Berosus aragua 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 : 8-12

Berosus aragua Oliva & Short sp. n. Fig. 5

Type material.

Holotype (male): "VENEZUELA: Anzoategui State/ 9°17'16.3"N, 64°13'39.1"W, 274 m/ Transect #1; 15.viii.2009/ temporary rain pond/ leg. R. Cordero; VZ09-0815-12A", "[barcode]/ SEMC0889759/ KUNHM-ENT", "HOLOTYPE/ BEROSUS/ aragua sp. n./ des. Oliva & Short 2010" (MIZA). Paratypes (50): VENEZUELA: Anzoátegui State: Transect 1, 09°07'19.7"N, 64°11'11.4"W, 216 m, 13.viii.2009, temporary rain pond on clay road, leg. R. Cordero, VZ09-0813-08A (1 ex., SEMC); same data as holotype (4 exs., SEMC); Transect 1, 09°17'58.0"N, 64°13'39.2"W, 276 m, 15.viii.2009, pond with shrubs and grass, leg. R. Cordero, VZ09-0815-13A (1 ex., SEMC). Aragua State: Cagua, 28.vi.1961 (23 exs., MSUC, SEMC, MIZA, MALUZ). Falcón State: E. Dabajuro, river at bridge crossing on Rt. 3, 8.vii.2009, 11°02.305'N, 70°38.467'W, 98 m, gravel/sand margins of river and associated sidepools, leg. Short, Gustafson, & Inciarte, VZ09-0708-01A (6 exs., SEMC); same data but leg. Sites & Shepard, VZ09-0708-01B (4 exs., SEMC); ca. 18 km E. Urumaco, Lagoon along Rt. 3, W. of Coro, 11°14.228'N, 70°05.312'W, 79 m, marginal, vegetated areas of lagoon, 8.vii.2009, leg. Short, Gustafson, García, Camacho, & Inciarte, VZ09-0708-02A (2 exs., SEMC); SE Tocopero, 10.vii.2009, leg. Short et al., muddy pool in roadside ditch, VZ09-0710-03C (1 ex., MIZA). Guárico State: 8 km N. Corozo Pando, 11.vi.1984, leg. F.W. Eiland (4 exs., USNM); same locality but 20-21.vi.1984, blacklight, leg. F.W. Wiland & V. Linares (3 exs., USNM); same data but 17-18.vi.1984 (1 ex., USNM).

Diagnosis.

This species appears to be closely related to Berosus alternans Brullé, 1841 (Argentina), by the shape of the male genitalia and the metaventral process not produced at the posterolateral angles. Berosus aragua has a much longer row of hairs on the paramera and a slightly shorter basal piece. Additionally, this new species has more deeply impressed elytral striae; the mesoventral process has the posterior tooth rounded, the posterior angle of the metaventral process is not raised and the apical notch of the fifth ventrite is produced into a pair of acute teeth. In Berosus alternans , the elytral striae are reduced to rows of punctures in anterior half, the posterior angle of the mesoventral process is not rounded, the posterior angle of the metaventral process is carinate and the apical notch of the fifth ventrite is produced into a pair of rounded (not acute) projections.

Description. Body length 3.1-4.5 mm (holotype: body length: 3.7 mm; humeral width: 1.55 mm). Shape depressed, moderately elongate (Fig. 5). Labrum melanic, dorsum of head melanic with strong metallic luster. Pronotum testaceous with small medial melanic spot, divided by a wide median testaceous line. Scutellum dark. Elytra testaceous with small melanic spots, with additional spots extending between the h umeral spot and the first sutural spot, in some specimens forming an oblique dark band. Venter of thorax reddish. Abdomen black (Fig. 5A, B). Maxillary palpi with distal palpomere darkened on apical half. Femora with pubescent portion darkened, glabrous portion testaceous.

Head densely punctate, punctures on clypeus 1-2 times as large as ommatidia, regularly spaced; punctures on frons 2-4 times as large as ommatidia, irregular, sometimes contiguous.

Pronotal punctures dense and coarse, with punctures on disc about the same size as those on frons, on posterolateral areas polygonal. Pronotum between punctures very sparsely micropunctate, shining. Scutellum coarsely punctate, shining. Elytral striae well-impressed, with small round punctures about the same size as pronotal ones, not overflowing outwards except on striae 4-6, the intervals between punctures lower than interstriae. Interstriae flat, wide, three times or more as wide as striae, the fourth, fifth and sixth slightly step-shaped at disc due to overflowing strial punctures; tenth weakly convex on anterior half; eleventh flat, but raised with respect to spaces between strial punctures. Inner interstriae with punctures about half the size of the strial ones, 1-2 seriated; outer interstriae with much finer punctures. Surface of elytra smooth and shining in males, reticulate in females. Elytral apices simple; spine-like hairs absent.

Mesoventral process with large curved anterior tooth pointed downwards and backwards, behind this the ventral margin concave, describing a quarter of circle; posterior angle rounded, less prominent than anterior tooth. Metaventral process narrow; posterolateral angles not produced, posterior angle not raised. First ventrite carinate between metacoxae and a little behind them. No lateral depressions. Ventrites 2-4 without carinate or teeth. Fifth ventrite with a wide, shallow apical notch, which is set medially with two distinct sharp teeth. Margins of all abdominal ventrites smooth.

Maxillary palpi short, apical palpomere about twice as long as penultimate, slender, subcylindrical. Basal pubescence on basal half of mesofemora and three-fifths of metafemora, limit convex towards apex. Protarsus of male with adhesive soles on the two basal tarsomeres, the first of which is thickened, as long as the second and third combined; fourth tarsomere thickened, as long as the first and second taken together. Claws slender, weakly arched, toothed at base.

Male genitalia laterally compressed (Fig. 5D). Basal piece two-fifths of total length. Parameres long, narrow, gradually acuminate, weakly curved towards the sternal side. Row of hairs on the parameres long, taking up about half the total length. In sternal view the parameres parallel-sided taken together, gently rounded distally, not broadened, with apices turned inwards. Median lobe shorter than parameres, subcylindrical, slender, straight.

Variation.

This species exhibits a wider range of color variation than typical for most other Venezuelan Berosus , ranging from very pale to very dark, although some of the more darkened specimens appear to be so due to specimen preservation. Most material from Falcón State, the dorsal coloration is very pale, with some specimens entirely lacking pronotal maculae.

Regardless, the apical abdominal and aedeagal morphology are identical in these various color morphs.

Etymology.

The name refers to the Venezuelan region of Aragua, one of the states where this species was found.

Distribution.

Venezuela ( Anzoátegui, Aragua, Falcón, Guárico).

Remarks.

This species has been taken along the densely vegetated margins of ponds, in the gravel sidepools of rivers, and at lights.