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Elasmosauridae (elasmosaur)

Reptilia - Sauropterygia - Elasmosauridae

Taxonomy

Elasmosauridae was named by Cope (1869). Its type is Elasmosaurus. It was considered monophyletic by Gasparini et al. (2001).

It was assigned to Sauropterygia by Cope (1871) and Cope (1875); to Cercidopleura by Seeley (1892); to Plesiosauria by Andrews (1910) and Kuhn (1946); to Euplesiosauria by O'Keefe (2001); to Plesiosauria by Wegner (1914), White (1940), Cabrera (1941), Welles (1949), Sato (2003) and Druckenmiller and Russell (2006); to Plesiosauroidea by Welles (1943), Delair (1960), Welles (1962), Persson (1963), Brown (1981), Thurmond and Jones (1981), Carroll (1988), Gasparini and Spaletti (1993), Carpenter (1999), Gasparini et al. (2001), Gasparini et al. (2003), Schumacher and Everhart (2005), O'Keefe and Street (2009), Ketchum and Benson (2010) and Ketchum and Benson (2011); to Plesiosauria by Nicholls and Meckert (2002) and Otero et al. (2014); and to Xenopsaria by Benson and Druckenmiller (2014) and Serratos et al. (2017).

Subtaxa

Alexeyisaurus, Alzadasaurinae, Alzadasaurus kansasensis, Alzadasaurus tropicus, Aristonectinae, Brimosaurus, Callawayasaurus, Callowayosaurus, Cardiocorax, Cimoliasaurus (syn. Discosaurus, Hunosaurus, Piptomerus, Oligosimus, Iserosaurus), Cimoliasaurus andium, Cimoliasaurus cantabrigiensis, Cimoliasaurus caudalis, Elasmosaurinae, Elasmosaurus amalitskii, Elasmosaurus kurskensis, Elasmosaurus orskensis, Elasmosaurus serdobensis, Elasmosaurus sternbergi, Eromangasaurus, Gronausaurus, Hydrotherosaurus, Kawanectes, Leurospondylus, Libonectes, Mauisaurus, Mauisaurus gardneri, Morturneria, Plesiosaurus constrictus, Plesiosaurus crassicostatus, Plesiosaurus gulo, Plesiosaurus gurgitis, Plesiosaurus helmersenii, Plesiosaurus holmesii, Plesiosaurus hoodii, Plesiosaurus mackayii, Plesiosaurus mauritanicus, Plesiosaurus sutherlandi, Pliosaurus gigas, Pliosaurus macrospondylus, Scanisaurus, Stereosaurus, Styxosaurinae, Thalassiosaurus, Thalassiosaurus ischiadicus, Thalassomedon, Thalassonomosaurus, Thalassonomosaurus nobilis, Tuarangisaurus, Vegasaurus, Wapuskanectes, Woolungasaurus, Woolungasaurus glendowerensis, Zarafasaura

View classification of included taxa

Synonyms

Cimoliasauridae was named by Delair (1959).

It was synonymized subjectively with Elasmosauridae by O'Keefe and Street (2009).

It was assigned to Plesiosauroidea by Delair (1960), Persson (1963) and Antunes (1964); to Tricleidia by O'Keefe (2001); and to Cryptocleidoidea by O'Keefe (2004).
Plesiosaurus crassicostatus was named by Owen (1870). It is a 3D body fossil.

It was synonymized subjectively with Cimoliosaurus australis by Lydekker (1889); it was considered a nomen vanum by Welles (1962) and Welles and Gregg (1971).
Plesiosaurus hoodii was named by Owen (1870). It is a 3D body fossil.

It was recombined as Cimoliosaurus hoodii by Lydekker (1889); it was recombined as Elasmosaurus hoodii by Pravoslavlev (1918); it was synonymized subjectively with Mauisaurus haasti by Persson (1963); it was considered a nomen vanum by Welles (1962) and Welles and Gregg (1971).
Plesiosaurus holmesii was named by Hector (1874). It is not a trace fossil. Its type locality is Amuri Bluff, which is in a Campanian/Maastrichtian basinal (siliciclastic) sandstone in the Conway Formation of New Zealand.

It was synonymized subjectively with Mauisaurus haasti by Persson (1963); it was considered a nomen vanum by Welles (1962) and Welles and Gregg (1971).
Plesiosaurus mackayii was named by Hector (1874). It is not a trace fossil. Its type locality is Amuri Bluff, which is in a Campanian/Maastrichtian basinal (siliciclastic) sandstone in the Conway Formation of New Zealand.

