Research Article |
Corresponding author: Mingyi Tian ( mytian168@aliyun.com ) Academic editor: Achille Casale
© 2021 Mingyi Tian, Sunbin Huang, Xinyang Jia, Yi Zhao.
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:
Tian M, Huang S, Jia X, Zhao Y (2021) Two new genera and three new species of cavernicolous trechines from the western Wuling Mountains, China (Coleoptera, Carabidae, Trechinae). ZooKeys 1059: 57-78. https://doi.org/10.3897/zookeys.1059.70009
|
Two new genera and three new species of cave-adapted ground beetles belonging to the tribe Trechini are established and described: Wulongius qilinger gen. nov. and sp. nov. from limestone cave Qiankou Dong (Chongqing: Wulong), Qianotrechus congcongae sp. nov. from cave Shigao Dong (Chongqing: Nanchuan), and Qianlongius zhoui gen. nov. and sp. nov. from cave Qianlong Dong (Guizhou: Songtao). Wulongius qilinger sp. nov. is a small aphaenopsian beetle with a thin and elongated body, while Qianlongius zhoui sp. nov. is a semi-aphaenopsian with a stout body. Both new genera are not closely related to any genus of Trechini occurring in the South China Karst, and so their systematic positions remain unclear.
Aphaenopsian, cave-dwelling, Chongqing, ground beetles, Guizhou, semi-aphaenopsian
The scientific discoveries made in recent years have revealed that the Wuling Mountains harbour a very rich fauna of cavernicolous trechine beetles which is composed of over 30 species in 13 genera (
All beetles for this study were collected with the naked eyes using an aspirator in dark zones of the caves and kept in vials with 50% ethanol before studying. One exemplar of each species (but three legs removed from the holotype of Wulongius qilinger gen. nov. and sp. nov.) were kept into 95% ethanol for DNA sequencing. Dissections and observations were made by using a binocular Leica MZ75 dissecting microscope (Wetzlar, Germany). Dissected genitalia, including the median lobe and parameres of the aedeagus, were glued on small transparent plastic cards and pinned under the specimen from which they were removed. Digital pictures were taken using a Canon EOS 5D Mark III camera (Tokyo, Japan) and then processed by means of Adobe Photoshop CS5 software (Adobe System Incorporated, California, USA). Measurements and terminologies used in the text are as in
Wulongius qilinger Tian & Huang, sp. nov. (cave Qiankou Dong, Wulong, Chongqing).
Medium-sized for cavernicolous trechine beetles, aphaenopsian and depigmented; body thin and elongate, with thin and slender appendages. Head glabrous, pronotum covered with dense and long erected setae; apical portions of elytra covered with very sparse and short hairs; head strongly elongate, much longer than wide (excluding mandibles); widest at about middle, gently narrowed posteriad, neck constriction short; 2 pairs of supra-orbital setiferous pores present; frontal furrows short and incomplete, ending at the level of the head widest portion; vertex strongly convex; mandibles thin, sharply hooked at apices, right mandibular tooth completely reduced; labial suture clear; mentum with 2 setae on each side of median tooth, base of mentum with small basal pits on each side; submentum with a row of 10 setae; palps thin and very elongate, all glabrous but bisetose on inner margin of 2nd labial palpomere; antennae very thin and long, extending over apices of elytra. Propleura visible from above; pronotum cylindrical, distinctly elongated, much longer than wide, lateral margins nearly parallel-sided though slightly divergent medially, presence of only anterior latero-marginal setae (posterior ones lacking), both fore and hind angles widely obtuse. Scutellum present. Elytra elongated ovate, dorsum strongly convex and expanded laterally, partly concealing lateral margin of elytra in middle portion; humeral angle indistinct, lateral margin well bordered and ciliate throughout; striae almost obsolete though traceable; 2 pairs of dorsal setiferous pores present on the 3rd stria, preapical pores present; basal pores located behind scutellum; the humeral group of the marginal umbilicate pores not aggregated, 1st pore inwardly and backwardly shifted to the site of 6th stria and located at level between 2nd and 3rd pores, 5th and 6th pores widely spaced each other.
