PBDB Taxon

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Trinacromerum bentonianum

Reptilia - Plesiosauria - Polycotylidae

Taxonomy

Trinacromerum bentonianum was named by Cragin (1888). Its type specimen is USNM 10945 and is not a trace fossil. Its type locality is near Downs (USNM), which is in a Turonian marine limestone in the Carlile Shale Formation of Kansas. It is the type species of Trinacromerum.

It was considered a nomen vanum by Welles (1962).

Synonyms

Ceraunosaurus brownorum was named by Thurmond (1968). Its type specimen is SM 3025, a skeleton (nearly complete skeleton), and it is a compression fossil. Its type locality is Lake Waco Dam, which is in a Cenomanian marine shale in the Lake Waco Formation of Texas.

It was synonymized subjectively with Trinacromerum bentonianum by Carpenter (1996); it was recombined as Trinacromerum brownorum by Adams (1997).
Trinacromerum anonymum was named by Williston (1903). It is a 3D body fossil. Its type locality is near Paradise Creek (KUVP), which is in a Turonian marine horizon in the Carlile Shale Formation of Kansas.

It was synonymized subjectively with Trinacromerum bentonianum by Carpenter (1996); it was considered a nomen vanum by Welles (1962).
Trinacromerum willistoni was named by Riggs (1944) [Here sometimes misspelled as "Trinocromerum" Here sometimes misspelled as "Trinocromerum"]. Its type specimen is KUVP 5070, a partial skeleton (Skull, 50 vertebrae, and most of the girdles), and it is a 3D body fossil. Its type locality is U.S. highway 81 roadcut, south of Concordia (FHSM 1331, T. willistoni type), which is in a Cenomanian marine horizon in the Greenhorn Limestone Formation of Kansas.

It was recombined as Dolichorhynchops willistoni by Welles (1962) and Junk (1962); it was synonymized subjectively with Trinacromerum bentonianum by Carpenter (1996).

Synonymy list

Year	Name and author
1888	Trinacromerum bentonianum Cragin
1902	Trinacromerum bentonianum Hay p. 458
1903	Trinacromerum anonymum Williston
1903	Trinacromerum bentonianum Williston p. 11
1903	Trinacromerum anonymum Williston p. 66 figs. pl. 28
1908	Trinacromerum bentonianum Williston p. 716
1908	Trinacromerum anonymum Williston p. 729
1930	Trinacromerum anonymum Hay p. 117
1930	Trinacromerum bentonianum Hay p. 117
1944	Trinacromerum willistoni Riggs pp. 78-87 figs. 1-8
1962	Dolichorhynchops willistoni Junk
1962	Dolichorhynchops willistoni Welles p. 50
1968	Ceraunosaurus brownorum Blank
1968	Ceraunosaurus brownorum Thurmond p. 1290
1996	Trinacromerum bentonianum Carpenter p. 279 figs. 3, 5, 13-17
1997	Trinacromerum anonymum Adams p. 182
1997	Trinacromerum bentonianum Adams p. 182
1997	Trinacromerum brownorum Adams p. 182
2001	Trinacromerum bentonianum O'Keefe p. 17
2004	Trinacromerum bentonianum O'Keefe p. 336 figs. Fig. 11
2007	Trinacromerum bentonianum Albright et al. p. 52 fig. 14

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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
subclass	Amphibiosauria	Kuhn 1967

Rank	Name	Author
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()
suborder	Sauropterygia
order	Plesiosauria	de Blainville 1835
superfamily	Plesiosauroidea	Welles 1943
family	Polycotylidae	Williston 1908
subfamily	Polycotylinae
genus	Trinacromerum	Cragin 1888
species	bentonianum	Cragin 1888

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.

†Trinacromerum bentonianum Cragin 1888

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Invalid names: Ceraunosaurus brownorum Thurmond 1968 [synonym], Trinacromerum anonymum Williston 1903 [synonym], Trinacromerum willistoni Riggs 1944 [synonym]

Diagnosis

Reference	Diagnosis
E. S. Riggs 1944 (Trinacromerum willistoni)	Related to Trinocromerum osborni, but differing in having the premaxillaries extending farther back; in having a larger maxillary tooth series (at least 34 as compared to a possible 26), interclavicle relatively much larger, and lacking the large foramen.
K. Carpenter 1996	Differs from Trinacromerum kirki in the lack of a posterior extension on the coracoid, straight ilium, and less elongated ischium.