Oocyclus coromoto 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 : 11-12

Oocyclus coromoto Short & García sp. n.

( Figs. 4 B, 7, 10C)

Type material. Holotype: VENEZUELA: Amazonas: female, “ VENEZUELA: Amazonas State/ Tobogan de la Selva; 8.viii.2008 / leg. A. Short, M. García, L. Joly/ AS-08-080b; “old tobogancito”, “[barcode]/ SM0829209/ KUNHM-ENT”, “ HOLOTYPE / OOCYCLUS / coromoto sp.n. / des. Short & García 2010 ” ( MIZA). Paratypes (2): VENEZUELA: Amazonas: same data as holotype (1 female, KSEM); same locality but 23.i.1989, leg. P.J. Spangler, R.A. Faitoute & C.B. Barr, “seep at upper shelter” (1 female, USNM).

Diagnosis. Smaller species (less than 4.0 mm) ( Fig. 4 B). Posterolateral corners of pronotum broadly rounded. Procoxae strongly spinose. Elytra with sparse but distinct rows of larger systematic punctures, usually represented by a series of widely spaced punctures bearing a short seta or small clusters of several punctures bearing fine, decumbent setae. Elytral suture not raised. Elytral margins not explanate, and with a fringe of long yellow setae.

Among smaller Oocyclus species, O. coromoto is most similar to O. zulianus , O. bolivari , and O. floccus , all of which share the features of broadly rounded posterolateral corners of the pronotum and the presence of at least some dorsal elytral setae. The ground punctuation is coarser in O. zulianus and also bears setae, while it does not in O. coromoto . Oocyclus bolivari and O. floccus both possess more distinct clumps of setae which are usually erect, rather than decumbent as in O. coromoto .

Description. Size and form. Body length = 3.6–3.7 mm. TL/GW = 1.63. Body oval, moderately convex.

Color. Dorsum of head, pronotum, and elytra black with a general faint iridescent green sheen. Anterolateral margins of pronotum with a very small pale patch; may appear very dark and indistinct. Elytra with green maculae, most pronounced on lateral regions. Maxillary and labial palps yellow. Mentum and stipes light to reddish brown, slightly paler than ventral face of head. Legs, epipleura, lateral margins of prosternum yellowish brown. Abdominal ventrites reddish brown.

Head. Ground punctation on labrum, clypeus and frons fine, distance between punctures 2.0–3.0× the width of one puncture. Systematic punctures on labrum consisting of several indistinct punctures medially. 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 moderately short, subequal in length to width of labrum; segment 2 slightly bulbous, apical segment slightly longer than penultimate. Labial palps three-fourths as long as width of mentum. Mentum quadrate, anterior margin slightly convex, bearing very fine punctures.

Thorax. Ground punctation on pronotum and elytra composed of fine, evenly distributed punctures of generally uniform size. Pronotal systematic punctures with short fine setae, similar to slightly larger in size to ground punctures, blending with larger ground punctures. Lateral margins of pronotum and elytra with dense row of yellow setae, creating fringed appearance. Posterolateral corners of pronotum rounded. Sutural punctation on elytra absent or unmodified from ground punctation. Elytra with five indistinct rows of systematic punctures, with some punctures coalesced to form aggregations of several punctures; each puncture set with very fine, usually decumbent setae. Prosternum with sharp, high carina which is elevated anteromedially, the elevation bearing two long coarse spine-like setae. Elevated process of mesoventrite raised to a point medially, with nearly flat, even posteriorly sloping face set with 4–5 thickened spine-like setae. Metaventrite with oval glabrous area posteromedially, about twice long as wide, length of glabrous area less than half the length of metaventrite. Procoxae with a few coarse, distinct spine-like setae, with those situated mesally more thickened. Protibiae each with 5–7 spine-like setae on dorsal face.

Abdomen. Ventrites with sparsely scattered long erect setae, loosely arranged into two to three rows, the setae distinctly longer than the longest setae on metaventrite.

Etymology. Coromoto , in honor of the indigenous community and river of the same name in which the species is found.

Distribution. Known only from the type locality in Amazonas State (Tobogan de la Selva) ( Fig. 7 ).

Remarks. The two recently collected specimens were taken at wet rock seepage on granite covered with detritus, a few meters from the flowing Caño Coromoto ( Fig. 10 C).

Figures

FIGURE 4. Dorsal and lateral habitus of Oocyclus species found in the Venezuelan Guiana Shield region. A) O. petra sp. n., B) O. coromoto sp. n.; C) O. floccus sp. n. Scale bar = 2.0 mm.

FIGURE 7. Distribution of Oocyclus species in Venezuela.

FIGURE 10. Habitat of Oocyclus species. A) Amazonas State, 15 km S. Puerto Ayacucho, collecting event AS- 07 - 009 a; locality and habitat of O. petra. B) Amazonas State, Tobogan de la Selva; habitat for O. petra. C) Amazonas State, Tobogan de la Selva, habitat for O. petra and O. coromoto.