Oocyclus giganteus 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 giganteus

description: Oocyclus giganteus sp. n.
(Figs. 4a–e, 11c, 14)
Type material. Holotype (male): “ BRASIL: BAHIA, Abaíra, Waterfall Guarda Mor, long -41.8606, lat -13.3127, 1272 m a.s.l., vertical surfaces with water, 13.iii.2020, leg. J.B. R. Alencar” (INPA, Coleoptera, in alcohol). Paratypes (173 exs.): BRAZIL: Bahia: Same data as holotype (94 exs. INPA; 10 exs. SEMC, in alcohol); except: “BA-564 Piatã-Mucugê, near the road, long -41.5931, lat -13.1546, 844 m a.s.l., vertical surfaces with water and green algae, 26.vi.2019, leg. J.B. R. Alencar” (31 exs. INPA, in alcohol); “Rio de Contas, Waterfall of Fraga, long -41.5931, lat -13.1546, 844 m a.s.l., vertical surfaces with water, 23.iii.2020, leg. J.B. R. Alencar” (38 exs. INPA, in alcohol).
Diagnosis. Large-sized species. Pronotum with angulate posterolateral margins. Elytra surface even, with very fine ground punctation, with faint rows of systematic punctures (some of these punctures can be detected by presence of setae). Elytral sutural interval raised (e.g. Fig. 12d) margins explanate (e.g. Fig. 13b). Prosternum with two anteromedial spine-like setae. Abdominal ventrites dark brown, not paler than thoracic ventrites.
Adult. Body length 5.7–6.3 mm (n= 10, mean= 6.02, SD= ±0.15); TL/GW 1.60± 0.04 mm. General body shape broadly oval, slightly convex.
Color. Dorsum black (Fig. 4a), covered with dense, irregular green or bronze sheen. Anterolateral margins of pronotum with pale strip, extending slightly beyond the half of margin length. Elytra with irregular patches of bronze or green iridescence; with row of rounded black [=without sheen] spots along suture. Each elytron with 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; pseudoepipleura and epipleura yellowish 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 1.5–2.0× width of one puncture (Fig. 4d). 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; sometimes bearing short setae. Frons with irregular row of systematic punctures toward 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 evenly distributed and moderately coarse (Figs. 4a, c, d). Pronotal systematic punctures with short fine setae, at least 2× size of surrounding ground punctures; anterior and posterior series each forming irregular field. Lateral margins of pronotum with fine setae distributed along of its length, being more densely pubescent on anterior half. Pronotal posterolateral angles angulate. Sutural interval on elytra slightly raised along its length. Elytral interval with weak or non-existent pubescence in ground punctation (e.g. Fig 12a, c, d). Rows of systematic punctures on elytra present but not larger than surrounding ground punctuation and as such hardly distinguishable, blending uniformly with ground punctuation. Elytral surface with shallow longitudinal depressions medially on posterior half. Humeral region (in frontal view) without antero-medial elevation. Elytral margins with short spine-like setae situated along its length and explanate on posterior half. Prosternum with clearly defined median carina; slightly elevated anteromedially (Fig. 4e); elevated region with two spine-like setae. Elevated process of mesoventrite wide and elongate, about twice as long as wide; slightly raised anteriorly; with 6–7 coarse spine-like setae. Metaventrite with oval glabrous area posteromedially, slightly longer than wide; length of glabrous area about half length of metaventrite. Procoxae with fine short pubescence and set with coarse, short spine-like setae; grouped on basal. Protibiae each with 6–7 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; pubescence usually with suberect to recumbent setae; longest setae shorter to subequal in length to longest setae around margin of metasternal glabrous area (Fig. 4b). Aedeagus: outer margin of parameres weakly sinuous, gradually tapering to apex, curving inward; inner margin, straight, tapering from the distal half (dorsal view); median lobe subequal in length to the parameres, without hook in apex. Gonopore located at four-fifths the length of median lobe. Basal piece constricted (Fig. 11c).
Etymology. The specific epithet giganteus derived from giga- (G.), meaning giant, refers to the large size of the body. To be treated as a noun in apposition.
Distribution. Brazil (Bahia) (Fig. 14).
Remarks. This species shares several diagnostic features with O. flexus Clarkson & Short, 2012: non-pale abdominal ventrites, elytral suture raised, and the presence of two prosternal spines. However, in O. flexus the posterolateral margins of the pronotum are broadly rounded and shorter body length (4.4–5.2 mm), while the posterolateral margins of the pronotum are angulate and the body size varies from 5.7–6.3 mm in O. giganteus sp. n.
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 281-283, DOI: 10.11646/zootaxa.5087.2.3, http://zenodo.org/record/5824101