HCA: Hermit Crab Association

so, i just got my newest mini crab and i was checking him out today for a molt sac, I found one but I also found these yellow balls behind the molt sac. i can't get a good picture of them and i'm just worried they might be something harmful. My first thought were eggs but they're too big to be eggs. Help!!

Sometimes i cough up little yellow balls out of the back of my throat. What are those things? Sulfur? Do people with tonsils only get those? I still have my tonsils. On a crab? Oh i have noooo clue.

Pretty sure what you're seeing is the sides of the crab. Not sure what they are technically called, but many crabs have rolley lumpy fatty-looking yellowish skin folds on either side. They can be shocking to see the first few times and on some crabs the color can be super bright and alarming.

DaJimmer, those are probably tonsiliths. They're basically balls of bacteria, kind of like cheese, that form in some people who have tonsils with holes like swiss cheese. I got my tonsils out at 20 because I was growing them the size of lima beans and it hurt like heck.

Lol the doc is in. Thanks!

If you zoom in you can see them. I’m hoping that’s all they are the skin fold things. I’d be devastated of something were to happen to my baby


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Those are skin folds!

I had to go digging since my photos are a wreck since Photobucket went down. Here are some images that show the folds. The naked E was a pity purchase years ago that sadly did not make it.

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So it's driving me crazy that I can't find the name for those little yellow blob-ules.

Scouring Farrelly & Greenaway's 2005 paper, The morphology and vasculature of the respiratory organs of terrestrial hermit crabs (Coenobita and Birgus): gills, branchiostegal lungs and abdominal lungs , I found:

The intense yellow fatty looking patches along the abdomen are the surface of the abdominal lung, which is covered by a thin cuticle and then an even thinner 'epithelium' - like a permeable, two-layered skin covering the respiratory surface - and its the cuticle that I assume is pigmented.

Underneath the cuticle, the tissue that makes up the lung is full of microscopic folds & air channels that (upcoming simplification-> ) channel air to where a network of vescles (like blood vescles) lead air into the haemolymph (crab blood in essence). Then it goes on a haemolymph adventure, oxigenating all sorts of stuff.

BUT what are those blobs near the beginning of the abdomen? Looks like they're hanging out on the first abdominal segment (called the pedicel), or maybe the second segment (called just 'the second sement') ... but what are they doing there? Just gossiping about the gills or something?

Two possibilities I've considered: they're either called...

A) "contractile abdominal lobes"
...no Internet search will tell me what they're for, and there's no apparent vasculature running through them
OR
B) John & Andy; two non-contributing dudes sitting in a coffee shop, forever complaining about how inefficient the the branchialstergites are.

Oh that is weeeird! crabs are aliens!

Wow. I’m not sure. He’s currently down for a molt so let’s hope that she makes it through. And I’ll update you and let you know if he still has them afterwords.


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LJJ, I've always assumed that they are used for blocking the opening to the shell. Remember that Es wear tiny shells they can pick up and run with, and they come from some rather arid locations. Those skin folds fit perfectly to plug around the opening. Probably a combination of dessication protection and some security against other Es.

That seems like a solid hypothesis.

Have you seen them especially on other species? (I haven't noticed anything like that on my PPS, really... though I may just have missed them.)

I'm closing my eyes and trying to remember what was in front of the squiggles, and I am drawing a complete blank. I'll try to remember to go through my photos on the comp and see if I have anything.

Those look strange!

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