Hydrochus sagittarius, 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 : 20-21

Hydrochus sagittarius new species

Figs. 1 , 4B , 13

Type Material. Holotype (male): “ Venezuela: Barinas State: 8° 16.954’ N, 70° 23.867’ W, 149m, 20 km S. Ciudad Bolivia, 25.i.2012, leg. Short, Arias & Gustafson, Muddy creek ; VZ12-0125-01A” ( MIZA) . Paratypes (283): Venezuela: Anzoategui: VZ09-0812-02A (1 SEMC) ; VZ10-0204 - 01 A (1 SEMC) . Apure: VZ09-0118- 02X (3 SEMC) ; VZ09-0118 - 03X (1 SEMC) . Aragua: Rancho Grande 20 km NW of Maracay El. 1100M, 23 July 1976, at lights, M. H. Sweet V-31 (5 TAMU) . Barinas: Same data as holotype (2 SEMC) ; VZ09-0119 - 01X (2 SEMC) . Bolivar: 22km E Upata , 18–19.VI.1996, H. &A. Howden (4 CMN) ; Anacoco , 60m, 60d 5’N; 61d 8’O, 10-30 VIII-1979, Expedicion La Salle (3 SEMC) ; Guri, Rio Caroni , 100m, 16-XI-1966, J. & B. Bechyne, E. Osuna (1 SEMC) . Falcon: VZ09-0710-03B (2 SEMC) . Guarico: VZ09-0108- 03X (7 SEMC, MIZA, MALUZ) ; San Fernando , II-12-1969, P. & P. Spangler (117 NMNH, CNC) ; Calabozo (44 km S), Hato Masaguaral , 6 Mar 1986, PJSpangler & SBeaujon, colln#31 (26 NMNH) ; Corozo Pando, (8kmN), 17–18 June 1984, blacklight, F. W. Eiland & V. Linares (44); Corozo Pando, (8kmN), 20–21 June 1984, blacklight, F. W. Eiland & V. Linares (9 NMNH) ; Hato La Lajas , 15-VIII-1964, C. J. Rosales, A. D. Ascoli (6 SEMC) . Miranda: Guatopo NP, El Lucero , 28km N Altagracia, 620m, 1–14.VI.1987, S&J Peck, UV light trap 87-17 (14 CMN) . Monagas: VZ10-0131-03B (2 SEMC) . Portuguesa: Guanare , IX-10 to 13-1957, Borys Malkin Collector (29 CAS) . Sucre: VZ10-0129-04A (1 SEMC); VZ10-0130 - 02 A (1 SEMC) . Yaracuy: La Hoya , 100m, 28- 30-VI-1973, en la luz, F. Fernandez, J. Salcedo, J. Clavijo (2 SEMC) .

Differential Diagnosis. Among Venezuelan species, males recognized by the combination of moderate size (ca. 3.08–3.77 mm), the relatively impunctate pronotal reliefs, and the distinctive male genitalia, with sagittate paramere tips ( Fig. 13 ; described below). Dorsally, specimens can be confused with H. bicarinatus ; H. sagittarius males lack metaventral carinae, and the reliefs are much less punctate. Reliable determinations will require dissection of males.

Description. Habitus as illustrated ( Fig. 13 ). Size: holotype (length/width, mm): body (length to elytral apices) 3.50/1.14; head width 0.86; pronotum l/w 0.75/0.78; PA 0.71; PB 0.64; elytra 2.14/1.14. Body size moderately large (ca. 3.08–3.77 mm). Dorsum grey, 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. 0.5– 1x strial puncture diameter. Interstria 9 th more convex than others, not overhanging 10 th interstria. Usual area of callus on 5 th very slightly raised.

Pronotum slightly wider than long, widest at or just behind anterior margin, narrowed at base, sides arcuate or very weakly sinuate, infrequently nearly straight, smooth; depressions moderately deep, much more densely punctate than raised reliefs between depressions, latter almost entirely impunctate.

Elytral strial punctures ca. 2– 3x size of pronotal punctures, spaces between them 0.5– 1x 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.

Male genitalia ( Fig. 13 ) general characters: paramere tips sagittate, distal ends and plsa sharply pointed, lateral margins emarginate, medial margins of distal ½ of tips parallel and nearly touching one another, only distal ½ of tips extending beyond aedeagus, in lateral view tips with emarginately arcuate ventral margin; basal piece large and long, almost as long as parameres; parameres with distinctive elongate pwsa on ventral surface.

Dorsal surface: adtl subapical, membranous area small and rather narrow; pdmm narrowly separated, overlapping alm; adbl comparatively small.

Ventral surface: avtl U-shaped, near basal 1/3 of aedeagus; pvmm much more widely separated than pdmm; parameres each with large pwsa; large pseudoparamere on each side, generally in location against pwsa.

Etymology. Named in reference to the arrowhead shape of the apices of the male genitalia parameres.

Figures

FIGURE 1. Dorsal habitus of Hydrochus species.

FIGURES 4A–B. Male genitalia characters of (A) H. pseudosecretus Oliva (ventral); (B) H. sagittarius n. sp. (ventral; diagrammatical, showing locations of muscles).

FIGURE 13. Hydrochus sagittarius n. sp., habitus and male genitalia of holotype.