Two Studies in Green

I'm falling a bit behind on processing photos these days (just too much going on outdoors!), and things have been a bit bug-heavy recently, so here's something completely different:

Emerald Tree Boa, (Corallus caninus), Louisville Zoo, 3/28/2013

This is an Emerald Tree Boa (Corallus caninus) from South America. (Well, this one's from the Louisville Zoo, actually.) At least, I think it's caninus. According to a recent paper, there's actually two species that have been historically lumped into this name, (1) and I don't know which one this guy might be.

Green Tree Python (Morelia viridis), Milwaukee County Zoo, 1/15/2012

These are Green Tree Pythons (Morelia viridis) from Indonesia, New Guinea, or northeastern Australia. (These live at the Milwaukee County Zoo.) I say or, because another paper looking at these guys suggests that there may be more than one species here as well. (2) Given how difficult dispersal over the New Guinea mountains or between islands must be, the idea of multiple species here makes a lot of sense.

These two species (or groups thereof) are impressive examples of convergent evolution -- boas and pythons are clearly different families, so the two species in question aren't closely related. Yet they're both similar shades of green, with similar patterning, they're similar in size, and they both rest in that odd looped position. Aside from the range, the easiest way to distinguish them is the size of the scales on the snout. Can their propensity to forming cryptic species also be chalked up to convergence? I rather suspect instead that cryptic species are simply much more common than we've believed.

(1) Henderson, R. W., Passos, P., & Feitosa, D. (2009). Geographic variation in the emerald treeboa, Corallus caninus (Squamata: Boidae). Journal Information, 2009(3).

 

(2) Rawlings, L. H., & Donnellan, S. C. (2003). Phylogeographic analysis of the green python,< i> Morelia viridis</i>, reveals cryptic diversity. Molecular Phylogenetics and Evolution, 27(1), 36-44.