Ochrotrichia rivasi Ramírez-Carmona & Thomson sp. nov.

Fig. 3

Diagnosis.

This species is most similar to Ochrotrichia aldama (Mosely, 1937) . Both have a divided long tenth tergum and an inferior appendage bearing a peg-like setae at the apex. However, the 2 nd process of the tenth tergum of O. rivasi is not as long and shaped as the 1 st process (Fig. 3 B); also, peg-like setae are distributed on the apex and along the inferior appendage (Fig. 3 A, B), while O. aldama only bears peg-like setae at the apex.

Description.

Male. Forewing length 3.0 mm (N = 3). Head unmodified, with 3 ocelli; antennae unmodified. Tibial spur formula 0, 3, 4. Sternum VII and VIII unmodified, annular. Genitalia. Abdomen sternum VII with very short, tapered mesoventral process (Fig. 3 A). Segment IX anterolateral margin convex (Fig. 3 A), in dorsal view posterior margin fused with tergum X (Fig. 3 B). Tergum X membranous basally, asymmetrical with two processes (Fig. 3 A); 1 st process elongate, with hooked projection near midlength, apex pointed and sclerotized; 2 nd process ¾ the length of 1 st process, margin irregular, with membranous pocket in lateral view (Fig. 3 A, B). Inferior appendage setose, length 3 times greater than width, with slight upward curve, apex rounded; inner surface bearing stout spines; inner surface of right appendage with hook-like basal process (Fig. 3 A, B, C). Phallus simple, elongate, threadlike (Fig. 3 D).

Material examined. Holotype: Mexico • ♂; Baja California: Ensenada, Rancho Mike´s Sky; San Rafael River waterfall; 31°05.649'N, 115°37.436'W; el. 1232 m; 02.vii.2022; A. Contreras, A. Gómez, Y. Marquez, A. Ramírez & M. Ramírez leg.; UV, White lights (in alcohol) (UMSP 000281127) . Paratypes: Mexico • 2 ♂; Same data as holotype (in alcohol) (CNIN) .

Etymology. Named in honor of Dr Gerardo Rivas, an aquatic acarologist at Facultad de Ciencias of Universidad Nacional Autónoma de México, a friend and former advisor of the first author.