PBDB Taxon

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Osteopygis

Reptilia - Testudines

Taxonomy

Osteopygis was named by Cope (1868) [Sepkoski's age data: K Camp-u T Eo Sepkoski's reference number: 987,1069]. Its type is Osteopygis emarginatus.

It was assigned to Chelydrinae by Cope (1870); to Propleuridae by Cope (1884); to Thalassemydidae by Hay (1902), Hay (1908), Hay (1930) and Bohlin (1953); to Osteopyginae by Zangerl (1953), Foster (1980) and Weems (1988); to Toxochelyidae by Yeh (1963) and Carroll (1988); to Cheloniidae by Hirayama (1995); to Chelonia by Sepkoski (2002); to Macrobaenidae by Parham (2005) and Brinkman et al. (2010); and to Macrobaenidae by Gentry et al. (2023).

Species

O. backmani, O. emarginata, O. emarginatus (syn. O. gibbi, Amblypeza entellus, O. borealis, O. chelydrinus, O. platylomus, O. erosus, O. robustus, Catapleura chelydrina) (type species), O. kranzi, O. russelli

Synonymy list

Year	Name and author
1868	Osteopygis Cope p. 147
1870	Osteopygis Cope p. 132
1884	Osteopygis Cope
1902	Osteopygis Hay p. 441
1908	Osteopygis Hay p. 127
1930	Osteopygis Hay p. 75
1953	Osteopygis Bohlin p. 69
1953	Osteopygis Zangerl p. 205
1963	Osteopygis Yeh
1980	Osteopygis Foster
1988	Osteopygis Carroll
1988	Osteopygis Weems p. 115
1995	Osteopygis Hirayama p. 282
2002	Osteopygis Sepkoski
2005	Osteopygis Parham p. 76
2010	Osteopygis Brinkman et al.
2023	Osteopygis Gentry et al.

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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

Rank	Name	Author
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
—	Testudinata	(Oppel 1811)
order	Testudines	Batsch 1788
—	Pancryptodira	Joyce et al. 2004
—	Macrobaenidae	(Sukhanov 1964)
genus	Osteopygis

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. †Osteopygis Cope 1868

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†Osteopygis backmani Russell 1934

†Osteopygis emarginata Cope 1868

†Osteopygis emarginatus Cope 1868

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Invalid names: Amblypeza entellus Hay 1908 [synonym], Catapleura chelydrina Cope 1875 [synonym], Osteopygis borealis Wieland 1904 [synonym], Osteopygis chelydrinus Cope 1868 [synonym], Osteopygis erosus Cope 1875 [synonym], Osteopygis gibbi Wieland 1904 [synonym], Osteopygis platylomus Cope 1870 [synonym], Osteopygis robustus Hay 1908 [synonym]

†Osteopygis kranzi Weems 2014

†Osteopygis russelli Brinkman 2015

Diagnosis

Reference	Diagnosis
O. P. Hay 1908	Carapace including 8 pairs of costal plates and 1 1 pairs of peripherals, with all or only a part of the peripherals suturally articulated with the costals and the suprapygals. All the costals sending the ends of their ribs into pits of the corresponding peripherals. Five vertebral and 4 pairs of costal scutes. The nuchal scute much wider than long. Plastron relatively small; its connection with the peripherals extensive, reaching from the second to the eighth peripherals, not by close sutures. Bridge relatively narrow. Fontanels in the midline and at the ends of the hyohypoplastral suture. Inframarginal scutes present. Lower jaw with a broad and flat crushing surface; not beakt.
B. Bohlin 1953	Carapace including 8 pairs of costal plates and 11 pairs of peripherals, with all or only a part of the peripherals suturally articulated with the costals and the suprapygals. All the costals sending their ribs into pits of the corresponding peripherals. Five vertebral and 4 pairs of costal scutes. The nuchal scute much wider than long. Plastron relatively small; its connection with the peripherals extensive, reaching from the second to the eighth peripherals, not by closed sutures. Bridge relatively narrow. Fontanels in the midline and at the ends of the hyohypoplastral suture. Inframarginal scutes present. Lower jaw with a broad and flat crushing surface; not beaked. (Hay 1908 p. 127).
A. D. Gentry et al. 2023	Osteopygis can be differentiated from A. ebersolei and J. sukhanovi by the presence of a central plastral fenestra and from A. gaffneyi in having an ovoid carapace that is longer than wide.