Hydrochus cracentis, Perkins, 2020

Hydrochus cracentis View in CoL , new species

Figs. 1 View FIGURE 1 , 7 View FIGURE 7

Type Material. Holotype (male): “ PERU: Tambopata Prov., Madre de Dios Dpto, 15km NE Puerto Maldonado, Reserva Cuzco Amazonico , 12°33’S, 69°3’W, 200m, camp, 21 June 1989, J. S. Ashe, R. A. Leschen, #213, ex., at light” ( SEMC). GoogleMaps

Differential Diagnosis. Differentiated from other Peruvian species by the combination of the small body size (ca. 2.11 mm), the narrow body form (width/length ca. 0.33), the numerous dorsal microsetae, and the male genitalia ( Fig. 7 View FIGURE 7 ; described below). Completely reliable determinations will include dissection of males.

Description. Habitus as illustrated ( Fig. 7 View FIGURE 7 ). Size: holotype (length/width, mm): body (length to elytral apices) 2.11/0.71; head width 0.54; pronotum l/w 0.49/0.47; PA 0.47; PB 0.40; elytra 1.33/0.71. Body size small (ca. 2.11 mm), very narrow. Dorsum brown to copper ( holotype teneral), with slight to moderately strong iridescence, elytra with black spots. Dorsum with numerous microsetae. Legs testaceous, with tibiofemoral joints and basal ½ of femora darker. Punctation on elytra ca. 2–3x that of pronotum. Elytra interstriae ca. 0.5–1x strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th very weakly if at all raised.

Pronotum very slightly longer than wide, widest at anterior margin, narrowed at base, sides very weakly arcuate, almost straight, smooth; anterior margin arcuate; depressions moderately deep, coarsely densely punctate, reliefs between depressions less punctate.

Elytra with spaces between strial punctures ca. 0.5–1x their diameter; apices rather sharply conjointly rounded in dorsal view, in lateral view outer margin without angulation.

Ventral characters: Mentum densely punctate, with median fovea. Submentum with two foveae.

Male genitalia ( Fig. 7 View FIGURE 7 ) general characters: genitalia very small, wider in dorsal/ventral views than lateral view; paramere tips extending slightly beyond tip of aedeagus, in dorsal/ventral views slightly widened, arcuate toward midline, with apical portions separated one from the other, in lateral view tips straight, distal end rounded; aedeagus broad in both dorsal/ventral and lateral views, in distal ½ much wider than parameres in dorsal/ventral views; basal piece longer and slightly wider than parameres; basal piece much wider in dorsal/ventral views than lateral view.

Dorsal surface: pdmm slightly separated from alm in distal portion, contiguous or nearly so for remainder of length.

Ventral surface: ventrally parameres in distal ½ distinctly wider than dorsal part of parameres, pvmm in this area very thin and nearly straight, overlapping alm; pvmm in proximal ½ becoming narrowly separate one from the other and with thin, finely striated ridge; pseu small, appear to be between parameres and aedeagus.

Etymology. Named in reference to the slender body form.