This passage is comparing the late Plesiosaurian genera Elasmosaurus and Cimiolasaurus: It is not certain that Elasmosaurus was a fast swimmer because its very long neck must have made it awkward. However, the other Plesiosaur was not of a type that would have gone after Elasmosaurus, it ate smallish fishes and squids instead.
(Sometimes spelled as Cimoliosaurus)
Named By: Joseph Liedy - 1851.
Synonyms: Cimoliasaurus brevior, Cimoliasaurus maccoyi, Discosaurus, Oligosimus, Piptomerus.
Classification: Chordata, Reptilia, Sauropterygia, Pleisoauria.
Species: C. magnus, C. valdensis, C. snowii.
Diet: Probably piscivorous.
Size: Uncertain sue to the assemblage of remains and partial incomplete preservation of many specimens.
Known locations: Europe, North America and Australasia. *Possibly not an accurate representation of the genus.
Time period: Cretaceous (sometimes credited as mid Jurassic to end of the Cretaceous). *Possibly not an accurate representation of the genus.[**Some specimens indicated as Post-Cretaceous when originally collected, Particularly the New Jersey specimens-DD]
Fossil representation: Multiple partial and incomplete remains. Possibly not all indicative of the genus.
Because of this the validity of Cimoliasaurus as a genus remains dubious, but more may come from the remains attributed to Cimoliasaurus such as the discovery of new plesiosaur genera. This has happened already with the creation of the species Cimoliasaurus laramiensis by Knight in 1900, which was renamed as a species of Tricleidus (T. laramiensis) by Mehl in 1912 before eventually being raised as a new genus called Tatenectes by O'Keefe and Wahl in 2003.
With more in depth study it is probable that one day Cimoliasaurus may one day be cleaned up enough to get an accurate description of a specific genus. Such cases of a wastebasket taxon being cleaned up is nothing new, with one of the best known examples being that for the dinosaur Megalosaurus.
Aristonectes (meaning 'best swimmer') is an extinct genus of plesiosaur from the Late Cretaceous of what is now South America and Antarctica. The type species is Aristonectes parvidens, first named by Cabrera in 1941. [Having been called called Cimiolasaurus before then]
Aristonectes has been classified variously since the 1941 description, but a 2003 review of plesiosaurs conducted by Gasparini et al. found that Aristonectes was most closely related to elasmosaurid plesiosaurs like Elasmosaurus. A similar plesiosaur, Morturneria, may be a junior synonym of Aristonectes, the study found.
Aristonectes has been recently placed within its own family, along with Tatenectes, Kaiwhekea, and Kimmerosaurus, by O'Keefe and Street (2009). Aristonectids are the sister family of the polycotylid cryptoclidoids.
- Gasparini, Z., Bardet, N., Martin, J.E. and Fernandez, M.S. (2003) "The elasmosaurid plesiosaur Aristonectes Cabreta from the Latest Cretaceous of South America and Antarctica". Journal of Vertebrate Paleontology 23(1): 104-115
|Skeleton of a related genus presumably in the same family, with reconstructed outline.|
It should be noted that fossils of this family have been taken to indicate that the creatures were more tolerant of cold climate (including Antarctica!) and to be able to tolerate either freshwater or saltwater. They are modest-sized as Plesiosaurs go, mostly in the range of 15-30 feet long as adults. This also might be all we need for our purposes in dealing with Longnecked Cryptids reported in more modern times.