The unusual fossil mammal skull posted here yesterday was, of course, that of the astrapotheriid astrapothere Astrapotherium magnum, as many as you said. But I’m a bit surprised that more people didn’t get it straight away, given that astrapotheres were covered and covered again at Tet Zoo only a couple of months ago. However, I suppose that reading about something doesn’t necessarily mean that you know how to identify its fossils… I’m still planning to post a write-up of the CEE Functional Anatomy meeting here ASAP, but haven’t had time to finish it yet. Meanwhile…
… the modern animal shown above is an enigmatic British lizard, captured at Great Goswell Copse, Hampshire (southern England), by ecologist Dave Hubble. Dave took this photo in 1995. The lizard’s colour is bizarre. It’s a lacertid, and neither of our two native lacertids (Viviparous lizard Zootoca vivipara and Sand lizard Lacerta agilis) look at all like this. Yes, we have those (probably alien) Green lizards (L. bilineata… and perhaps L. trilineata too), but they look nothing like this either. And we have lots of Wall lizards Podarcis muralis too (go here for more), but they’re entirely different as well (sharper snout, longer limbs etc.). The conclusion seems to be that this specimen is a freaky mutant Viviparous lizard, an identification supported by the animal’s head scalation. You probably know of the Viviparous lizard as Lacerta vivipara: however, Mayer & Bischoff (1996) argued that the traditionally conceived version of this genus is horrendously paraphyletic and that multiple species must be removed and given their own (usually old) generic names. Indeed the rampant paraphyly of traditional ‘Lacerta‘ has been quite widely recognised (e.g., Arnold 1989, Fu 1998, 2000). Zootoca isn’t a new name, but was coined by Wagler in 1830. Mean to do more on European lacertids some time: some real surprises in there what with the evolution of giantism, herbivory, viviparity, and incipient adaptation to marine life, and don’t forget the super-rapid morphological evolution just documented in an introduced colony of Podarcis sicula by Herrel et al. (2008)*. Thanks to Dave for use of the image.
* Within the space of 36 years, a colony introduced to a Croatian island have evolved herbivory and now have more voluminous guts than other P. sicula populations. The Croatian herbivores also have caecal valves – an anatomical novelty not present in other P. sicula populations and in fact rare in lizards as a whole – and a more robust cranial architecture than populations of the species elsewhere. Incidentally, this was not the lacertid population featured on Attenborough’s Life in Cold Blood – those were P. lilfordi, and their recent evolutionary history is an altogether different (but no less astonishing) story (so far it’s only been publish in abstracts and we have yet to see the full paper, to my knowledge).
Oh yeah – and am in the field this weekend in search of native reptiles. Will hopefully see Smooth snake Coronella austriaca, our only constricting colubrid. Yes – we have constricting snakes in Britain!
Refs – –
Arnold, E. N. 1989. Towards a phylogeny and biogeography of the Lacertidae: relationships within an Old-World family of lizards derived from morphology. Bulletin of British Museum of Natural History (Zoology) 55, 209-257.
Fu, J. 1998. Toward the phylogeny of the family Lacertidae: implications from mitochondrial DNA 12S and 16S gene sequences (Reptilia: Squamata). Molecular Phylogenetics and Evolution 9, 118-130.
– . 2000. Toward the phylogeny of the family Lacertidae – why 4708 base pairs of mtDNA sequences cannot draw the picture. Biological Journal of Linnean Society 71, 203-217.
Herrel, A., Huyghe, K., Vanhooydonck, B., Backeljau, T., Breugelmans, K., Grbac, I., Van Damme, R. & Irschick, D. J. 2008. Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource. Proceedings of the National Academy of Sciences 105, 4792-4795.
Mayer, W. & Bischoff, W. 1996. Beiträge zur taxonomischen Revision der Gattung Lacerta (Reptilia: Lacertidae). Teil 1. Zootoca, Omanasaura, Timon und Tiera als eigenständige Gattungen. Salamandra 32, 163-170.