Hydrochus pertuberculatus, Perkins, 2020

Perkins, Philip D., 2020, Taxonomy of Guatemalan water beetles in the genus Hydrochus (Coleoptera: Hydrochidae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 291-301 : 297-299

Hydrochus pertuberculatus sp. nov.

( Figs 1 , 5 )

Type material. HƟĿƟŦYPൾ: male ( NMNH): ‘ GUATEMALA, 20 Mi. SW Puerto Barrios VIII-16-1965 Paul J. Spanglerʼ. PARAŦYPൾ: 1 male ( NMNH): same data as holotype.

Differential diagnosis. The largest of known Guatemalan species (body length 3.56–3.85 mm), recognized by the combination of the body size, the densely punctate pronotum with deep foveae, the elytral sculpture, having a very large callus on the 5 th interstria, the 3 rd interstria slightly raised over the basal ¼, and the 4 th interstria raised in the area anterior to 5 th callus, and the male genitalia ( Fig. 5 ; described below).

Description. Habitus as illustrated in Fig. 5 . Size (in mm): holotype: body (length to elytral apices / width) 3.56 / 1.28; head width 0.86; pronotum length / width 0.84 / 0.91; PA 79; PB 0.77; elytra 2.33 / 1.28. Body size moderate (ca. 3.56–3.85 mm). Dorsum black, with very slight, if any, iridescence, elytra without black spots. Legs dark brown, with tibiofemoral joints slightly darker. Punctation on elytra ca. 2–4× that of pronotum. Elytra interstriae ca. 0.5–1.5× strial puncture diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Usual area of callus on 5 th large, very strongly raised.

Pronotum length slightly less than width, widest at ca. anterior third, narrowed at base, sides sinuate, minutely denticulate; anterior margin bisinuate; depressions, especi- ally anteromedian, deep, reliefs sharply raised, depressions and reliefs densely punctate.

Elytra with spaces between strial punctures ca. 0.5–1.0× their diameter; 3 rd interstria slightly raised over basal fourth; 4 th interstria raised in area anterior to large callus of 5 th; posterior declivity abrupt and suture raised in this area, apices rather sharply conjointly rounded in dorsal view, in lateral view with submarginal row of large punctures, bordered above by low ridge, outer margin with strong angulation.

Male genitalia ( Fig. 5 ). General characters: genitalia long and narrow; paramere tips small, sagittate, distal ends pointed, lateral margins between distal end and plsa straight, not emarginate, medial margins of tips slightly emarginate and well separated from lateral margins of aedeagus, distal end of tips not extending beyond aedeagus, in lateral view tips narrow, sharply pointed; aedeagus very narrow in both dorsal/ventral and lateral views, widest at adbl, narrowest at ca. proximal third, with narrowly sclerotized lateral margins; basal piece shorter than parameres, with rim of orifice strongly sclerotized.

Dorsal surface: adtl located slightly distal to midlength of aedeagus; pdmm very slightly narrowly overlapping alm at base; adbl large, distinctively shaped.

Ventral surface: avtl subapical, U-shaped; pvmm overlapping alm at base.

Etymology. Named in reference to the very large tubercles on the 5 th elytral interstriae. Adjective.

Figures

Fig. 1. Dorsal habitus of Guatemalan Hydrochus species.

Fig. 5. Hydrochus pertuberculatus sp. nov., habitus and male genitalia of holotype.