Echinodermata

Taxonavigation Kingdom: Animalia Sub Kingdom: Eumetazoa Super Phylum: Bilateria:Deuterostomia Phylum: Echinodermata Sub Phylum: Asterozoa - Crinozoa - Echinozoa

Introduction

Organisms within this phylum are typically called Echinoderms. They are colourful and conspicuous reef invertebrates. The name is derived from the Greek words for spiny skin as their skin contains calcareous plates or spines. In some species these are so crowded that even after the echinoderm dies, the their shape is preserved.

Characteristics

Echinoderms lack a front, back, left or right and are considered to have an oral surface (typically the under surface) and an aboral surface (typically the upper surface). Movement is achieved using hundreds of hollow papillae (tube feet) which are radially arranged and operated by a unique hydralulic system, the water vascular system. Feeding can be by filtering plankton from the water, digesting fauna from the sediment, predation of other animals, or grazing of algae from rock surfaces. Sexes are separate and fertilization is external by broadcast spawning into the water. The delicate larvae live briefly as zooplankton then undergo a dramatic metamorphosis and settlement.

Classification

The phylum Echinodermata is divided into three sub-phyla as follows;

• Asterozoa - sea stars, brittle stars and basket stars.
• Crinozoa - feather stars.
• Echinozoa - sea urchins and sea cucumbers

Resources

• Echinoderms in Aquaria… by Ronald Shimek - Reefkeeping Magazine
• Echinodermata - Tree of Life
• wikipedia:Echinodermata
• Classification of the Extant Echinodermata - California Academy of Sciences Echinoderm Webpage
• (http://www.ispub.com/ostia/index.php?xmlFilePath=journals/ijeicm/vol10n1/marine.xml): E. P. Monico, A. Calise & D. Nottingham, Marine Envenomations Among Home Aquarium Hobbyists, The Internet Journal of Emergency and Intensive Care Medicine, 10 (2007).