Oocyclus extensus, Jia & Mai, 2024

Jia, Feng-long & Mai, Zu-qi, 2024, Three new species of Oocyclus Sharp, 1882, with additional records from China (Coleoptera, Hydrophilidae, Laccobiini), ZooKeys 1205, pp. 17-38 : 17-38

publication ID	https://doi.org/ 10.3897/zookeys.1205.123579
publication LSID	lsid:zoobank.org:pub:EB9D907F-1554-484A-9399-79FA6C6A4F7B
DOI	https://doi.org/10.5281/zenodo.12172856
persistent identifier	https://treatment.plazi.org/id/2A7B3F2F-10FB-4431-8C33-67ED91F49C00
taxon LSID	lsid:zoobank.org:act:2A7B3F2F-10FB-4431-8C33-67ED91F49C00
treatment provided by	ZooKeys by Pensoft
scientific name	Oocyclus extensus
status	sp. nov.

Treatment

Oocyclus extensus sp. nov.

Figs 1 A – D View Figure 1 , 4 A – D View Figure 4 , 6 A View Figure 6 , 7 A View Figure 7 , 8 A View Figure 8

Type material.

Holotype: China • ♂; Xizang Autonomous Region, Xigazê, Dinggyê County, Zhêntang Town , on wet rock with a fine film of flowing water (西藏日喀则定结县陈塘镇流水岩壁表面); 27.8733 ° N, 87.4117 ° E; 2482 m elev.; 2023. VII. 10; Zu-qi Mai, Cheng Liang & Yue-zheng Tu leg.; SYSU SYSBMZ 2370001 GoogleMaps . Paratypes: 8 ♂♂, 8 ♀♀ ( SYSU SYSBMZ 2370002 to 0017), 2 ♂♂, 2 ♀♀ ( IZCAS COLMZD 2370001 to 0004); same data as the holotype GoogleMaps .

Diagnosis.

Body large, length 5.3–6.2 mm, oblong-oval, and moderately convex. Dorsum black, with greenish luster under lateral illumination, slightly iridescent. Head, pronotum, and elytra with dense ground punctures consisting of extremely fine and moderately coarse punctures. Systematic punctures on labrum sparse and fine, not forming a continuous transverse row or groove. Posterolateral corners of pronotum angulate. Elytral suture slightly raised posteriorly; with 5 distinct rows of regular systematic punctures; lateral margins of elytra distinctly expanded outwards. Pseudepipleura wide from base to apex. Procoxae with sparse, spine-like setae scattered in fine pubescence. Meso- and metafemora without microsculpture on intervals of punctures. Abdominal ventrites with uniform pubescence over entire surface. Aedeagus (Fig. 1 D View Figure 1 ) with parameres almost as long as median lobe; gradually narrowed from apical fourth to apex; apex of paramere slightly curved inwards and rounded. Median lobe slightly narrowed apically, gonopore situated apically, anterior margin of gonopore rounded.

Description.

