Re: Major problems with Elaphe...

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Posted by Terry Cox on October 07, 2002 at 18:27:57:

In Reply to: Major problems with Elaphe... posted by vvvddd on October 07, 2002 at 00:15:55:

:One really huge reason American Elaphe are believed to be more closely related to Lampropeltis and Pituophis than Asian Elaphe is that all three of those american genera lack duvernoy's glands, while most (if not all) Asian Elaphe have duvernoy's. As said, major revisions need to be done. I think a major component in this argument is convergent evolution. Asian and American ratsnakes both have extremely similar body structure, but that doesn't necessarily mean that they are closely related. Look at Morelia viridis and Corallus caninus!

:More work needed (I hope to accomplish some in my just-starting career)!
:Van

Hi, Van.
Natricines and Crotalines all have keeled scales, but it doesn't make them closely related. I don't know much about the Duvernoy's glands in Elaphines, but I'd venture to say that the Old World ratsnakes are closer to the origin of the ancestral stock and kept some ancient characteristics, whereas, the New World Elaphe are more evolved, and probably lost these glands in the process. I tried to find some info in Schulz ('96), but couldn't find anything. Maybe that info wasn't available when he wrote his monograph.

I agree that more revisions are needed. Let me say that I don't mind if new genera are created. There are many genera I believe are related to Elaphe evolutionarily already. But I just hope that species put into these genera really fit.

For instance, in the latest revision by Helfenberger about a year ago (see link in my initial post), it was said that E. conspicillata was in the "porphyracea group", whereas, E. mandarina was in the "moellendorffi group". I keep both of these species, mandarina and conspicillata, and they are much more like each other than either is to moellendorffi or porphyracea. I just can't buy into some of the methods used to do groupings until the groupings make more sense.

PS: Good luck in your studies. I'll try to help ya anyway I can.

Follow Ups:

Re: Major problems with Elaphe... vvvddd 10/11/02 (5)
- Re: Major problems with Elaphe... Terry Cox 10/12/02 (4)
  - continuation of my post....> Terry Cox 10/12/02 (3)
    - Re: continuation of my post....> vvvddd 10/12/02 (2)
      - Re: continuation of my post....> Terry Cox 10/12/02 (1)
        
        thank you too! vvvddd 10/12/02 (0)