Oocyclus bellus, Short & Torres-Gavosto & Hettinger, 2023

Short, Andrew E. Z., Torres-Gavosto, Juan Martin & Hettinger, Ty, 2023, A review of the Oocyclus Sharp of Ecuador with description of 12 new species (Coleoptera: Hydrophilidae: Laccobiini), Zootaxa 5277 (1), pp. 91-112 : 97-98

Oocyclus bellus sp. n.

( Figs. 6G , 7 )

Type material. Holotype (male): “ECUADOR: Napo; / Lago Papallacta / 19 July 1979 / Jos. J. Anderson ”, “Collected at/ seep, 3280mtrs/ #79 VIII 19:8” ( USNM) . Paratypes (6 exs.): ECUADOR: Napo Province: same data as holotype (5 exs., USNM, SEMC) ; Papallacta , 2900 m, 19.vii.1979, leg. J. Anderson, seep (1 ex., USNM) .

Diagnosis. Smaller species. Posterolateral corners of pronotum angulate to weakly spinose. Prosternal carinae set with a pair of spines anteriorly. Elytra with the first row of systematic punctures bearing a row of erect setae that contains gaps, not appearing as a dense continuous row. Elytral margins not explanate, with a fringe of long setae. Abdominal ventrites dark brown.

Among Ecuadorian species, O. bellus can be distinguished from all others except O. lepidus by the presence of a pale white spot on the posterior third of each elytron. From O. lepidus it can be distinguished by the discontinuous row of erect setae on the elytra (continuous in O. lepidus ).

Description. Size and Form. Length = 3.3–4.0 mm. Body oval, moderately convex. Color. Dorsum of head, pronotum, and elytra black, with faint iridescent green reflections. Lateral margins of pronotom and elytra slightly paler. Anterolateral margins of pronotum with pale spot, but less distinct as the entire margin of the pronotum is slightly paler. Elytra with small but distinct white spot in posterior quarter. Elytra with 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 the venter of the head. Thoracic and abdominal ventrites dark brown, legs light brown to orange.

Head. Ground punctation on labrum, clypeus and frons moderately fine, distance between punctures 1.0–2.0× the width of one puncture. Systematic punctures on labrum consisting of several indistinct punctures, sometimes bearing a short seta. Frons with an irregular row of systematic punctures bearing setae 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 approximately the same length as penultimate. Labial palps less than half as long as width of mentum; with clump of long setae on second segment. Mentum quadrate and mostly smooth, anterior margin slightly convex and depressed. Thorax. Ground punctation on pronotum and elytra composed of fine, evenly distributed punctures. Pronotal systematic punctures with short fine setae, only slightly larger than the size of surrounding ground punctures. Lateral margins of pronotum set with a few sparsely distributed setiferous punctures. Posterolateral corners of pronotum angulate to weakly spinose. Sutural punctation on elytra absent or unmodified from ground punctation; sutural interval not raised in posterior half. Elytra with five irregular rows of systematic punctures: the first row is represented by sparse, discontinuous line of coarse punctures set with long, erect setae. The remaining rows represented by irregular series of punctures that blend with the surrounding punctation and sometimes bearing a short setae, but they are never erect. Prosternum with a clearly defined median carina; slightly elevated anteromedially, the elevation set with two thin spines. Elevated process of the mesoventrite roughly round in appearance and elongate, roughly as long as wide; surface nearly flat; set with 5–6 thickened, coarse spines. Metaventrite with oval glabrous area posteromedially, ca. as long as wide, length of glabrous area less than half the width of metaventrite. Procoxae covered with dense pubescence and set with a few smaller indistinct spines posteromedially. Protibiae with 7–9 spines on dorsal face.

Abdomen. Ventrites covered with fine setae, the longest setae not longer than the longest setae surrounding the glabrous area of the metaventrite. Aedeagus as in Figure 6G .

Etymology. Bellus, the Latin word for pretty, after the very handsome dorsal coloration of this species.

Distribution. Known from a pair of very closely situated localities at very high elevation (2900–3280m) on the eastern slopes of the Andes ( Fig. 7 ). We believe this is the first record of the genus from elevations greater than 3000m.

Figures

FIGURE 6. Aedeagi of Oocyclus species in Ecuador with angulate or spinose posterolateral corners of the pronotum. (A) ustulatus sp. n. (B) radiatus sp. n. (C) pakcha sp. n. (D) sumak sp. n. (E) ankas sp. n. (F) lepidus sp. n. (G) bellus sp. n. (H) zamora sp. n. (I) specimen of the morgani/trujillo species group (J) specimen of the morgani/trujillo species group.

FIGURE 7. Distribution of Oocyclus spp. in Ecuador.