Orthoconic cephalopods and associated fauna from the late Ordovician Soom Shale Lagerstatte, South Africa

Orthoconic cephalopods from the Soom Shale Member (Ashgill) are exceptional ly preserved and are colonized by lingulate brachiopods and cornulitids. Ot her fossils commonly associated with orthocones include myodocopid ostracod es and chitinozoans. Size distribution analysis of the brachiopods on one o rthocone indicates that it was colonized in in vivo. Four orthocone radulae are preserved extending the record of these structures 50 My back to the l ate Ordovician. Orthocone radula configuration is more similar to that of a mmonoids and coleoids than to that of nautiloids.