Oocyclus sulcatus Alencar & Short & Hamada 2022, sp. n.
Creators: name: Alencar, Janderson Batista R.
name: Short, Andrew Edward Z.
name: Hamada, Neusa
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydrophilidae
Oocyclus
Oocyclus sulcatus

description: Oocyclus sulcatus sp. n.
(Figs. 8a–d, 11g, 12d, 13b, 14)
Type material. Holotype (male): “ BRASIL: BAHIA, PARNA Chapada Diamantina, Waterfall da Fumaça, long -41.456278, lat -12.600333, 1286 m a.s.l., vertical surfaces with water, 19.iii.2020, leg. J.B. R. Alencar” (INPA, in alcohol). Paratypes (41 exs.): BRAIL: Bahia: Same data as holotype (4 exs. INPA, in alcohol); except “Waterfall of Mosquito, long -41.3705 lat -12.3706, 517 m a.s.l., vertical surfaces with water, 29.vi.2019, leg. J.B. R. Alencar” (3 exs. INPA, in alcohol); “Waterfall da Matinha, long -41.3358 lat -13.0765 1021 m a.s.l., vertical surfaces with water, 21.iii.2020, leg. J.B. R. Alencar” (21 exs. INPA; 10 exs. SEMC, in alcohol); “ Palmeiras, Waterfall of Riachinho, long -41.5157, lat -12.5721, 935 m a.s.l., vertical surfaces with water, 18.iii.2020, leg. J.B. R. Alencar” (1 ex. INPA, in alcohol).
Diagnosis. Large-sized species. Pronotum with rounded posterolateral margins. Elytra surface with impressed longitudinal grooves and shallow longitudinal depressions medially in posterior half, rows of systematic punctures present, but blending with surrounding coarse ground punctation and as such hardly distinguishable (Fig. 12d). Elytral sutural interval raised (Fig. 12d) and margins explanate (Fig. 13b). Prosternum with two anteromedial spine-like setae. Abdominal ventrites dark brown, not paler than thoracic ventrites.
Adult. Body length 5.2–6.2 mm (n= 10, mean= 5.88, SD= ±0.31); TL/GW 1.60± 0.08 mm. General body shape broadly oval, strongly convex.
Color. Dorsum black (Fig. 8a), covered with dense, irregular green or bronze sheen. Anterolateral margins of pronotum with pale strip, extending to ca. 4/5 of lateral margin length. Elytra with faint, often indistinct yellowish or bronze maculae, especially near suture; with row of rounded black [=without sheen] spots along suture. Each elytron with one rounded pale spot on distal quarter. Antennomeres 1–5 yellowish brown, club dark brown. Maxillary and labial palps yellow. Ventral face of head dark brown to black. Lateral margins of prosternum and pseudoepipleura yellowish brown; and epipleura brown. Thorax dark brown to black ventrally. Legs dark brown, except for light brown tarsi. Abdominal ventrites dark brown with posterior margin of each ventrite light to brown.
Head. Ground punctation on clypeus and frons moderately coarse, distance between punctures 2.0–3.0× width of one puncture (Fig. 8d). Ground punctation on labrum denser than punctation of clypeus, distance between punctures 0.5–1.5× width of one puncture; with few distinct systematic punctures medially. Labrum sometimes bearing short setae. Clypeus with several scattered indistinct systematic punctures laterally; and sometimes bearing short setae. Frons with irregular row of systematic punctures toward the median plane of each eye and few fine setae around ocular suture. Maxillary palps shorter than width of labrum; segment 3 shorter than segment 2; apical segment longer than penultimate segment. Labial palps about two-thirds as long as width of mentum. Mentum smooth, with scattered coarse punctures; subquadrate, anterior margin slightly convex and depressed.
Thorax. Ground punctation on pronotum and elytra unevenly distributed and moderately coarse; elytra with distinctly larger punctures and with shallowly impressed longitudinal grooves (Figs. 8a, c, d). Pronotal systematic punctures similar in size to surrounding ground punctures; anterior and posterior series each forming an irregular field. Lateral margins of pronotum with fine setae distributed along its length, more densely pubescent on anterior half. Pronotal posterolateral angles rounded. Sutural interval on elytra (Fig. 12d) slightly raised. Elytral interval with weak or non-existent pubescence in ground punctation. Rows of systematic punctures on elytra present but blending with surrounding coarse ground punctation and as such hardly distinguishable (Fig. 12d). Elytral surface with shallow longitudinal depressions medially on posterior half (Fig. 13b). Humeral region (in frontal view) distinctly elevated anteromedially. Elytra margins with short spine-like setae spaced along its length and explanate on posterior half. Prosternum with clearly defined median carina; slightly elevated anteromedially (Fig. 8e); elevated region with two spine-like setae. Elevated process of mesoventrite wide and elongate, about twice as long as wide; slightly raised anteriorly; with six coarse spine-like setae. Metaventrite with posteromedial oval glabrous area ca. twice as long as wide; length of glabrous area about three-quarters of metaventrite. Procoxae with fine short pubescence and set with coarse, short spine-like setae; grouped on basal half. Protibiae each with 7–9 spine-like setae on dorsal face. Meso- and metafemora with scattered punctures bearing short thickened, spine-like setae.
Abdomen. Ventrites covered with setae of varying lengths; ventrites 1–4 with scattered long erect setae, distinctly longer than longest setae on metaventrite (Fig. 8b). Aedeagus: outer margin of parameres weakly sinuous, gradually tapering to apex, curving inward; inner margin, straight, tapering from distal half (dorsal view); median lobe subequal in length to parameres, without apical hook. Basal piece rounded (Fig. 11g).
Etymology. The specific epithet sulcatus (L.), refers to the grooved elytra. To be treated as a noun in apposition.
Distribution. Brazil (Bahia) (Fig. 14).
Remarks. This species shares some diagnostic features with O. iguazu (Oliva, 1996): such as non-pale abdominal ventrites, large-size (>5.0 mm) and two prosternal spines. However, O. sulcatus sp. n. can be easily distinguished by its impressed longitudinal grooves and shallow longitudinal depressions medially on the posterior part of elytra (Fig. 13b). In some specimens, the visualization of the diagnostic spots and green or bronze sheen (iridescence) depends on the view and lighting, sometimes they are not captured in the photographs, visible by moving the specimen or by changing the lighting system of the photographic equipment.
description: Published as part of Alencar, Janderson Batista R., Short, Andrew Edward Z. & Hamada, Neusa, 2022, New species and new distributional records of the hygropetric water scavenger beetle genus Oocyclus Sharp (Coleoptera, Hydrophilidae) from the Brazilian Shield, pp. 275-305 in Zootaxa 5087 (2) on pages 290-291, DOI: 10.11646/zootaxa.5087.2.3, http://zenodo.org/record/5824101