Two new Paleozoic Asteroidea (Echinodermata) and their taxonomic and evolutionary significance

Abstract

AbstractSertulaster keslinginew genus new species (Palaeasteridae) andDelicaster hotchkissinew species (Permasteridae) are asteroid echinoderms described, respectively, from the Ordovician and Carboniferous of eastern North America. The new genus and species help to document diversity within taxa of lower rank.S. keslingiis similar to the Early OrdovicianEriasterBlake and Guensburg, 2005 but exhibits less differentiation of the skeletal elements from beyond the ambulacral column, that of the so-called extraxial skeleton, whereas the comparatively robust construction ofDelicaster hotchkissiclearly departs from that of the type species,D. enigmaticus(Kesling, 1967). Small sample sizes and incomplete exposure of available specimens illustrate ambiguities typically encountered in the study of fossil asteroids.UUID:http://zoobank.org/fb44075c-396b-4f95-b997-29cdf3c4f3c1