Aptilotella simplex Luk & Marshall, sp. n.

Figures 234–244

Description. Body length 1.3 mm. Head ground color red-orange. Frons with polished interfrontal plate. Ocellar tubercle scarcely raised; ocelli absent; small medial seta present; ocellar bristle subequal to the length of frons. Orbital bristle absent; orbital setulae minute, in three pairs. Interfrontal setae in two pairs. Face, clypeus, and posterior half of gena brown; gena rugose, lower margin with several long setae. Antenna reddish-brown, pedicel darker. Scutum red-orange, shining, rugose; uniformly setose, posterior third microtrichose. Scutellum dark reddish-brown, finely microtrichose; 2.5 times as wide as long, 0.6 times width of scutum. Apical scutellar bristles long, 0.9 times as long as basal. Pleurites reddish-brown, weakly shining; laterotergite black. Legs dark reddishbrown; coxae dark brown; fore tibia and first fore tarsomere dark brown; distal tarsomeres of fore tarsus off-white; mid tibia with two anterodorsal and one preapical posterodorsal bristle. Wing rudiment black. Abdomen black, shining, finely rugose; tergites and sternites uniformly setose and microtrichose.

Male terminalia. Sternite 5 (Fig. 237) rectangular with scattered short setae; posterior margin slightly pointed medially. Synsternite 6+7 (Fig. 236) with medial bridge flanked by a stout prong on both sides, posteromedially with a membranous pouch clothed in minute denticles. Cercus (Figs. 234, 235) 1.7 times as long as basal width; base swollen, broad, medially with a seta, lower margin with a long seta subequal to the length of cercus; the distal half curving, with two sensory setae. Surstylus (Figs. 234, 235) pyramidal; posterior face with numerous long setae, interior half with a thick finger-like bristle; anterior margin with triangular medial excavation. Postgonite (Fig. 239) 3 times as long as wide; posterior margin sinuate; descending portion half the length of postgonite, with two sensory setulae along inner margin; articulatory process for pregonite triangular; articulatory process for basiphallus broad, with two blunt teeth. Hypandrium (Fig. 240) with medial rod apically broadly fan-shaped; posteromedial fork thick and shallow; hypandrial arms short, irregularly truncate; pregonite minute, irregularly rectangular. Aedeagus as in Figure 238. Basiphallus compressed, squared, with truncate epiphallus; anterior margin weakly arched; articulatory process for postgonite short and divergent. Ejaculatory apodeme discoid, inconspicuous. Ventrobasal sclerite divided. Lateral flanking sclerite narrowly fused ventrobasally; dorsal margin darkened, straight; distal quarter clothed in very fine spinules, dorsally with a field of suspended spinules. Ventral flanking sclerites darker; the basal article fused along ventral margin of lateral flanking sclerite, with a thin, tapered dorsal arm; the rod-shaped medial article originating ventrodistally to basal article; the paddle-shaped distal article originating above dorsal margin of medial article, distal margin with a dark, rod-shaped lobe.

Female terminalia. Epiproct (Figs. 241, 242) rectangular, weakly sclerotized. Each half of tergite 8 (Figs. 241–243) triangular, convex; dorsal margin curved; apex truncate; with scattered setae. Cercus twice as long as wide; with numerous preapical setae. Spermathecae (Fig. 244) cylindrical, finely ridged; apex invaginated; ducts short, less than the diameter of a spermatheca, lightly sclerotized, bent at collar.

Etymology. The specific epithet refers to the unusually featureless sternite 5.

Type material. Holotype ♂, INBC. COSTA RICA: Guanacaste, Santa Elena Cloud Forest Reserve, 10°20’42”N, 84°47’53”W, 1650 m, cloud forest litter, 11.vi.2001, R.S. Anderson.

Paratypes. COSTA RICA: Guanacaste, same label as holotype (♀, DEBU); Puntarenas, Monteverde Biological Station, 10°18’53”N, 84°47’49”W, 1800 m, cloud forest litter, 10.vi.2001, R.S. Anderson (2♂, ♀, DEBU) .

Comments. Aptilotella simplex is distinctive in having a nearly straight posterior margin of the male sternite 5. The fore leg is boldly patterned in both sexes, and is strikingly similar to that of A. gracilis and A. gladia, the apterous limosinine Myrmolimosina andersoni Marshall and even a brachypterous Aluligera from Africa (Richards, 1955). Field observations could yield insight into the potential behavioural functions of these remarkably convergent fore limbs.