Thursday, September 15, 2011

Nile crocodile is two species : Nature News

Still waiting for the formal description, but very interesting implications for Nile crocodiles.

Nile crocodile is two species : Nature News:

'via Blog this'

UPDATE: Here's a link to the recently-published paper by Hekkala et al.


sigourd said...

It's moments like this that remind me why I want to get in to Reptile Taxonomy. Must get better at genetics lol

Jahn Hornung said...

I think there is hardly any doubt after the initial Schmitz et al. (2003) and the more comprehensive Hekkala et al. (2011) studies that there exists a separate West African Crocodile (I would prefer this common name over 'Desert Crocodile' as most of its population lives south of the Sahara). However I have two issues with it:

1) It has been constantly stated that the correct binomen of this species is C. suchus Geoffroy, 1807. This was based in the first on the fact that this was the oldest available synonym of C. niloticus Laurenti 1768 and further supportet by the fact that Geoffroy based it on a mummified specimen from Egypt. Although all of the tested mummies seem to belong to the West African Croc, to my knowledge the holotype of C. suchus (still existant?) was not tested yet. And Geoffroy (1807, 1827) described 4 species of crocodile from ancient Egypt. So other names applicable may be C. marginatus, C. lacunosus, or C. complanatus (all from 1827). If the type of C. suchus is lost and one of the others can be tested positively to be a West African Croc one should consider to ressurrect its name (e.g. by an ICZN decision). In the worst case (no type specimen can be tested) one will have to coin a new name, or apply an older name to a new type, again by ICZN decision.

2) However, it is more aggravating that -while being well separated in genetic studies- there is still a lack of a clear phenotypical diagnosis of the West African species. This seems to be a problem especially for conservational purposes, for the determination of collection specimens, and of subfossil and fossil specimens. The latter are especially concerned as there seem to have been a larger overlap in range of both species during the early and mid Holocene (Hekkala et al. 2011).

Jahn Hornung