Thursday, 2 November 2017

PrehiscotInktoberfest Day 2: Leptopleuron lacertinum

PrehiscotInktoberfest continues with another cool wee beastie from Elgin's fossil beds - and one with an interesting history of discovery.

Leptopleuron lacertinum ("slender ribs of a lizard") is a procolophonid, a creature which is similar to but taxonomically destinct from modern reptiles. Leptopleuron has a bit of controversy in its discovery: it was the focus of one of many disagreements between palaeontological giants Richard Owen and Gideon Mantell. The discoverer - whose name is sadly lost to history - originally sent the fossil skull to London for a formal description. Richard Owen. Owen published a brief account, naming it Leptopleuron and that seemed to be that. However, at the same time, Gideon Mantell was also working on a more detailed description, allegedly at the request of the discoverer: he named it Telerpeton elginense ("faraway reptile of Elgin"). It was only in the 1980s that previously unpublished archive materials deepen the controversy - it was in fact the great Scottish geologist Charles Lyell who approached Mantell, in the full knowledge that Owen was working on a description.

It's important to note that the 1850s was a time of great change in the field of palaeontology: Darwin was just getting started, and even revolutionaries like Lyell were skeptical of conventions we take for granted today. At this point, Lyell was a strong opponent of progressionism - the hypothesis that lifeforms evolve based upon internal mechanisms towards a goal - and he viewed Leptopleuron as evidence against that hypothesis. Since he and Owens did not get along at the best of times, it is sadly typical of the times for palaeontologists to engage in such conflicts. In the end, Owen's description was published first, and the name stuck: by 1860, Lyell was convinced of the merits of progressionism, and became a good friend of Charles Darwin himself.

For such a controversial fossil, Leptopleuron was a very small thing, estimated to only 270mm, with a notably long tail compared to its family members. The horned, triangular skull and pronounced overbite elicit comparisons to the modern horned sand lizard, suggesting that Leptopleuron was a burrowing creature.

It also reminds me a bit of a little tiny dragon with its horns and fangs: fossil evidence for fire breathing is slim.

"Ah'm naw cute! Ah'm a fearfu beastie frae time's abyss! FEAR ME!"

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