Oocyclus galbus Short & García, 2010

Short, Andrew E. Z. & García, Mauricio, 2010, A review of the Oocyclus Sharp of Venezuela with description of twelve new species (Coleoptera: Hydrophilidae: Laccobiini), Zootaxa 2635, pp. 1-31 : 13-14

Oocyclus galbus Short & García sp. n.

( Figs. 2 A, 6B, 7, 8B)

Type material. Holotype: VENEZUELA: Zulia State: male, “ VENEZUELA: Zulia State/ 10°02.962'N, 72°42.615'W / road to Toromo; 23.ix.2007 / 432 m; Rock seeps and pools/ AS-07-022; leg. A.E.Z. Short”, “[barcode]/ SM0827899/ KUNHM-ENT”, “ HOLOTYPE / OOCYCLUS / galbus sp.n. / des. Short & García 2010 ” ( MIZA). Paratypes (62 exs.): VENEZUELA: Zulia State: Perijá National Park, Toromo, SW of Machiques, 10°02.962'N, 72°42.615'W, 432 m, narrow ravine, 31.xii.2005, leg. A. Short & P. Torres, AS-06- 0 0 2 (16 exs.); same data as holotype (44 exs.); same locality but 28.i.2009, leg. A. Short, M. García, J. Camacho, VZ09-0128-02A (2 exs.).

Diagnosis. Larger species ( Fig. 2 A). Posterolateral corners of pronotum angulate, but not spinose. Procoxae spinose. Elytra with distinct rows of larger systematic punctures; the larger punctures usually without distinct setae. Elytral suture slightly raised at apex. Elytral margins slightly explanate, and without a fringe of long setae. Abdominal ventrites uniformly very pale in color, from yellow to orange.

The uniformly yellow/orange abdominal ventrites is a unique feature to Venezuelan Oocyclus and readily separates the species, especially from the sympatrically occurring O. substillus . The species is also unique in possessing very coarse rows of elytral systematic punctures in which the first row of these punctures lacks a dense row of setae; at most, there is a small patch of erect setae medially in this row ( Fig. 2 A).

Description. Size and form. Body length = 4.6–5.5 mm. TL/GW = 1.55 mm. Body very broadly oval, slightly convex.

Color. Dorsum of head, pronotum, and elytra black, with faint iridescent green reflections. Anterolateral margins of pronotum broadly pale. Elytra with very faint iridescent green maculae which often appear faint and with defuse borders. Maxillary and labial palps yellow. Mentum and stipes dark brown, similar in color to venter of head. Thoracic and abdominal ventrites and legs light brown to pale yellow, appearing depigmented and translucent in some cases.

Head. Ground punctation on labrum, clypeus and frons moderately coarse, distance between punctures 1.0–2.0× the width of one puncture. Systematic punctures on labrum consisting of several indistinct punctures, sometimes bearing short setae. Frons with irregular row of systematic punctures mesad of each eye. Clypeus with a few very indistinct systematic punctures along anterolateral margins, slightly larger than surrounding punctation. Maxillary palps short, about as long as width of labrum; segment 2 slightly bulbous, apical segment slightly longer than penultimate. Labial palps less than three-fourths as long as width of mentum. Mentum quadrate and slightly rugose, anterior margin slightly convex and depressed, bearing scattered coarse punctures.

Thorax. Ground punctation on pronotum and elytra composed of very fine, evenly distributed punctures. Pronotal systematic punctures with short fine setae, at least 3x the size of surrounding ground punctures, anterior and posterior series each forming an irregular field. Lateral margins of pronotum with a few sparsely distributed setiferous punctures; with punctures almost appearing absent. Posterolateral corners of pronotum sharply angulate, but not spinose. Sutural punctation on elytra absent or unmodified from ground punctation; sutural interval not raised in posterior half. Elytra with five very irregular rows of systematic punctures: row 1 represented by sparsely arranged coarse punctures, interrupted on disc by short, densely aggregated row bearing coarse erect setae, giving an abbreviated “Mohawk”-like appearance; rows 2–5 represented by irregular series of large coarse punctures usually bearing small recumbent setae. Prosternum with a clearly defined median carina; slightly elevated anteromedially, the elevation set with two spine-like setae. Elevated process of mesoventrite narrow and elongate, more than three times as long as wide; surface nearly flat; with 6–7 thickened, coarse spine-like setae. Metaventrite with oval glabrous area posteromedially, ca. twice as long as wide, length of glabrous area slightly more than two-thirds the length of metaventrite. Procoxae with dense, fine short pubescence and nearly throughout with numerous short spine-like setae. Protibiae each with 12 spine-like setae on dorsal face.

Abdomen. Ventrites covered with dense, short setae, the longest setae shorter than the longest setae surrounding glabrous area of metaventrite. Aedeagus as in Figure 6 B.

Etymology. Galbus , Latin word for yellow, after the coloration of the abdominal ventrites. To be treated as a noun in apposition.

Distribution. Known only from the type locality in the Serranía de Perijá in the northwestern state of Zulia ( Fig. 7 ).

Remarks. The single locality where the species has been found ( Fig. 8 B) is a small stream with several waterfalls/cascades and surrounding seepages during the wet season, but is reduced to a dripping seep in the dry season, and may even become dry altogether. This species was found in hygropetric habitats along wet rock walls of the small canyon through which the stream flows, as well as in marginal areas of the stream that mimic seepages due to low flow. It was taken together with O. substillus . It is the same type locality as another recently described hygropetric species, Hydroscapha perijaensis Hall & Short, 2010 (Myxophaga: Hydroscaphidae ).

Figures

FIGURE 2. Dorsal and lateral habitus of Oocyclus species found in the Serranía de Perijá. A) O. galbus sp. n.; B) O. zulianus sp. n.; C) O. substillus Short & Perkins; D) O. maculatus Sharp. Scale bar = 2.0 mm.

FIGURE 6. Aedeagi of Oocyclus species. A) O. petra sp. n., B) O. galbus sp. n.; C) O. pico sp. n. D) O. bolivari sp. n. Scale bar = 0.2 mm.

FIGURE 7. Distribution of Oocyclus species in Venezuela.

FIGURE 8. Habitat of Oocyclus species. A) Aragua State, collecting event AS- 06 - 023; type locality for O. pico and O. pittieri, locality for O. sapphirus. B) Zulia State, near Toromo, collecting event AS- 07 - 022, type locality for O. galbus and locality for O. substillus.