Hydrochus bicarinatus, Perkins, 2019

Perkins, Philip D., 2019, Taxonomy of Venezuelan water beetles in the genus Hydrochus Leach, 1817, and an analysis of male genitalia morphology (Coleoptera: Hydrochidae), Zootaxa 4708 (1), pp. 1-59 : 23-24

Hydrochus bicarinatus new species

Figs. 1 , 15

Type Material. Holotype (male): “Venezuela: Zulia State: 8° 33.108’ N, 72° 20.163’ W, 47m, Puente del Zulia , finca by road, leg. Short, Arias & Gustafson, lagoon, 27.i.2012, VZ12-0127-01A” ( MIZA) . Paratypes (180): Venezuela: Anzoategui: Pariaguan , 13-VIII-1967, J. & B. Bechyne leg. (2 SEMC) . Apure: VZ09-0118- 03X (1 SEMC) . Barinas: VZ12-0126-01B (1 SEMC); VZ12-0125 - 01 A (1 SEMC) ; 10 Km NE Barinas , II-23-1969, P. & P. Spangler (2 NMNH) . Bolivar: El Dorado (65 km S), 1 Nov. 1982, John L. Hellman (5 NMNH) . Falcon: VZ09-0710-03B (5 SEMC) ; Tucacas , 1m, 4.VIII.1989, S. & J. Peck, coastal lagoon and coconut grove, ex: UV trap, 89-287 (1 CMN) . Guarico: VZ10-0706-01A (1 SEMC) ; San Fernando , II-12-1969, P. & P. Spangler (54 NMNH) ; 15 km S. Calabozo II-9-13-1969, collected in Lago de Los Patos , P. & P. Spangler (9 NMNH) ; Calabozo II-7-1969, P. & P. Spangler (1 NMNH) ; Corozo Pando , (8kmN), 17–18 June 1984, blacklight, F. W. Eiland & V. Linares (60 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 6 Mar 1986, PJSpangler, colln#30 (7 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 6 Mar 1986, gate lagoon, PJSpangler, colln#28 (1 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 65 Mar 1986, PJSpangler, colln#25 (3 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 7 Mar 1986, PJSpangler, colln#32 (3 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 6 Mar 1986, PJSpangler & SBeaujon, colln#31 (1 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 4 Mar 1986, large lake, PJSpangler, colln#22 (7 NMNH) . Monagas: VZ10- 0202-01B (1 SEMC); VZ10-0719 - 01 A (1 SEMC) ; 42 km. SE. Maturin , June 18, 1958, Arnold Menke (2 NMNH) . Tachira: VZ09-0716-05A (1 SEMC) . Trujillo: VZ12-0128-06A (3 SEMC) . Yaracuy: La Hoya , 100m, 28-30-VI- 1973, en la luz, F. Fernandez, Y. J. Salcedo, J. Clavijo (6 SEMC) . Zulia: Same data as holotype (1 SEMC) .

Differential Diagnosis. Among Venezuelan species, males recognized by the presence of a pair of submedian, longitudinal, parallel carinae of the metaventrite. The dorsal sculpture is only moderately coarse, with the elytral strial punctures about as wide as the interstriae, but with the spaces between punctures of a row less than puncture diameter. The male genitalia are distinctive ( Fig. 15 ; described below). and should be examined for reliable determinations.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 3.37/1.17; head width 0.80; pronotum l/w 0.77/0.80; PA 0.67; PB 0.60; elytra 2.13/1.17.

Habitus as illustrated ( Fig. 15 ), size ca. 2.77–3.62 mm. Dorsum grey to gold, with slight iridescence, elytra with black spots. Legs testaceous, with tibiofemoral joints darker. Dorsal punctation small to moderately large, larger on elytra than pronotum. Elytra interstriae ca. 1x strial puncture diameter. Interstria 9 th more convex than others, not overhanging 10 th interstria. Callus on 5 th small.

Pronotum slightly wider than long, widest just behind anterior margin, narrowed at base, sides arcuate or very weakly sinuate, smooth; depressions moderately deep, pit-like geminate depressions near posterior angles rather large and deep.

Elytral strial punctures ca. 2– 3x size of pronotal punctures, spaces between them less than their diameter; apices conjointly rounded in dorsal view, in lateral view outer margin with slight angulation.

Ventral characters: Mentum coarsely punctate, with median fovea. Submentum with two foveae. Metaventrite of male with pair of submedian longitudinal parallel carinae.

Male genitalia ( Fig. 15 ) general characters: paramere tips pointed, slightly asymmetrical, in lateral view tips slightly upturned; adeagus very slender, with well sclerotized lateral margins (alsm); basal piece orifice with rim strongly sclerotized.

Dorsal surface: adtl at about distal 1/3; adbl large; pdmm overlapping aedeagus lateral margins over about middle 1/3.

Ventral surface: avtl near midlength; pvmm closely approximating alm.

Etymology. Named in reference to the metaventral carinae.

Figures

FIGURE 1. Dorsal habitus of Hydrochus species.

FIGURE 15. Hydrochus bicarinatus n. sp., habitus and male genitalia of holotype.