hitchhiker crab id

[JCM0521]

 

[littlefoxx]

Ooo thats an odd one. @ISpeakForTheSeas

 

[ISpeakForTheSeas]

Ooo thats an odd one. @ISpeakForTheSeas

It definitely is unique - particularly the striping on the legs.

OP, do you know what the crab hitchhiked in on/where it came from?

Also, a bit of a long shot here, but I don't suppose you have any pics of the claws, do you?

 

[JCM0521]

It definitely is unique - particularly the striping on the legs.

OP, do you know what the crab hitchhiked in on/where it came from?

Also, a bit of a long shot here, but I don't suppose you have any pics of the claws, do you?

Came from an Aussie rasta Torch colony from a coral wholesaler. No pics of claws

 

[littlefoxx]

It looks like a spider to be honest!!

 

[ISpeakForTheSeas]

Came from an Aussie rasta Torch colony from a coral wholesaler. No pics of claws

I'm fairly confident you've got a young Chlorodielline crab of some variety there, probably a Chlorodiella sp., possibly C. nigra, but I'm not entirely sure.

The pattern on the legs may change a bit as it ages, and it should develop a somewhat rougher carapace, but it should stay small (adults of most of these species have a carapace size typically right around ~0.4"-0.75" full grown, so it really shouldn't pose a threat to most livestock - no guarantees with corals though) - there are claims that these can reach 8 cm/~3.14" full grown; I have seen absolutely no evidence to support that (even if you include the legs in the measurements).

I have seen one exceptionally large individual with a carapace width slightly less than 3 cm (it was ~1" carapace, and ~6 cm total counting fully outstretched legs); even at that size, it should be around the same size to somewhat smaller than a grown emerald crab.

I have also seen these for sale as "Black Mithrax Crabs" (no, they are not Mithrax crabs, nor are they closely related) - they're purportedly reef-safe, but I've also heard they may eat small inverts (like brittle stars).