Plestiodon skiltonianus in Southern Sierra Nevada (??)

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Fieldnotes
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Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

:?: Could people post pictures of the Western Skinks (P. skiltonianus) that they have found in the Greenhorn, Breckenridge, Piute, or elsewhere in the Southern Sierra Nevada. Precise locations are not needed. However a general mountain range is needed to make the information/picture useful.
Robert Hansen
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Will:

Animals from all of the areas you mentioned look pretty much like this, although the blue tail color fades to a blue-gray in older lizards. This is one from the Kern Plateau.

Image

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Bob
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

Thanks Bob. Have you actually seen Western Skinks in the Greenhorn-Breckenridge Mtns. My theory is that those animals are possibly miss identified P. gilberti. Your skink form the Kern Plateau is obviously skiltonianus. Gilbert skinks are thick in the Greenhorn mountains, thus in theory, they should be outcompeted and absent from the Greenhorns

BTW do you agree with the arrangement that the animals from Kern Plateau align with P. skiltonianus utahensis?
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Will:

There really are skiltonianus in the Greenhorns and on Breckenridge Mtn. There are mis-ID'd animals in collections, but mostly it is juvenile gilberti that are labeled as skiltonianus. Here's an example of a reproductive adult skiltonianus from the Tule River drainage, Tulare Co. at a site where both species occur, at the apparent northern range limit for the former on the Sierran west flank.

Image

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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

Interesting stuff thanks. Do you know if skiltonianus is on Piute too?
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Fieldnotes wrote:Interesting stuff thanks. Do you know if skiltonianus is on Piute too?
yes...they are there, too.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by jonathan »

This skink was found in the Greenhorn Mountains - what do you guys think of its ID?

Image

Image

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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

looks like gilberti to me.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Your skink is a skiltonianus. The juvenile gilberti in that area are reliably pink-tailed. What makes ID-ing your animal tricky is that the striping does not extend very far onto the tail, a feature diagnostic for gilberti. However, there are parts of the range where that is not terribly reliable. Here is a juv gilberti from the same area but at lower elevation.
Image

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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

Ooops. Forgot about the blue tail, pink tail thing.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Brad Alexander »

Correct me if I'm wrong, but I thought gilberti in some locations show up with blue tails as well, including in their upper range of the Greenhorns. Yes? No?
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Brad Alexander wrote:Correct me if I'm wrong, but I thought gilberti in some locations show up with blue tails as well, including in their upper range of the Greenhorns. Yes? No?
There is a transition from blue-tailed juvenile gilberti (E. g. gilberti) to pink-tailed juvs (E. g. rubricaudatus) somewhere in the vicinity of the Tulare/Kern Co. line, but details are unknown. Springtime fieldwork is needed between the South Fork Tule River and White River/Arrastre Creek areas to map this change, and also to note whether the juvenile tail color change is abrupt (are the tails obviously blue or obviously pink?) or gradual (tails displaying a mix of both colors). If juvenile tail color plays a prominent role in predator defense, selection ought to favor unambiguous color signals.

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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by jonathan »

Robert Hansen wrote:
Brad Alexander wrote:Correct me if I'm wrong, but I thought gilberti in some locations show up with blue tails as well, including in their upper range of the Greenhorns. Yes? No?
There is a transition from blue-tailed juvenile gilberti (E. g. gilberti) to pink-tailed juvs (E. g. rubricaudatus) somewhere in the vicinity of the Tulare/Kern Co. line, but details are unknown.

Well, that guy I posted is ~5 miles south of the county line, so does that add potential confusion to the ID?
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

jonathan wrote:
Robert Hansen wrote:
Brad Alexander wrote:Correct me if I'm wrong, but I thought gilberti in some locations show up with blue tails as well, including in their upper range of the Greenhorns. Yes? No?
There is a transition from blue-tailed juvenile gilberti (E. g. gilberti) to pink-tailed juvs (E. g. rubricaudatus) somewhere in the vicinity of the Tulare/Kern Co. line, but details are unknown.

Well, that guy I posted is ~5 miles south of the county line, so does that add potential confusion to the ID?
What elevation?
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by jonathan »

Robert Hansen wrote:
jonathan wrote:
Robert Hansen wrote:There is a transition from blue-tailed juvenile gilberti (E. g. gilberti) to pink-tailed juvs (E. g. rubricaudatus) somewhere in the vicinity of the Tulare/Kern Co. line, but details are unknown.

Well, that guy I posted is ~5 miles south of the county line, so does that add potential confusion to the ID?
What elevation?
PM'd you.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Fieldnotes »

Image
Here is a known P. gilberti gilberti from the mid-Sierras and it looks very much like the one above. It just goes to show how difficult those things can be to identify.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by Robert Hansen »

Okay...I shared Jonathan's Hwy 155 blue-tailed skink pic with Jon Richmond (who has worked extensively with western skinks), and as they say in the NFL, "Upon further review..." we agree that it is in fact a gilberti...not a skiltonianus as I originally called it. Jonathan's skink was taken at fairly high elevation, close to the point where skiltonianus might be expected to occur, but Richmond has found gilberti even higher along that same route. What this does reveal, however, and therefore offers a future field challenge, is that the transition from blue to pink-tailed juvenile gilberti lies somewhere south of the Kern-Tulare Co. border. For those with the interest, what would be especially helpful is to photo-document hatchling skinks from anywhere between the Kern-Tulare Co. line and the Kern River using any standard color chart in the photo. GPS data would be important as well.
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Re: Plestiodon skiltonianus in Southern Sierra Nevada (??)

Post by tamara-saurus »

I found this one this past weekend in the Kings River area (don't know if that is too far north to be relevant to your discussion, but just in case). I assumed an ID of skiltonianus because of the clear striping well beyond the base of the tail.

Image

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