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Posted by Terry Cox on October 12, 2002 at 06:53:27:
In Reply to: Re: Major problems with Elaphe... posted by vvvddd on October 11, 2002 at 23:53:11:
:Hey
:It bugs me that Helfenberger did not (according to the website on your link anyway, I'm having trouble finding the paper in my school's tiny library) mention anything about American ratsnakes.
Yaa, that's interesting. I didn't think about it much, since I have been more interested in the phylogeny of Old World ratsnakes (Elaphe) anyway. I guess we're going to treat the Americans separately, and everyone assumes at this point they're not closely related to the Old World snakes.
:What I was saying about the Duvernoy's gland is that it seems to be a much more prevalent trait in many eurasian colubrines, but it is largely absent from many american colubrines. I have no idea how that fits in to the evolutionary relationships.
Same with me not knowing how it fits. I understand it's a trait that is retained by the oldest, less evolved species, probably mostly from s.e. Asia. They have lots of traits that didn't make the transition to the more modern species. As the world biogeography changed, the more northerly, cool-adapted, species evolved to adapt to new habitats, and they lost some traits. With some species it's seems a little difficult to link them to the really old ratsnake groups.
:About your experiences with the Elaphe species, its very possible that Helfenberger saw more molecular simularities between conspicillata and the porphyracea group, and also between mandarina and the moellendorffi group, than Mandarina and conspicillata showed between each other.
Yes. I keep mandarina and, as of last spring, conspicillata. Rex Knight has kept them for quite awhile and has bred them. He thinks the two species are very close too. I assume the molecular studies Helfenberger did showed some rather large differences. I admit I don't understand the molecular studies very well. My education stopped with a Masters, and my work was mostly in ecology and behavior studies. I'm afraid molecular data is not going to be definative and can't stand by itself to do phylogeny. These above mentioned species are so very alike in behavior and morphology. This is one of the groupings that's difficult for me to accept.
:Molecular studies generally show evolutionary relationships. What you are describing (I'm assuming behavior, general morphology) are traits that could have evolved more recently than the split between the species. What I am saying is that mandarina and conspicillata are probably not very related to each other, but have evolved to fill the same niches in their different geographic ranges.
:Do you see what I'm trying to get at?
:Van
Yes. I see what you're getting at, exactly. That's why I'm saying, I don't know if I trust genetic studies, and would like to know more about how they're done, and how reliable they are. I think that if two species are very alike in many ways, both behaviorally and morphologically, they should be similar genetically too. I don't understand how a "moellendorffi-like" ancestor can evolve into mandarina, and a "porphyracea-like" ancestor can evolve into conspicillata. It's much easier to see how mandarina could evolve into conspicillata. Also, you have to consider how the Japanese islands have evolved through time. The oldest migration to the islands came in warmer times from a subtropical mainland. Both mandarina and porphyracea live there and could have made the trip. They are ecologically similar. Conspillata has evolved since, but should resemble one or the other ancestral species.
I agree with the groupings of Helfenberger to a large extent. I'm glad we have some of these groups to refer to, such as Coelognathus, which I agree with completely. But some groupings don't go along with accepted groupings by hobbyists (and amateur taxonomists:). In the European-Mediterranean groupings, I like a Quatuorlineata
