Abstract
The genera Tyrannochthonius Chamberlin, 1929 and Nesocheiridium Beier, 1957 are recorded from the Tonga Islands, Polynesia, for the first time. Tyrannochthonius eua sp. nov. is described from the island of Eua. Nesocheiridium onevai sp. nov. is described from the island of Onevai. This is the first discovery of a representative of the genus Nesocheiridium in more than 60 years. The holotype of the type species, Nesocheiridium stellatum Beier, 1957, is redescribed, allowing a better understanding of this poorly known genus. The genus Nesocheiridium is diagnosed by the following combination of characters: integument coarsely granulate, dorsally granulo-reticulate; vestitural setae either relatively long, with a leaf-like outline, or arcuate with a small spine; cucullus short; only 10 abdominal tergites visible in dorsal view; cheliceral rallum of four blades; venom apparatus present in both chelal fingers; fixed chelal finger with granulate swelling mesally and seven trichobothria; trichobothria ib and ist located distad of granulate swelling; eb and esb situated close together at the base of the finger; moveable chelal finger with two trichobothria.