What are the indentations on this Spotted salamander?

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skybutton
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What are the indentations on this Spotted salamander?

Post by skybutton »

Alright, so I took this photo of a Spotted salamander this April and this is something that I've been wanting to know since. Go to the image, and look at the head. Along the edge of both eyelids are small indentations if you look closely that line up with the eyelids (not sure if they actually count as eyelids, but it's whatever the thing covering the tops of their eyes is). There are like 6-8 small but noticeable indentations on the left side of the body along the eye, and others on the right side along the other eye (though they're harder to see). What are these? I've been told that these are chemoreceptors, but what is their specific purpose? I thought maybe they were for sensing mating pheromones I've been told that most mating pheromone receptors in Spotted salamanders are on the underside of their head.

Also, if you look near the top of the visible part of the tail in the image, there's another subtle but interesting feature: a series of even smaller circular bumps lining up near the top of the tail. Any idea what these are as well?

Any insights into either of these things would be awesome, thanks!

https://www.flickr.com/photos/124459046 ... 155497945/
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Don Becker
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Re: What are the indentations on this Spotted salamander?

Post by Don Becker »

NM... I didn't take the time to read your whole post :P
skybutton
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Re: What are the indentations on this Spotted salamander?

Post by skybutton »

I'm afraid I don't understand.
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PNWHerper
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Re: What are the indentations on this Spotted salamander?

Post by PNWHerper »

You can also see them on the tail and to a lesser degree on the back. I believe these are the pores through which the noxious skin secretions are exuded. Good close observation! Many herpers don't bother noticing that kind of detail.
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Josh Holbrook
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Re: What are the indentations on this Spotted salamander?

Post by Josh Holbrook »

I would guess part of its lateral line system (I don't know for sure if Ambystomatids have a lateral line though).
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Antonsrkn
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Re: What are the indentations on this Spotted salamander?

Post by Antonsrkn »

Josh Holbrook wrote: I would guess part of its lateral line system (I don't know for sure if Ambystomatids have a lateral line though).
That was my assumption as well. Ambystoma definitely have a lateral line system as larvae, Im pretty sure they retain some of it as adults. I would say that those dots you are referring to may be mechanoreceptive neuromasts which are part of the lateral line system.
I've been told that most mating pheromone receptors in Spotted salamanders are on the underside of their head.
I'm not saying this info is wrong cause im no expert, but maybe the person that told you was confused and thinking of plethedontiids? Just cause I haven't heard of there being any receptors on the chins of ambystomids but I know plethodontids have them there.
skybutton
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Re: What are the indentations on this Spotted salamander?

Post by skybutton »

Very fascinating stuff, thank you all!

I did some googling about the lateral line system and neuromasts in Ambystoma maculatum and found this neat paper if anyone is interested: http://www.lannoolab.com/pdfs/Cannibal% ... 201985.pdf

I'm not entirely sure what is meant by "cephalic stitches" in the paper. I think that this phrase is referring to the indentations on the head, each one having numerous neuromasts - but I might be mistaken as I couldn't find any references to "cephalic" and "stitches" being used together anywhere else. Anyone have any insights into this?

Regardless, pretty awesome stuff, thanks again for the help everyone.
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PNWHerper
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Re: What are the indentations on this Spotted salamander?

Post by PNWHerper »

Cool, that makes sense. That was my other thought, part of the sensory system. Great to see discussions about things other than just color morphs or locations! ;)
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