Grouvellinus loong, Grouvellinus buyi, Grouvellinus wangmoensis, Grouvellinus lihaitaoi and Grouvellinus muyinlini are new riffle beetles
NEWS - Loong riffle beetle (Grouvellinus loong sp. nov.), Chinese riffle beetle (Grouvellinus buyi sp. nov.), Wangmo riffle beetle (Grouvellinus wangmoensis sp. nov.), Hai-Tao Li riffle beetle (Grouvellinus lihaitaoi sp. nov.), Yin-Lin Mu riffle beetle (Grouvellinus muyinlini sp. nov.) from China live in small ravine streams where submerged rocks live.
Grouvellinus Champion 1923 is widely distributed in the Eastern and Palearctic regions including 60 species with 28 species recorded from mainland China and only one species in Guizhou Province (Grouvellinus huaxiensis Jiang, Huang & Chen 2023) found in the urban river of Guiyang City.
Researchers conducted a survey of aquatic beetles in Guizhou Province in 2021 and collected more than 5000 specimens of riffle beetles, many of which belong to Grouvellinus. Now they report 5 new species.
G. loong is placed in the Grouvellinus acutus group based on small body; elytra with yellowish brown markings; pronotum without longitudinal impression; elytra surface with granular carinae at strial intervals III, V, VII, and VIII; ventrite I with a pair of well-developed admedian carinae.
The G. acutus species group includes three known species, all of which occur in China. Members of this group have similar habitus. G. loong can easily distinguished from other members of the group by the distinctly different shape of the aedeagus: strongly tapered in the middle (vs. none as above).
G. loong most closely resembles Grouvellinus acutus Bian & Jäch 2018 in habitus. However, the prosternal process has a slightly curved apex, ungranulated surface, densely covered with large punctures (vs. prosternal process with a broadly rounded apex, sparsely granulated surface in G. acutus); the metatibia is distinctly tapered near the apex, without a hook-shaped appendix at the apex (vs. metatibial apex broad and sclerotized, usually with a hook-shaped appendix); the parameres of the aedeagus are strongly tapered in the basal 1/3 (vs. only slightly tapered near the base).
G. buyi is similar to Grouvellinus sinensis Grouvelle 1906 and Grouvellinus ligulaceus Bian & Zhang 2023 in habitus. However, it can be distinguished by very large strial elytra puncture at basal 1/2 (vs. much smaller in G. ligulaceus); prosternal process with straight apex (vs. somewhat rounded); median lobe of aedeagus slender (vs. much broader); parameres of aedeagus distinctly curved at apex (vs. not as above).
The new species can be distinguished from G. sinensis by having a body with metallic sheen and shiny metaventrite and abdominal ventrite surfaces (vs. body lacking metallic sheen and distinctly rough metaventrite and abdominal ventrite surfaces in G. sinensis).
G. wangmoensis is similar to Grouvellinus pilosus Jeng & Yang 1998, G. huaxiensis Jiang, Huang & Chen 2023, G. muyinlini and G. lihaitaoi in habitus. However, the base of the pronotum has a pair of central rounded foveae (vs. a pair of elongated oval impressions in G. pilosus), a granular carina present at the VIII strial elytron interval (vs. a granular carina present at the VII strial elytron interval).
The new species can be distinguished from the three other species mentioned above by the very short sublateral carinae of the pronotum, not in contact with the oblique impression, and by the thin and slender aedeagus parameres.
G. lihaitaoi is most similar to G. muyinlini. However, the pronotum is widest at the base (vs. widest near the middle of G. muyinlini); the median sulcus of the metaventrite is short, ~1/2 the length of the metaventrite (vs. much longer, ~3/4 the length of the metaventrite); the aedeagus parameres are much wider, apex almost straight (vs. much narrower, apex curved).
G. muyinlini is most similar to G. lihaitaoi.
Original research
Jiang R-X, Wu P-L, Chen X-S (2024). Five new species of the genus Grouvellinus Champion, 1923 from Guizhou Province, China (Coleoptera, Elmidae). ZooKeys 1219: 73-97, DOI:10.3897/zookeys.1219.125754
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