PBDB Taxon

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Polycotylidae

Reptilia - Plesiosauria - Polycotylidae

Taxonomy

Polycotylidae was named by Williston (1908). Its type is Polycotylus.

It was assigned to Plesiosauria by Kuhn (1946); to Sauropterygia by Thurmond (1968); to Tricleidia by O'Keefe (2001); to Cryptocleidoidea by O'Keefe (2004); to Pliosauroidea by Welles (1943), Delair (1960), Persson (1963), Kuhn (1966), Thurmond and Jones (1981) and Schumacher and Everhart (2005); to Plesiosauria by Williston (1908), Hay (1930), White (1940), Buchy et al. (2005), Schumacher (2007), Salgado et al. (2007) and O'Gorman et al. (2011); to Leptocleidia by Ketchum and Benson (2010), Ketchum and Benson (2011), Benson and Druckenmiller (2014) and Frey et al. (2017); to Plesiosauria by Novas et al. (2015) and Zverkov et al. (2023); and to Plesiosauroidea by Gasparini and Goñi (1985), Carpenter (1996), Gasparini et al. (2007), O'Keefe (2008), O'Gorman and Gasparini (2013), O'Gorman (2015), Gasparini et al. (2015), O'Gorman (2016), O'Gorman et al. (2019), O'Gorman (2022), O'Gorman and Otero (2023) and Clark et al. (2024).

Subtaxa

Ceraunosaurus, Cimoliasaurus leucoscopelus, Edgarosaurus, Manemergus, Mauriciosaurus, Pahasapasaurus, Palmulainae, Palmulasaurinae, Plesiopleurodon, Polycotyilnae, Polycotylinae, Polycotylus brevispondylus, Polycotylus ichthyospondylus tanais, Sulcusuchus, Thililua

Synonyms

Dolichorhynchopidae was named by Welles (1962). It is not extant. Its type is Dolichorhynchops.

It was synonymized subjectively with Polycotylidae by Thurmond (1968) and Carpenter (1996).

It was assigned to Plesiosauria by Welles (1962).
Cimoliasaurus leucoscopelus was named by Etheridge (1897). It is a 3D body fossil.

It was recombined as Trinacromerum leucoscopelus by Molnar (1991); it was considered a nomen vanum by Persson (1960) and Welles (1962); it was considered a nomen dubium by Kear (2005).
Polycotylus brevispondylus was named by Bogolubov (1911). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Adams (1997).
Polycotylus ichthyospondylus tanais was named by Bogolubov (1911). It is a 3D body fossil.

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

Synonymy list

Year	Name and author
1897	Cimoliasaurus leucoscopelus Etheridge, Jr. p. 19 figs. Pls. 5-7
1908	Polycotylidae Williston
1911	Polycotylus brevispondylus Bogolubov p. 317 figs. 11, figs 1-2
1911	Polycotylus ichthyospondylus tanais Bogolubov p. 321 figs. pl. 9, figs 1-3
1930	Polycotylidae Hay p. 116
1940	Polycotylidae White p. 465 fig. 10a
1943	Polycotylidae Welles p. 212
1946	Polycotylidae Kuhn p. 59
1960	Polycotylidae Delair p. 69
1962	Dolichorhynchopidae Welles p. 4
1963	Polycotylidae Persson p. 6
1963	Polycotylus brevispondylus Persson p. 21
1963	Polycotylus ichthyospondylus tanais Persson p. 21
1966	Polycotylidae Kuhn p. 116
1968	Polycotylidae Thurmond p. 1289
1981	Polycotylidae Thurmond and Jones p. 141
1985	Polycotylidae Gasparini and Goñi
1991	Trinacromerum leucoscopelus Molnar p. 632
1996	Polycotylidae Carpenter p. 267
2001	Polycotylidae O'Keefe p. 19 fig. 20
2004	Polycotylidae O'Keefe p. 336 figs. Fig. 11
2005	Polycotylidae Buchy et al. p. 99
2005	Polycotylidae Schumacher and Everhart p. 40
2007	Polycotylidae Gasparini et al. p. 194
2007	Polycotylidae Salgado et al. p. 352
2007	Polycotylidae Schumacher p. 134
2008	Polycotylidae O'Keefe p. 665
2010	Polycotylidae Ketchum and Benson p. 15
2011	Polycotylidae Ketchum and Benson p. 126
2011	Polycotylidae O'Gorman et al. p. 130
2013	Polycotylidae O'Gorman and Gasparini
2014	Polycotylidae Benson and Druckenmiller figs. 2-3
2015	Polycotylidae Gasparini et al.
2015	Polycotylidae Novas et al. p. 564
2015	Polycotylidae O'Gorman p. 189
2016	Polycotylidae O'Gorman p. 42
2017	Polycotylidae Frey et al. p. 94
2019	Polycotylidae O'Gorman et al.
2022	Polycotylidae O'Gorman
2023	Polycotylidae O'Gorman and Otero p. 78
2023	Polycotylidae Zverkov et al. p. 3
2024	Polycotylidae Clark et al. p. 2

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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
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()
suborder	Sauropterygia
order	Plesiosauria	de Blainville 1835
superfamily	Plesiosauroidea	Welles 1943
family	Polycotylidae	Williston 1908
family	Polycotylidae	Williston 1908

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.

