Arrhopalites dubius Christiansen, 1966: 59 –60, figs. 5d, 6b, 27, 28, 48, 59, 70, 80, 92, 96.

Type locality: USA, Iowa, Jackson Co., Hunters Cave.

Pygmaeus ­group s. str. Total length, 0.8 mm. Color white with slight traces of pigment, eyes 1+1. Weak posterior cephalic spines present. Ant. III swollen basally. Ant. IV divided into five subsegments. All ungues with a clear inner tooth, and tunica. First and second unguiculi with corner tooth, and apical filament exceeding the unguis tip. Dental chaetotaxy in table 3, ventral dental formula 3: 2: 1: 1. Anal valve chaetotaxy in table 2.

Biogeographic zone 8 and 24a in Neotropical region.