Bass anatomy: what is this thing?

[hawgenvy]

Largemouth bass have a round crater-like depression on the top of the snout, in the midline, between the nostrils. We've all seen it a million times. What is it, what is it called, and what's its function? Anyone know? No guessing, please!

 

 

[Sam]

Are you writing about the olfactory nerves that send impulses to the brain?

 

 

[hawgenvy]

11 hours ago, Sam said:

Are you writing about the olfactory nerves that send impulses to the brain?

 

 

No, I mean the round depression you see in the photo. You can put your thumb in it. It's a little smaller than the eye. It's external, in the middle of the snout, behind the upper lip.

[J Francho]

I believe that is part of the maxillary process.  The premaxilary process are the sliding parts the allw the lips to extend out.  The maxillary process is the part on their face that controls all that.  I'll have to look it up in one of my old text books to be sure though.  Cool Question!

[MKK]

I'm much more familiar with human anatomy, but this piqued my interest.

 

As best as I can tell, it's basically the anterior limit of the skull and the posterior limit of the nasal cavity, essentially making it a structural part of the olfactory system. I believe it's part of the ethmoid area or mesethmoid area which would make sense given its proximity to the nostrils (at least if there is any sort of similarity to mammals). If it IS similar to mammals, it would be likely that the olfactory nerve travels through foramina in this region on its way back to the brain.

 

I've had a really difficult time finding a straightforward explanation for this, but that was the best I could logically piece together for the time being. I'm going to keep reading a bit and I'll post if I find anything else.

[hawgenvy]

30 minutes ago, MKK said:

I'm much more familiar with human anatomy, but this piqued my interest.

 

As best as I can tell, it's basically the anterior limit of the skull and the posterior limit of the nasal cavity, essentially making it a structural part of the olfactory system. I believe it's part of the ethmoid area or mesethmoid area which would make sense given its proximity to the nostrils (at least if there is any sort of similarity to mammals). If it IS similar to mammals, it would be likely that the olfactory nerve travels through foramina in this region on its way back to the brain.

 

I've had a really difficult time finding a straightforward explanation for this, but that was the best I could logically piece together for the time being. I'm going to keep reading a bit and I'll post if I find anything else.

 

Thanks, MMK. I tried Googling info on it and couldn't find anything. If you find out more be sure to post.

[geo g]

Looks like a Chernobyl fish!  Was there a power plant close bye.  Lol

[J Francho]

10 hours ago, MKK said:

I'm much more familiar with human anatomy, but this piqued my interest.

 

As best as I can tell, it's basically the anterior limit of the skull and the posterior limit of the nasal cavity, essentially making it a structural part of the olfactory system. I believe it's part of the ethmoid area or mesethmoid area which would make sense given its proximity to the nostrils (at least if there is any sort of similarity to mammals). If it IS similar to mammals, it would be likely that the olfactory nerve travels through foramina in this region on its way back to the brain.

 

I've had a really difficult time finding a straightforward explanation for this, but that was the best I could logically piece together for the time being. I'm going to keep reading a bit and I'll post if I find anything else.

 

Nailed it.

 

https://en.wikipedia.org/wiki/Fish_anatomy#/media/File:Seahose_(Hippocampus)_skull_labeled.png

[hawgenvy]

Thanks, J Francho, but the seahorse skull doesn't quite do it for me.  I have submitted my query to Florida Fish and Wildlife (they ought to have a whole team of biologists) and if I get a response I will post it here. The dishlike depression reminds me of a satellite dish or radio-telescope receiver and suggests to me that the feature may have some interesting sensory function.

[Team9nine]

50 minutes ago, hawgenvy said:

Thanks, J Francho, but the seahorse skull doesn't quite do it for me.  I have submitted my query to Florida Fish and Wildlife (they ought to have a whole team of biologists) and if I get a response I will post it here. The dishlike depression reminds me of a satellite dish or radio-telescope receiver and suggests to me that the feature may have some interesting sensory function.

 

I think MKK identified the overall structures and how to reference them, and J Francho just gave an example of a similar creature with the same features and nomenclature, corroborating MKK's assessment. I could easily be wrong, but I'm guessing Florida F&W won't have a clue, or at least won't have anything beyond what MKK posted. I think we'll also find out it actually serves no direct purpose, otherwise it would have likely already been named and described in literature somewhere. I'm thinking it's just a feature formed by the underlying structures, and nothing special or unique to bass, but be certain to let us know.

