Posted by:
b1eagar
at Tue Sep 13 02:03:38 2005 [ Email Message ] [ Show All Posts by b1eagar ]
Peter,
Here is your garter.
It definately looks most like a valley garter to me based upon the side stripes and its locality. Its locality is right where pickeringii and fitchi come togeather. This is a good example of what I was talking about above. I believe that these western sirtalis are not defined very well and that it is useless to categorize them by arbitrary things like head color and amount of black touching the ventrals because they show a wide degree of variation accross their range. I believe that geography is the only real divider of this species.
Here is a Valley Garter from Utah with a typical amount of red on its head and I have seen some with more. This specimen doesn't have much black touching its ventrals but I have seen specimens from Utah some of which are from the same locality as the snake below that do.
From what I have seen of most of the common garters from the northern California cost, I would say they "look" more closely related to fitchi than they do concinnus. So I don't understand why some herpetologists would want to merge infernalis and concinnus into one subspecies based on looks. Herpetologist Alan St. John who has seen and photographed tons of common garters in the northwest says this about concinnus in his book Reptiles of the Northwest 2002,
"The most typical examples are found in Oregon's Willamette Valley, whereas those from the surrounding areas often have some characteristics of the fitchi subspecies." In his range map he also does not connect the ranges of concinnus with infernalis.
I would like to research how many specimens were used and how diverse in geography and range those specimens were which Rossman, etal used to come to their conclusions. I am not as familiar with their work as I am the work of other herpetologists who have studied Western Sirtalis.
Brian
>>Hallo,
>>I followed your dicussion with much interest because I have nearly the same open question regarding my garter, caught southwest from vancouver city, BC. According to this area (see Rossmann) it should be a Th. sirtalis pickeringii. But the typical morphol. criteria are missing. The white/yellow lateral stripes have more or less connection to the gray-white ventral, a clear wide dorsal stripe and nearly a red head, like the pictues before from the female caught in oregon.
>>I suppose itīs a Valley Garter?
>>
>>I tryed to attache a picture but until know I do not know how to manage this.
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RE: Here is a Valley Garter from the Gorge. - b1eagar, Tue Sep 13 02:03:38 2005