A unique edrioasteroid from the upper Middle Cambrian of Iran,its phylogenetic implications and paleoecology

One of the earliest isorophid edrioasteroids from the upper Middle Cambrian-lower Upper Cambrian (upper part of Series 3-lower part of the Furongian Series) of northern Iran is described. It has unusual branched ambulacra, which extend beyond the theca almost to the marginal rim. These unusual features reflect the latent possibility of appearance of separated from the theca and even branching food-gathering appendages, such as arms in crinoids and brachials in blastozoans, in common ancestor of all radially symmetrical echinoderms.