The position of Wulongius gen. nov. within Trechini is undetermined. It might be related to the genus Xiangxius Tian & X. Huang, 2021, which has been recently described from Tangle Dong cave in western Hunan, in the eastern Wuling Mountains. Both genera are aphaenopsian, with highly specialized morphological characters. They are somewhat similar in thoracic configuration and, in particular, in the elytral chaetotaxy, in which the 1st pore of the marginal umbilicate series is backwardly and inwardly shifted and both 5th and 6th pores are widely spaced. However, there are many different important characters between them including the body shape: (1) elytra are much more convex and expanded laterally in Wulongius, concealing median part of the lateral margins, and without aprotruding humeral angle on each elytron, versus elytra less expanded laterally in Xiangxius, whole lateral margin visible from above, and with a distinct protruding humeral angle on each elytron; (2) pronotum covered with long setae, without posterior latero-marginal setae in Wulongius, versus pronotum glabrous, with posterior latero-marginal setae in Xiangxius; (3) mentum glabrous in Wulongius, but pubescent in Xiangxius; (4) labial suture clear in Wulongius, whereas mentum fused with submentum in Xiangxius; (5) right mandibular tooth edentate in Wulongius, while bidentate in Xiangxius; (6) submentum with a row of 10 setae in Wulongius, instead of 15 or 16 setae in Xiangxius; (7) head slender in Wulongius, not thickened, with longer antennae extending beyond the apices of elytra, versus head stout, widely convex laterally, and with shorter antennae extending only to apical 2/3 of elytra in Xiangxius.
“Wulong”+ “-ius”, indicating the homeland of this new genus. Gender masculine.
China (Chongqing). Known only from limestone cave Qiankou Dong (Fig.
Holotype female, cave Qiankou Dong, Tongluo, Jiangkou, Wulong, Chongqing, 29.32°N, 107.91°E, 1103 m, 2021-IV-14, leg. “Wu Ya” (a nickmane of Mr Hongying Wu) & Mingyi Tian, in SCAU.
A medium-sized aphaenopsian trechine species, with a distinctly elongated body and thin appendages, without eyes and pigmentation, elytra remarkably expanded laterally and partially concealing median part of elytral margins.
Length: 6.5 mm, width: 1.6 mm. Habitus as in Figure
Head much longer than wide, HLm/HW = 2.68, HLl/HW = 1.96; genae not expanded, widest at about middle of head excluding mandibles, gradually narrowed posteriad, neck short and narrow; frons and vertex moderately convex; frontal furrows nearly parallel-sided, shortly divergent apically, ending at about middle of head; anterior and posterior supraorbital pores located at about basal 3/8 and 1/5 of head, respectively; clypeus 4-setose; labrum transverse, frontal margin almost straight, 6-setose; mentum bisetose, tooth rather narrow, bifid at tip, slightly longer than half of the lateral lobes; ligula 10-setose at apex, inner 2 much longer than others; distal palpomeres of maxilla and labium 1.3 times as long as the penultimate palpomeres; suborbital pores much closer to neck constriction than to submentum (Fig.
Prothorax distinctly tumid at sides, propleura slightly wider than pronotum, PrW/PnW = 1.1, visible from above, widest a little before basal 1/3, wider than head, PrW/HW = 1.2; pronotum much longer than wide, PnL /PnW = 1.6, shorter than head excluding mandibles, PL/HL l = 0.9; widest at about 3/7 of pronotum from base; lateral margins finely bordered throughout, gently contracted forwards and backwards, slightly sinuate before hind angles which are wide and blunt though more or less rectangular; frontal angles rounded off; base straight, front margin slightly arcuate, both unbordered, base slightly wider than front margin; only anterior latero-marginal setae present, at about 2/9 from front margin; disc slightly convex, mid-line well-marked; both fore and basal transversal impressions faint, basal foveae shallow. Scutellum quite large.
Elytra (Fig.
Legs densely pubescent; 1st tarsomere shorter than 2nd–4th combined in fore legs, whereas slightly longer and as long as in middle and hind legs, respectively; tibiae without longitudinal sulci.
Ventrite IV–VI bisetose, VII quadrisetose in female.
Male. unknown.
Referring to the Qilinger Cave Exploration Team (Nanning), led by Mr Lixin Chen, a famous TV reporter on cave exploration in China.
China (Chongqing). Known only from limestone cave Qiankou Dong (Fig.
Holotype male, cave Shigao Dong, Hexi, Nanchuan, Chongqing, 28.82° N, 107.32°E, 729 m, 2021-IV-13, leg. Yi Zhao, Xinyang Jia and Mingyi Tian, in SCAU.
