Palaeontology

How does one pronounce the names?

Question

I am looking for a guide to the pronunciation and meanings of the names of all the species. DO you have any suggestions about where I could look?

Answer

Try this web site: "http://www.dinosauria.com/dml/names/ples.html

How do I identify teeth and vertebrae?

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I'm an undergrad at Uni of Queensland, Australia, and I'm doing a special project on a plesiosaur (sensu lato) specimen kept at the Queensland Museum. Amoungst the mostly fragmentary material are some good vertebrae (with neural arches), girdle bits and teeth. Some badly damaged skull and other material was also collected. Vertebrae (and perhaps girdle fragments) look like the best bet for identifying what type of beastie it was. So I'm looking for literature that includes these parts of anatomy against which I can compare these... I've found a few articles along these lines, but library database searches show over 600 articles on plesiosaurs. Currently I'm checking through these to see which are applicable (and a suprisingly high amount aren't held at our local libraries). Do you know of a couple of good articles that describe and compare vertebrae? Or even girdle and teeth?

Answer

There are no good articles or papers comparing vertebrae or teeth - you need to trawl through the literature, I'm afraid.

Teeth are reasonably good for general guidance. Pliosaurs have big, robust, conical teeth, usually marked by striations running from root to tip. Elasmosaur teeth are more slender, less prominently marked, but still fairly robust. Cryptoclidid teeth are very slender, and frequently lightly or partially ornamented. However, they tend to give more information on feeding strategies than taxonomy (Massare, 1987).

Richard Owen is notorious for having erecting taxa based on single vertebrae, and this habit has caused great confusion in plesiosaur taxonomy, and given diagnosis based on vertebrae a bad name. The morphology of vertebrae varies ontogenetically (Brown 1981) as well as along the vertebral column. I'm currently researching the use of the ways in which we can use vertebral centra taxonomically, but have not yet reached as stage at which I can apply my methods with confidence.

Girdles have been used in the past for taxonomic identification, but need to be treated with caution. Their form changes during growth, and mistakes have been made in the past. David Brown's 1981 paper and C.W.Andrews monograph on the Oxford Clay (1910-13)are essential reading in this respect. D.M.S. Watson (1924) looked at the shoulder girdle taxonomically, but over a limited range of material. There are also papers by Andrews (1895) on the shoulder girdles of Cryptoclidus and Muraenosaurus.

Your main problem is that these do not cover the material you are looking at. As far as I know (and I'm no great expert on Australian material) the Queensland material is Cretaceous rather than Jurassic as is so much of the British and European material. You need to work back from the known genera to narrow down your field of investigation. If the material is very large, it is most likely Kronosaurus, of which I'm sure you are aware. Colin McHenry should be in the process of finishing his PhD on Kronosaurus. He is working at the Age of Fishes Museum in Canowindra (email: [email protected]) though he's a bit preoccupied with his first-born at the moment.

Looking at the smaller forms, we have Leptoclidus (see Andrews 1922; Cruickshank & Long, 1997; Cruickshank 1997), well known as the opalised plesiosaur 'Eric'. Woolungasaurus, an elasmosaur, is also known. (Thulborn & Turner, 1993). Arthur Cruickshank and Ewan Fordyce have a paper in press at the moment on a cryptoclidid Kaiwheikia, but I'm not sure when this will appear. It may be worth having a close look at the fragmentary skull material to see what you can find.

Plesiosaur skulls were full of cartilage and poorly ossified, and usually fell to pieces during taphonomy so they usually need a lot of work to find out their morphology. My colleague Mark Evans has just published a paper (1999) on the skull of Muraenosaurus based on very limited material. A lot of plesiosaur taxonomy is based on skull morphology (Andrews 1896, 1897 and 1910, Brown 1981 and 1993, Cope 1894, Brown & Cruickshank 1994, Storrs & Taylor 1996, Taylor 1992 and 1993, White 1935, Williston 1890 and 1907).

Are there any skin impressions from plesiosaurs?

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I just read Allen Debus article on Kronosaurus in Fossil News v. 7, n. 3. He said that a Jurassic Pliosaur had been found with skin impressions. I’ve never heard about this, has anyone else? As far as I know there isn’t any skin impression in sauropterygians.

Answer

As far as I'm aware there are no reported cases of skin impressions in any of the pliosaurs. The tail of Liopleurodon ferox is commonly reconstructed with a tail vane, but this is based on a specimen of the plesiosaur Plesiosaurus guilelmi imperatoris DAMES 1895 from the German Lias, in which soft tissue has apparently been preserved. However, the specimen may have been 'doctored' like some of the Holzmaden ichthyosaurs where a larger area of apparent soft part preservation has been shaped to give an expected outline.