Form and color (Fig. 1 A – C View Figure 1 ). Length 5.3–6.2 mm, width 3.4–4.0 mm; oblong-oval and moderately convex; elytra longer than wide. Dorsum black, with greenish luster under lateral illumination, slightly iridescent, more vividly colored when alive. Maxillary and labial palps yellowish brown, with last maxillary palpomere apically darkened. Antennae yellowish brown, with cupule (sixth antennomere) dark reddish brown or dark brown; club black. Ventral surface black. Epipleura, lateral margins of prosternum, and tarsomeres reddish brown; femora, tibiae, and sternites black or blackish brown. Head. Labrum, clypeus, and frons with both extremely fine and moderately coarse ground punctures; distance between punctures 0.2–3.0 × width of 1 puncture. Systematic punctures on labrum sparse, not forming a continuous transverse row or groove, each systematic puncture with a long seta. Systematic punctures on clypeus almost undetectable. Frons with an irregular row of systematic punctures mesad of each eye, slightly larger than largest ground punctures and usually bearing long setae. Clypeus with a few very indistinct systematic punctures along anterolateral margins, slightly larger than surrounding ground punctures, and bearing short setae. Antennae with scape as long as antennomeres 2–5 combined, first 2 antennomeres of club subequal in length, and apical antennomeres slightly shorter than preceding 2 antennomeres combined. Maxillary palps short, subequal in length to the width of labrum, palpomere 2 slightly dilated, apical palpomeres ca 1.3 × as long as penultimate. Labial palps ca 3 / 4 × as the width of mentum. Mentum quadrate, anterior margin slightly convex; with coarse punctures on anterior and lateral portion, only with few punctures posteromedially. Thorax. Ground punctation on pronotum and elytra composed of extremely fine and moderately coarse punctures evenly mixed and distributed. Pronotal systematic punctures present, ca 1.5 × the size of ground punctation and set with a fine seta, sometimes partially blending with coarser ground punctures; anterior and posterior series each forming an irregular row. Lateral margins of pronotum set with a few sparsely distributed setiferous punctures. Pronotum with anterior and lateral marginal rims, posterior marginal rim absent. Posterolateral corners of pronotum angulate. Prosternum moderately tectiform, with median carina along entire length, with a small blunt tooth anteriorly. Elytra with 5 distinct rows of punctures, diameter of systematic punctures ca 2 × as wide as the coarse ground punctures; lateral margin of elytra distinctly expanded outwards, especially in posterior half; elytral suture slightly raised but easily detectable. Pseudepipleura wide throughout. Mesoventral process with lateral extensions sloping evenly downward. Metaventrite with an oval glabrous area posteromedially, slightly longer than wide, length of glabrous area as long as the total length of metaventrite. Pro- and mesocoxae densely pubescent; procoxae with sparse spine-like setae. Ventral surface of profemora densely pubescent at basal fifth, remainder scattered with fine punctures, interstices without microsculpture; meso- and metafemora glabrous, with coarse punctures and without microsculpture. Protibiae with several spines on dorsal face. Fifth tarsomere of pro- and mesotarsus subequal in length to the preceding 4 tarsomeres combined. Fifth metatarsomere equal in length to second tarsomere. Abdomen. Abdominal ventrites 1–5 with uniform pubescence, longest setae about as long as the setae around the metaventral glabrous area. Fifth ventrite entire. Aedeagus (Fig. 1 D View Figure 1 ). Phallobase with basal 2 / 3 arcuate, manubrium gradually narrowed at posterior 1 / 3 and rounded posteriorly. Parameres almost as long as phallobase, widest at the base, arcuate medially outwards, gradually narrowed from apical fourth to apex; apex of paramere slightly curved inwards and rounded. Median lobe slightly narrowed apically, gonopore triangular, apically situated, and with rounded anterior margin.

Remarks.

This species is similar to Oocyclus rupicola Minoshima, 2009 from Laos. It can be distinguished from O. rupicola by its on average larger body size (length 5.3–6.2 mm, width 3.4–4.0 mm vs length 4.93–5.85 mm, width 3.03–3.53 in O. rupicola ), sparse, fine systematic punctures on labrum which do not form a continuous transverse row (vs forming a row of coarse punctures in O. rupicola ), and rounded apex of the paramere of the aedeagus (vs narrowed and obliquely truncate inwards in O. rupicola ) ( Minoshima 2009).

Etymology.

This species is named extensus, Latin, meaning “ stretched out ” and referring to the outwardly expanded elytra.

Biology.

(Fig. 4 A – D View Figure 4 ) The examined specimens were collected on exposed, seeping rock surfaces on the valley edge. They were together with other species of the family Hydrophilidae : Oocyclus bhutanicus Satô, 1979 , Agraphydrus nepalensis Komarek, 2018 , Laccobius regalis Knisch, 1924 , and Coelostoma gentilii Jia, Aston & Fikáček, 2014 . Adults hide in rock crevices during the day and are active at night.

Distribution.

(Fig. 9 View Figure 9 ) China (Xizang). Only known from type locality. Zhêntang Town is in a valley on the southern side of the central Himalayas and is a border town on the China – Nepal border and lies on the Pum Qu River.