Hydrochus ramcharani Makhan, 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 : 16-17

Hydrochus ramcharani Makhan new status

Figs. 2 , 11

Hydrochus ramcharani Makhan, 1992: 96 .

Hydrochus drakei Knisch : Oliva (1996: 329); misidentification

Material examined (8): Venezuela: Anzoategui: VZ10-0204-01A (1 MIZA) . Bolivar: 5 km E. Caicara, 11.VI.1996, at light, H. & A. Howden (4 CMN) . Guarico: San Fernando , II-12-1969, P. & P. Spangler (3 NMNH) .

Differential Diagnosis. Among Venezuelan species, recognized by the combination of moderate size (ca. 3.85– 4.12 mm), the fine (pronotal) to only moderately coarse (elytral) dorsal punctation, with well separated punctures, and the distinctive male genitalia ( Fig. 11 ; described below). H. ramcharani has a generalized habitus; reliable determinations will require dissection of males.

Description. Habitus as illustrated ( Fig. 11 ). Size of imaged specimen (length/width, mm): body (length to elytral apices) 4.12/1.44; head width 0.96; pronotum l/w 0.88/0.92; PA 0.84; PB 0.76; elytra 2.52/1.44. Size ca. 3.85–4.12 mm. Dorsum grey with very slight iridescence, elytra with black spots. Legs testaceous to dark brown to black. Dorsal punctation small to moderately large, larger on elytra than pronotum. Elytra interstriae ca. 1.5– 2x strial punctures diameter. Interstria 9 th more convex than others, overhanging 10 th interstria. Callus on 5 th moderately large.

Pronotum slightly wider than long, widest just behind anterior margin, narrowed at base, sides arcuate or very weakly sinuate, smooth; depressions moderately sized.

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

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

Male genitalia ( Fig. 11 ) general characters: genitalia very stout, wide in lateral view; paramere tips extending slightly beyond distal end of aedeagus, lateral margins sinuate, medial margins parallel, in lateral view extreme end of tips upturned slightly; aedeagus lanceolate; pseudoparameres large, extending to level of distal end of aedeagus, extending beyond plsa; basal piece with orifice strongly sclerotized, and with strongly sclerotized midline ventrally.

Dorsal surface: adtl located near midlength of aedeagus; pdmm overlapping lateral margins of aedeagus; adbl large, distinctively shaped.

Ventral surface: avtl U-shaped, near basal 1/3 of aedeagus; pvmm overlapping lateral margins of aedeagus, but more widely separated than pdmm; pseudoparameres enveloping most of basal ¼ of parameres.

Remarks. The specimen imaged ( Fig 11 ) is from locality VZ10-0204-01A. I have examined a male paratype of H. ramcharani , including the genitalia, and must disagree with Oliva (1996), who placed H. ramcharani as a junior synonym of H. drakei Knisch. See also Perkins (2019) on the identity of Hydrochus drakei Knisch.

Figures

FIGURE 2. Dorsal habitus of Hydrochus species.

FIGURE 11. Hydrochus ramcharani Makhan, habitus and male genitalia of holotype.