Slowworm pits?

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   Hi All

in the spirit of scientific enquiry about our native herps, which is surely the lifeblood of this forum and so much better than any of the more general nat. hist. forums out there! I have a genuine slowworm enquiry.

I took this photo of a big old bruiser and only when I enlarged it did I notice the 'rivets' on the trailing edge of many of the scales - especially the labials, supralabials and nasal areas - they look like tiny dimples - what are they?  could they be sense organs of some kind?  I am ashamed not to have a clue even though I've been a slowworm voyeur for more decades than I care to admit to...

If you click and then magnify the image you'll see what I mean:

https://www.flickr.com/photos/100121190@N06/33258122574/in/datetaken-public/

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will Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1758	Post Options Post Reply Quote will Report Post Thanks(0) Quote Reply Topic: Slowworm pits? Posted: 17 Apr 2017 at 9:01pm
	Hi All in the spirit of scientific enquiry about our native herps, which is surely the lifeblood of this forum and so much better than any of the more general nat. hist. forums out there! I have a genuine slowworm enquiry. I took this photo of a big old bruiser and only when I enlarged it did I notice the 'rivets' on the trailing edge of many of the scales - especially the labials, supralabials and nasal areas - they look like tiny dimples - what are they? could they be sense organs of some kind? I am ashamed not to have a clue even though I've been a slowworm voyeur for more decades than I care to admit to... If you click and then magnify the image you'll see what I mean: https://www.flickr.com/photos/100121190@N06/33258122574/in/datetaken-public/

Tom Omlette Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 07 Nov 2013 Location: Stoke on Trent Status: Offline Points: 409	Post Options Post Reply Quote Tom Omlette Report Post Thanks(0) Quote Reply Posted: 17 Apr 2017 at 9:14pm
	don't know what they are will but the look and the positioning suggests something sensory seems likely

will Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1758	Post Options Post Reply Quote will Report Post Thanks(0) Quote Reply Posted: 17 Apr 2017 at 9:21pm
	thanks Tim, they seem to become more concentrated at the front of the head, so that would make sense - maybe they're slug detectors??

GemmaJF Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 25 Jan 2003 Location: Essex Status: Offline Points: 4157	Post Options Post Reply Quote GemmaJF Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 12:27pm
	Interesting one Will! I took a look at several close-up shots on the web and the 'dots' are visible on several individuals in similar patterns. I do not recall anything in the literature about them. I got to thinking if they had a purpose there may be some underlying structure, so looked at slow-worm skulls. Interestingly they are grouped vaguely with the 'holes' in the side of the maxillary arch, a feature of slow-worm skulls that always intrigued me, I have seen illustrations showing 'pitting' on the outside of the lower jaw also which roughly corresponds to the positions of the 'dots':

will Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1758	Post Options Post Reply Quote will Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 4:36pm
	Interesting Gemma - perhaps routes for nerves going from the 'pits' to the cranium... or maybe I'm reading too much into this, but I'd love there to be something to it!

GemmaJF Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 25 Jan 2003 Location: Essex Status: Offline Points: 4157	Post Options Post Reply Quote GemmaJF Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 5:05pm
	It is interesting, my gut feeling is they are just a little anomaly in the scales or the work of mites or something lol. But it might be worth looking at the heat sensitive structures of the pit vipers and particularly the labial pits found in the boas and pythons. We know other reptile species have developed specialist sense organs in this area so it could be worth investigating it further. Edited by GemmaJF - 18 Apr 2017 at 5:16pm

will Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1758	Post Options Post Reply Quote will Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 5:14pm
	Hi Gemma I definitely don't think they're anomalies or mites as they are distributed so regularly along the trailing edges of the scales - like rivets, almost. But as to what they are, or how I could prove my hunch I have no idea - I guess I need to find out who is a world expert on Anguid lizards.

GemmaJF Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 25 Jan 2003 Location: Essex Status: Offline Points: 4157	Post Options Post Reply Quote GemmaJF Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 5:18pm
	I thought they seemed reasonably uniform on the images I looked at. But there were some images where I could not make them out at all, but then that could be colour variation of individuals making them hard to spot in some images.

GemmaJF Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 25 Jan 2003 Location: Essex Status: Offline Points: 4157	Post Options Post Reply Quote GemmaJF Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 5:22pm
	If there is nothing in the literature and I cannot find anything, what about a 'prey targeting' experiment? Cover the pits with Vaseline and see if it reduces a slow worms ability to detect and target prey? It is a simple non-invasive and non-harmful experiment that 'might' reveal the pits actually have a function?

Caleb Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 11 Apr 2011 Status: Offline Points: 650	Post Options Post Reply Quote Caleb Report Post Thanks(0) Quote Reply Posted: 18 Apr 2017 at 7:17pm
	My wild guess is that they're pheromone-secreting pores. They haven't got anywhere to put femoral pores...