Berosus ornaticollis Oliva & Short

Oliva, Adriana & Short, Andrew E. Z., 2012, Review of the Berosus Leach of Venezuela (Coleoptera, Hydrophilidae, Berosini) with description of fourteen new species, ZooKeys 206, pp. 1-69 : 38-40

Berosus ornaticollis Oliva & Short sp. n. Figs 16B, 17B, 27

Type material.

Holotype (male): "VENEZUELA: Amazonas State/ 5°30.623'N, 67°36.109'W; 100 m/ ca. 15 km S. Puerto Ayacuho/ rock pools on top [of granite outcrop]; 14.ix.2007/ AS-07-011b; leg. A.E.Z. Short", "[barcode]/ SM0828174/ KUNHM-ENT", "HOLOTYPE/ BEROSUS/ ornaticollis sp. n./ des. Oliva & Short" (MIZA). Paratypes (61): VENEZUELA: Amazonas State: nr. Iboruwa, “Tobogancito”, 5°48.414'N, 67°26.313'W, 80 m, rock pool with detritus, 7.viii.2008; leg. Short, García, & Joly, AS-08-078 (11 exs., SEMC, MIZA); Same data as holotype (7 exs., SEMC); same locality and data but 8.viii.2008, leg. Short & García, AS-08-81b (40 exs., MIZA, MALUZ, SEMC); same locality and data but 14.i.2009, VZ09-0114-03B (1 ex., SEMC). Bolívar State: Los Pijiguaos, 6°35.617'N, 66°49.238'W, 80 m, morichal/rock outcrop, 16.ix.2007, leg. Short, García, & Joly, AS-07-015 (1 ex., SEMC); same locality and data but 6.iii.2008, AS-08-076 (1 ex., SEMC).

Diagnosis.

Moderate-sized, broad-shaped, not very convex species with strong metallic luster on dorsum of head and often with weak metallic sheen on medial spot on pronotum. Elytra with small, well-defined black spots, including an additional pair below the humeral humps (Fig. 16B). Mesoventral process entirely laminar. First ventrite carinate in anterior half. Male genitalia as in Fig. 17B. The melanic spots below the humeral humps are most distinctive; they are shared with Berosus humeralis sp. n., but they are less extended, taking up only a part of the ninth interstria. This species belongs to the auriceps-complex. The shape of the median lobe is most characteristic; in Berosus auriceps the median lobe is narrowly rounded at the apex; in Berosus aulus d’Orchymont, 1941 the moderately thick median lobe is much shorter than the parameres, and in Berosus ethmonotus Oliva, 1989 the apices of the parameres are broader and directed outwards. The new species may be distinguished from all the others by the toothed claws.

Description.

Body length 3.4-4.6 mm. Shape short and wide, moderately convex. Eyes moderately prominent in both sexes. Labrum black, dorsum of head melanic with strong metallic luster. Pronotum with remarkably large central melanic spot, without a testaceous median line, in most specimens with a metallic sheen; sides of the pronotum testaceous. Scutellum black. Elytra testaceous with small melanic spot in the normal generic pattern, save for a pair of additional spots which delimit the humeral humps on their ventral side and extend over a short stretch of the ninth interstria. Venter of thorax and abdomen melanic. Maxillary palpi darkened on apical one-third of distal segment. Femora with pubescent portion darkened, glabrous portion testaceous.

Head coarsely and densely punctured, punctures on frons about twice the size of ommatidia. Pronotal punctures larger than the ones on head, round, dense, irregular in spacing. Ground sparsely and finely micropunctate, shining. Scutellum with a few deeply impressed punctures, smaller than pronotal ones; ground alutaceous. Elytral striae shallow, not distinctly impressed, with coarse punctures about the same size as pronotal ones, overflowing outwards. Interstriae wide, flattened, bearing punctures smaller than those on striae, 1-2 seriated; outer interstriae slightly convex; background smooth in males, reticulate in females. Elytral apices simple. Spine-like hairs absent.

Mesoventral process small, laminar, with curved anterior tooth pointing downwards, a little thickened; posterior tooth raised but less prominent than anterior one. Metaventral process wide, flat. First ventrite carinate in anterior half, without lateral depressions. Ventrites second to fourth not carinate. Fifth ventrite with shallow apical notch, the bottom of the latter bearing two short rounded teeth.

Maxillary palpi short, with second palpomere short and thick. Basal pubescence of mesofemora and of metafemora slightly oblique, extending to a little less than half of the femoral length on anterior margin, and a little more than half on the posterior margin. Protarsus of male with basal tarsomere weakly thickened, bearing adhesive sole, about twice as long as the second tarsomere that does not bear a sole. Claws weakly arched, angular at base, bearing a small sub-basal tooth.

Male genitalia (Fig. 17C): basal piece two-fifths of total length. Parameres acuminate, in lateral aspect almost sickle-shaped, in tergal aspect weakly and regularly curved inwards. Apices broadly rounded; short subapical row of hairs. Median lobe a little shorter than the parameres, cylindrical and rather slender in basal three-fifths, very thick and subconical in apical two-fifths, with a sternal ridge.

Etymology.

The name alludes to the deeply sculptured, shining, brightly colored pronotum of this species.

Distribution.

Venezuela (Amazonas, Bolívar).

Remarks.

As with Berosus humeralis sp. n., this taxon is known only from granite outcrops in along the northwestern fringe of the Guiana Shield. It has only been found in distinctive "rock pools" that collect rainwater or in small streamlets that drain such pools. The allied Berosus auriceps and Berosus aulus are found in marginal pools of streams with rocky to sandy substrates ( Oliva 1989).