Ocular shell structures in some Cretaceous trachyleberid Ostracoda

This is the first study of internal ocular shell structures of Cretaceous ostracodes. Internal molds from eight species of four genera from Santonian, Campanian, and Maastrichtian strata revealed a stalked ocular sinus constricted along its length and distally inflated. The latter part has anterior and posterior lobes and a subcentral concavity. These Cretaceous trachyleberids have ocular shell structures similar to Cenozoic taxa and it is presumed they functioned similarly. However, each taxon has a diagnostic ocular sinus and an inner surface of the eye tubercle that distinguishes each from all other forms examined.