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Elasmosauridae (elasmosaur)

Reptilia - Plesiosauria - 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 Hay (1902), Wegner (1914), Hay (1930), White (1940), Cabrera (1941), Welles (1949), Sato (2003), Martinelli and Forasiepi (2004), Druckenmiller and Russell (2006), O'Gorman and Varela (2010), O'Gorman et al. (2011), Otero et al. (2013), Otero et al. (2014), Araujo et al. (2015), O'Keefe et al. (2017) and O'Gorman et al. (2018); to Xenopsaria by Benson and Druckenmiller (2014), Otero et al. (2015), Hiller et al. (2017), Serratos et al. (2017), Otero et al. (2018), Miller et al. (2020) and Marx et al. (2021); to Plesiosauroidea by Welles (1943), Delair (1960), Welles (1962), Persson (1963), Kuhn (1966), Welles and Gregg (1971), Brown (1981), Thurmond and Jones (1981), Wiffen and Moisley (1986), Carroll (1988), Gasparini and Spalletti (1993), Carpenter (1999), Gasparini and Salgado (2000), Fostowicz-Frelik and Gazdzicki (2001), Gasparini et al. (2001), Gasparini et al. (2003), Lazo and Cichowolski (2003), Hiller and Mannering (2004), Hiller and Mannering (2005), Hiller et al. (2005), Schumacher and Everhart (2005), Gasparini et al. (2007), Previtera and González Riga (2008), O'Keefe and Street (2009), Ketchum and Benson (2010), Ketchum and Benson (2011), O'Gorman (2012), Mateus et al. (2012), O'Gorman et al. (2013), O'Gorman et al. (2013), Otero and O'Gorman (2013), Hiller et al. (2014), O'Gorman et al. (2014), O'Gorman et al. (2014), O'Gorman (2015), Gasparini et al. (2015), Otero et al. (2015), O'Gorman et al. (2015), O'Gorman et al. (2015), Bardet et al. (2015), O'Gorman et al. (2016), O'Gorman (2016), O'Gorman (2016), O'Gorman (2016), O'Gorman (2016), O'Gorman et al. (2017), O'Gorman and Coria (2017), O'Gorman et al. (2018), O'Gorman (2019), O'Gorman et al. (2019), Páramo-Fonseca et al. (2019), O'Gorman (2020), O'Gorman et al. (2021), O'Gorman et al. (2021), O'Gorman (2021), O'Gorman and Otero (2023) and O'Gorman et al. (2023); and to Plesiosauria by Nicholls and Meckert (2002), Martin and Crame (2006), Otero et al. (2009), Otero et al. (2012), Otero et al. (2014), Araújo et al. (2015), Otero et al. (2016), Sachs et al. (2017), O’Gorman et al. (2020), Otero and Soto-Acuña (2021), Moyano-Paz et al. (2022) and Otero (2024).

Synonyms
Synonymy list
YearName and author
1850Plesiosaurus constrictus Owen p. 398
1854Brimosaurus Leidy p. 72 figs. Pl. 2, fig. 1-3
1858Plesiosaurus gurgitis Renevier p. 5
1864Plesiosaurus constrictus Owen p. 1
1867Plesiosaurus macrospondylus McCoy p. 356
1867Plesiosaurus sutherlandi McCoy p. 356
1869Elasmosauridae Cope
1869Elasmosaurus constrictus Cope p. 42
1870Plesiosaurus hoodii Owen p. 51
1870Plesiosaurus crassicostatus Owen p. 52
1870Plesiosaurus hoodii Owen p. 53 figs. Pl. III, figs. 1-3
1871Elasmosauridae Cope p. 235
1872Plesiosaurus gulo Cope p. 127
1874Plesiosaurus crassicostatus Hector p. 341
1874Plesiosaurus hoodii Hector p. 343
1874Plesiosaurus holmesii Hector p. 344
1874Plesiosaurus mackayii Hector p. 345
1875Elasmosauridae Cope p. 15
1878Mauisaurus gardneri Seeley p. 541 figs. 2 & pl. 23
1881Plesiosaurus gardneri Whidborne
1882Plesiosaurus helmersenii Kiprijanoff pp. 18, 21 figs. pl. 11, figs 1-3; pl. 12, figs 1-2; pl. 13, figs 1-2
