Name this crab

[StirCrayzy]

Ok, i thought i could bump an old thread, but i guess i never started one.
So Im re inspired to ID this long term HH.
I did read through many posts, and Chuck's "every crab in the world" link, is what really makes me want to know more, as even going through that, i couldnt find a picture or accurate description.

I think what makes this one unique is the cupped claws, it seems as though this crab may be either feasting on pods and algae picked from rocks and glass.
i have yet to observe any assaults being given either to fish , GSP, leathers, or Nems.

This crab is very quick to hide when anything comes near, and only really comes out in the open at night, or during feedings.
Ive only a few times been able to observe it picking at rock between GSP sections.
It is mostly seen grasping at food floating by, or picking pods off glass.

Any help would be appreciated, Im not concerned that this crab is harmful, and i will not try to remove it, I am curious to know what it is, as it has become a interesting inhabitant.
i noticed it first about a year ago, and it has double in size + molted once since then.

 

[Clownfish518]

Need to see the back of the crab to be sure, looks a lot like a Mithraculas (formerly Mithrax) sp.; but really can't tell without pictures from different angles

 

[StirCrayzy]

Ya i figured i need a top down shot, but my camera is having issues, hopefully fixed tommorrow. That is an old pic.

 

[Varga]

I'd name him "EVIL" Look at that thing!

 

[Reefmack]

Looks like the Darth Vader version of an Emerald.

 

[tnwillia]

If it was brown it would be a twin of 1 of my mithrax. It's growth has been same as yours and not harmed anything to date.

 

[charlesr1958]

Those are a very common find for me when I collect live rock for my aquarium (Philippines) and am VERY familiar with them, they are a Mithraculas spp. and once large enough, they just LOVE zoanthids, and just about everything else for that matter. As with any and all free-ranging crabs, they really don't have a place in an enclosed ecosystem, being omnivores, they are simply too destructive.

Chuck

 

[StirCrayzy]

Those are a very common find for me when I collect live rock for my aquarium (Philippines) and am VERY familiar with them, they are a Mithraculas spp. and once large enough, they just LOVE zoanthids, and just about everything else for that matter. As with any and all free-ranging crabs, they really don't have a place in an enclosed ecosystem, being omnivores, they are simply too destructive.

Chuck

I Concur, definate mithrax, pentagonal body shape very similar to some pics ive seen on your site chuck ...
I dont have many corals, and i think plenty of algae,
At the moment I think I'll keep him, but if i notice a decline in GSP population, hes gone.
Thanks for the help everyone.