Adductor Scar on the Shell of the Early Cambrian Sinskolutella ordinata (Melnikova, 1983) (Bradoriida, Crustacea)

A large round spot in the anterior half of the shell, identified as the adductor muscle scar, was found in the bradoriid Sinskolutella ordinata (Melnikova, 1983) from the unique Sinsk locality (Lower Cambrian of the Siberian Platform). The pores on the valves of this species are characterized. Similarities in the outline, shell size, and the presence of a large muscle scar suggest that Sinskolutella is related to ostracods of the order Leperditicopida known beginning from the Ordovician and widely diversified during the Silurian and Devonian.