1885Plesiosaurus helmersenii Schröder p. 310
1885Pliosaurus gigas Schröder p. 322
1889Cimoliasaurus cantabrigiensis Lydekker
1889Cimoliosaurus cantabrigiensis Lydekker p. 183 fig. 60
1889Cimoliosaurus constrictus Lydekker p. 212
1889Cimoliosaurus hoodii Lydekker p. 245
1892Plesiosaurus sutherlandi Jack and Etheridge p. 412
1892Elasmosauridae Seeley p. 151
1894Cimoliasaurus caudalis Hutton p. 356 figs. pl. 42
1895Cimoliasaurus andium Deecke
1902Plesiosaurus gulo Hay p. 456
1902Elasmosauridae Hay p. 457
1903Plesiosaurus gulo Williston p. 7
1903Brimosaurus Williston p. 8
1903Polycotylus ischiadicus Williston p. 10
1904Cimoliasaurus sutherlandi Etheridge p. 312
1906Thalassonomosaurus nobilis Williston
1906Elasmosaurus ischiadicus Williston p. 231
1906Elasmosaurus nobilis Williston pp. 232-233
1906Elasmosaurus sternbergi Williston p. 232
1910Elasmosauridae Andrews p. 77
1911Elasmosaurus orskensis Bogolubov p. 36 figs. pl. 14, figs 1-3
1911Elasmosaurus kurskensis Bogolubov p. 353
1911Elasmosaurus helmersenii Bogolubov p. 359
1911Elasmosaurus serdobensis Bogolubov p. 374 figs. pl. 14, figs 4-5
1914Pliosaurus macrospondylus Chapman p. 278
1914Pliosaurus sutherlandi Chapman p. 278
1914Plesiosaurus gigas Wegner p. 303
1914Elasmosauridae Wegner p. 304
1916Elasmosaurus amalitskii Pravoslavlev p. 315
1917Ogmodirus ischiadicus Williston and Moodie p. 61
1918Elasmosaurus hoodii Pravoslavlev p. 1955
1930Plesiosaurus gulo Hay p. 116
1930Elasmosauridae Hay p. 117
1930Elasmosaurus ischiadicus Hay p. 118
1930Elasmosaurus nobilis Hay p. 118
1930Elasmosaurus sternbergi Hay p. 118
1930Brimosaurus Hay p. 119
1940Elasmosauridae White p. 466 figs. 12a-c
1941Elasmosauridae Cabrera pp. 114-129
1943Elasmosauridae Welles
1943Thalassiosaurus ischiadicus Welles
1943Thalassonomosaurus nobilis Welles pp. 190-191 fig. 33
1946Elasmosauridae Kuhn p. 59
1949Alzadasaurus tropicus Colbert p. 4 figs. 3-9
1949Cimoliasaurus andium Colbert p. 19
1949Elasmosauridae Welles
1952Plesiosaurus mauritanicus Arambourg
1952Alzadasaurus kansasensis Welles
1959Cimoliasauridae Delair
1959Elasmosaurus gigas Persson p. 445
1960Cimoliosauridae Delair pp. 59-60
1960Elasmosauridae Delair p. 67
1960Woolungasaurus Persson
1960Woolungasaurus glendowerensis Persson p. 11 figs. Pl. 1, figs. 3, 4, Pls. 2, 3
1960Elasmosaurus helmerseni Persson p. 444
1962Elasmosauridae Welles p. 2
1962Alzadasaurus kansasensis Welles pp. 3 & 62
1963Cimoliasauridae Persson p. 6
1963Elasmosauridae Persson p. 7
1963Elasmosaurus kurskensis Persson p. 19
1963Elasmosaurus orskensis Persson p. 19
1963Elasmosaurus serdobensis Persson p. 19
1963Mauisaurus gardneri Persson p. 19
1963Woolungasaurus Persson p. 22
1964Cimoliasauridae Antunes p. 133
1966Cimoliasauridae Kuhn p. 117
1966Elasmosauridae Kuhn p. 117
1971Elasmosauridae Welles and Gregg p. 22
1981Elasmosauridae Brown p. 340
1981Elasmosauridae Thurmond and Jones p. 139
1986Elasmosauridae Wiffen and Moisley p. 207
1988Brimosaurus Carroll
1988Elasmosauridae Carroll
1988Woolungasaurus Carroll
1991Woolungasaurus glendowerensis Fordyce p. 1173
1993Elasmosauridae Gasparini and Spalletti p. 250
1999Elasmosauridae Carpenter p. 150
2000Elasmosauridae Gasparini and Salgado p. 14
2001Elasmosauridae Fostowicz-Frelik and Gazdzicki
2001Elasmosauridae Gasparini et al.
