A new genus and species of sphaeromatid isopod (Crustacea) from Atlantic Costa Rica

Beatricesphaera ruthae, a new genus and species of sphaeromatid isopod inhabiting shallow water along the Atlantic Costa Rican coast is described. This small species is placed into a new genus as the combination of characters which describe it precludes inclusion into any known sphaeromatid genus. It is best recognized by these character states: short epistome, flattened antenna 1 peduncle articles 1 and 2, robust setose pereopods, lamellar uropods, simple pleopods 4 and 5, short and unfused penes and an elongate basally attached appendix masculina. It is not readily allied to any genus or group of genera within the Sphaeromatidae.