| Meyerasaurus | |
|---|---|
 | |
| The holotype in the State Museum of Natural History Stuttgart | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Superorder: | †Sauropterygia |
| Order: | †Plesiosauria |
| Family: | †Rhomaleosauridae |
| Genus: | †Meyerasaurus Smith & Vincent,2010 |
| Species: | †M. victor |
| Binomial name | |
| †Meyerasaurus victor (Fraas, 1910 [originallyThaumatosaurus]) | |
| Synonyms | |
| |
Meyerasaurus is anextinctgenus ofrhomaleosauridplesiosaur known from theEarly Jurassic ofHolzmaden, Baden-Württemberg in southwesternGermany.[1]
Between Holzmaden andZell unter Aichelberg, a chalkstone and shale quarry was operated. It intersected an extremely hard forty centimetres thick layer ofStinkstein chalk, which was deemed worthless. Even ichthyosaur "mummies" present in the layer were discarded as it was not cost-effective to prepare them. The rocks were dumped in a ravine. In May 1906, the famous fossil traderBernhard Hauff discovered in the dump broken-up boulders containing an uniquely complete and thus very rare plesiosaur skeleton. Up till that time, German plesiosaurs finds had tended to be much more fragmentary than British discoveries. Over nine months he recovered 2.5 tonnes of chalkstone, exposing and preparing the bones. Together with a second plesiosaurian skeleton, discovered nearby in shale in November 1906, much later referred toSeeleyosaurus, it was offered for sale. Financial support by D. Landauer and Victor Fraas allowed theStuttgarter Königliche Naturalienkabinett to obtain both specimens.[2]
In 1910Eberhard Fraas, the paleontology curator of the Stuttgart institution, named the specimen asThaumatosaurus victor. This name was mentioned on page 106 of the describing article. The heading of the description section on page 124 reads "Plesiosaurus (Thaumatosaurus) victor n. sp." which has been interpreted as his naming aPlesiosaurus victor coinciding with an immediate renaming into aThaumatosaurus victor. Fraas, after explaining that he preferredThaumatosaurus ("wonder reptile") Meyer overRhomaleosaurus Seeley, states "I name our new speciesThaumatosaurus victor".[2][3] The specific namevictor, "winner" inLatin, refers to the specimen being a "magnificent and all previous discoveries in beauty exceeding find" but also explicitly honours E. Fraas's brother Victor Fraas.[2]
Already by 1922, it was recognised that the type material ofThaumatosaurus oolithicus was very poor.[4] In 1932,T. victor was renamed as a species ofEurycleidus[5] and in 1960 byLambert Beverly Tarlo asRhomaleosaurus victor.[6] However, these names were rarely used. In 2007, Adam Stuart Smith announced that he would shortly name a separate genus for the taxon asThaumatosaurus was basically anomen dubium.[7]
Meyerasaurus was first named by Adam S. Smith and Peggy Vincent in2010 and thecombinatio nova isMeyerasaurus victor. Thegeneric name honors the German palaeontologistHermann von Meyer for proposing the generic nameThaumatosaurus.[1]
Meyerasaurus is known from theholotypeSMNS 12478, an articulated and completeskeleton which preserves theskull, exposed inventral view. It has a skull length of 37 centimetres (1 ft 3 in) and a body length of 3.35–3.44 m (11.0–11.3 ft).[1][7] It was collected from theHarpoceras elegantulum-falciferum ammonoid subzones,Harpoceras falcifer zone, of the famous Posidonien-Schieferlagerstätte (Posidonia Shale), dating to the earlyToarcian stage of theEarly Jurassic, about 183-180million years ago.[1]
In 1944,Stuttgart was repeatedly bombed. On 12 September, British bombers caused a firestorm that burnt the inner city. The museum was destroyed and the holotype smashed to pieces. However, this allowed to painstakingly salvage these from under the rubble and put it together again. It is now displayed in the new paleontology exhibition building, theMuseum am Löwentor.
Thecladogram below showsMeyerasaurus phylogenetic position among other plesiosaurs, following Bensonet al. (2012).[8]
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