A small, stout cave trechine, semi-aphaenopsian, with a brown body, rather short appendages and broadly tumid prothorax.
Length: 5.5–5.8 mm, width: 1.9 mm. Habitus as in Figure
Body brown, palps, antennae and tarsi yellow. Surface and underside smooth and glabrous. Microsculpture: isodiametric meshes on head, transversal meshes or striate on pronotum and elytra.
Head (Figs
Prothorax quadrate, as long as wide, widest behind middle; as long as head excluding mandibles, as wide as pronotum (Fig.
Elytra (Fig.
Legs moderately long and densely pubescent; fore and middle tibiae longitudinally grooved externally, whereas simple in hind tibiae; the 1st and 2nd protarsomeres dilated and spurred inwards at apex in male.
Ventrites IV–VI, each with a pair of paramedial setae, ventrite VII bisetose in male. Male genitalia (Fig.
Female. unknown.
The genus Qianotrechus Uéno, 2000 is comprised of three semi-aphaenosian trechine species and one subspecies (Fig.
Qianotrechus congcongae sp. nov. is closely similar to Q. laevis from Zheng’an County of northeastern Guizhou Province (
The name of this beautiful species is in honour of “Xiao Cong”, a nickname of Ms Jia Liu, an outstanding and leading caver in the Chongqing Cave Exploration Team, Chongqing, for her kind assistance in our collecting trips in Chongqing.
China (Chongqing). Known only from the limestone cave in Shigao Dong, Nanchuan (Fig.
Qianlongius zhoui Tian & Jia, sp. nov. (Qianlong Dong cave, Songtao, Guizhou).
Large for cavernicolous trechines, semi-aphaenopsian, but more or less pigmented; body stout, appendages moderate long; head and pronotum smooth and glabrous, elytra wholly pubescent; moderately shining. Head subquadrate, distinctly longer than wide excluding mandibles, nearly parallel-sided; frontal furrows sub-parallel-sided, 2 supra-orbital pores present; mandible thin and sharp at apices, right mandible tridentate; labial suture well-marked; mentum bisetose, slightly shallow at base; submentum with a row of 6 setae; palps thin and elongated, the 2nd labial palpomere without additional setae apart from the 2 setae on inner margin; antennae thin and long, extending almost to apices of elytra, scape as long as pedicel. Prothorax slightly tumid at sides and visible from above; prothorax longer than wide, slightly shorter than head excluding mandibles, widest at about basal 1/3; pronotum subquadrate, evidently longer than wide, wider than head, slightly narrower than prothorax; 2 pairs of latero-marginal setae present, both front and hind angles broadly obtuse. Elytra stout, but longer than fore body including mandibles, slightly expanded at sides, widest a little before middle, strongly convex, partly concealed marginal gutter in middle; humeral angles widely rounded, lateral margins smooth, not ciliate, apices almost rounded; elytral striae obliterated though still traceable; 2 dorsal pores present on the 3rd stria, the preapical dorsal pores present; apical striole invisible; humeral group (the 1st–4th pores) of marginal umbilicate series not aggregated, 2nd, 3rd and 8th pores close to the marginal gutter, 1st pore inwardly and backwardly shifted, 4th pore widely isolated; median group (the 5th and 6th pores) backwardly shifted, close from each other. Protarsomeres not modified in male; the 1st tarsomere much shorter than 2nd to 4th tarsomeres combined in fore legs, whereas as long in middle and hind legs. Ventrite VII with 2 pairs of apical setae in male. Male genitalia short and thick, moderately sclerotized.
The position of this new genus within the tribe Trechini remains unclear. However, Qianlongius gen. nov. is, on the first sight, more or less similar in body shape and colouration to Guizhaphaenopsodes Tian & X. Huang, 2020 (from Tangle Dong cave in Jishou, western Hunan), but these genera belong to different lineages on account of the following differences in important charateristics. First of all, Qianlongius is more aphaenopsian than Guizhaphaenopsodes due to its thinner body with a more elongated head, distinctly reduced frontal furrows, propleura tumid and visible from above, and thinner antennae reaching the elytral apices. Second, the right mandibular tooth is tridentate, and mentum and submentum are not fused in Qianlongius, versus bidentate right mandibular tooth, and completely fused mentum and submentum in Guizhaphaenopsodes. Third, the male protarsi of Qianlongius are simple, while the first protarsomere is modified in Guizhaphaenopsodes. Fourth, ventrite VII is 4-setose in the male of Qianlongius, instead of bisetose in Guizhaphaenopsodes. And fifth, the male genitalia are quite large and moderately elongated in Qianlongius, while small and very short in Guizhaphaenopsodes.
