Urchin ID

[MikeDeL]

This is the urchin Sam sent me. Anyone know exactly what kind it is?

[Ram_Puppy]

mine is not nearly so red as that, it is actually yellowish pink... I think they are Echinometra Mathaei, if they are the same species, Mine looks almost exactly like the one I am using for ID (as iffy as that is anyhow) and that assumes they are the same species.

It may be rock boring, not sure, the best I can say is they are probably in the echinometra family.

[Jenn]

Mine is just like it. I'm glad you did this because I was looking in all my books and online trying to figure out which type it is. I asked Sam on our order thread, maybe he will chime in here.
I have a new facination with these little guys. I've never had one before and they are neat to watch move around.
Check out this article and look at the armored-looking urchin, very bizarre!!!
http://www.reefkeeping.com/issues/2004-08/rhf/#z

[Ram_Puppy]

Here are some interesting links:


Sea urchins of Hawaii
http://www.coralreefnetwork.com/marlife/inverts/echinoid.htm

More on E. Mathaei
http://www.intertidalhawaii.org/test/species/speciesPages/groups/echinoderms/EchinometraMathaei.htm

pics (this one looks kinda like mine)
http://www.barra.nl/echino/027-Echinometra%20mathaei.htm

[Jenn]

Ram, I think you've found it! I believe that they are the rock-boring, here is where mine was when the first set of lights came on:

[Ram_Puppy]

found mine today in a natural hole in the rock, sure enough, I think we can consider this a pretty positive id. I would post a picture of mine right now, but he's right behind my current aptasia farm... I'm to embarrassed.

[Jenn]

Mine has not moved AT ALL from the spot in the pic. The spines are all still attached, but no movement. Think I should be worried?

[donniekim]

I really like urchins and had one when I first set up my tank. It was really cool and I loved to watch it. i kept trying to get some coraline growth and couldn't figure out why my new rocks with coraline on them would be bare in a few days?!?!?! Then I was researching and came up on the fact that MY long spined urchin was a coraline buldozer! So I traded it off! I want to get another tuxedo urchin for a FOWLR!

Enjoy Guys
Donnie

[Andrew]

Jenn,
Many urchins are nocturnal in the wild (to avoid being eaten), hiding during the day. It's possible that yours returns to the same hide every morning before the "sun" comes up. The spines usually fall off rapidly if they're dead/dying.

HTH, best of luck

Andrew

[MikeDeL]

The first day I had mine I could not find it at all. I was scared. Thought it climbed out or died somewhere in the tank. As soon as the lights went out though there it was on front of the glass.

[Jenn]

Ok, thanks guys. I will check out the tank tonight after the lights go out.

[samiam_orami]

sorry for not posting eariler ....
My DSL is still down and I have to do all my work at the Library ...

the urchins are -
common name : Rock-Boring Urchin
Hawaiian name : inakea
scientific name : Echinometra mathaei

hope the info helps ...
glad you all like them ....

aloha ....

[Ram_Puppy]

yay. I id'd correctly! :)

[MikeP]

My diadema urchin grew from golfball to volleyball size in about a year. I really like him but it makes working in the tank tough since it's easy to get stuck - also coralline is eaten as soon as it appears.

Jenn - generally if you see an urhcin dropping spines it means it's in poor health otherwise they are fairly hardy as long as you maintain stable salinity/ph/alkalinity.

[DeAngelove]

Mine has been hiding in the rocks for days in my nano, but he is a lot more active at night. :) Seems like a happy critter though... very cool to watch him move around the tank! ;)

[Jenn]

Thanks again Mike.

Denise, does he go back to his same spot each day?