High Quality Content by WIKIPEDIA articles! This list of prehistoric echinoderms is an attempt to create a comprehensive listing of all genera that have ever been included in the Echinoderms that have been preserved as fossils. This list excludes purely vernacular terms. It includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered echinoderms.