Refering to Qianlong Dong cave, locality of the type species Qianlongius zhoui sp. nov. Gender masculine.
China (Guizhou). Known only from cave Qianlong Dong (Fig.
Holotype male, cave Qianlong Dong, Qianlong, Wuluo, Songtao, Tongren, Guizhou Province, 28.16° N, 108.84°E, 908 m, 2021-IV-2, leg. Yi Zhao, Xinyang Jia and Mingyi Tian, in SCAU. Paratype: 1 male, ibid.
A medium-sized, semi-aphaenopsian species, with a rather stout body though both head and pronotum longer than wide, head and pronotum dark brown, elytra reddish-brown, fore body including mandibles slightly shorter than elytra, antennae extending to apices of elytra, propleura visible from above.
Length: 6.5–7.0 mm, width: 2.0–2.1 mm. Habitus as in Figure
Head moderately elongate, longer than wide, HLm/HW = 2.0–2.4, HLl/HW = 1.5–1.7; nearly parallel-sided, widest at about middle of head excluding mandibles; frons and vertex convex; frontal furrows wide and incomplete, more or less parallel-sided, but slightly and shortly convergent backwards, ending about middle of head; anterior and posterior supraorbital pores located at about 4/7 and ¼ of head from labrum to neck; clypeus 6-setose, labrum transverse, faintly bisinuate in the front margin, 6-setose; mandibles developed and moderately curved at apices; mentum tooth short but sharp at apex, bifid at tip, slightly shorter than the lateral lobes; ligula fused with paraglossae, 8-setose; palps thin and slender, the 2nd labial palpomere about 1.2 times as long as 3rd; 3rd maxillary palpomere 1.1times as long as 4th; suborbital pores absent (Fig.
Legs moderately long and densely pubescent; fore tibiae longitudinally grooved externally, whereas middle and hind tibiae simple.
Ventrites IV–VI each with a pair of paramedial setae. Ventrite VII with 2 setae in male.
Male genitalia (Fig.
Female. unknown.
In honour of Mr Wenlong Zhou, an active speleologist (Guizhou Institute of Mountainous Region Resources, Guiyang) to thank him for supporting our survey in Qianlong Dong.
China (Hunan). Known only from limestone cave Qianlong Dong (Fig.
Qianlong Dong is a show cave located at Qianlong village, Wuluo Zhen, Songtao Miao Autonomous County, northeastern Guizhou. This beautiful cave is 1481 m long and with many wonderful speleothems (
First of all, we thank Prof. Yuanhai Zhang (Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin) and Ms Lin Duo (Head of the Administrative Committee of Wulong World Natural Heritage, Wulong) for their kind invitation to survey in Wulong. Our deep appreciations also extend to Mr Lixin Chen, “Wu Ya”, “Ye Gong”, “Ye Po”, and “La Pi” (Qilinger Cave Exploration Team, Nanning) and Ms Jia Liu (Chongqing Cave Exploration Team) for their assistance during our survey in Wulong, to Mr Tongwang Yang (Manager of Qianlong Dong Scenic Spot) for his help during the investigation in Qianlong Dong, and Mr Wenlong Zhou (Guizhou Institute of Mountainous Region Resources, Guizhou Academy of Sciences, Guiyang) for providing the cave map of Qianlong Dong and an important literature. For the identification of other cave animals, we thank the following colleagues: Dr Guchun Zhou (Gannan Normal University, Ganzhou) for spiders, Dr Ziwei Yin (Shanghai Normal University, Shanghai) for ant-loving beetles, and Dr Weixin Liu (South China Agricultural University, Guangzhou) for millipedes. In particular, we thank Dr Arnaud Faille (Stuttgart State Museum of Natural History, Stuttgart) and Dr Igor A. Belousov (All-Russian Institute of Plant Protection, Podbelskogo) for their critical comments and suggestions which helped us improve the manuscript. This study was sponsored by a project of the National Foundation of Natural Science of China (grant number 41871039).