For a long time, Muschelkalk sea urchins were almost exclusively known from isolated spines and platelets of their corona. During the last decades complete articulated specimens were found with their spines attached. Like the Middle Triassic asteroids they combine ancestral and advanced characters. The genera Triadotiaris and Serpianotiaris were dispersed over vast areas of the Muschelkalk Sea. The Lower Muschelkalk in Silesia, the fauna of which was strongly influenced by Tethyan faunas, yielded additional genera. A unique find of a complete Palaeozoic-type echinoid in the Upper Muschelkalk of Lorraine sheds new light on the end-Permian extinction and the phylogeny of the post-Palaeozoic Echinoidea.
Extant sea cucumbers inhabit shallow coastal environments as well as abyssal depths. In contrast to other echinoderms they have a bilateral symmetrical, cylindrical or worm-shaped body and a leathery skin with incorporated isolated, bizarre looking calcareous sclerites. Articulated sea cucumbers are among the rarest invertebrate fossils. The only find in the Muschelkalk described in literature comprising a number of calcareous rings is held in the Muschelkalk Museum.