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Re: Reptilian feats: Atlantic-swimming crocodiles and cooperative lizard burrow-digging



On Fri, May 13th, 2011 at 11:23 AM, "bh480@scn.org" <bh480@scn.org> wrote:

> OK--this is not dinosaur stuff but it shows that archosaurs and squamates
> should not be underestimated.
> 
> Crocodiles swam Atlantic from Africa to Americas
> http://www.newscientist.com/article/dn20464-crocodiles-swam-the-atlantic-to-
> reach-america.html
> 
> 
> Robert W. Meredith, Evon R. Hekkala, George Amato and John Gatesy (2011)
> A phylogenetic hypothesis for Crocodylus (Crocodylia) based on
> mitochondrial DNA: Evidence for a trans-Atlantic voyage from Africa to the
> New World. 
> Molecular Phylogenetics and Evolution (advance publication)
> doi:10.1016/j.ympev.2011.03.026 
> 
> The phylogenetic relationships among extant species of Crocodylus
> (Crocodylia) have been inconsistently resolved by previous systematic
> studies. Here we used nearly complete mitochondrial (mt) genomes (16,200
> base pairs) for all described Crocodylus species, eight of which are new to
> this study, to derive a generally well-supported phylogenetic hypothesis
> for the genus. Model-based analyses support monophyly of all Asian +
> Australian species and paraphyly of Crocodylus niloticus (Nile crocodile)
> with a monophyletic New World clade nested within this species. Wild-caught
> Nile crocodiles from eastern populations group robustly with the four New
> World species to the exclusion of Nile crocodiles from western populations,
> a result that is also favored by parsimony analyses and by various
> subpartitions of the overall mt dataset. The fossil record of Crocodylus
> extends back only to the Late Miocene, while the earliest fossils assigned
> to C. niloticus and to New World Crocodylus are Pliocene. Therefore, in
> combination with paleontological evidence, mt DNA trees imply a relatively
> recent migration of Crocodylus from Africa to the Americas, a voyage that
> would have covered hundreds of miles at sea.

Not surprising, given the 'surfing' abilities of saltwater crocs:
http://www.livescience.com/6534-secret-revealed-crocodiles-cross-oceans.html

-- 
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
_____________________________________________________________