Oocyclus armstrongorum, Short, 2009

Short, Andrew Edward Z., 2009, Two new species of the hygropetric genus Oocyclus from eastern India (Coleoptera: Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 49 (2), pp. 625-630 : 626-628

Oocyclus armstrongorum sp. nov.

( Figs. 1 , 3 )

Type material. HOLOTYPE: male, ‘ INDIA, Meghalaya State (10) / E Khasi Hills, 11km SW Cherra- / punjee, Laitkynsew, 21-24.iv. / 2008, 25°13′N 91°39′E, 810m / Fikáček, Podskalská, Šípek lgt.’ // ‘seepage: wet rocks algae / blue algae/moss ca. 1.5-2 km / via rd. from ‘Cherrapunjee Holid. / Resort’ in direct. Cherrapunjee, / exposed’ ( NMPC) . PARATYPES: 16 spec., same data as holotype ( KSEM, NHMW, NMPC, USNM).

Diagnosis. Posterolateral corners of pronotum angulate. Procoxae distinctly spinose. Raised medial glabrous region of the metaventrite extended along its entire length. Abdominal ventrites dark brown to black; finely and evenly pubescent. Elytra with detectable but often obscured rows of systematic punctures. This species shares many diagnostic characters with O. melinoventris Short & Swanson, 2005 (currently only known from Thailand), and the extended glabrous region of the metaventrite is currently known only from these two species (see SHORT & SWANSON 2005, Fig. 11). However, they are easily distinguished by the color of the ventrites, which is bright yellow in O. melinoventris while nearly black in O. armstrongorum sp. nov. Oocyclus melinoventris is also smaller in size, never exceeding 5.0 mm, while the smallest individuals of O. armstrongorum sp. nov. are 5.2 mm.

Description. Size and form. Total body length = 5.2–5.6 mm. Broadly oval, moderately convex. Elytra slightly longer than wide.

Color. Dorsum black, without any distinct colored iridescence. Maxillary palps yellow except apex of the apical segment, which is slightly darkened. Labial palps yellow. Mentum and stipes dark brown to black, the same color as ventral surface of head. Pseudoepipleura and tarsi reddish brown, with the remainder of the sternum and legs very dark brown to black. Ventrites uniformly dark brown, similar in color as the sternum.

Head. General punctation on labrum, clypeus and frons variable in size from almost very fine to moderately coarse; dense, distance between punctures 0.5–1.0× the width of one puncture. Systematic row of punctures on labrum composed of coarse, setiferous punctures laterally with center row appearing absent or with punctures reduced in size or density. Frons with an irregular row of systematic punctures mesad of each eye, bearing fine recumbent to erect setae. Clypeal systematic punctures not apparent, blending with the surrounding course ground punctation. Antennae with scape subequal to slightly longer in length to segments 2–5; first two segments of club subequal in length and apical segment slightly shorter than two preceding segments combined. Maxillary palps short, as long to slightly longer in length than width of labrum; apical segment ca. 1.5× as long as penultimate. Labial palps three-fourths as long as width of mentum. Mentum quadrate, anterior margin slightly convex; bearing distinct scattered punctures on anterior two-thirds, some of which bear fine setae.

Thorax. General punctation on elytra very dense, distance between punctures absent to 1.0× the width of one puncture, composed of punctures of varying size, from very fine to very coarse; becoming extremely dense posteriorly, making elytra appear almost rugose. Pronotal punctation similar but distinctly less impressed. Pronotal systematic punctures distinct, 1.5–2.0× the size of larger general punctation punctures and set with a fine recumbent seta; anterior and posterior series each forming an irregular row. Lateral margins of pronotum with a sparse row of setiferous punctures. Posterolateral corners of pronotum angulate, but not spinose. Sutural punctation on elytra unmodified from general punctation. Elytra with five diffuse rows of systematic punctures, which are mostly obscured by the larger ground punctures, but generally detectable. Prosternum with fine median carina along entire length, without a tooth or long setae anteriorly. Process of the mesoventrite with lateral extensions sloping evenly downward; apex set with a few fine setae. Mesoventrite with glabrous area extending to entire length, slightly narrower than width of process of the mesoventrite anteriorly, becoming evenly narrowed anteriorly. Procoxae covered with short spines and coarse long setae; mesocoxae without spines, at most with a few coarse, long setae. Protibiae with 9–11 spines on dorsal face. Protarsal segments 1–4 small, subequal in length; apical segment ca. as long as segments 1–4 combined.

Abdomen. Ventrites with moderately dense pubescence, the longest setae shorter to subequal in length to longest setae around mesosternal glabrous area. Fifth ventrite entire, with pubescence slightly denser than ventrites 1–4. Aedeagus ( Fig. 3 ) with parameres evenly curved along outer margin, slightly curving inwards apically; inner margins bisinuate. Apex of median lobe nearly subequal with apex of parameres.

Etymology. It is my pleasure to name this species after my friends Dr. Andrew Armstrong and Ms. Christina Lamneck in honor of their recent marriage.

Biology. As is typical for nearly all members of the genus, the examined specimens of O. armstrongorum sp. nov. were collected on a rock seepage habitat that was covered in algae. A detailed account of that locality is provided by FIKÁČEK & ŠÍPKOVÁ (2009) and GENTILI & FIKÁČEK (2009).

Distribution. Known only from the type locality in Meghalaya State of India.

Figures

Figs. 1–2. Dorsal habitus. 1 – O. armstrongorum sp. nov., 2 – O. madidus sp. nov.

Figs. 3–4. Aedeagus, dorsal view. 3 – Oocyclus armstrongorum sp. nov., 4 – O. madidus sp. nov. Scale bar = 0.33 mm.