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Issue: Vol. 5671 No. 1: 1 Aug. 2025
Type: Monograph
Published: 2025-08-01
DOI: 10.11646/zootaxa.5671.1.1
Page range: 1-74
Abstract views: 295
PDF downloaded: 21

Taxonomic Revision and Phylogeny of the Genus Peltocercyon d'Orchymont, 1925 (Coleoptera: Hydrophilidae: Megasternini)

Faculty of Environmental Sciences; Department of Ecology; Czech University of Life Sciences Prague; Czech Republic.; Life Sciences School; Sun Yat-sen University; Guangzhou; 510275; Guangdong; China.
Life Sciences School; Sun Yat-sen University; Guangzhou; 510275; Guangdong; China.
Baranavichy State University; 21 Voykova str.; Baranavichy; Brest Reg. 225404; Belarus.
Division of Life Sciences (Insects); The Natural History Museum; Cromwell Road; London SW7 5BD; U.K.
Natural History Division; Kitakyushu Museum of Natural History and Human History; 2-4-1 Higashida; Yahatahigashi-ku; Kitakyushu-shi; Fukuoka; 805-0071 Japan.
Department of Biological Sciences; National Sun Yat-sen University; No.70 Lien-hai Rd.; Kaohsiung City 80424.; Department of Entomology; National Museum; Cirkusová 1740; Praha – Horní Počernice; CZ-19300 Czech Republic.
Faculty of Environmental Sciences; Department of Ecology; Czech University of Life Sciences Prague; Czech Republic.
Coleoptera Hydrophilidae Sphaeridiinae Megasternini molecular systematics revision new species new combination new record Asia

Abstract

The Asian-endemic genus Peltocercyon d'Orchymont, 1925 (Coleoptera: Hydrophilidae: Sphaeridiinae: Megasternini) is revised and redefined based on morphological characters and DNA data (five nuclear and three mitochondrial fragments). The metaventrite, with complete femoral lines crossing the arcuate ridges, is confirmed as the best diagnostic character for Peltocercyon in contrast to the morphology of the prosternum and mesoventrite which vary within the genus. DNA data reveal that Peltocercyon contains two separate lineages and that aedeagal morphology is more phylogenetically informative than external characters. A total of 17 species are recognized, of which nine are newly described: Peltocercyon basirugosus sp. nov. (China: Hainan, Yunnan; Laos: Bolikhamsai, Phongsaly Luang Prabang), P. carnarius sp. nov. (Indonesia: West Sumatra; Philippines: Mindanao; Malaysia: Sabah, Sarawak), P. kouwenkaii sp. nov. (China: Xizang), P. latifossus sp. nov. (Indonesia: Sumba), P. maculipennis sp. nov. (China: Taiwan, Sichuan, Chongqing, Guizhou and Guangxi; Laos: Houaphanh; Vietnam: Tam Dao; India: Arunachal Pradesh), P. medogensis sp. nov. (China: Xizang), P. rugosipennis sp. nov. (China: Xizang), P. splendidus sp. nov. (China: Xizang, Yunnan, Sichuan, Shaanxi, Hubei; India: Arunachal Pradesh), P. taylorae sp. nov. (China: Yunnan; Laos: Houaphanh, Phongsaly; India: Arunachal Pradesh). Three species are transferred to Peltocercyon from Cercyon Leach, 1817: Peltocercyon vagus (Sharp, 1884), comb. nov., P. vividus (d'Orchymont, 1925), comb. nov., and P. sanaii (Hoshina, 2008), comb. nov. Peltocercyon coomani d'Orchymont, 1925 is newly recorded from China, Laos, Thailand and Malaysia, P. lunulatus (Gemminger & Harold, 1868) from China, Laos, Malaysia, Cambodia and Myanmar, and P. vividus for Malaysia, Thailand and Indonesia. The closely related species P. maculipennis sp. nov., P. medogensis sp. nov., P. splendidus sp. nov. and P. taylorae sp. nov. are treated as the P. splendidus group. The Japanese and Far East species P. vagus (Sharp, 1884), P. subopacipennis (Nakane, 1965), P. sanaii (Hoshina, 2008), P. shigehisai Hoshina, 2018 and P. ohoni Hoshina, 2021 are treated as the P. vagus group, both groups being based on elytral sculpture, aedeagal morphology and distribution. Members of the P. vagus group are not treated taxonomically in detail due to limited material available. Diagnostic characters of all species and species groups are illustrated by photographs and SEM micrographs and an identification key and distribution maps of all species are provided. All known Peltocercyon inhabit decaying organic material; we provide the first hypothesis on the evolution of their habitat preferences.

 

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How to Cite

Mai, Z., Jia, F., Ryndevich, S.K., Angus, R., Minoshima, Y.N., Fikáček, M. & Růžička, J. (2025) Taxonomic Revision and Phylogeny of the Genus Peltocercyon d’Orchymont, 1925 (Coleoptera: Hydrophilidae: Megasternini). Zootaxa, 5671 (1), 1–74. https://doi.org/10.11646/zootaxa.5671.1.1