Haplostatus Illg & Dudley, 1961

Diagnosis. Body vermiform, cylindrical, without any metameric division. Urosome not demarcated from prosome, indistinctly 3-segmented. Anal somite tipped with pair of claws. Rostrum distinct, semicircular. Antennule as unsegmented lobe. Antenna 2-segmented. Antennae and vestigial mouthparts positioned within pre-oral cavity. Labrum distinct. Mouthparts absent or represented by 1 pair of small, bimerous lobes. Legs absent.

Type species. Haplostatus incubatrix Illg & Dudley, 1961 by original designation.

Remarks. The discovery of a second species enables us to better define the genus Haplostatus . In both species the urosome is segmented and carries a pair of claws posteriorly on the anal somite, and the antennae and mouthparts are located within a pre-oral cavity. These are the major diagnostic features of Haplostatus . The genera Pholeterides and Sicyodelphys were described as possessing a 3- or 4-segmented urosome, terminating in a pair of claws on the anal somite, as in Haplostatus, but these two genera both have legs, unlike Haplostatus .