It was considered a nomen vanum by Welles (1962) and Welles and Gregg (1971).
Polycotylus ischiadicus was named by Williston (1903). Its type specimen is KUVP 434, a set of postcrania (ilia, ischia, sacral vertebrae and othe rbones), and it is a 3D body fossil.

It was recombined as Elasmosaurus ischiadicus by Williston (1906); it was recombined as Ogmodirus ischiadicus by Williston and Moodie (1917); it was recombined as Thalassiosaurus ischiadicus by Welles (1943) and Welles (1943); it was synonymized subjectively with Styxosaurus snowii by Carpenter (1999); it was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Storrs (1999) and Otero (2016).
Elasmosaurus sternbergi was named by Williston (1906). Its type specimen is KUVP 1312, a set of vertebrae (a few vertebrae and fragments), and it is a 3D body fossil. Its type locality is Elasmosaurus sternbergi type locality, Gove County, which is in a Santonian marine chalk in the Niobrara Formation of Kansas.

It was considered a nomen dubium by Welles (1943); it was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Storrs (1999).
Elasmosaurus nobilis was named by Williston (1906). Its type specimen is YPM 1640, a set of postcrania (femur, ilia, dorsal and sacral vertebrae, partial scapula and coracoid), and it is a 3D body fossil. Its type locality is Elasmosaurus nobilis type locality, 4.8 km west of Jewell City, which is in a Coniacian marine horizon in the Niobrara Formation of Kansas.

It was recombined as Thalassonomosaurus nobilis by Williston (1906) and Welles (1943); it was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Storrs (1999).
Alzadasaurus kansasensis was named by Welles (1952). Its type specimen is YPM 1130, a set of postcrania (63 vertebral centra, comprising 28 cervicals, 5 pectorals, 3 dorsals, 5 sacrals, and 22 caudals; associated spine and other vertebral fragments, and the nearly ), and it is a 3D body fossil. Its type locality is Alzadasaurus kansasensis type, Logan County [PROXY], which is in a Campanian marine horizon in the Niobrara Formation of Kansas.

It was considered a nomen dubium by Storrs (1999); it was synonymized subjectively with Styxosaurus snowii by Carpenter (1999).
Cimoliosaurus cantabrigiensis was named by Lydekker (1889). It is a 3D body fossil.

It was recombined as Cimoliasaurus cantabrigiensis by Lydekker (1889); it was considered a nomen vanum by Welles (1962); it was synonymized subjectively with Plesiosaurus bernardi by Persson (1963).
Plesiosaurus constrictus was named by Owen (1850). It is a 3D body fossil. Its type locality is Steyning chalk-pit, which is in a Cenomanian/Coniacian marine chalk in the United Kingdom.

It was recombined as Elasmosaurus constrictus by Cope (1869) and Cope (1869); it was recombined as Cimoliosaurus constrictus by Lydekker (1889); it was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Persson (1963).
Mauisaurus gardneri was named by Seeley (1878).

It was recombined as Plesiosaurus gardneri by Whidborne (1881); it was synonymized subjectively with Cimoliosaurus constrictus by Lydekker (1889); it was considered a nomen vanum by Welles (1962).
Pliosaurus gigas was named by Schroder (1885). It is a 3D body fossil.

It was synonymized subjectively with Cimoliosaurus constrictus by Lydekker (1889); it was recombined as Plesiosaurus gigas by Wegner (1914); it was recombined as Elasmosaurus gigas by Persson (1959); it was considered a nomen vanum by Welles (1962).
Plesiosaurus gurgitis was named by Renevier (1858).

It was synonymized subjectively with Cimoliosaurus neocomiensis by Lydekker (1889); it was considered a nomen vanum by Welles (1962).
Alzadasaurus tropicus was named by Colbert (1949). Its type specimen is AMNH 6796, a partial skeleton (partial skeleton with a posterior cervical, four pectoral and eight dorsal vertebrae, left scapula, part of a coracoid, humerus and paddle), and it is a 3D body fossil.

It was considered a nomen vanum by Welles (1952) and Welles (1962).
Cimoliasaurus andium was named by Deecke (1895). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Otero et al. (2014).
Brancasauridae was named by White (1940).

It was synonymized subjectively with Elasmosauridae by Persson (1963).

