Oocyclus thysanus, Alencar & Short & Hamada, 2022

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, Zootaxa 5087 (2), pp. 275-305 : 295-298

publication ID

https://doi.org/ 10.11646/zootaxa.5087.2.3

publication LSID




persistent identifier


treatment provided by


scientific name

Oocyclus thysanus

sp. nov.

Oocyclus thysanus View in CoL sp. n.

( Figs. 10a–e View FIGURE 10 , 11i View FIGURE 11 , 12a View FIGURE 12 , 14 View FIGURE 14 )

Type material. Holotype (male): “ BRASIL: MINAS GERAIS, PARNA Serra do Cipó, Waterfall da Farofa , long -43.5761, lat -19.3794, 866 m a.s.l., vertical surfaces with water, 8.vi.2019, leg. J.B. R. Alencar” ( INPA, Coleoptera , in alcohol) . Paratypes (10 exs.): BRAZIL: Minas Gerais: Same data as holotype (2 exs. INPA , in alcohol); except: “ PARNA Serra do Gandarela, Waterfall of Mingu, long -43.7596, lat -20.0622, 1006 m a.s.l., rock-face seepages, 15.vi.2019, leg. J.B. R. Alencar” (2 exs. INPA ; 1 ex. SEMC, in alcohol); “Parque Estadual Rola-Moça, Waterfall of Sazona , long-43.9899, lat -20.0966, 1335 m a.s.l., rock-face seepages, 18.vi.2019, leg. J.B. R. Alencar” (2 exs. INPA ; 1 ex. SEMC, in alcohol). Goias : “ GOIÁS: Alto Paraíso de Goiás, Waterfall of Muralha , long -47.7507, lat -14.2774, 957 m a.s.l., 2.VII.2019, leg. J.B. R. Alencar” (2 exs. INPA , in alcohol) .

Diagnosis. Large-sized species. Pronotum with angulate posterolateral margins. Elytral surface even, with rows of fine systematic punctures, row 1 very distinctly impressed and bearing erect setae, interrupted in some regions along their length; lateral rows very indistinct, blending with surrounding ground punctation. Elytral sutural interval not raised ( Fig. 12a View FIGURE 12 ). Prosternum with two anteromedial spine-like setae. Abdominal ventrites dark brown, not paler than thoracic ventrites.

Adult. Body length 4.7–5.4 mm (n= 10, mean= 5.11, SD= ±0.22); TL/GW 1.60± 0.07 mm. General body shape broadly oval, slightly convex.

Color. Dorsum black ( Fig. 10a View FIGURE 10 ), 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 irregular patches of bronze or green iridescence; without 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 black to dark brown; pseudoepipleura yellowish brown; epipleura brown. Thorax, ventrally brown to black. Legs brown to dark brown, except for the 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. 10d View FIGURE 10 ). 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 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. 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 punctures slightly larger ( Figs. 10a, c, d View FIGURE 10 ). Pronotal systematic punctures with short fine setae, at least 2× size of surrounding ground punctures; the anterior and posterior series each forming one irregular field. Lateral margins of pronotum with fine setae distributed along its length, more densely pubescent on anterior half. Pronotal posterolateral angles angulate. Sutural interval on elytra ( Fig. 12a View FIGURE 12 ) not raised. Elytral interval with weak or non-existent pubescence in ground punctation ( Fig 12a View FIGURE 12 ). Five rows of systematic punctures: row 1 represented as nearly continuous row of densely distributed, small punctures bearing long, erect setae, ( Fig. 12a View FIGURE 12 ). Rows 2–5 each represented by punctures only slightly larger than surrounding ground punctuation and hardly distinguishable, some set with short setae. Elytral surface with shallow longitudinal depressions medially on posterior half. Humeral region (in frontal view) without anteromedial elevation. Elytral margins with short spine-like setae situated along their length and explanate on posterior half. Prosternum with clearly defined median carina; slightly elevated anteromedially ( Fig. 2e View FIGURE 2 ); elevated region with two spine-like setae. Elevated process of mesoventrite wide and elongate, about twice as long as wide; slightly raised anteriorly; with 5–6 coarse spine-like setae. Metaventrite with oval glabrous area posteromedially, slightly longer than wide; length of glabrous area about one-third length of metaventrite. Procoxae with fine short pubescence and set with coarse, short spine-like setae; grouped on basal half. Protibiae each with eight 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 setae, distinctly longer than longest setae on metaventrite, ventrite 5 more densely pubescent ( Fig. 10b View FIGURE 10 ). Aedeagus: outer margin of parameres weakly sinuous, gradually tapering to apex, curving inward; inner margin, straight, tapering from distal half (dorsal view); median lobe shorter than parameres, with hooked apex. Gonopore apically on median lobe. Basal piece rounded ( Fig. 11i View FIGURE 11 ).

Etymology. The specific epithet is derived from thysanus = fringe (G) and refers to the first elytral row densely set with erected setae. To be treated as a noun in apposition.

Distribution. Brazil (Minas Gerais) ( Fig. 14 View FIGURE 14 ).

Remarks. This species shares several diagnostic features with O. decorus (Kuwert, 1890) : non-pale abdominal ventrites, two prosternal spines, and elytra surface with distinct rows of systematic punctures bearing erect setae. However, O. decorus has a weakly spinose posterolateral pronotal angle and brightly iridescent blue elytral maculae, while O. thysanus sp. n. has the posterolateral margins of pronotum angulate, but not spinose and lacks brightly iridescent blue elytral maculae.


Departamento de Geologia, Universidad de Chile


Instituto Nacional de Pesquisas da Amazonia


University of Kansas - Biodiversity Institute













GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF