Chinese Istiodactylids – what’s not to like?

OK, so I am being facetious with the title since very few people have even heard of the istiodactylids, let alone Chinese ones, and in this case we are mostly dealing with just a lower jaw. Still, you can get a lot even from a single bone when it’s the right bone and this is a nice demonstration of that. Or alternatively, it’s only of even vague interest to really obsessed pterosaur nuts, but as it is reported in a paper from the Zitteliana volume by my friend Jungchang Lü, you are going to have top read about it. Unless you have already clicked onto another site that is. Oh…

Well, I’ll assume at least one of you carried on reading, so here is the review. First off, istiodactylids are one of those groups that crop up in palaeontology from time to time to make life more interesting. They have really diagnostic characters which means we can pretty much instantly recognise them and won’t get them mixed up with other groups, and they appear to be really quite unusual which makes them potentially very interesting. However, until recently they were mostly known only from a few isolated bits, so while they clearly were different and exciting, it was hard to say much beyond that. They are pterodacyloid pterosaurs from the Early Cretaceous of Eurasia that are characterised but having very rounded jaw tips with lots of teeth pack in there, but nowhere else, giving them a bit of a cookie-cutter appearance. There are several species of istiodacytlid known in China (perhaps inevitably, there seems to be several of everything over here once you start looking) and here two of them are given the once over with redescriptions and new photos which are always welcome. This is largely a nuts-and-bolts descriptive paper of the kind which is always needed. It’s really hard to do good research without the basic tools of information about fossil specimens so any good description or redescription of a specimen in generally valuable. (Istiodactylid reconstruction below courtesy of Mark Witton).

Liaoxipterus is known from a single lower jaw and hyoid apparatus (those are the bones that support the tongue – a much underappreciated set of bones, more on them at some point) which as I say does not sound like much, but is in fact most interesting. This is one of the few hyoids preserved for pterosaurs in good condition and of course one can extrapolate much about the size of the animal just from the jaws and the teeth are (as far as I am aware) a little unusual for istiodactylids (though I have already written pretty much everything I know about them, so I could be wrong). Also since it is nice diagnostic we can be certain that it is indeed different to the other istiodactlyids and thus increases the known diversity of the group, even when known from so little material.

Longchengpterus (seen at the top) is rather more complete with a partial skull and almost complete shoulder girdle and forelimb and some vertebral and other bits also being preserved. There are some potentially interesting, but subtle, differences in tooth and jaw morphology going on between these two taxa, and the other Chinese istiodactyloids which adds some issues over identifications and in this paper the authors suggest that the genus Nurhachius is in fact just a junior synonym of Liaoxipterus.

That’s it really, the paper as a whole is just a short review of a couple of species. It may not be much, but when information on such unusual animals is at a premium, everything is good to have. The istiodactyloids are a group that get little attention, at least in part through their poor fossil record compared to many other, and of course not everyone can just waltz over to Beijing to look at a couple of fossils on a whim, and thus these kinds of papers are essential to integrative research.

Lü, J., Li, X. & Ji, Q. 2008. Restudy of Liaoxipterus (Istiodactylidea: Pterosauria), with comments on the Chinese istiodactylid pterosaurs.