Muscle scars in euomphaline gastropods from the Ordovician of Baltica

Muscle scars in euomphaline gastropods from the Ordovician of Baltica

Blog Article

A discrete pair of muscle scars is described for the first time on the umbilical wall of the open-coiled, Duckbill Clips hyperstrophic ophiletoidean gastropod Asgardispira, a close relative of the widely distributed Lytospira, from the middle Ordovician of the eastern Baltica.In a unique specimen of the euomphaloidean Lesueurilla of similar age and derivation, the muscles have coalesced into a single scar.A pair of pedal retractor muscles is characteristic of several major groups of gastropods both in the Lower Palaeozoic and at the present day, and was non-metal-chastity likely an ancestral character of the class.

The consolidation of muscle attachment to a single site may reflect the tightening of the logarithmic spiral of the shell and is probably related to the increasing development of anisostrophic coiling and shell re-orientation during gastropod evolution.