Research Article |
Corresponding author: Zu-qi Mai ( maizq5@mail2.sysu.edu.cn ) Academic editor: Mariano Michat
© 2024 Feng-long Jia, Zu-qi Mai.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Jia F-long, Mai Z-qi (2024) Three new species of Oocyclus Sharp, 1882, with additional records from China (Coleoptera, Hydrophilidae, Laccobiini). ZooKeys 1205: 17-38. https://doi.org/10.3897/zookeys.1205.123579
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Three new species of the water scavenger beetle genus Oocyclus Sharp, 1882 from China (Oocyclus extensus sp. nov., from Xizang, O. latiorificialis sp. nov. and O. ximaensis sp. nov. from Yunnan) are described and illustrated in detail. Additional faunistic data, illustrations of habitus and male genitalia, and a key to Chinese species are provided.
Identification key, Oriental Region, water scavenger beetles, Xizang, Yunnan
Oocyclus Sharp, 1882 is a pantropical genus of water scavenger beetle that is highly adapted to waterfalls and seepages. All known species are restricted to rock-face seeps, margins of waterfalls, and various kinds of vertical surfaces with water (
Recently, we had the opportunity to visit some nature reserves in Yunnan and Xizang and discovered several Oocyclus species, of which three are described here as new to science. We also studied the Oocyclus collections at the Biological Museum, Sun Yat-sen University, and added information about the distribution of Chinese species.
Some of the specimens were dissected. Dissected male genitalia were transferred to a drop of distilled water, remaining membranes were removed under a compound microscope, and the cleaned genitalia were then mounted in a drop of soluble resin on a paper card attached below the respective specimen. For photography, the cleaned and relaxed male genitalia were placed in a drop of glycerin. Photographs of genitalia were taken using a Zeiss AxioCam HRc camera mounted on a Zeiss AX10 microscope with the Axio Vision SE64 software. These images were then stacked in Helicon Focus v. 7.0.2. Habitus photographs were taken using a Nikon DS-Ri2 mounted on a Nikon SMZ25; layers were captured and stacked in the NIS-Elements software. Habitat images were taken using Canon 7D digital camera. The generic characters are described in detail by
Examined specimens are deposited in the following collections:
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.;
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.
Form and color
(Fig.
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) (
This species is named extensus, Latin, meaning “stretched out” and referring to the outwardly expanded elytra.
(Fig.
(Fig.
Holotype
: China • ♂; Yunnan Province, Nujiang Lisu Autonomous Prefecture, Lushui County, Pianma Village, on wet rock with fine flowing water (怒江傈僳族自治州泸水市片马村流水岩壁); 26.014039°N, 98.650640°E; 2131 m elev.; 2021.V.17; Zhuo-yin Jiang, Zhen-ming Yang & Zu-qi Mai leg.;
Body medium-sized, length 4.1–4.3 mm, oval, and rather convex. Dorsum black, with distinct 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 moderately dense, forming a nearly continuous transverse row. Posterolateral corners of pronotum evenly rounded. Elytral 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 with fine microsculpture on intervals of punctures. Abdominal ventrites with uniform pubescence over entire surface. Aedeagus (Fig.
Form and color
(Fig.
This species is very similar to O. bhutanicus Satô, 1979, but can be easily distinguished by meso- and metafemora with fine microsculpture on intervals of punctures (vs lacking microsculpture in O. bhutanicus), aedeagus with median lobe as long as parameres and almost parallel-sided medially, slightly widened at level of gonopore (vs median lobe shorter than parameres and gradually narrowed from base to apex in O. bhutanicus), anterior margin of gonopore pointed (vs rounded in O. bhutanicus), and inner margin of paramere sinuate in dorsal view and distinctly curved subapically (vs inner margin of paramere almost straight in dorsal view in O. bhutanicus). This species also shares diagnostic features with O. ximaensis sp. nov., but it can be distinguished from the latter by dorsum with distinct greenish luster under lateral illumination (vs greenish luster weaker in O. ximaensis), meso- and metafemora with fine microsculpture (lacking microsculpture in O. ximaensis), and aedeagus with median lobe almost parallel-sided medially, slightly widened at level of gonopore (vs median lobe gradually narrowed from base to apex in O. ximaensis).
Species name is combination of Latin latus, “wide”, and orificialis, “orifice”, referring to the widely open gonopore.
This species was founding living on wet rock surface at the margins of a waterfall.
(Fig.
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.;
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.
Form and color
(Fig.
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).
This species is named after Xima Town, where the type locality is located.
