Hydrochus argutus

Perkins, Philip D., 2021, Taxonomy of water beetles in the genus Hydrochus Leach, 1817, from Bolivia, Brazil and Paraguay (Coleoptera: Hydrochidae), Zootaxa 4994 (1), pp. 1-93: 12

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Hydrochus argutus


H. argutus   species group

Figs. 2 View FIGURE 2 , 5 View FIGURE 5 , 40 View FIGURES 40–41 , 67 View FIGURES 67–68 , 70 View FIGURE 70

Members of the H. argutus   species group are recognized by the combination of the following characteristics: 1) very small size, length ca. 1.95–2.70 mm; 2) pronotum notably narrowed at base; 3) dorsum densely coarsely punctate, brown or reddish brown, with very slight or no iridescence; 4) elytra apices slightly widened, with sub-marginal groove having large translucent punctures; 5) male genitalia paramere tips appearing sagittate, but only in lateral view, in dorsal/ventral views tips have contiguous medial margins, which extend beyond distal end of aedeagus; parameres slightly longer than basal piece (ratio ca. 15/12), basal piece proximal 1/2 strongly arcuate ventrad, enlarged at orifice. The male genitalia shape is very unusual, and characteristic for the species group. Members include H. argutus   ( Brazil, Ecuador, Peru), H. argutulus   ( Bolivia), H. argutissimus   ( Venezuela) ( Fig. 67 View FIGURES 67–68 ), and an undescribed species from Costa Rica (Perkins, in prep.).