Oocyclus humboldti, 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 : 283-286

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

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scientific name

Oocyclus humboldti

sp. nov.

Oocyclus humboldti View in CoL sp. n.

( Figs. 5a–e View FIGURE 5 , 11d View FIGURE 11 , 14 View FIGURE 14 )

Type material. Holotype (male): “ BRASIL: MINAS GERAIS, Parque Estadual Serra do Cabral, Waterfall of Demir , long -44.211975 lat -17.920439, 833 m a.s.l., rock-face seepages, 14.iv.2019, leg. J.B. R. Alencar” ( INPA , in alcohol) . Paratypes (266 exs.): BRAZIL: Minas Gerais: Same data as holotype (20 exs. INPA ; 10 exs. SEMC, in alcohol); except: “ Waterfall of Boqueirão , long -44.178528, lat -17.758333, 680 m a.s.l., rock-face seepages , 13.iv.2019,leg. J.B. R.Alencar” (32 exs. INPA , in alcohol); “ Waterfall of Fervedouro , long -44.247978,lat -17.917764, 1071 m a.s.l., rock-face seepages , 14.iv.2019, leg. J.B. R. Alencar” (1 ex. INPA , in alcohol); “Curimataí, Waterfall of Simão , long -43.955333, lat -17.896139, 650 m a.s.l., rock-face seepages , 16.iv.2019, leg. J.B. R. Alencar” (28 exs. INPA , in alcohol); “ PARNA Sempre Vivas, Waterfall of Felipes , long -43.703639, lat -17.907472, 1090 m a.s.l., rock-face seepages , 24.iv.2019, leg. J.B. R. Alencar” (2 exs. INPA , in alcohol); “Parque Estadual Grão Mogol, Waterfall of Almas , long -42.931194, lat -16.618139, 691 m a.s.l., rock-face seepages , 29.iv.2019, leg. J.B. R. Alencar” (2 exs. INPA , in alcohol); “Parque Estadual Grão Mogol, Stream of the Dé, long -42.963833, lat -16.592361, 746 m a.s.l., rock-face seepages , 29.iv.2019, leg. J.B. R. Alencar” (10 exs. INPA , in alcohol); “Parque Estadual Grão Mogol, Waterfall of Almas , long -42.870111, lat -16.511139, 624 m a.s.l., rock-face seepages , 30.iv.2019, leg. J.B. R. Alencar” (27 exs. INPA , in alcohol); “Lassance, Waterfall of Palmeiras , long -44.504167, lat -17.834333, 520 m a.s.l., vertical surfaces with water , 1.v.2019, leg. J.B. R. Alencar” (2 exs. INPA , in alcohol); “ PARNA Serra do Cipó , Waterfall Capão dos Palmitos, long -43.609556, lat -19.377472, 830 m a.s.l., rock-face seepage , 8.vi.2019, leg. J.B. R. Alencar” (9 exs. INPA , in alcohol); “Waterfall Taioba, long -43.571806 lat -19.391806, 863 m a.s.l., vertical surfaces with water , 9.vi.2019, leg. J.B. R. Alencar” (7 exs. INPA , in alcohol); “Canyon of the Bandeirinhas, long -43.562722, lat -19.423917, 880 m a.s.l., seepage habitat , 11.vi.2019, leg. J.B. R. Alencar” (8 exs. INPA , in alcohol); “Itabirito, Corrego Prox a Fazenda Velha, long -43.809139, lat -20.299111, 862 m a.s.l., rock-face seepages , 20.vi.2019, leg. J.B. R. Alencar” (82 exs. INPA , in alcohol); “Serro, Waterfall of Amaral , long -43.406944, lat -18.388528, 1043 m a.s.l., vertical surfaces with water , 22.vi.2019, leg. J.B. R. Alencar” (2 exs. INPA , in alcohol); “Gameleiras, Waterfall of Andorinhas , long -43.079419, lat -14.981272, 931 m a.s.l., vertical surfaces with water and green algae , 24.iii.2019, leg. J.B. R. Alencar” (5 exs. INPA , in alcohol); “Mato Verde, Waterfall Maria Rosa, long -42.795444, lat -15.432167, 725 m a.s.l., vertical surfaces with water and green algae , 25.iii.2020, leg. J.B. R. Alencar” (3 exs. INPA , in alcohol); Bahia: “ BAHIA, BA-564 Piatã-Mucugê, near the road, long -41.593139, lat -13.154611, 844 m a.s.l., vertical surfaces with water and green algae , 26.vi.2019, leg. J.B. R. Alencar” (16 exs. INPA , in alcohol) .