(Fig.
(Fig.
5 ♂♂, 3 ♀♀; China• Xizang Autonomous Region, Xigazê, Dinggyê County, Zhêntang Town, on wet rock with fine flowing water (西藏日喀则定结县陈塘镇流水岩壁表面), 2482 m, 27.8733°N, 87.4117°E, 2023.VII.10, Zu-qi Mai.;
Dorsal view of Chinese Oocyclus spp. A O. extensus sp. nov. B O. magnificus Hebauer & Wang, 1998 C O. sumatrensis Orchymont, 1932 D O. bhutanicus Satô, 1979 E O. latiorificialis sp. nov. F O. ximaensis sp. nov. G O. fikaceki Short & Jia, 2011 H O. shorti Jia & Maté, 2012 I O. dinghu Short & Jia, 2011. Scale bars: 1 mm.
Lateral view of Chinese Oocyclus spp. A O. extensus sp. nov. B O. magnificus Hebauer & Wang, 1998 C O. sumatrensis Orchymont, 1932 D O. bhutanicus Satô, 1979 E O. latiorificialis sp. nov. F O. ximaensis sp. nov. G O. fikaceki Short & Jia, 2011 H O. shorti Jia & Maté, 2012 I O. dinghu Short & Jia, 2011. Scale bars: 1 mm.
Aedeagus of Chinese Oocyclus spp. (dorsal view) A O. extensus sp. nov. B O. magnificus Hebauer & Wang, 1998 C O. sumatrensis Orchymont, 1932 D O. bhutanicus Satô, 1979 E O. latiorificialis sp. nov. F O. ximaensis sp. nov. G O. fikaceki Short & Jia, 2011 H O. shorti Jia & Maté, 2012 I O. dinghu Short & Jia, 2011. Scale bar: 0.5 mm.
12 unsexed spec.; China• Guangdong Prov., Fengkai County, Heishiding Natural Reserve (广东省封开黑石顶自然保护区), 23.31°N, 111.52°E, 2014.IX.20–22, Ren-chao Lin, Feng-long Jia & Yu-dan Tang leg;
(Fig.
China • Zhejiang: 2 ♂♂, 3 ♀♀, 14 unsexed spec.; Longquan, Fengyangshan Natural Reserve (龙泉凤阳山自然保护区), on wet rock, N.R. ca 1150m, 27°54′51″N, 119°11′56″E, 2018.IV.28, Yin & Miao.;
(Fig.
3 ♂♂, 4 ♀♀; China • Taiwan, Taidong, Hairui, Lidao village (台东海瑞乡利稻), 1000m, 2017.V.13, Wen-yi Zhou leg.;
(Fig.
China • Guangdong: 3 ♂♂ 2 ♀♀, 47 unsexed spec.; Huizhou Prefecture, Longmen County, Nankunshan, Zhongpingwei Village (惠州龙门县南昆山中坪尾村), 23.6224°N, 113.8660°E, 639.0m, 2021.IX.26, Wei-cai Xie, Zhuo-yin Jiang & Zu-qi Mai leg.;
(Fig.
2 ♂♂, 1 ♀, 11 unsexed spec.; China • Hainan Prov., Limushan Mt., Limu temple (黎母山黎母庙), 2011.V.5, Shuang Zhao leg.;
(Fig.
