Crustacea glossary

CARAPACE COSTELLAE

Fine radial ridges that run from ventral margin to and across umbo, and are usually numerous on any given valve (e.g. Conchostraca) [Moore and McCormick, 1969].
(Order Diplostraca):
Fine radial ridges extending from ventral margin across umbo [McLaughlin, 1980].

  1. carapace costellae—ARTHROPODA Crustacea Fine radial ridges extending from the ventral margin to and across the umboem generally numerous on any given valve especially in Conchostraca....Dictionary of invertebrate zoology