TYPE: Male holotype from Berlese sample of forest litter taken at an elevation of 250 m at Limoncocha, Sucumbios, Ecuador (June 25, 1976; S. Peck), deposited in FMNH (33720, PBI_OON 10212).

ETYMOLOGY: The specific name is a patronym in honor of Adalberto Santos, of the Universidade Federal de Minas Gerais, in recognition of his many contributions to the success of the Niarchos Expedition.

DIAGNOSIS: Males can easily be recognized by the long, narrow distal flange on the embolus (figs. 392–396), females by the procurved sclerotization near the posterior margin of the epigastric scutum (figs. 404– 406).

MALE (PBI_OON 10212, figs. 386–396): Total length 1.25. Posterior eye row recurved from above; PLE-PME separated by less than PME radius. Sternum surface smooth. Endites with anterior projections situated almost apically. Leg spination: tibiae IV v0- 0- 1p. Embolus with long, narrow distal flange (figs. 392–396).

FEMALE (PBI_OON 10225, figs. 397– 406): Total length 1.34. Leg spination: tibiae IV v0-0- 1p. Anterior receptaculum with narrow median rod (figs. 405, 406).

OTHER MATERIAL EXAMINED: Ecuador: Orellana: Reserva Etnica Waorani, 1 km S Onkone Gare Camp, 0u39925.770S, 76u279 10.80W, Oct. 8, 1995, elev. 216 m (T. Erwin et al., USNM 2044717, PBI_OON 442), 1 -, 3 U. Sucumbios: Limoncocha, June 18, 1976, Berlese, Ficus litter with fruits, elev. 250 m (S. Peck, FMNH PBI_OON 38347), 1 U, June 21, 1976, Berlese, Bactris spiny palm, elev. 250 m (S. Peck, FMNH 33723, PBI_OON 10225), 2 -, 1 U.

DISTRIBUTION: Relatively lowland areas in Orellana and Sucumbios provinces of northeastern Ecuador.