Saturday, December 19, 2015

The Giving of December. Cetiosauriscus

Cetiosauriscus is often confused with the similarly named Cetiosaurus,‭ ‬and this is no accident.‭ ‬The name Cetiosauriscus means‭ ‘‬whale-lizard-like‭’‬,‭ ‬a reference to Cetiosaurus which itself means‭ ‘‬whale-lizard‭’‬,‭ ‬so when Friedrich von Huene named the genus in‭ ‬1927,‭ ‬he was actually saying that Cetiosauriscus was similar to Cetiosaurus.‭ ‬When the genus was first named the type species of Cetiosauriscus was C.‭ ‬leedsi,‭ ‬however later studies cast doubt upon the validity of the type fossil material used to designate this species.‭ ‬In what was a landmark study for the Cetiosauriscus genus,‭ ‬A.‭ ‬J.‭ ‬Charig named a new species of Cetiosauriscus as C.‭ ‬stewarti,‭ ‬based upon a partial post cranial skeleton‭ (‬BMNH R.3078‭) ‬found near the town of Peterborough.‭ ‬Noting that other species of Cetiosauriscus,‭ ‬including the type species were dubious on the grounds that the remains were fairly indistinct,‭ ‬Charig successfully petitioned the ICZN‭ (‬The body that governs the naming of animals‭) ‬to make Cetiosauriscus stewarti the genoholotype of Cetiosauriscus.‭ ‬What this means is that from now on all fossil material submitted to the Cetiosauriscus genus must now be compared to the fossils of C.‭ ‬stewarti and not C.‭ ‬leedsi before being added as new specimens.
       Although the basis of the name Cetiosauriscus means a similarity to Cetiosaurus‭ ‬von Huene himself noted that Cetiosauriscus had much longer vertebrae than those attributed to Cetiosaurus.‭ ‬Because of the length of these vertebrae,‭ ‬Cetiosauriscus has been identified as a possible diplodocid sauropod dinosaur‭ (‬similar to Diplodocus‭) ‬upon more than one occasion.‭ ‬The type fossil material of C.‭ ‬stewarti‭ (‬BMNH R.3078‭) ‬has even been reported as possibly containing the whiplash of the tail that is commonly associated with diplodocid sauropods.‭ ‬If the interpretation of Cetiosauriscus as a diplodocid is correct,‭ ‬then Cetiosauriscus may well represent one of if not the earliest appearance of a sauropod dinosaur.‭ ‬However a‭ ‬2007‭ ‬paper‭ (‬Naish‭ & ‬Martill‭) ‬cast some doubt upon the diplodocid interpretation,‭ ‬stating that the vertebrae of Cetiosauriscus are also similar to those of the mamenchisaurid sauropods‭ (‬similar to Mamenchisaurus‭)‬.

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