posterior to the entoplastron.

Measurements

part	N	mean
carapace height	1	157.0

Composition:

phosphaticsubp

Environment:

terrestrialf

Locomotion:

actively mobilec

Life habit:

ground dwellingf

Diet:

herbivoref

Diet 2:

herbivoref

Reproduction:

oviparousf

Created:

2005-08-26 07:16:55

Modified:

2005-09-09 16:16:46

Source: f = family, c = class, subp = subphylum

References: Hendy et al. 2009, Carroll 1988, Ernst and Barbour 1989

Age range: base of the Chadronian to the top of the Clarendonian or 37.20000 to 9.40000 Ma

Collections (31 total)

Time interval	Ma	Country or state	Original ID and collection number
Bartonian - Rupelian	41.3 - 28.1	Mexico (Oaxaca)	S. sp. (166797)
Chadronian	37.2 - 33.9	USA (Colorado)	Testudo amphithorax, Testudo ligonius (16977)
Chadronian	37.2 - 33.9	USA (Nebraska)	S. nebrascensis (99591 99593 99595) S. sp. (16930 17014)
Chadronian	37.2 - 33.9	Canada (Saskatchewan)	S. nebrascensis (101961)
Chadronian - Orellan	37.2 - 33.3	USA (Nebraska)	S. nebrascensis (99594)
Orellan	33.9 - 33.3	USA (Nebraska)	S. nebrascensis (99590 99592)
Orellan	33.9 - 33.3	USA (Wyoming)	S. nebrascensis (17152)
Orellan	33.9 - 33.3	USA (South Dakota)	S. nebrascensis (17133) S. sp. (17094 17102 17103 17173 17174)
Early/Lower Oligocene	33.9 - 28.4	USA (Wyoming)	S. nebrascensis (99836)
Rupelian	33.9 - 28.1	USA (South Dakota)	Emys culbertsonii, Emys oweni, S. nebrascensis, Emys hemispherica, Testudo lata (190539)
Oligocene	33.9 - 23.03	Kyrgyzstan	S. karakolensis (198240)
Whitneyan - late Early Arikareean	33.3 - 18.5	USA (California)	Gopherus neglectus (17527)
Arikareean	29.5 - 18.5	USA (Oregon)	S. capax, S. conspecta, S. oregonensis (180202)
Chattian	28.1 - 23.03	USA (Oregon)	S. oregonensis (190997)
Harrisonian	24.8 - 18.5	USA (South Dakota)	Testudo emiliae (17745)
Early/Lower Miocene	23.03 - 15.97	USA (Montana)	Testudo primaeva (74503)
Miocene	23.03 - 5.333	France	S. bottii (197471)
Hemingfordian	20.43 - 15.97	USA (Montana)	Testudo inusitata (17885)
Barstovian - Clarendonian	16.3 - 9.4	USA (Nebraska)	Testudo niobrarensis (190543)
Clarendonian	12.5 - 9.4	USA (Nebraska)	Testudo niobrarensis (18483)
Clarendonian	12.5 - 9.4	USA (South Dakota)	Testudo niobrarensis (18487)