Seeleyosaurus Explained

Seeleyosaurus is an extinct genus of plesiosaur that was initially placed within the genus Plesiosaurus in 1895^[1] and was given its own genus in 1940.^[2] Two species were known: the type, S. guilelmiimperatoris, and the now obsolete species S. holzmadensis, which has since been absorbed into S. guilelmiimperatoris. It was a relatively small plesiosaur, measuring long.^{[3] [4]} The holotype is MB.R.1992, a large almost complete skeleton from the Upper Lias (Toarcian) Lias Group Formations of Württemberg, Germany. There seems to be the impression of a rhomboidal flap of skin in a vertical plane; if so, many plesiosaurs may have been equipped in this way.^[5] A second specimen (SMNS 12039), preserved in 3D, is the holotype of S. holzmadensis.

Classification

The following cladogram follows an analysis by Ketchum & Benson, 2011.^[5]

See also

• List of plesiosaur genera
• Timeline of plesiosaur research

References

1. Dames, H. W. (1895). Die Plesiosaurier der süddeutschen Liasformation. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin 2:1-83
2. White, T. E. (1940). Holotype of Plesiosaurus longirostris Blake and classification of the plesiosaurs. Journal of Paleontology 14(5):451-467
3. Peggy Vincent . 2011 . A re-examination of Hauffiosaurus zanoni, a pliosauriod from the Toarcian (Early Jurassic) of Germany . Journal of Vertebrate Paleontology . 31 . 2 . 340–351 . 10.1080/02724634.2011.550352 . 2011JVPal..31..340V . 84743241 .
4. Valentin Fischer . Nikolay G. Zverkov . Maxim S. Arkhangelsky . Ilya M. Stenshin . Ivan V. Blagovetshensky . Gleb N. Uspensky . 2020 . A new elasmosaurid plesiosaurian from the Early Cretaceous of Russia marks an early attempt at neck elongation . Zoological Journal of the Linnean Society . 192 . 4 . 1167–1194 . 10.1093/zoolinnean/zlaa103 . 2268/251614 . Supplementary Information
5. Hillary F. . Ketchum . Roger B.J. . Benson . 2011 . A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids . Special Papers in Palaeontology . 86 . 109–129 .