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Posted by regalringneck on February 28, 2003 at 21:23:10:
In Reply to: Re: Indigo Snake Systematics...very nice update WW, thnx.... written by WW on February 27, 2003 at 07:00:52
Thankyou for your response, I have addressed several of your points below & added "RxR or WW" under a line to make it easier to track the discussion. I always enjoy (& learn) from your posts, C&B; jg
Written by WW on February 27, 2003 at 07:00:52:
In Reply to: Indigo Snake Systematics...very nice update WW, thnx.... Written by regalringneck on February 27, 2003 at 06:18:26:
:Nice series of photos.
:As I said earlier, I'd prefer to see a larger sample size,
So would I.... but beggars can't be choosers ;-)
: but your argument is a reasonable one. The lack of face & neck slashes pushes your beast towards corais corais,
Agree - I suspect it is closest to D. corais and D. margaritae than to the C. and N. American forms.
> & I'll bet you a pint that somewhere to the East/Southeast theirs a cline.
Hmmmm - I'l hold you to that, because I am not so sure about that. After all, as evidenced from the PCA analysis, D. corais is pretty uniform all the way from N. Venezuela to at least SE. Brazil - it would seem strange that it should be uniform over 1000s of miles,a nd then sudenly show a steep cline to a very strongly differentiated form within a very short distance in NW Venezuela.
RxR: Well I'll be happy to share a drink w/you in any case! But your example re: uniformity of subspp. to a steep cline is what I observe in the viridis rattlesnakes, and getulus kingsnakes here in Az where they intergrade???
RxR: I guess what I'd like to hear is your definition of a species...
WW: An independently evolving lineage. The major question, of course, is defining "independently evolving" and what evidence is required to fulfill that criterion.
RxR: Im old fashioned & like the "reproductively isolated" criteria & ideally some niche differentiation to boot.
WW: Personally, when I see two "forms" such as melanurus and corais, which are morphologically +/- invariant over vast ranges, consistently distinct, and sympatric in N Venezuela, and approaching a third, equally distinctive form, then to me, the most parsimonious interpretation is that they are 3 species. After all, what evidence is there that they are NOT separate species? Sure, it's a hypothesis that should be tested, but with the evidence available at the moment, the multiple species hypothesis seems the most parsimonious interpretation.
RxR: I was unaware of the sympatry in Venezuela, this more than anything else requires me to accept your thesis that they are "good spps". Your DNA work will be most interesting. Meanwhile if one of the lads here would just cross melanurus & corais, we might create the pattern of that most unattractive guardian...caudomaculatus! Lastly for now...I submit if the morphometric characters you have chosen & measured occur as a range in larger sample sizes...the most parsimonious interpretation is for your beast to be an intergrade. Also be aware some pretty odd looking cribos have shown up here before, purportedly from Peru, one of the organized waifs of this forum probably archived those jpgs...
WW: I am hoping to do a DNA follow-up, as well as a more comprehensive morphological study of the entire genus one of these days, but at the moment, I don't have samples for enough taxa. Too many snakes, too little time, to quote Rick Shine.
WW: Just a few thoughts... Cheers, Wolfgang
RxR: Please keep us in mind as others come to you, I wish you would spend more time here & less on that %#@-elapid forum :)
One day I hope you'll share what you learned about Clelia whilst prowling the tierras del sur...
Respectfully, John Gunn