2001Cimoliasauridae O'Keefe p. 19 fig. 20
2001Elasmosauridae O'Keefe p. 19 fig. 20
2002Elasmosauridae Nicholls and Meckert p. 1593
2002Brimosaurus Sepkoski
2002Woolungasaurus Sepkoski
2003Elasmosauridae Gasparini et al. p. 105
2003Elasmosauridae Lazo and Cichowolski p. 785
2003Elasmosauridae Sato p. 90
2004Elasmosauridae Hiller and Mannering p. 1
2004Elasmosauridae Martinelli and Forasiepi p. 260
2004Cimoliasauridae O'Keefe p. 336 figs. Fig. 11
2005Elasmosauridae Hiller and Mannering p. 30
2005Elasmosauridae Schumacher and Everhart p. 48
2006Elasmosauridae Druckenmiller and Russell p. 186
2006Elasmosauridae Martin and Crame p. 113
2006Woolungasaurus glendowerensis Scanlon p. 283
2007Elasmosauridae Gasparini et al. p. 190
2008Elasmosauridae Previtera and González Riga
2009Elasmosauridae O'Keefe and Street p. 49
2009Elasmosauridae Otero et al. p. 345
2010Elasmosauridae Ketchum and Benson p. 15
2010Elasmosauridae O'Gorman and Varela
2011Elasmosauridae Ketchum and Benson p. 126
2011Elasmosauridae O'Gorman et al. p. 130
2012Elasmosauridae Mateus et al. p. 78
2012Elasmosauridae O'Gorman
2012Elasmosauridae Otero et al. p. 128
2013Elasmosauridae O'Gorman et al. p. 76
2013Elasmosauridae O'Gorman et al. p. 262
2013Elasmosauridae Otero and O'Gorman
2013Elasmosauridae Otero et al. p. 774
2014Elasmosauridae Benson and Druckenmiller p. 12 figs. 2-3
2014Elasmosauridae Hiller et al. p. 29
2014Elasmosauridae O'Gorman et al. p. 43
2014Elasmosauridae O'Gorman et al.
2014Elasmosauridae Otero et al.
2015Elasmosauridae Araujo et al. p. 94
2015Elasmosauridae Araújo et al. p. 2
2015Elasmosauridae Bardet et al. p. 11
2015Elasmosauridae Gasparini et al.
2015Elasmosauridae O'Gorman p. 190
2015Elasmosauridae O'Gorman et al. p. 376
2015Elasmosauridae O'Gorman et al.
2015Elasmosauridae Otero et al. p. 3
2015Elasmosauridae Otero et al. p. 242
2016Elasmosauridae O'Gorman p. 11
2016Elasmosauridae O'Gorman et al. p. 65
2016Elasmosauridae Otero et al.
2017Elasmosauridae Hiller et al.
2017Elasmosauridae O'Gorman and Coria p. 242
2017Elasmosauridae O'Gorman et al. p. 120
2017Elasmosauridae O'Keefe et al.
2017Elasmosauridae Sachs et al.
2017Elasmosauridae Serratos et al.
2018Elasmosauridae O'Gorman et al. p. 250
2018Elasmosauridae O'Gorman et al.
2018Elasmosauridae Otero et al. p. 216
2019Elasmosauridae O'Gorman
2019Elasmosauridae O'Gorman et al. p. 40
2019Elasmosauridae Páramo-Fonseca et al.
2020Elasmosauridae Miller et al. p. 97
2020Elasmosauridae O'Gorman
2020Elasmosauridae O’Gorman et al. p. 3
2021Elasmosauridae Marx et al. p. 9
2021Elasmosauridae O'Gorman
2021Elasmosauridae O'Gorman et al.
2021Elasmosauridae O'Gorman et al.