1 | Elytra with distinct rows of systematic punctures. Pronotum with posterolateral corners angulate (Figs |
2 |
– | Elytra without distinct rows of systematic punctures. Pronotum with posterolateral corners rounded (Figs |
4 |
2 | Body length over 5.3 mm (Fig. |
O. extensus sp. nov. |
– | Body length less than 5.2 mm (Fig. |
3 |
3 | Body length 5.0–5.2 mm. Elytra with 6 irregular rows of large punctures, a short scutellar row of punctures on elytra present (Figs |
O. magnificus Hebauer & Wang |
– | Body length less than 4.5 mm. Elytra with 5 distinct rows of punctures, without scutellar row of punctures (Figs |
O. sumatrensis Orchymont |
4 | Abdomen covered only with fine pubescence, without rows of long setae. Aedeagus with gonopore at apex of median lobe (Fig. |
5 |
– | Abdomen covered with fine pubescence and rows of long setae. Aedeagus with gonopore below apex of median lobe (Fig. |
7 |
5 | Meso- and metafemora with fine microsculpture on intervals of punctures. Inner margin of paramere sinuate in dorsal view and distinctly subapically curved; median lobe almost parallel-sided medially, slightly widened at level of gonopore (Fig. |
O. latiorificialis sp. nov. |
– | Meso- and metafemora without microsculpture on intervals of punctures. Inner margin of paramere straight or slightly sinuate in dorsal view, not subapically curved; median lobe gradually narrowed from base to apex | 6 |
6 | Dorsum with distinct greenish luster under lateral illumination. Aedeagus with median lobe shorter than parameres; anterior margin of gonopore rounded (Fig. |
O. bhutanicus Satô |
– | Dorsum with weak greenish luster under lateral illumination. Aedeagus with median lobe as long as parameres; anterior margin of gonopore pointed (Fig. |
O. ximaensis sp. nov. |
7 | Maxillary palps with last palpomere not darkened, punctures on dorsal face finer and sparser. Aedeagus with parameres widely rounded and more or less expanded inwards apically. Median lobe with gonopore situated subapically (Fig. |
O. dinghu Short & Jia |
– | Maxillary palps with last palpomere darkened apically, punctures on dorsal face coarser and denser. Aedeagus with paramere narrowly rounded, not expanded inwards apically. Median lobe with gonopore situated at the middle or slightly above the middle | 8 |
8 | Aedeagus with the outer margin of parameres distinctly curved inwards and clearly narrowed apically; median lobe abruptly narrowed at apical fourth, gonopore wider than long, situated 1.5× its length below apex (Fig. |
O. shorti Jia & Mate |
– | Aedeagus with parameres not distinctly curved, and not narrowed apically; medial lobe slightly narrowed subapically, gonopore shaped as a long triangle, longer than wide, situated 1× its length below apex (Fig. |
O. fikaceki Short & Jia |
Three patterns of elytral punctures are known among known species from the Oriental region: 1) elytra with distinct rows of large punctures (including rows of systematic punctures), with ground punctures of almost uniform size, such as O. sumatrensis Orchymont, 1932, O. magnificus Hebauer & Wang, 1998, and O. namtok Short & Swanson, 2005; 2) elytra with a mixture of fine and coarse ground punctures, systematic punctures of almost the same size as coarse ground punctures and interspersed with coarse ground punctures, such as O. bhutanicus Satô, 1979, O. dinghu Short & Jia, 2011, O. fikaceki Short & Jia, 2011, O. shorti Jia & Mate, 2012, O. latiorificialis sp. nov., and O. ximaensis sp. nov.; 3) elytra with distinct rows of large punctures (including rows of systematic punctures), with fine punctures mixed with more coarse ground punctures, such as O. sitesi Short & Swanson, 2005, O. rupicola Minoshima, 2009 and O. extensus sp. nov.
Among Chinese species, two are assigned to pattern 1: O. sumatrensis, occurring on Hainan, and O. magnificus, endemic to Taiwan. Seven species are assigned to pattern 2: O. dinghu, O. fikaceki, O. shorti, O. latiorificialis, O. bhutanicus, and O. ximaensis, occurring on the Chinese mainland. Only one species, O. extensus, is assigned to pattern 3. As in South America, knowledge of the distribution of Oocyclus is still very incomplete (
Although Oocyclus species are similar in shape, some Neotropical and Oriental groups have evolved some special characters. All 24 Brazilian Oocyclus possess pale spots (or “taillights”) on the posterior quarter of the elytra (
The distributions of most species show strong geographic patterns. The pattern of distributions of Venezuelan Oocyclus strongly corresponds to mountain ranges and rock outcrops (
We thank Dr Robert B. Angus, a specialist on Hydrophiloidea, the Natural History Museum, London, UK, who reviewed the manuscript. We are very grateful to Mr Wen-yi Zhou for collection and donation of the specimen of O. magnificus Hebauer & Wang. We thank Mr Cheng Liang (Chinese Academy of Sciences, Institute of Zoology), Mr Yu-chen Zheng and Mr Yue-zheng Tu (both from China Agricultural University) for helping Zu-qi Mai in the fieldwork. We are grateful to Dr. Bing-Lan Zhang, School of Life Sciences, Sun Yat-Sen University, for providing the equipment for macrophotography.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This study was financially supported by “Science & Technology Fundamental Resources Investigation Program (grant no. 2022FY202100)”.
Writing – original draft: F-l Jia, Z-q Mai. Writing – review and editing: Z-q Mai.
Feng-long Jia https://orcid.org/0000-0003-2391-5038
Zu-qi Mai https://orcid.org/0000-0003-3124-2021
All of the data that support the findings of this study are available in the main text.