Echinoderms

Abstract

Echinoderms, a sister group of chordates, is a group of exclusively marine animals. The Echinodermata is an ancient phylum dating to at least 450 million years old and including more than 10,000 extant species present throughout the world’s oceans. The modern echinoderms belong to five classes: Echinoidea (e.g., sea urchins and sand dollars), Asteroidea (e.g., starfishes), Ophiuroidea (e.g., brittle stars), Holothuroidea (e.g., sea cucumbers) and Crinoidea (e.g., sea lilies and feather stars). Sea urchin represents a well-established marine model in biological sciences. This chapter provides a general description of echinoderms and focuses on the significant advances in cell and developmental biology that the study of sea urchins has made possible. During the last decade, many genomic data concerning echinoderms and sea urchins, in particular, have become available. These new molecular tools have facilitated gene regulation analysis during development and have boosted the possibilities offered by sea urchins as experimental models.