Hydrochus subovatus, 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 : 80-81

Hydrochus subovatus , new species

Figs. 1 , 13

Type Material. Holotype (male): “ PERU: Madre de Dios, Tambopata, Terrafirme, Drinking Quebrada , (13°0’S, 69°33’W) // 11.ix.1983, leg. J. J. Anderson, ex leaf packs” ( NMNH) . Paratype: Same data as holotype (1 NMNH) .

Differential Diagnosis. Among Peruvian species, recognized by the combination of small size (ca. 2.30 mm), the sub-oval body form, the elytra with odd-numbered interstriae raised, and the male genitalia ( Fig. 13 ; described below).

Description. Habitus as illustrated ( Fig. 13 ). Size: holotype (length/width, mm): body (length to elytral apices) 2.30/0.93; head width 0.58; pronotum l/w 0.53/0.60; PA 0.55; PB 0.47; elytra 1.43/0.93. Body size moderate (ca. 2.30 mm). Dorsum dark brown, with slight iridescence, elytra without black spots. Legs brown, 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 raised, moderately elongate.

Pronotum slightly wider than long, widest slightly behind anterior margin, narrowed at base, sides arcuate or very weakly sinuate, denticulate, each process with moderately long arcuate seta; anterior margin bisinuate; depressions, especially anterior, deep, much more densely punctate than reliefs between depressions.

Elytra with odd numbered interstriae raised, spaces between strial punctures ca. 0.5–1x their diameter; apices rather sharply conjointly rounded in dorsal view, with sublateral punctate groove, in lateral view outer margin with slight angulation.

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

Male genitalia ( Fig. 13 ) general characters: genitalia very small, very slender, length ca. 6x width; paramere distal ends sharply rounded in dorsal/ventral and lateral views, slightly longer than aedeagus, lacking plsa, tips beyond aedeagus with medial margins parallel or nearly so, distal ½ of parameres with distinct pmsm; aedeagus narrowly lanceolate, agw slightly distal to midlength, alw just distal to adbl; basal piece slightly longer than parameres, width slightly greater in dorsal/ventral than lateral views, orifice weakly sclerotized.

Dorsal surface: adbl moderately large, almost as wide as agw; pdmm approximating shape of alm.

Ventral surface: pvmm basally overlapping aedeagus, margins very narrowly separated one from the other, otherwise approximating shape of alm.

Etymology. Named in reference to the oval habitus.

Figures

FIGURE 1. Dorsal habitus of Hydrochus species.

FIGURE 13. Hydrochus subovatus n. sp., habitus and male genitalia of holotype.