Id sea urchin? Cannot find info online

[SnipeEasyC]

So been lurking around past several years on and off. Been a reef keeper since 2005ish. Not an expert by no means but been around awhile. But this one has stumped me not seen this kind. So i never purchased this urchin or any urchin in my life. My father purchased some premium aquacultered live rock. I ended up with a few pieces. Stuff is amazing covered in macro, even orange coraline even corals. We have between us both identified half dozen or so corals with one of his being a grapefruit sized elkhorn. Some were their on delivery. Others appeared over time. I had this rock for probably 6 to 8 months and this urchin appeared. Only saw it once never again and today it was out. Buts its odd.

It is black like a black long spine urchin. But its spines are on the bottom half. And short like 1 inch long max. The top is all long waving tentacle like objects. They look like spines but wave around on the current like a soft coral. It is only about 1 1/2" without spines. Tried to include pics sorry glass needs scraped. And using cell phone tried to make pics smaller.

 

[blaxsun]

Slate pencil urchin?

 

[vetteguy53081]

Pics very blue and fuzzy to tell

 

[happyhourhero]

Here’s what came in on my gulf rock. I cleaned the rock with a toothbrush and somehow didn’t see this guy. Looks like yours but using rogaine.

 

[jt8791]

Try taking a picture with just whites if possible, might make it easier for everyone to identify. But looks too pointy from what I see to be a pencil

 

[Isopod80]

Appears to be a juvenile rock boring urchin to me. Echinometra sp. Pretty common hitchikers on liverock. The tentacle like objects are tube feet. It's how the urchin travels. Many species will also use them to hold onto and carry small loose objects for camouflage and protection. All urchins have them.

 

[SnipeEasyC]

I have to zoom in so much to get a photo is why it starts to get blurry. It really isnt very big. For size reference first pic in the bottom is a black and white clown thats about 3" long. And about half the distance as the urchin. Ill try to get a better one. I need a magnifying glass. It makes for excellent macro shots.

 

[blaxsun]

Just a regular black sea urchin then? (not a long-spine)

 

[SnipeEasyC]

But the top half the spines are probably like 1/8" these spines are all small like a long spine but very short and the top half the tube feet are longer than the spines on the bottom half of the urchin.

 

[Isopod80]

If the live rock was harvested in the Gulf of Mexico, it is likely Echinometra lucunter. Some individuals of the species turn red on top with age, others remain black as adults. Here's a red adult.

 

[SnipeEasyC]

I added a short video see how long the tube feet are to the spines. Very odd not like a typical looking urchin.

 

[jt8791]

Either way it’s a free urchin but I’m also a big urchin fan

 

[Isopod80]

I added a short video see how long the tube feet are to the spines. Very odd not like a typical looking urchin.

I have a pincursion urchin that extends it's tube feet twice the width of its body at times. It's normal. They also use them to sense their environment. Often they will extend them when on the move.

 

[blaxsun]

If the live rock was harvested in the Gulf of Mexico, it is likely Echinometra lucunter. Some individuals of the species turn red on top with age, others remain black as adults. Here's a red adult.

It indicates those urchins are elliptical rather than circular. But basically we know it's an urchin, it's black - and it only comes at night (mostly).

 

[Isopod80]

Search Arbacia punctulata as well. Florida purple spined urchin. Another pretty common hitchiker. It's possible that you have a darker individual or perhaps it simply looks black under your lighting. The individual in the picture is lighter than most but I wanted a top view shot thinking that maybe this is what you meant by "tentacles ".

 

[Spare time]

I think its a short spine urchin

 

[Isopod80]

I think its a short spine urchin

If it is, it has a pretty big bald spot up top.....get that thing a toupee.

 

[Cantusaurus]

It is a Shortspine Urchin. I actually was looking for a Reef Safe Urchin yesterday, and I almost accidentally bought a Purple spine Pincushion (which are usually not reef safe).
BUT I was assured these Shortspines are reef safe. I did a bunch of research, and they seem to not be a problem as long as rocks are relatively stable, and small corals are not loose.
They are reef safe, and they only get about 3 inches
I was surprised about these guys. It seems they're pretty underrated. I only just added mine so I cannot say too much. But I think they should at least be a decent CUC member.
Why they are called a shortspine urchin is beyond me, but whatever. lol

 

[WVNed]

It is a Shortspine Urchin. I actually was looking for a Reef Safe Urchin yesterday, and I almost accidentally bought a Purple spine Pincushion (which are usually not reef safe).
BUT I was assured these Shortspines are reef safe. I did a bunch of research, and they seem to not be a problem as long as rocks are relatively stable, and small corals are not loose.
They are reef safe, and they only get about 3 inches
I was surprised about these guys. It seems they're pretty underrated. I only just added mine so I cannot say too much. But I think they should at least be a decent CUC member.
Why they are called a shortspine urchin is beyond me, but whatever. lol

Maybe because the spines are short.
I have short spine, long spine, tuxedo and pincushion urchins. I like to watch them