Oocyclus lacia, 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 : 286-288

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

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scientific name

Oocyclus lacia

sp. nov.

Oocyclus lacia View in CoL sp. n.

( Figs. 6a–e View FIGURE 6 , 11e View FIGURE 11 , 14 View FIGURE 14 )

Type material. Holotype (male): “ BRASIL: MINAS GERAIS, Serro, Waterfall of Amaral , long -43.4069, lat -18.3885, 1043 m a.s.l., vertical surfaces with water, 22.vi.2019, leg. J.B. R. Alencar” ( INPA, Coleoptera , in alcohol).

Diagnosis. Large-sized species. Pronotum with rounded posterolateral margins. Elytra surface with shallowly impressed longitudinal grooves and sparse short setae. Elytral sutural interval raised (e.g. Fig. 12d View FIGURE 12 ). Prosternum with six anteromedial spine-like setae. Abdominal ventrites dark brown, not paler than thoracic ventrites.

Adult. Body length 4.9 mm (n= 1); TL/GW 1.73 mm. General body shape broadly oval, slightly convex.

Color. Dorsum black ( Fig. 6a View FIGURE 6 ), 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 the suture; with row of rounded black [=without sheen] spots along suture. Each elytron with two to three small circular pale spots: two anterior pale spot very close together in distal third, about twice as far from suture than posterior spot; posterior spot situated in 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 dark brown to black. Thorax dark brown to black ventrally. Legs brown to dark brown, except for light brown tarsi. Abdominal ventrites dark brown, with slightly lighter posterior margins in ventrites 1–4, sometimes with pale patches laterally in ventrites 2–3.

Head. Ground punctation on clypeus and frons moderately coarse, distance between punctures 2.0–3.0× width of one puncture ( Fig. 6d View FIGURE 6 ). 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 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 evenly distributed and moderately coarse ( Figs. 6a, c, d View FIGURE 6 ). 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 rounded. Sutural interval on elytra slightly raised along its length. Elytral interval with weak or non-existent pubescence in ground punctation (e.g. Figs. 12a, c, d View FIGURE 12 ). Rows of systematic punctures on elytra present but blending with surrounding ground punctation and as such hardly distinguishable. Elytral surface without shallow longitudinal depressions medially on posterior half. Humeral region (in frontal view) without anteromedial elevation. Elytral margins with short spine-like setae situated along its length. Prosternum with clearly defined median carina; strongly elevated anteromedially ( Fig. 6e View FIGURE 6 ); elevated region with six spine-like setae. Elevated process of mesoventrite wide and elongate, about three times as long as wide; slightly raised anteriorly; with five coarse spine-like setae. Metaventrite with posteromedial oval glabrous area ca. twice as long as wide; length of glabrous area about three-quarters length 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 rather sparsely pubescent with scattered, long setae, distinctly longer than longest setae on metaventrite, ventrite 5 more densely pubescent ( Fig. 6b View FIGURE 6 ). Aedeagus: outer margin of parameres weakly sinuous, gradually tapering to apex, not curving inward; inner margin, straight, tapering from distal half (dorsal view); median lobe shorter than parameres, without apical hook. Gonopore located at four-fifths of median lobe. Basal piece tapered ( Fig. 11e View FIGURE 11 ).

Etymology. The specific epithet lacia derived from the acronym of the Laboratório de Citotaxonomia e Insetos Aquáticos, within the Instituto Nacional de Pesquisas da Amazônia, in Brazil. It is a tribute to all the support received for the development of this work. To be treated as a noun in apposition.

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

Remarks. This species shares diagnostics feature with O. fryanus , such as non-pale abdominal ventrites, large size (>5.0 mm), and six prosternal spines. However, O. fryanus has a lateral indentation on the elytra, the shape of the body is very elongated (TL/GW = 1.85) and does not have elytra grooves, in O. lacia sp. n. a lateral elytral indentation is absent, body is more oval (TL/GW =1.73) and elytra have grooves.


Departamento de Geologia, Universidad de Chile


Instituto Nacional de Pesquisas da Amazonia













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