Forums / TEAM Marine Depot / Invertebrates; Morphology, Ecology, and Behavior – by Dr. Ron Shimek / Crinoid…weird / Latest Posts

RE: Crinoid…weird

reifen — Sat, 10 May 2008 23:40:34 GMT

It is a mariametrid (I think) and in the stock list appears as Himerometra bartschi other than that I might get a photo…

RE: Crinoid…weird

TidePool Geek — Sat, 10 May 2008 06:35:34 GMT

Hi Reifen,

It strikes me that the first thing you need to do is stop thinking of the animal as "a crinoid". There are something over 600 identified species of this group. There seem to be some marked differences in what type of flow regime is required to allow different types to feed so to have any chance for success you'll want to figure out what sort of animal you have.

To that end, here's a very good website on crinoids done by a biologist that specializes in them (Charles Messing):

http://www.nova.edu/ocean/messing/crinoids/

The site includes a Key to help you identify your animal and three separate articles on feeding, feeding behavior, and diet.

FWIW: Here's a YouTube video I found, ostensibly of a crinoid feeding:

http://www.youtube.com/watch?v=gqrv7v52G64

As Ron said, without magnification there's little or nothing to be seen.

Planktivorously yours,

Alex

RE: Crinoid…weird

Ron Shimek — Thu, 08 May 2008 07:43:49 GMT

Hi,

Yes, one can watch them feed, if one knows what to look for. However, it takes a special microscope and tank apparatus.

The feeding apparatus consists of "units" of six tiny tentacles located along each of the finest branches of the arms. There are thousands of these units. As currents push water through the branches of the each tentacle (the branches are called pinnules), the food particles are caught in small currents that pull it from the back to the front of the pinnule. The particles imact on the tentacle.

If the particle is appropriate (gives the "right" chemical signature), that tentacle, in less than the blink of an eye knocks the particle to another tentacle on the far side of the pinnule. That tentacle in turn knocks the food item into the food groove in the center of the pinnule and from there it gets moved to the mouth. So... if one is lucky one can see the animals feeding by watching the tentacles on the smallest branches of the arms. These tentacles are difficult to see, it often takes a magnification of 20 to 40 diameters to bring them into view. Typically, feeding has been watched in special tanks that allow the animal to be extended right across the tank wall from a focused microscope.

There is no other overt indication of feeding.

The animal has to be unfurled in a fully extended posture to feed. The currents passing through the arms must be a good approximation of laminar flow, although this requirement will vary with the crinoid species. Requirements as to the velocity of the currents are really unknown - but are probably in excess of 20 cm per sec.

RE: Crinoid…weird

reifen — Wed, 07 May 2008 14:41:24 GMT

Do we know how reacts when it feeds?

I know my chances but still I want to try something and not just give up.

RE: Crinoid…weird

Ron Shimek — Wed, 07 May 2008 09:11:26 GMT

Hi,

Well, they need very clean water that is rich in gelatinous plankton. So they need well skimmed water; and most of them seem to need specific types of invertebrate lavae (not rotifers and not phytoplankton) as food. Your odds of success are nil.

Crinoid…weird

reifen — Wed, 07 May 2008 05:25:11 GMT

I bought a crinoid ,I know you will tell me I shouldn’t and the same things I told the store owner 3 days before buying it.

But I found a source I could get phyto, rotifers and others, plus recently I set up a 10 g algae tank with no fish and no skimmer.

So at the first 2 days it was in my 45g tank sitting under the skimmer outlet and I decided to move it to the smaller tank which I thought it was a better place for it to feed.

Now the weird part starts as soon it hit the bottom of the tank it stop moving just sitting there lifeless and wide open , I thought I killed but left it there thinking it was just shocked maybe from the deferent light (regular warm osram pc lamp) or ph .

And I waited and waited from 15:00 yesterday until now still with no signs of life so I decided it was time to take it out of the tank.

I grab it and it curls a little so instead going to the garbage I take cup put a little water in it and headed to my other tank thinking if it dies there or it is dead the tank will hardly be effected at all.

I soon the first drops of water fell into the glass it came to life, the cup Is almost full now and it is still fine moving inside the cup.

I am happy that I didn’t kill yet it but it is weird

Word helps when I am writing in English but not as much I need …sorry