Three new species of Oocyclus Sharp, 1882, with additional records from China (Coleoptera, Hydrophilidae, Laccobiini) Author Jia, Feng-long 0000-0003-2391-5038 Institute of Entomology, Life Sciences School, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China Author Mai, Zu-qi 0000-0003-3124-2021 Institute of Entomology, Life Sciences School, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China & Faculty of Environmental Sciences, Department of Ecology, Czech University of Life Sciences Prague, Czech Republic text ZooKeys 2024 2024-06-19 1205 17 38 journal article 298668 10.3897/zookeys.1205.123579 7cc6f525-e465-4ce5-92de-b7b4c7ed5d8e EB9D907F-1554-484A-9399-79FA6C6A4F7B Oocyclus ximaensis sp. nov. Figs 3 A – D , 5 A – C , 6 F , 7 F , 8 F Type material. Holotype : China • ♂ ; Yunnan Prov. , Dehong Dai and Jingpo Autonomous Prefecture , Yingjiang County , Xima Town , Xingyun Secondary power stations (星云二级电站), at seepage rock wall by the river , 24.7854 ° N , 97.6472 ° E , 1021 m , 2022. VIII. 19 , Zu-qi Mai , Yu-chen Zheng & Yue-zheng Yu leg.; SYSU SYSBMZ 2370036 . Paratypes : 2 ♂♂ , 5 ♀♀ ( SYSU SYSBMZ 2370037 to 0043), same data as the holotype . Diagnosis. Body medium-sized, length 3.8–4.4 mm , oval, and rather convex. Dorsum black, with weak greenish luster, slightly iridescent. Head, pronotum, and elytra with dense ground punctures consisting of extremely fine, moderately coarse punctures. Systematic punctures on labrum moderately dense, forming a nearly continuous transverse row. Posterolateral corners of pronotum evenly rounded. Elytra suture not raised, without distinct rows of systematic punctures; lateral margins of elytra not expanded outwards. Pseudepipleura narrowed posteriorly. Procoxae without distinct, spine-like setae in fine pubescence. Meso- and metafemora without microsculpture on intervals of punctures. Abdominal ventrites with uniform pubescence over entire surface. Aedeagus (Fig. 3 D ) with parameres almost as long as median lobe; inner margin of paramere slightly sinuate in dorsal view and hardly curved subapically; apex of paramere rounded. Median lobe gradually narrowed from base to apex; gonopore situated apically; anterior margin of gonopore pointed. Figure 3. Oocyclus ximaensis sp. nov. A dorsal view B lateral view C ventral view D dorsal view of aedeagus. Scale bars: 0.5 mm. Description. Form and color (Fig. 3 A – C ). Length 3.8–4.4 mm , width 2.3–2.7 mm , oval, rather convex; elytra longer than wide. Dorsum black with weak greenish luster under lateral illumination, slightly iridescent, more vividly colored when alive. Maxillary palps yellow with apex black, labial palpi yellow. Mentum and stipes yellowish brown, paler than ventral face of head. Legs, epipleura, lateral margins of prosternum, and posterior margin of each ventrite light brown to yellowish brown, with remainder of venter darker yellowish brown. Head. Labrum, clypeus, and frons with both extremely fine and moderately coarse ground punctures, distance between punctures 1.0–3.5 × width of 1 puncture. Systematic punctures on labrum moderately dense, forming a nearly continuous transverse row setting with moderately long setae. Frons with an irregular row of systematic punctures mesad of each eye, bearing fine, erect 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 subequal in length to antennomeres 2–5 combined, first 2 antennomeres of club subequal in length, and apical antennomere slightly longer than 2 preceding 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 width of mentum. Mentum quadrate, anterior margin slightly convex, bearing very fine and scattered punctures. Thorax. Ground punctation on pronotum and elytra composed of extremely fine and moderately coarse punctures evenly mixed and distributed. Pronotal systematic punctures present, ca 1.5–2.0 × 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 evenly rounded. Prosternum moderately tectiform, with median carina along entire length but without distinct anteromedial tooth. Elytra without distinct rows of larger punctures, systematic punctures almost as coarse as coarser ground punctures, distinguished by the presence of fine and short setae; lateral margins of elytra not expanded outwards; elytra suture not raised. Pseudepipleura narrowed posteriorly. Mesoventral process with lateral extensions sloping evenly downward. Metaventrite posteromedially with an oval, glabrous area, slightly longer than wide, length of glabrous area ca 2 / 3 of total length of metaventrite. Pro- and mesocoxae densely pubescent; without distinct spine-like setae. Ventral surface of profemora densely pubescent at basal 1 / 5, remainder scattered with fine punctures, interstices smooth, 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 setae around metaventral glabrous area. Fifth ventrite entire. Aedeagus (Fig. 3 D ). Phallobase slightly arcuate at basal 2 / 3; manubrium gradually narrowed at posterior 1 / 3 and rounded posteriorly. Parameres slightly longer than phallobase, widest at the base and gradually narrowed; inner margin of paramere slightly sinuate in dorsal view and hardly subapically curved; apex rounded. Median lobe almost as long as parameres, gradually narrowed from base to apex; gonopore triangular, apically situated; anterior margin of gonopore pointed. Remarks. This species is very similar to O. bhutanicus Satô, 1979 , but it can be distinguished from the latter by dorsum with weak greenish luster under lateral illumination (vs distinct greenish luster in O. bhutanicus ), aedeagus with median lobe as long as parameres (vs shorter than parameres in O. bhutanicus ), anterior margin of gonopore pointed (rounded in O. bhutanicus ). Etymology. This species is named after Xima Town, where the type locality is located. Biology. (Fig. 5 A – C ) This species was found on the surface of vertical stone walls with seepage on the side of the river valley. Figure 4. Habitats of Oocyclus extensus sp. nov. A valley at Zhêntang Town (Xizang), roadside with waterfalls B wet rock with fine flowing water C, D adults at night. Figure 5. Habitat of Oocyclus ximaensis sp. nov. A river valley with forests on both sides in Xima Town (Yunnan); the red arrow indicates the rock wall with flowing water B, C adults at night. Distribution. (Fig. 9 ) China ( Yunnan ). Only known from type locality.