Diagnosis. Small to medium-sized species. Pronotum with rounded posterolateral margins. Elytra surface even, with rows of fine systematic punctures bearing short setae, interrupted in some regions along their length; lateral rows very indistinct, blending with surrounding ground punctation. Elytral sutural interval not raised ( Figs. 12a–c View FIGURE 12 ). Prosternum with two anteromedial spine-like setae. Abdominal ventrites pale, all ventrites usually with distinct medial dark macula (varying in width).

Adult. Body length 3.5–4.2 mm (n= 10, mean= 3.91, SD= ±0.24); TL/GW 1.65± 0.10 mm. General body shape broadly oval, strongly convex.

Color. Dorsum black ( Fig. 5a View FIGURE 5 ), covered with dense, irregular green or bronze sheen. Anterolateral margins of pronotum with wide 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. Antennae with antennomeres 1–5 and 3-segmented club yellowish brown. Maxillary and labial palps yellow. Ventral face of head dark brown to black. Lateral margins of prosternum black to dark brown; pseudoepipleura and epipleura yellowish brown. Thorax, ventrally brown to black, with lighter posterior margins in metaventrite, sometimes extending laterally along entire length of anepisternum. Legs light brown, except for dark brown coxae and basal region of femora. Abdominal ventrites brownish yellow, usually with distinct medial dark macula, sometimes completely covering ventrite.

Head. Ground punctation on clypeus and frons moderately coarse, distance between punctures 2.0–3.0× width of one puncture ( Fig. 5d View FIGURE 5 ). 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 evenly distributed and moderately coarse ( Figs. 5a, c, d View FIGURE 5 ). Pronotal systematic punctures with short fine setae, at least 2× size of surrounding ground punctures; anterior and posterior series each forming an irregular field. Lateral margins of pronotum with fine setae distributed along its length, being more densely pubescent on anterior half. Pronotal posterolateral angles rounded. Sutural interval on elytra not raised. Elytral interval composed of short setae forming inconspicuous rows. Five rows of systematic punctures: rows 1 and 2 each represented by regular series of punctures; punctures not larger that surrounding punctuation and at about the same spacing. Rows 3–5 with punctures not larger than surrounding ground punctuation 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; slightly elevated anteromedially ( Fig. 5e View FIGURE 5 ); 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 two-thirds of 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 scattered, long setae; ventrites 1–4 with scattered, long setae, distinctly longer than longest setae on metaventrite, ventrite 5 more densely pubescent ( Fig. 5b View FIGURE 5 ). Aedeagus: outer margin of parameres weakly sinuous, gradually tapering to apex, straight; inner margin, straight, gradually tapering towards apex (dorsal view); median lobe shorter than parameres, without apical hook. Gonopore located at four-fifths of median lobe. Basal piece tapered ( Fig. 11d View FIGURE 11 ).

Etymology. The specific epithet humboldti is in honor to Friedrich Wilhelm Heinrich Alexander von Humboldt, he was one of the pioneers to propose relationships between South American mountain environments and biodiversity. To be treated as a noun in apposition.

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

Remarks. This species was found in rock-face seepages along streams, as well as in marginal areas that simulate infiltrations due to low flow. This species shares distinguishable diagnostic features with O. rotundus Clarkson & Short, 2012 such as pale abdominal ventrites (in most specimens), absence of black circular spots along the elytral suture and a nearly circular, strongly convex body. However, in O. rotundus the median lobe is distinctly shorter than the parameres and it has a tapered basal piece in contrast to O. humboldti sp. n. which has short setae on the elytral surface and the median lobe is slightly shorter than the length of the parameres, and the basal piece is rounded ( Fig. 11d View FIGURE 11 ).


Departamento de Geologia, Universidad de Chile


University of Kansas - Biodiversity Institute













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