Echinobase - a resource for studies of evolution and development
Echinoderms are an exclusively marine phylum of Deuterostomes which emerged in the lower Cambrian (>540 MYA) and split from Chordata 400-500 MYA. Echinodermata includes 7,000 extant and 13,000 extinct species.
The echinoderms are split into five classes: the basal branch Crinoidea (feather lilies), Ophiuroidea (brittle stars), Asteroridea (star fish), Echinoidea (sea urchins and sand dollars), and Holotheroidea (sea cucumber). The Ophiuroids and Asteroids form the superclass Asterozoa, the Echinoids and Holotheroids from the superclass Echinozoa, and these two superclasses form the subphyla Eleutherozoa which contains all four motile classes of Echinodermata.
Echinoderms are model organisms for studying embryo development and regeneration due to many unique features including:
- the ability to synchronize fertilization of millions of eggs providing abundant material for developmental research
- transparent embryos and larvae have enabled detailed descriptions of anatomical structures and developmental stages
- there is variation in development within and between a genus providing insights from evolutionary "experiments"
The Echinoderm Anatomical Ontology (ECAO), a structured ontology of anatomical structures is in development for Echinobase so that molecular data can be mapped to developmental cell types and stages of echinoderms.