2021Elasmosauridae Otero and Soto-Acuña p. 7
2022Elasmosauridae Moyano-Paz et al. p. 17
2023Elasmosauridae O'Gorman et al.
2023Elasmosauridae O'Gorman and Otero p. 78
2024Elasmosauridae Otero p. 4

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Life
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
RankNameAuthor
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
Sauropsida
classReptilia
subclassEureptilia()
Romeriida
Diapsida()
suborderSauropterygia
orderPlesiosauriade Blainville 1835
superfamilyPlesiosauroideaWelles 1943
familyElasmosauridaeCope 1869
familyElasmosauridaeCope 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.

Fm. †Elasmosauridae Cope 1869 [elasmosaur]
show all | hide all
G. †Alexeyisaurus Sennikov and Arkhangelsky 2010
+
Alexeyisaurus karnoushenkoi Sennikov and Arkhangelsky 2010
Subfm. †Alzadasaurinae
+
G. †Alzadasaurus Welles 1943
G. †Ogmodirus Williston and Moodie 1913
+
Invalid names: Ogmodirus martinii Williston and Moodie 1917 [nomen dubium]
G. †Callawayasaurus Carpenter 1999
+
G. †Cardiocorax Araújo et al. 2015
+
Cardiocorax mukulu Araújo et al. 2015
G. †Chubutinectes O'Gorman et al. 2023
+
Chubutinectes carmeloi O'Gorman et al. 2023
G. †Cimoliasaurus Leidy 1851
+
Cimoliasaurus magnus Leidy 1851
Cimoliosaurus magnus Leidy 1851
Cimoliosaurus snowii Williston 1890
Invalid names: Brimosaurus grandis Leidy 1855 [nomen dubium], Cimoliasaurus brevior Lydekker 1889 [nomen dubium], Cimoliasaurus maccoyi Etheridge 1904 [nomen dubium], Hunosaurus Fritsch 1905 [synonym], Iserosaurus Fritsch 1905 [synonym]
G. †Eromangasaurus Kear 2005
+
Unr. †Euelasmosaurida O'Gorman 2019
+
+
G. †Albertonectes Kubo et al. 2012
+
Albertonectes vanderveldei Kubo et al. 2012
G. †Hydrotherosaurus Welles 1943
+
G. †Nakonanectes Serratos et al. 2017
+
Nakonanectes bradti Serratos et al. 2017
G. †Styxosaurus Welles 1943
+
Styxosaurus browni Welles 1952
Styxosaurus snowii Williston 1890
+
Invalid names: Alzadasaurus pembertoni Welles and Bump 1949 [synonym]
Invalid names: Hydralmosaurus Welles 1943 [synonym], Thalassonomosaurus marshii Williston 1906 [nomen dubium]
G. †Terminonatator Sato 2003
+
Invalid names: Styxosaurinae Otero 2016 [synonym]
G. †Libonectes Carpenter 1997 [southwest diver]
+
Libonectes morgani Welles 1949
+
Invalid names: Libonectes atlasense Buchy 2005 [synonym]
G. †Thalassomedon Welles 1943
+
+
Invalid names: Alzadasaurus riggsi Welles 1943 [synonym]
G. †Fluvionectes Campbell et al. 2021
+
Fluvionectes sloanae Campbell et al. 2021
G. †Fresnosaurus Welles 1943
+
Fresnosaurus drescheri Welles 1943
G. †Gronausaurus Hampe 2013
+
Gronausaurus wegneri Hampe 2013
G. †Jucha Fischer et al. 2020
+
Jucha squalea Fischer et al. 2020
Jucha squalea Fischer et al. 2020
Jucha squalea Fischer et al. 2020
G. †Lagenanectes Sachs et al. 2017
+
Lagenanectes richterae Sachs et al. 2017
G. †Leivanectes Páramo-Fonseca et al. 2019
+
Leivanectes bernardoi Páramo-Fonseca et al. 2019
G. †Leurospondylus Brown 1913
+
Leurospondylus ultimus Brown 1913
G. †Scanisaurus Persson 1960
G. †Stereosaurus Seeley 1869
G. †Thalassiosaurus Welles 1943
G. †Thalassonomosaurus Welles 1943
G. †Wapuskanectes Druckenmiller and Russell 2006
