Hydrochus kellymilleri, 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 : 48-50

Hydrochus kellymilleri new species

Figs. 2 , 27

Type Material. Holotype (male): “ Venezuela : Guarico State: 8° 31.705’ N, 66° 22.602’ W, 145m, c. 65 km S Las Mercedes, 09.i.2009, leg. Short, Miller, Garcia & Camacho, large lagoon w/ veg.; VZ09-0109- 01X ” ( MIZA) . Paratypes (159): Venezuela: Apure: VZ09-0118- 03X (9 SEMC) . Barinas: VZ12-0125-01A (13 SEMC); VZ12-0126 - 01 B (5 SEMC) ; Guanare, 13-IX-1957, Borys Malkin, Carrotera National 5, 1 km. W. of Puente Gen. Paez on Rio Bocono , pond in meadow, clear water, much vegetation (1 CAS) . Bolivar: VZ09-0111- 02X (11 SEMC) . Carabobo: Tocuyito , 13-XII-1965, J. & B. Bechyne leg. (12 NMNH) . Cojedes: VZ12-0121-02A (1 SEMC) . Guarico: Same data as holotype (6 SEMC); VZ09-0108 - 03X (6 SEMC); VZ09-0110 - 01 A (2 SEMC) ; Corozo Pando , (8 km N), 20–21 June 1984, blacklight, F. W. Eiland & V. Linares (3 NMNH) ; San Fernando , II-12-1969, P. & P. Spangler (31 NMNH) ; 15 km S. Calabozo II-9-13-1969, collected in Lago de Los Patos , P. & P. Spangler (8 NMNH) ; Calabozo II-9-13-1969, collected in Lago de Los Patos , P. & P. Spangler (3 NMNH) ; 12 km S. Calabozo II-6-12-1969, P. & P. Spangler (1 NMNH) ; Calabozo (44 km S), Hato Masaguaral , 5 Mar 1986, PJSpangler, colln#24 (12 NMNH) ; Esteros Camaguan , 9-IV-60, leg. C. Bordon (1 NHM) . Miranda: Guatopo NP, El Lucero , 28km N Altagracia, 620m, 1–14.VI.1987, S&J Peck, UV light trap 87-17 (3 CMN) . Monagas: VZ10-0202-01B (18 SEMC); VZ10-0202 - 03 A (1 SEMC) . Portuguesa: VZ09-0119-02B (1 SEMC); VZ09-0119 - 02 C (1 SEMC) ; Guanare , IX-10 to 13-1957, Borys Malkin Collector (6 NMNH) ; Guanare , II-26-1969, P. & P. Spangler (1 NMNH) . Tachira: VZ09-0716-07A (1 SEMC) . Zulia: VZ12-0127-01A (2 SEMC) .

Differential Diagnosis. Among Venezuelan species, recognized by the combination of small size (ca. 2.00– 2.69 mm), the bright metallic silver dorsum, the pronotum with moderately deep, densely punctate impressions, the pronotal shape, the very large black spots on the elytra, and the male genitalia ( Fig. 27 ; described below). Differentiation from other similarly small sized species with similarly shaped pronotum will require dissection of males.

Description. Habitus as illustrated ( Fig. 27 ). Size: holotype (length/width, mm): body (length to elytral apices) 2.12/0.76; head width 0.54; pronotum l/w 0.48/0.52; PA 0.50; PB 0.40; elytra 1.28/0.76. Body size small (ca. 2.00– 2.69 mm). Dorsum grey, with moderately strong iridescence, to bright silver metallic, elytra with several large black spots. Legs brown to testaceous, with tibiofemoral joints darker. Punctation on elytra deep, ca. 2– 3x that of pronotum. Elytra interstriae narrow ridges to ca. 1x strial puncture diameter. Interstriae 5 th and 9 th more convex than others, 9 th overhanging 10 th interstria. Usual area of callus on 5 th slightly raised.

Pronotum slightly wider than long (as ca. 48/52), widest slightly behind anterior margin, markedly narrowed at base, sides very slightly sinuate, smooth; anterior margin bisinuate; depressions moderately deep, depressions much more densely punctate than reliefs.

Elytra with spaces between strial punctures narrow ridges to ca. 0.5x their diameter; apices rather sharply separately rounded in dorsal view, in lateral view outer margin with very slight to no angulation.

Ventral characters: Mentum densely, moderately coarsely punctate, with median fovea. Submentum without foveae.

Male genitalia ( Fig. 27 ) general characters: genitalia very small; lateral margins of parameres almost parallel; paramere tips rounded and curving toward midline, but not contacting one another, tips smaller than distal part of aedeagus, very lightly sclerotized; aedeagus wide, much wider that narrowest part of parameres; basal piece markedly tapering from distal to proximal, widened at orifice, in lateral view, with ventral ½ very weakly sclerotized, dorsal ½ strongly sclerotized, rim of orifice sclerotized, strongly produced apicoventrally in point, toward dorsad.

Dorsal surface: without distinct adtl; pdmm separated from alm, except in basal 1/3 where overlapping; adbl very small.

Ventral surface: pvmm overlapping basal part of aedeagus; each paramere, in basal 1/3, with thin margin produced toward midline, and margin very finely striated.

Etymology. Named for Kelly B. Miller, an outstanding water beetle collector who has netted many new species of Hydrochus .

Figures

FIGURE 2. Dorsal habitus of Hydrochus species.

FIGURE 27. Hydrochus kellymilleri n. sp., habitus and male genitalia of holotype.