Squat Lobster (Allogalathea elegans)

[Leviathan_XE]

Just curious, saw that LA had a couple in the diver's den and thought thet they looked interesting. Has anyone ever kept one or had any experiance with them in a reef set-up?

 

[mollymonticello]

I do! I LOVE mine. He is very cute. He eats mysis and filter feeds. I target feed him with frozen cyclops and mysis.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1246451

 

[Leviathan_XE]

Wow that's sweet, nice pics! Thx for the info molly, glad to know that they're reef safe. Is he out and about all day and takes nights off? I take it thet stay pretty small.

 

[LeslieH]

Hi Molly -- Your's is a relative of Allogalathea elegans but it's not a crinoid commensal. This is what A. elegans looks like - http://forum.kapalselam.org/2005/07/29/please-tell-me-what-is-the-name-of-this-crab-thanx-alot-guys/
notice how the carapace is elongated forwards in a point between the eyes and then look at yours which has a blunt carapace.

 

[mollymonticello]

Hi Leslie! Thanks for clarifying. I have been wondering about that. I haven't been able to find the exact scientific name of this one. I, too, thought the rostrum is too short to be Allogalathea. Either way, the one I have is the ones LA is selling, and they call them Allogalathea elegans. So these aren't crinoid commensals? That is interesting. I wonder if they are commensal on anything.

 

[LeslieH]

I just found it - Galathea inflata - and I was wrong about it not being a crinoid commensal. Oops!
http://catalog.digitalarchives.tw/dacs5/System/Exhibition/Detail.jsp?ContentID=6&CID=4946&OID=294600

 

[Leviathan_XE]

OK, now I'm kinda lost here.... Crinoid commensal means what exactly? Do they need a some sort of companion with whom they share a symbiotic relationship? The true A. elegans is stunning! I've never seen anything like that before. How are they suited for a reef enviornment? Athough I'm sure that I'd never find one for my tank.

 

[mollymonticello]

Thank you so much Leslie! You are awesome! I have been trying to ID this guy for months!

Being a Crinoid commensal means they hitch a ride on Crinoids, which are starfish like feather stars. They don't require their Crinoids in captivity, thank goodness, because Crinoids are impossible to keep in captivity.

 

[LeslieH]

Commensalism, mutualism, and parasitism are all different aspects of symbiosis. Symbiosis is latin for "live together". Animals tht live together are called symbionts so Allogalathea elegans and Galathea inflata and their host crinoids are symbionts. If the association is beneficial for both partners it is called mutualism. If only one partner benefits but the other is not harmed it's commensalism. When one partner benefits but the other is harmed it's parasitism. These aren't always absolute; it's more like a sliding scale with intermediate phases and shifts. for example, a shrimp that is normally a commensal may become a parasite if there is overcrowding or environmental stress & start feeding on the host's flesh. Or it may act as an mutualist if the host is infected by parasites or microbes and the shrimp acts as a cleaner & keeps the host in good health. Crab, shrimp, and even worm commensals will defend their hosts against predators in which case they're acting as mutualists. Then there's obligate and non-obligate symbionts and again different degrees of both. Generally speaking obligates cannot survive without their partners while non-obligates will mange. These crinoid galatheids can survive without their host but since their main feeding mode is taking plankton away from the crinoid they usually don't do as well without them.

 

[Leviathan_XE]

I thank you so much for the enlightenment.