Echinoderms

Phylum: Echinodermata    

Classes: Crinoidea, Ophiuroidea, Asteroidea, Echinoidea, Holothuroidea     

Echinoderms are a group of exclusively marine animals found at all depths of the ocean. There are approximately 7,000 species worldwide. Adults are radially symmetrical with the body usually arranged in five segments around a central axis. The skin is covered in calcareous plates or ossicles which give it a bumpy or spiky appearance – the name echinoderm comes from the Greek for “spiny skin”.

West Indian Sea Egg Urchin, Tobago

The most commonly encountered echinoderms for most people in Trinidad will be the flattened sand dollars seen on sandy beaches in the surf. The dead skeletons of some species are often found washed up amongst beach debris. Other echinoderms will generally only be seen by divers or snorkelers including the black long-spined sea urchin which can be the cause of great discomfort if accidentally stepped on or handled.

Brittle stars, seastars and sea urchins in spirit

The collection consists of around 50 jars and several dried specimens. They were collected from all over Trinidad. The variety of sea urchins and seastars is quite low but there is a good range of sea cucumbers from different locations.

For more information on echinoderms in general go to http://en.wikipedia.org/wiki/Echinoderm

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