It was assigned to Plesiosauria by White (1940); and to Plesiosauria by Kuhn (1946).
Plesiosaurus sutherlandi was named by McCoy (1867). Its type specimen is NMV 2572, a set of vertebrae (single centrum), and it is a 3D body fossil.

It was recombined as Cimoliasaurus sutherlandi by Etheridge (1904); it was recombined as Pliosaurus sutherlandi by Chapman (1914); it was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Kear (2003).
Plesiosaurus macrospondylus was named by McCoy (1867). Its type specimen is NMV P22548, a set of vertebrae (single cervical centrum), and it is a 3D body fossil.

It was recombined as Pliosaurus macrospondylus by Chapman (1914); it was considered a nomen vanum by Persson (1960) and Welles (1962); it was considered a nomen dubium by Kear (2003).
Woolungasaurus glendowerensis was named by Persson (1960). Its type specimen is QM F6890, a partial skeleton (46 vertebral centra and prts of the pectoral girdle, pelvis, and limb bones), and it is a 3D body fossil. Its type locality is Glendower Station, near Prairie , which is in an Aptian marine horizon in the Wallumbilla Formation of Australia.

It was considered a nomen dubium by Welles (1962); it was considered a nomen dubium by Kear (2003).
Plesiosaurus mauritanicus was named by Arambourg (1952). It is a 3D body fossil. Its type locality is Louis Gentil, which is in a Maastrichtian marine horizon in Morocco.

It was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Persson (1963); it was considered a nomen vanum by Mulder et al. (2000); it was considered a nomen dubium by Vincent et al. (2011).
Elasmosaurus kurskensis was named by Bogolubov (1911). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962).
Elasmosaurus amalitskii was named by Pravoslavlev (1916). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962).
Elasmosaurus orskensis was named by Bogolubov (1911). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962).
Elasmosaurus serdobensis was named by Bogolubov (1911). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962).
Plesiosaurus helmersenii was named by Kiprijanoff (1882). It is a 3D body fossil.

It was recombined as Elasmosaurus helmersenii by Bogolubov (1911); it was considered a nomen vanum by Welles (1962).
Plesiosaurus gulo was named by Cope (1872). Its type specimen is KUVP 1329, a set of postcrania (11 cervical, 13 dorsal and other vertebrae, and parts of the pectrum and pelvis), and it is a 3D body fossil. Its type locality is McAllaster ('Plesiosaurus' gulo type locality), which is in a Santonian/Campanian marine horizon in Kansas.

It was considered a nomen vanum by Welles (1962); it was considered a nomen dubium by Storrs (1999).
Cimoliasaurus caudalis was named by Hutton (1894). It is a 3D body fossil.

It was considered a nomen vanum by Welles (1962).
Brimosaurus was named by Leidy (1854) [Sepkoski's age data: K u].

It was synonymized subjectively with Cimoliasaurus by Cope (1869); it was synonymized subjectively with Cimoliosaurus by Lydekker (1889); it was synonymized subjectively with Elasmosaurus by Williston (1906); it was considered a nomen dubium by Welles (1943) and Persson (1963).

It was assigned to Plesiosauria by Williston (1903), Carroll (1988) and Sepkoski (2002).
Woolungasaurus was named by Persson (1960) [Sepkoski's age data: K l]. It is not extant.

It was considered a nomen dubium by Kear (2003).

It was assigned to Elasmosauridae by Persson (1963) and Carroll (1988); and to Plesiosauria by Sepkoski (2002).