[The Bassman]

I cringe every time a big single hook from a buzzbait and such comes out through a nostril or worse, an eye socket.  For all my love of the sport this is one aspect I dread.  A little off topic but the pic brought it to mind.

[hawgenvy]

2 hours ago, Team9nine said:

 

I think MKK identified the overall structures and how to reference them, and J Francho just gave an example of a similar creature with the same features and nomenclature, corroborating MKK's assessment. I could easily be wrong, but I'm guessing Florida F&W won't have a clue, or at least won't have anything beyond what MKK posted. I think we'll also find out it actually serves no direct purpose, otherwise it would have likely already been named and described in literature somewhere. I'm thinking it's just a feature formed by the underlying structures, and nothing special or unique to bass, but be certain to let us know.

Someone is bound to know what it is and perhaps its function.  There are virtually no anatomic features in nature that don't have some function.

 

Here is another photo that shows the mystery crater rather well.

 

[scaleface]

Its a sonar detector  .  

[WRB]

Difinatley not a normal physical facial element of a LMB anatomy that I have noticed, other than soft tissue areas in front of the eye socket. I think you are showing deformation or desease of some type that may be common to were you fish.

Tom

[hawgenvy]

43 minutes ago, WRB said:

Difinatley not a normal physical facial element of a LMB anatomy that I have noticed, other than soft tissue areas in front of the eye socket. I think you are showing deformation or desease of some type that may be common to were you fish.

Tom

 

Thanks, Tom. But next time you catch a fish, take a moment to see if the feature in question is there or not. I believe the little snout-residing satellite dish is ubiquitous yet typically unnoticed by the angler, especially in the rush to place the guys in the live well or back to the lake.

[WRB]

What is shown in the photos is some type of fungus or parasite ( purple coloration) in the soft tissue, the discoloration isn't normal in any bass I have caught over the past 60+ years.

If you are asking about facial depression, then yes some bass with less body fat can have them do to loss of tissue on the skull.

Tom

[hawgenvy]

I HAVE A DEFINITIVE ANSWER, thanks to Dr Motta at USF!  I caught a bass tonight and the dimple indeed disappeared when the mouth was closed and reappeared when opened.  I made a video with my iphone but haven't yet figured out how to compress it enough to post it here. When I do, I will.

 

"Robert I saw the picture. I am going to guess that depression mostly disappears when you close the bass mouth. AS the mouth opens and protrudes it appears. If that is so you are seeing an artifact of jaw protrusion. I have seen this on other teleost fishes. There is a ligament that runs across the two maxillae bones, over the premaxilla (upper jaw bone). As the premaxilla is protruded it pulls on this ligament (plus pulls on others) protruding the jaw. As the premaxilla slides forward to protrude it slides on the vomer bone. This causes a dimple to appear in that exact region, probably because the skin there is more tightly adhered to the premaxilla ascending process, or the movement away of the premaxilla simply causes a depression to form. This is really apparent in the mojarras (Gerreidae) when they protrude. So that’s my anatomical take on that depression area.

Phil

 

Philip J Motta, PhD

Professor of Biology

Department of Integrative Biology

University of South Florida

4202 East Fowler Ave

Tampa, Florida 33620"

[Team9nine]

On 7/21/2017 at 6:39 PM, Team9nine said:

 

I think MKK identified the overall structures and how to reference them, and J Francho just gave an example of a similar creature with the same features and nomenclature, corroborating MKK's assessment. I could easily be wrong, but I'm guessing Florida F&W won't have a clue, or at least won't have anything beyond what MKK posted. I think we'll also find out it actually serves no direct purpose, otherwise it would have likely already been named and described in literature somewhere. I'm thinking it's just a feature formed by the underlying structures, and nothing special or unique to bass, but be certain to let us know.

 

Cool ?If I read it right, sounds like I was pretty darn close in my assessment. Learn something new every day...

[NorthwestBasser]

Nice to get an answer, after seeing this post originally, I started paying closer attention and it has definitely been on every fish I've caught. Fat ones, skinny ones, didn't matter. For sure not a disease or deformation.