Luck o’ the Lepospondyls

17 March 2010

By Nobu Tamura / Creative Commons 2.5 Attribution Generic

There once was a beast from Kilkenny

Whose legs were so few there waren’t any

You could call him a snake

But tha’d be a mistake:

‘Though scaly, the beast was amphibiany

Yeah, I know, that last line could use some work.  But, you try rhyming something with “aïstopod.”

The critter in question is Ophiderpeton the closest thing that Ireland has (or rather, has had) to a snake, so far as we know.  It’s quite possible that there were snakes in Ireland before the Pleistocene but so far no one has produced the fossil evidence to prove it.  At any rate, there’s no real reason to blame Roman-Briton missionaries for the depauperate herpetofauna of the Emerald Isle.

The genus was described by T.H. Huxley in 1866 based on Carboniferous fossils found in an Irish Coal Mine.  Huxley wrote a letter to geologist Charles Lyell about the discovery:

My dear Sir Charles–I returned last night from a hasty journey to Ireland, whither I betook myself on Thursday night, being attracted vulture-wise by the scent of a quantity of carboniferous corpses. The journey was as well worth the trouble as any I ever undertook, seeing that in a morning’s work I turned out ten genera of vertebrate animals of which five are certainly new; and of these four are Labyrinthodonts, amphibia of new types. These four are baptised Ophiderpeton, Lepterpeton, Ichthyerpeton, Keraterpeton. They have ossified spinal columns and limbs. The special interest atttaching to the two first is that they represent a type of Labyrinthodonts hitherto unknown, and corresponding with Siren and Amphiuma among living Amphbia. Ophiderpeton, for example, is like an eel, about three feet long with small fore legs and rudimentary hind ones.

In the year of grace 1861, there were three genera of European carboniferous Labyrinthodonts known, Archegosaurus, Scleroceplus, Parabatrachus.

The vertebral column of Archegosaurus was alone known, and it was in a remarkably imperfect state of ossification. Since that date, by a succession of odd chances, seven new genera have come into my hands, and of these six certainly have well-ossified and developed vertebral columns.

I reckon there are now about thirty genera of Labyrinthodonts known from all parts of the world and all deposits. Of these eleven have been established by myself in the course of the last half-dozen years, upon remains which have come into my hands by the merest chance.

Five and twenty years ago, all the world but yourself believed that a vertebrate animal of higher organisation than a fish in the carboniferous rocks never existed. I think the whole story is not a bad comment upon negative evidence. (T.H. Huxley to C. Lyell 1865)

I would love to tell you more about Aïstopods, a bizarre group of limbless amphibians that invented “snakiness” about 200 million years before actual snakes came along, but, I’ve got a St. Patrick’s Day party to go to.  So why don’t I just take the easy way out and divert you over to TetZoo.  Have fun, but please come back safe.

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