Synonymy list

Year	Name and author
1850	Plesiosaurus constrictus Owen p. 398
1854	Brimosaurus Leidy p. 72 figs. Pl. 2, fig. 1-3
1858	Plesiosaurus gurgitis Renevier p. 5
1864	Plesiosaurus constrictus Owen p. 1
1867	Plesiosaurus macrospondylus McCoy p. 356
1867	Plesiosaurus sutherlandi McCoy p. 356
1869	Elasmosauridae Cope
1869	Elasmosaurus constrictus Cope p. 42
1870	Plesiosaurus hoodii Owen p. 51
1870	Plesiosaurus crassicostatus Owen p. 52
1870	Plesiosaurus hoodii Owen p. 53 figs. Pl. III, figs. 1-3
1871	Elasmosauridae Cope p. 235
1872	Plesiosaurus gulo Cope p. 127
1874	Plesiosaurus crassicostatus Hector p. 341
1874	Plesiosaurus hoodii Hector p. 343
1874	Plesiosaurus holmesii Hector p. 344
1874	Plesiosaurus mackayii Hector p. 345
1875	Elasmosauridae Cope p. 15
1878	Mauisaurus gardneri Seeley p. 541
1881	Plesiosaurus gardneri Whidborne
1882	Plesiosaurus helmersenii Kiprijanoff pp. 18, 21 figs. pl. 11, figs 1-3; pl. 12, figs 1-2; pl. 13, figs 1-2
1885	Pliosaurus gigas Schroder p. 322 figs. pl. 16, fig. 1
1889	Cimoliasaurus cantabrigiensis Lydekker
1889	Cimoliosaurus cantabrigiensis Lydekker p. 183 fig. 60
1889	Cimoliosaurus constrictus Lydekker p. 212
1889	Cimoliosaurus hoodii Lydekker p. 245
1892	Elasmosauridae Seeley p. 151
1894	Cimoliasaurus caudalis Hutton p. 356 figs. pl. 42
1895	Cimoliasaurus andium Deecke
1903	Plesiosaurus gulo Williston p. 7
1903	Brimosaurus Williston p. 8
1903	Polycotylus ischiadicus Williston p. 10
1904	Cimoliasaurus sutherlandi Etheridge p. 312
1906	Thalassonomosaurus nobilis Williston
1906	Elasmosaurus ischiadicus Williston p. 231
1906	Elasmosaurus nobilis Williston pp. 232-233
1906	Elasmosaurus sternbergi Williston p. 232
1910	Elasmosauridae Andrews p. 77
1911	Elasmosaurus orskensis Bogolubov p. 36 figs. pl. 14, figs 1-3
1911	Elasmosaurus kurskensis Bogolubov p. 353
1911	Elasmosaurus helmersenii Bogolubov p. 359
1911	Elasmosaurus serdobensis Bogolubov p. 374 figs. pl. 14, figs 4-5
1914	Pliosaurus macrospondylus Chapman p. 278
1914	Pliosaurus sutherlandi Chapman p. 278
1914	Plesiosaurus gigas Wegner p. 303
1914	Elasmosauridae Wegner p. 304
1916	Elasmosaurus amalitskii Pravoslavlev p. 315
1917	Ogmodirus ischiadicus Williston and Moodie p. 61
1918	Elasmosaurus hoodii Pravoslavlev p. 1955
1940	Brancasauridae White p. 461 figs. 9a-c
1940	Elasmosauridae White p. 466 figs. 12a-c
1941	Elasmosauridae Cabrera pp. 114-129
1943	Elasmosauridae Welles
1943	Thalassiosaurus ischiadicus Welles
1943	Thalassonomosaurus nobilis Welles pp. 190-191 fig. 33
1946	Brancasauridae Kuhn p. 59
1946	Elasmosauridae Kuhn p. 59
1949	Alzadasaurus tropicus Colbert p. 4 figs. 3-9
1949	Cimoliasaurus andium Colbert p. 19
1949	Elasmosauridae Welles
1952	Plesiosaurus mauritanicus Arambourg
1952	Alzadasaurus kansasensis Welles
1959	Cimoliasauridae Delair
1959	Elasmosaurus gigas Persson p. 445
1960	Cimoliosauridae Delair pp. 59-60
1960	Elasmosauridae Delair p. 67
1960	Woolungasaurus Persson
1960	Woolungasaurus glendowerensis Persson p. 11 figs. Pl. 1, figs. 3, 4, Pls. 2, 3
1962	Elasmosauridae Welles p. 2
1962	Alzadasaurus kansasensis Welles pp. 3 & 62
1963	Cimoliasauridae Persson p. 6
1963	Elasmosauridae Persson p. 7
1963	Elasmosaurus kurskensis Persson p. 19
1963	Elasmosaurus orskensis Persson p. 19
1963	Elasmosaurus serdobensis Persson p. 19
1963	Mauisaurus gardneri Persson p. 19
1963	Woolungasaurus Persson p. 22
1964	Cimoliasauridae Antunes p. 133
1981	Elasmosauridae Brown p. 340
1981	Elasmosauridae Thurmond and Jones p. 139
1988	Brimosaurus Carroll
1988	Elasmosauridae Carroll
1988	Woolungasaurus Carroll
1991	Woolungasaurus glendowerensis Fordyce p. 1173
1993	Elasmosauridae Gasparini and Spaletti p. 250
1999	Elasmosauridae Carpenter p. 150
2001	Elasmosauridae Gasparini et al.
2001	Cimoliasauridae O'Keefe p. 19 fig. 20
2001	Elasmosauridae O'Keefe p. 19 fig. 20
2002	Elasmosauridae Nicholls and Meckert p. 1593
2002	Brimosaurus Sepkoski, Jr.
2002	Woolungasaurus Sepkoski, Jr.
2003	Elasmosauridae Gasparini et al. p. 105
2003	Elasmosauridae Sato p. 90
2004	Cimoliasauridae O'Keefe p. 336 figs. Fig. 11
2005	Elasmosauridae Schumacher and Everhart p. 48
2006	Elasmosauridae Druckenmiller and Russell p. 186
2009	Elasmosauridae O'Keefe and Street p. 49
2010	Elasmosauridae Ketchum and Benson p. 15
2011	Elasmosauridae Ketchum and Benson p. 126
2014	Elasmosauridae Benson and Druckenmiller figs. 2-3
2014	Elasmosauridae Otero et al.
2017	Elasmosauridae Serratos et al.

