Hello. My name is Francisco Solís. I'm a taxonomist of Echinoderms, and I'm in charge of the national collection in the Autonomous University of Mexico. I've been working for almost one year now, probably looking at the taxonomy of echinoderms here at the Beaty Biodiversity Museum. I have examined more than 1000 specimens. At the moment we have 79 species. of echinoderms here now in the, in the collections.

An echinoderm is a marine invertebrate. There are only marine species of echinoderms. They are in five groups which are the starfish, sea cucumbers, ophiuroids, or brittle stars, sea urchins and sea lilies, or Crinoids. To identify the different classes of echinoderms.

The first step is to recognize the shape of the body in general. It could be a starfish shape which automatically will take you to the starfish or the Sea Stars. If you have a sphereic form, that will be a sea urchin with the spines. If you have a central body with five arms or more, that will be a brittle star. If you have the cylindrical body and it’s kind of fleshy, that's a sea cucumber. If it looks like a plant and it came solely from one point, with arms, then you have a crinoid.

The second part, will be you get closer to the animal. Let's say that you are working with the starfish. First of all, you recognize the starfish because the five arms or more. And then we go and we have to use a microscope to look for the shape of the pedicellaria. We use the shape of them to tell us the genus and species.

It’s exactly the same with sea urchins. We look into the shape of the spines. They are short, they are long? Exactly. And then you go inside and look into the skin to look for the shape of the pedicellaria. A sand dollar is exactly the same. You will see the general shape of the body, which in this case is thin and flat. You will see they have holes on it, or doesn't have any hole. So that's a difference. And then also, again, you go inside the skin and look for pedicellaria. And in this case they have a very tiny spines all over the body.

To identify the brittle stars, you have to take a very close look to the the shape of the center of the body and look for all the characteristics, any kind of spines or irregular skin or even, granules, etc, and then you go to the mouth. This is very important to identify them. The parts around the mouth will give you the name of the genus and species.

The sea cucumbers are kind of a different world because you have to use the skin to identify them. So you have to dissolve a tiny little bit of skin on bleach, wait a little bit, and then look in the microscope and try to recognize the species using taxonomic keys or taxonomic references to to identify them.