+
Wapuskanectes betsynichollsae Druckenmiller and Russell 2006
Unr. †Weddellonectia O'Gorman and Coria 2017
+
G. †Aphrosaurus Welles 1943
+
Aphrosaurus furlongi Welles 1943
Subfm. †Aristonectinae Otero et al. 2012
+
G. †Alexandronectes Otero et al. 2016
+
Alexandronectes zealandiensis Otero et al. 2016
G. †Aristonectes Cabrera 1941
+
Aristonectes parvidens Cabrera 1941
Aristonectes quiriquinensis Otero et al. 2014
Invalid names: Turneria Chatterjee and Small 1989 [synonym]
G. †Morturneria Chatterjee and Creisler 1994
+
Morturneria seymourensis Chatterjee and Creisler 1994
+
Invalid names: Turneria seymourensis Chatterjee and Small 1989 [replaced]
G. †Wunyelfia Otero and Soto-Acuña 2021
+
Wunyelfia maulensis Otero and Soto-Acuña 2021
Invalid names: Mauisaurus Hector 1874 [nomen dubium], Mauisaurus haasti Hector 1874 [nomen dubium], Tuarangisaurus cabazai Gasparini et al. 2003 [nomen dubium]
G. †Futabasaurus Sato et al. 2006
+
Futabasaurus suzukii Sato et al. 2006 [Futaba Suzuki Ryu]
G. †Kaiwhekea Cruickshank and Fordyce 2002
+
Kaiwhekea katiki Cruickshank and Fordyce 2002
G. †Kawanectes O'Gorman 2016
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Kawanectes lafquenianum Gasparini and Goni 1985
G. †Morenosaurus Welles 1943
+
Morenosaurus stocki Welles 1943
G. †Tuarangisaurus Wiffen and Moisley 1986
+
Tuarangisaurus keyesi Wiffen and Moisley 1986
G. †Vegasaurus O'Gorman et al. 2015
+
Vegasaurus molyi O'Gorman et al. 2015
G. †Zarafasaura Vincent et al. 2011
+
Zarafasaura oceanis Vincent et al. 2011
Invalid names: Alzadasaurus kansasensis Welles 1952 [nomen dubium], Alzadasaurus tropicus Colbert 1949 [nomen vanum], Cimoliasauridae Delair 1959 [synonym], Cimoliasaurus andium Deecke 1895 [nomen dubium], Cimoliasaurus cantabrigiensis Lydekker 1889 [nomen vanum], Cimoliasaurus caudalis Hutton 1894 [nomen vanum], Elasmosaurus amalitskii Pravoslavlev 1916 [nomen vanum], Elasmosaurus kurskensis Bogolubov 1911 [nomen vanum], Elasmosaurus orskensis Bogolubov 1911 [nomen vanum], Elasmosaurus serdobensis Bogolubov 1911 [nomen vanum], Elasmosaurus sternbergi Williston 1906 [nomen dubium], Mauisaurus gardneri Seeley 1878 [nomen vanum], Plesiosaurus constrictus Owen 1850 [nomen vanum], Plesiosaurus crassicostatus Owen 1870 [nomen vanum], Plesiosaurus gulo Cope 1872 [nomen dubium], Plesiosaurus gurgitis Renevier 1858 [nomen vanum], Plesiosaurus helmersenii Kiprijanoff 1882 [nomen vanum], Plesiosaurus holmesii Hector 1874 [nomen vanum], Plesiosaurus hoodii Owen 1870 [nomen vanum], Plesiosaurus mackayii Hector 1874 [nomen vanum], Plesiosaurus mauritanicus Arambourg 1952 [nomen dubium], Plesiosaurus sutherlandi McCoy 1867 [nomen dubium], Pliosaurus gigas Schröder 1885 [nomen vanum], Pliosaurus macrospondylus McCoy 1867 [nomen dubium], Thalassiosaurus ischiadicus Williston 1903 [nomen dubium], Thalassonomosaurus nobilis Williston 1906 [nomen dubium], Woolungasaurus Persson 1960 [nomen dubium], Woolungasaurus glendowerensis Persson 1960 [nomen dubium]
Diagnosis
ReferenceDiagnosis
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."
D. S. Brown 1981Plesiosauroidea 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."