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Rank	Name	Author
kingdom	Animalia	()
—	Triploblastica
—	Nephrozoa
—	Deuterostomia
phylum	Chordata	Haeckel 1847
subphylum	Vertebrata
superclass	Gnathostomata
—	Osteichthyes	()
—	Sarcopterygii
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda	()
—	Reptiliomorpha
—	Anthracosauria
—	Batrachosauria	()

Rank	Name	Author
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()
order	Sauropterygia
—	Pistosauria	(Baur 1890)
—	Plesiosauria	(de Blainville 1835)
superfamily	Plesiosauroidea	Welles 1943
—	Cryptoclidia
—	Xenopsaria
family	Elasmosauridae	Cope 1869
family	Elasmosauridae	Cope 1869

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.

Diagnosis

Reference	Diagnosis
T. E. White 1940	"Mesocephalic; 20 to 76 cervical, dorsals 30 +, ? caudals; cervical ribs single- or double-headed; clavicles and interclavicle absent; scapula meeting coracoid medial to scapulo-coracoid fenestra; fenestrae large and separated in mature forms by a bar no wider than the diameter of one fenestra; posterolateral angles of coracoids not produced."
T. E. White 1940 (Brancasauridae)	"Brachycephalic; 27 to 37 cervical vertebrae, 19 to 22 dorsal, 2 to 3 sacral, and 25 to 43 caudal; cervical ribs single- or doubleheaded; clavicles and interclavicle present and well developed; interclavicle with posterior process; scapula meeting coracoid medial to scapulo-coracoid fenestra; fenestra small and with a broad bar between; one or two openings in the girdle anterior to scapulo-coracoid fenestrae."
D. S. Brown 1981	Plesiosauroidea with a maximum of five pairs of premaxillary teeth; upper tooth row of advanced forms characterized by the development of enlarged premaxillary and anterior maxillary teeth separated by smaller teeth around the maxillo-premaxillary suture; dentary teeth primitively 24 pairs, reducing to a minimum of 14 pairs in advanced forms; teeth ornamented with numerous longitudinal ridges; occipital condyle formed from the basioccipital only, and usually ringed by a constricting groove; overall length from about 3 m in primitive forms to a maximum of 14 m in advanced forms; number of cervical vertebrae primitively c. 32 and reaching a maximum of 71 in advanced forms; except for some primitive forms, cervical centra relatively elongated; cervical ribs (primitively double-headed) are single-headed in Upper Jurassic and later forms; ventral rami of the scapulae relatively broad and meeting in the ventral midline in 'adults'; epipodials primitively longer than broad, becoming broader than long in advanced forms; the fifth metapodial shifting proximally into the distal mesapodial row in advanced forms; hyperphalangy of up to 17 phalanges in the longest digit.
F. R. O'Keefe 2001	"Anterior quadrate embayment absent (reversal); premaxilla excluded from border of internal naris; vomer extends posterior to internal nares; number of cervical rib heads reduced to one; coracoids long with deep median embayment; ventro-medial margin of pubis concave; ulna not lunate (reversal); epipodials wider than long."
F. R. O'Keefe 2001 (Cimoliasauridae)	"Rostrum long, unconstricted, and hoop-like; paraoccipital process articulates with squamosal only; teeth very small and needle-like; number of maxillary teeth greater than thirty."