Muscle scars and mode of life ofCarinaropsis(Bellerophontoidea, Gastropoda) from the Ordovician of Tennessee

Muscle scars are described for the first time in the Ordovician bellerophontoidean gastropodCarinaropsisHall. Silica replicas from the Cannon Limestone of Tennessee preserve a pair of muscle scars, with a single elongate scar located on each umbilico-lateral angulation of the shell interior more than half a whorl back from the apertural margin. The scars are similar in general shape and position to muscle scars described inBellerophonde Montfort and the pleurotomarioideanPorcellia woodwardi(Sowerby). In addition to supporting the soft parts within the widely expanded shell, the characteristic internal septum ofCarinaropsisprobably facilitated clamping of the shell aperture against the substrate.