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Seeleyosaurus guilelmiimperatoris

Reptilia - Sauropterygia - Microcleididae

Taxonomy
Plesiosaurus guilelmiimperatoris was named by Dames (1895). Its type specimen is MB.R.1992, a skeleton, and it is a 3D body fossil. Its type locality is Hauff slate quarry, Holzmaden, epsilon II/4, SMNS, which is in a Falciferum marine shale in the Posidonia Shale Formation of Germany. It is the type species of Plesiosaurus.

It was recombined as Seeleyosaurus guilelmiimperatoris by Grossmann (2007) and Benson et al. (2012).

Synonyms
Synonymy list
YearName and author
1895Plesiosaurus guilelmiimperatoris Dames p. 16 figs. Plates 1-3
1910Plesiosaurus guilelmiimperatoris Fraas p. 106 figs. Figs 1-5; Plates 6, 7; Plate 10, fig. 6
1940Seeleyosaurus holzmadensis White p. 461
1963Plesiosaurus guilelmiimperatoris Persson p. 20
1997Plesiosaurus guilelmiimperatoris Storrs p. 150
2001Plesiosaurus guilelmiimperatoris O'Keefe p. 11
2007Seeleyosaurus guilelmiimperatoris Grossmann pp. 545-546 figs. 2-6
2012Seeleyosaurus guilelmiimperatoris Benson et al.

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RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
phylumChordataHaeckel 1847
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
Sarcopterygii
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda()
Reptiliomorpha
Anthracosauria
Batrachosauria()
RankNameAuthor
Cotylosauria()
Amniota
Sauropsida
classReptilia
subclassEureptilia()
Romeriida
Diapsida()
orderSauropterygia
Pistosauria(Baur 1890)
Plesiosauria(de Blainville 1835)
superfamilyPlesiosauroideaWelles 1943
familyMicrocleididae
genusSeeleyosaurus
speciesguilelmiimperatoris()

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
ReferenceDiagnosis
F. Grossmann 2007Moderate-sized plesiosauroid, adults up to 3Æ5 m in length with a skull length of c. 170 mm, temporal openings approximately the same size as the orbits; five premaxillary teeth, a maximum of 20 maxillary teeth, smaller teeth directly around the premaxillary-maxillary suture and 4–5 enlarged teeth in both premaxilla and maxilla near the premaxillary-maxillary suture; teeth with fine striae on the lingual side and distinctly less pronounced or absent striae on the buccal side; maxilla with a long posteroventral process reaching approximately to the middle of the jugal; small parietal foramen situated at the frontal-parietal suture; parasphenoid of oblong form without cultriform process and anterior interpterygoid vacuity with rounded posterior margin; straight pterygoid-ectopterygoid suture; four proximal carpals and tarsals; maximum number of phalanges more than ten in the third digit; limbs long, c. 25 per cent of the overall body length in adults.