Fm. †Polycotylidae Williston 1908

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G. †Ceraunosaurus Thurmond 1968

G. †Edgarosaurus Druckenmiller 2002

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†Edgarosaurus muddi Druckenmiller 2002

G. †Manemergus Buchy et al. 2005

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†Manemergus anguirostris Buchy et al. 2005

G. †Mauriciosaurus Frey et al. 2017

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†Mauriciosaurus fernandezi Frey et al. 2017

G. †Pahasapasaurus Schumacher 2007

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†Pahasapasaurus haasi Schumacher 2007

Subfm. †Palmulainae Albright et al. 2007

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G. †Palmulasaurus Albright et al. 2007

†Palmulasaurus quadratus Albright et al. 2007

Invalid names: Palmula Albright et al. 2007 [replaced]

G. †Plesiopleurodon Carpenter 1996

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†Plesiopleurodon wellesi Carpenter 1996

Subfm. †Polycotylinae Albright et al. 2007

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Unr. †Dolichorhynchia Clark et al. 2024

G. †Dolichorhynchops Williston 1902

†Dolichorhynchops herschelensis Sato 2005

†Dolichorhynchops osborni Williston 1902

Invalid names: Polycotylus osborni Watson 1951 [synonym]

Invalid names: Plesiosaurus ichthyospondylus Seeley 1869 [nomen vanum], Trinacromerum latimanus Williston 1908 [nomen vanum]

G. †Martinectes Clark et al. 2024

†Martinectes bonneri Adams 1997

G. †Unktaheela Clark et al. 2024

†Unktaheela specta Clark et al. 2024

G. †Eopolycotylus Albright et al. 2007

†Eopolycotylus rankini Albright et al. 2007

G. †Georgiasaurus Ochev 1977

†Georgiasaurus penzensis Otschev 1976

Invalid names: Georgia Otschev 1976 [replaced]

G. †Polycotylus Cope 1869

†Polycotylus latipinnis Cope 1869

Invalid names: Polycotylus dolichopus Williston 1906 [synonym]

†Polycotylus sopozkoi Efimov et al. 2016

†Polycotylus suprajurensis Sauvage 1876

G. †Scalamagnus Clark et al. 2024

†Scalamagnus tropicensis Schmeisser McKean 2012

G. †Serpentisuchops Persons IV et al. 2022

†Serpentisuchops pfisterae Persons IV et al. 2022

G. †Trinacromerum Cragin 1888

†Trinacromerum bentonianum Cragin 1888

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

†Trinacromerum kirki Russell 1935

G. †Sulcusuchus Gasparini and Spalletti 1990

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†Sulcusuchus erraini Gasparini and Spalletti 1990

G. †Thililua Bardet et al. 2003

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†Thililua longicollis Bardet et al. 2003

Invalid names: Cimoliasaurus leucoscopelus Etheridge, Jr. 1897 [nomen dubium], Dolichorhynchopidae Welles 1962 [synonym], Palmulasaurinae Albright et al. 2007 [empty], Polycotyilnae Albright et al. 2007 [empty]

Diagnosis

Reference	Diagnosis
S. W. Williston 1908	Skull with long facial rostrum and thin, high parietal crest. Supraoccipital bones separated. Palate with large interpterygoidal vacuity, the pterygoids articulating with vomers, and meeting in the middle line posteriorly; no palatine foramina. Neck but little longer than head, the vertebrae all short; ribs single headed. Coracoids meeting throughout in symphysis, with long clavicular processes articulating with clavicles and scapulae, the interclavicle present; a large interclavicular foramen; ischia elongate. Three or four epipodial bones, all broader than long. Colorado Cretaceous, North America.
T. E. White 1940	"Dolicocephalic; 19 to 26 cervical vertebrae, 28 to 30 dorsals, 3 sacrals, 25 caudals; cervical ribs single-headed; posterolateral Dolicocephalic; 19 to 26 cervical vertebrae, 28 to 30 dorsals, 3 sacrals, 25 caudals; cervical ribs single-headed; posterolateral."
K. Carpenter 1996	Plesiosaurs with large skulls and short necks as in Pliosauridae; long facial rostrum with long mandibular symphysis; high sagittal crest; 4-7 pairs of premaxillary teeth; teeth conical, more uniform in size than in Pliosauridae, none caniniform; pterygoids flat, plate-like underlying most of the basicranium except for long and slender interpterygoid vacuity; 19-26 cervicals; cervical ribs single-headed; epipodials short and wide.
F. R. O'Keefe 2001	"Neck length short; ischium longer than pubis; maxillary/squamosal sutuer present and formed by posterior expansion of maxilla; pterygoids with distinct medial processes which meet behind posterior interpterygoid vacuities; pterygoids dished lateral to posterior interpterygoid vacuities; mandibular symphysis scoop-like or long; splenial included in mandibular symphysis; number of cervical vertebrae reduced; longitudinal pectoral bar present and formed by clavicle and coracoid; posterior perforations in coracoid; supernumerary ossifications in propodial and epipodial rows; interlocking phalanges anterior to fifth digit."