Hydrochus lescheni, Perkins, 2020

Perkins, Philip D., 2020, Taxonomy of Peruvian water beetles in the genus Hydrochus Leach, 1817 (Coleoptera: Hydrochidae), Zootaxa 4868 (1), pp. 61-89 : 74

Hydrochus lescheni , new species

Figs. 2 , 9

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).

Differential Diagnosis. Among Peruvian species, recognized by the combination of small size (ca. 2.12 mm), the shallow pronotal depressions, more densely punctate than the low reliefs between depressions, latter almost entirely impunctate, and the male genitalia ( Fig. 9 ; described below). Completely reliable determinations will include dissection of males.

Description. Habitus as illustrated ( Fig. 9 ). Size: holotype (length/width, mm): body (length to elytral apices) 2.12/0.82; head width 0.59; pronotum l/w 0.52/0.55; PA 0.50; PB 0.44; elytra 1.29/0.82. Dorsum grey to silver grey, with slight to moderately strong iridescence, elytra with black spots (holotype specimen teneral). Legs testaceous, with tibiofemoral joints and basal ½ of femora darker. Punctation on elytra ca. 2–3x that of pronotum. Elytra interstriae ca. 1–1.5x strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th very weakly raised, moderately elongate, ca. 6 punctures in row on each side.

Pronotum length slightly less than width, widest slightly behind anterior margin, narrowed at base, sides arcuate or very weakly sinuate, smooth; anterior margin slightly bisinuate; depressions shallow, more densely punctate than low reliefs between depressions, latter almost entirely impunctate.

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 large median fovea. Submentum with two large foveae.

Male genitalia ( Fig. 9 ) general characters: genitalia very small; paramere tips extending well beyond tip of aedeagus, in dorsal/ventral views slightly widened, with apical portions well separated one from the other, and medial margins nearly parallel, in lateral view tips narrowing apically, slightly arcuate toward ventral, extreme tip with pointed apex; aedeagus broad in both dorsal/ventral and lateral views, much wider than parameres in dorsal/ventral views, internally in central portion with many concentric lines; basal piece shorter than parameres, widened at orifice in dorsal/ventral views, in lateral view basal piece markedly narrowed from distal end to base.

Dorsal surface: pdmm slightly overlapping alm.

Ventral surface: pvmm slightly overlapping alm for most of length, becoming more narrowly separated from one another basally.

Etymology. Named in honor of the collector, Richard A. Leschen.

Figures

FIGURE 2. Dorsal habitus of Hydrochus species.

FIGURE 9. Hydrochus lescheni n. sp., habitus and male genitalia of holotype.