Pages and pages and pages

Ichthyosaurs: a day in the life… is growing, the website that is. Following a hectic week of much reference checking and cross-checking, I have compiled a list: a list of ichthyosaurs.

You can find this list in the new ‘Ichthyosaur palaeontology’ tab at the top of the page. From that I’m sure that you can guess my aspirations. While there are many aspects of ichthyosaur palaeontology that can change rapidly, having such basic data can be important to keep up stock of the science. It also provides the ‘canvas’ to be worked upon within any particular group.

Taxonomy-nommy-nom-nom

This list is on the page entitled ‘Ichthyosaur taxonomy’. Taxonomy is the study of classifying organisms; plants, fungi, animals and more. Particularly, taxonomy, specifically ‘alpha taxonomy’ is concerned with the description, identification and naming of organisms. So this page of ichthyosaur taxonomy features a list of all valid ichthyosaur names, arranged alphabetically. As I’ve said before, and reminded last week, the naming of organisms is regulated by the International Code of Zoological Nomenclature. Each name has two parts: generic and specific, usually with the name of the first author following this.

The author included is the first to describe and name the species itself, so includes the author(s) surnames and the year of publication. This may or may not be enclosed in brackets: no brackets means that the name is the same as originally published, e.g. Cymbospondylus piscosus Leidy, 1868 was first named by Leidy in 1868, and hasn’t been changed.

Sometimes, the names of organisms can change. This may be because the name is given to a species which has been named before, or if the name has been used before. It can also happen if new material means that the genus should be changed. An example would be Ichthyosaurus enthekiodon Hulke, 1871 (as originally named by Hulke in 1871). The generic name was changed by Huene in 1922 to separate it from other Ichthyosaurus. So the genus is Nannopterygius Huene, 1922, but the species became Nannopterygius enthekiodon (Hulke, 1871).

The list itself

There are a few things that can be taken simply from the list, mostly related to diversity. The 108 98 species in 53 genera mean that many genera have only a single species. This is at odds with the state about 100 years ago, when all species were placed in only a few taxa (Ichthyosaurus was the only genus from 1818 until 1874, when Seeley erected Ophthalmosaurus). That situation is still found, particularly in the Cretaceous genus Platypterygius (11 genera), but also in Ichthyosaurus (5 genera), Temnodontosaurus (5 genera) and Ophthalmosaurus (4 genera). McGowan and Motani (2003, Handbook of Paleoherpetology) suggested that some genera should be synonymised, including questioning the relatively high diversity from the Middle Triassic Grenzbitumenzone in Switzerland and Italy. A later version will hopefully include all non-valid taxa, for whatever reason, too. This will show the development of ichthyosaur study through time.