Slowworm pits?
Printed From: Reptiles and Amphibians of the UK
Category: Herpetofauna Native to the UK
Forum Name: Slow Worm
Forum Description: Forum for all issues concerning Anguis fragilis
URL: http://www.herpetofauna.co.uk/forum/forum_posts.asp?TID=5136
Printed Date: 16 Apr 2024 at 2:51pm
Software Version: Web Wiz Forums 11.06 - http://www.webwizforums.com
Topic: Slowworm pits?
Posted By: will
Subject: Slowworm pits?
Date Posted: 17 Apr 2017 at 9:01pm
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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/ |
Replies:
Posted By: Tom Omlette
Date 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 
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Posted By: will
Date Posted: 17 Apr 2017 at 9:21pm
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thanks Tim, they seem to become more concentrated at the front of the head, so that would make sense - maybe they're slug detectors?? |
Posted By: GemmaJF
Date Posted: 18 Apr 2017 at 12:27pm
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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':  |
Posted By: will
Date Posted: 18 Apr 2017 at 4:36pm
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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! |
Posted By: GemmaJF
Date Posted: 18 Apr 2017 at 5:05pm
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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. |
Posted By: will
Date Posted: 18 Apr 2017 at 5:14pm
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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. |
Posted By: GemmaJF
Date 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. |
Posted By: GemmaJF
Date Posted: 18 Apr 2017 at 5:22pm
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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?
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Posted By: Caleb
Date 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... |
Posted By: will
Date Posted: 18 Apr 2017 at 7:57pm
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@Gemma - thanks for the suggestion. Playing devil's advocate I can see people asking how we know the vaseline didn't get wiped off/interfere with their nostrils/do we need them to wear tiny blindfolds to make it a properly controlled experiment etc etc and then you have the problem of getting the little darlings to feed in an observable setting like a small vivarium and also the question of controlling for size, appetite etc. I think a good quality scanning electron micrograph would be a start, but you'd need a dead animal for that - oh, and a good quality SEM as well  @Caleb - interesting, I hadn't considered that possibility - if analagous to femoral pores then only males should have them - ought to be easy enough to photograph females to see if this is the case. If so, how would they be used in the secretive world of the slowworm, I wonder? |
Posted By: GemmaJF
Date Posted: 19 Apr 2017 at 1:26pm
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I've read the results of experiments using Vaseline Will, though usually to be fair it is used to cover up much large 'pits' or the nostrils. I do not think they need mini blindfolds lol. I like Caleb's suggestion, the small size does seem to suggest secretion rather than detection. General males only have femoral pores, in some species of reptiles both species have them present but they are generally larger in the males. I would suggest checking images of males and females is the next logical step in the investigation. You are just going to have to get to the bottom of it Will!
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Posted By: GemmaJF
Date Posted: 19 Apr 2017 at 1:40pm
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There seems to have been study regarding pheromones in Anguis fragilis, for example: https://link.springer.com/article/10.1023%2FB%3AJOEC.0000042068.45418.d5?LI=true" rel="nofollow - https://link.springer.com/article/10.1023%2FB%3AJOEC.0000042068.45418.d5?LI=true Reading this research or referenced articles might help Will, as at some point someone may have defined or at least speculated on how the scents are deposited.
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Posted By: will
Date Posted: 19 Apr 2017 at 2:58pm
Thanks Gemma, that's very helpful - I wonder if they linked the ability to use pheromones with these pits? - as you say, I'll have to get to the bottom of it or I won't be able to sleep at night! |