Pincer Spines on Funky Pencil Urchin

[Europhyllia]

I finally caught my little hitchhiker.

I am pretty sure it's some kind of pencil urchin from the Caribbean.
Since I read the pencil urchins can be carniverous I got him out of the main tank and into the sump.

I took a picture of him before I released him in there because he had this interesting crown of spines on top that had pincer like tips and kind of a little bulb in the middle of those spines.

I wonder what the purpose of them is? Anybody know? Justahobby post your link ;)

http://www.dominopads.com/funkypencilurchin.jpg

http://www.dominopads.com/pincerspines.jpg

[justahobby]

Looks like part of it's Aristotle's Lantern. Possibly sensory organs?

[justahobby]

CLICK HERE (http://www.google.com/search?q=pedicellariae&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a) :D

pedicellariae

http://en.wikipedia.org/wiki/Pedicellaria


A pedicellaria (plural. pedicellariae) is a small wrench or claw-shaped structure commonly found on Echinoderms (http://en.wikipedia.org/wiki/Echinoderm), particularly in sea stars (class Asteroidea (http://en.wikipedia.org/wiki/Asteroidea)) and sea urchins (class Echinoidea). Pedicellariae are poorly understood but in some taxa, they are thought to keep the body surface clear of algae, encrusting organisms (http://en.wikipedia.org/wiki/Organism), and other debris in conjunction with the ciliated epidermis present in all echinoderms

[Europhyllia]

I found the thing about pedicellariae but the descriptions and pictures of them make them seem really small (some describe them as minute) and these are big old spine like things

[justahobby]

scratch that. those are the tiny tubes.

[justahobby]

Ohh, looking at the picture again...... they aren't only around the mouth. The others are just sucked in. Those are the secondary spines (i believe). Hollow for injecting venom

[Europhyllia]

Could be a good description of them but only the red ones around the top are shaped like that. I bet that's what they are though. Too bad! Theya re so pretty!

So who wants a venom injecting cool looking urchin? Any takers?

[justahobby]

That's the top of the urchin? Maybe they like to grab and hold on so you don't run away from the shot :P The more answers I come up with, the more loops you throw me for. I give up LOL

[Europhyllia]

Yes, that's the top. Very pretty right?

[justahobby]

Curious why you removed it from your tank? I know you cited being carnivorous, but that's scavenger style. And poison is a defense not predation.

[Europhyllia]

Curious why you removed it from your tank? I know you cited being carnivorous, but that's scavenger style. And poison is a defense not predation.


Dr. Ron Shimek states they (pencil urchins) are "Omnivorous, with a tendency toward carnivory (Marine Invertebrates pg. 403)." and goes on to warn that they will eat sessile animals

I haven't noticed anything missing but figured I'll use this opportunity to capture him just in case

[justahobby]

Sessile is the key word there. Tiny critters that inhabit the LR would largely go unnoticed if even at all.... (or plow through a monti cap :P). I would take it but I tried a tuxedo one time and it preferred my coralline and really made a dent in it.

[Kristy]

Beautiful looking pattern around its mouth! Neat find, Karin!

And Justin the professional googler strikes again. From now on I'm not even going to bother wasting my time, I'll just ask you!