Hydrochus tambopaticus, 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: 81-83

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Hydrochus tambopaticus

new species

Hydrochus tambopaticus   , new species

Figs. 1 View FIGURE 1 , 14 View FIGURE 14

Type Material. Holotype (male): “ PERU: Madre de Dios; Rio Tambopata Res ; 30 air km SW Pto. Maldonado, 290 m, 2–5 xi 1979, J. B. Heppner, subtropical moist forest” ( NMNH)   . Paratypes (75): PERU: Same   data as holotype (4 NMNH)   ; same locality, 6–10.xi.1979, leg. J. B. Heppner (9 NMNH)   ; same locality, 11–15.xi.1979, leg. J. B. Heppner (15 NMNH)   ; same locality, 16–20.xi.1979, leg. J. B. Heppner (5 NMNH)   ; same locality, 21–25.xi.1979, leg. J. B. Heppner (4 NMNH)   ; Ucayali, Rio Calleria, 15 km from Ucalagi , 3–13.x.1961, leg. Borys Malkin (1 NMNH)   ; Loreto, Pucallpa , 10–12.iv.1969, leg. P. & P. Spangler (8 NMNH)   ; Madre de Dios, Parque Manu, Pakitza, Trocha Dos , c.53, berlesed leaf litter, elev. 250 m (12°7’S, 70°58’W), 13.ix.1989, leg. R. A. Faitoute (39) (3 NMNH) GoogleMaps   ; same locality, 19.ix.1989, leg. R. A. Faitoute (47a) (2 NMNH) GoogleMaps   ; same locality, 20.ix.1989, leg. R. A. Faitoute (48) (4 NMNH) GoogleMaps   .

Differential Diagnosis. Among Peruvian species, recognized by the combination of large size (ca. 3.85–3.93 mm), the shallow pronotal depressions, the large elytral tubercles, and the male genitalia ( Fig. 14 View FIGURE 14 ; described below). This species has a generalized Hydrochus   habitus; reliable determinations will require dissection of males. The male genitalia are similar in general characters to that of H. elsjeae Makhan   from Bolivia, but differ in several characters including 1) larger size (length as ca. 5.60 to 4.35); 2) aedeagal apex more nearly attaining apex of parameres; 3) paramere tips with psla more acute and lateral margins less strongly emarginate; 4) pseudoparameres much wider in ventral view; 5) genitalia wider in lateral view.

Description. Habitus as illustrated ( Fig. 14 View FIGURE 14 ). Size: holotype (length/width, mm): body (length to elytral apices) 3.93/1.43; head width 0.95; pronotum l/w 0.86/0.90; PA 0.83; PB 0.76; elytra 2.52/1.43. Body size large (ca. 3.93 mm). Dorsum grey to black, with slight iridescence, elytra with black spots. Legs testaceous to brown, with tibiofemoral joints darker. Punctation on elytra ca. 0.5–1x that of pronotum. Elytra interstriae ca. 1–2x strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th markedly raised, moderately elongate, ca. 5 punctures in row on each side.

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

Elytra with spaces between strial punctures ca. 1x their diameter; apices rather sharply conjointly rounded in dorsal view, in lateral view outer margin with moderate angulation.

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

Male genitalia ( Fig. 14 View FIGURE 14 ) general characters: genitalia very stout, wide in lateral view; paramere tips extending slightly beyond distal end of aedeagus, plsa acutely pointed, lateral margin between plsa and distal end slightly emarginate, medial margin arcuate, in lateral view extreme end of tips upturned slightly; aedeagus lanceolate, greatest width distal to midlength, with alsm; pseudoparameres large, not extending to level of distal end of aedeagus or to plsa, pseudoparameres not wider in lateral than dorsal/ventral views; basal piece as long as parameres, and as long as aedeagus (including adbl), orifice in dorsal/ventral views much narrower than greatest width of basal piece, strongly sclerotized and, in lateral view, produced in rounded process.

Dorsal surface: adtl located slightly distal to midlength of aedeagus; pdmm sinuate, overlapping lateral margins of aedeagus; adbl moderately large; gp large.

Ventral surface: avtl U-shaped, near midlength of aedeagus; pvmm overlapping lateral margin of aedeagus only at midlength; pseudoparameres wide basally, narrowed apically and with minute spines.

Etymology. Named in reference to the geographical distribution.


Smithsonian Institution, National Museum of Natural History