Peltocercyon d'Orchymont, 1925

Mai, Zuqi, Jia, Fenglong, Ryndevich, Sergey K., Angus, Robert, Minoshima, Yûsuke N., Fikáček, Martin & Růžička, Jan, 2025, Taxonomic Revision and Phylogeny of the Genus Peltocercyon d'Orchymont, 1925 (Coleoptera: Hydrophilidae: Megasternini), Zootaxa 5671 (1), pp. 1-74 : 8-10

publication ID	https://doi.org/10.11646/zootaxa.5671.1.1
publication LSID	lsid:zoobank.org:pub:60D33D8C-BDC2-4C2A-B840-90014815E8CB
persistent identifier	https://treatment.plazi.org/id/1032930E-FF85-6B25-FF2C-24CBB47DE9D7
treatment provided by	Plazi
scientific name	Peltocercyon d'Orchymont, 1925
status

Treatment

Peltocercyon d'Orchymont, 1925 View in CoL

Peltocercyon d'Orchymont, 1925: 284 View in CoL . Type species: Peltocercyon coomani d'Orchymont. View in CoL

Diagnosis ( Figs 2 View FIGURE 2 , 3 View FIGURE 3 ). Body broadly oval, moderately convex, its outline not interrupted between pronotum and elytra. Antenna with 9 antennomeres, antennal bases not concealed by lateral parts of clypeus, club (antennomeres 7–9) compact. Elytra with 10 punctate striae, intervals flat or slightly convex in posterior half. Mentum (M) subtrapezoidal, anterior margin slightly concave medially. Posterior tentorial pits (PTP) of head simple or forming two large depressions. Prosternum (PR) tectiform or slightly bulging at middle portion, with sharp median carina; lateral portion of prosternum with ridge (R) ( Fig. 2B, C View FIGURE 2 ) or without it (most species; Fig. 2A View FIGURE 2 ); prosternal process (PP) notched ( Fig. 2B View FIGURE 2 ) or pointed posteriorly ( Fig. 2C View FIGURE 2 ). Antennal groove (AG) distinct with outer margin convex, not reaching lateral margin of prothorax. Mesoventral plate (MP) spindle-shaped, posterior apex overlapping the anterior ridge of metaventrite in a single point (most species) ( Fig. 2A, C View FIGURE 2 ) or subtriangular and widely contacting the anterior margin of metaventrite ( P. coomani ) ( Fig. 2B View FIGURE 2 ). Metaventrite densely pubescent except for the raised central area (CAM); anterior ridge of metaventrite (ARM) bent backwards at anterolateral corner and forming an arcuate ridge (AR); metaventrite with complete femoral lines (FL) crossing the arcuate ridges and reaching anterolateral corners of metaventrite. Epipleuron wedge-shaped and oblique at anterior half of elytron. First abdominal ventrite (FAV) sharply carinate medially. Male with a sucking-disc shaped appendage on maxilla. Male genitalia ( Fig. 3 View FIGURE 3 ) of typical form for subtribe Megasternina , with median lobe (MeL) of the aedeagus reaching deeply into phallobase; median lobe shorter than tegmen (Teg). Gonopore (Gop) triangular, located slightly below the apex of medial lobe. Phallobase (Phb) shorter than paramere (Prm). Paramere in two forms: (1) paramere expanded and broad apically, with a rounded or truncated apex; inner face of the paramere without fringe of setae ( Fig. 3B View FIGURE 3 ); (2) paramere slightly widened subapically and then gradually narrowing towards apex, with a bluntly pointed apex; inner face of the paramere with a fringe of long setae subapically ( Fig. 3A, C View FIGURE 3 ). Abdominal sternite 9 has a median portion (MeP) developed as a tongue-like projection ( Fig. 3E View FIGURE 3 ).

Biology ( Figs 36–40 View FIGURE 36 View FIGURE 37 View FIGURE 38 View FIGURE 39 View FIGURE 40 ). Occur in decaying plant material, or in faeces of large herbivorous mammals. Adults can be attracted to light, or to traps baited with excrement or carrion.

Distribution ( Figs 41–45 View FIGURE 41 View FIGURE 42 View FIGURE 43 View FIGURE 44 View FIGURE 45 ). The genus is distributed in the southeastern part of Asia, ranging from Sri Lanka eastward across Southeast Asia, southern and central China, Japan, extending north to the Russian Far East and south to Sumba Island in Indonesia. Oriental Region: China (Guangdong, Guangxi, Guizhou, Taiwan, Yunnan, southern part of Xizang), Cambodia, Indonesia (East Kalimantan, Sumatra, Sulawesi, Sumba), Vietnam, Singapore, Sri Lanka, India (northeast India), Laos, Malaysia (Sabah, Sarawak, Selangor, Langkawi), Myanmar, Nepal, Thailand, Philippines (Mindanao). Palearctic Region: China (Shaanxi, Hubei, Sichuan), Japan, Russia (Far East), South Korea.

A check list of the species of genus Peltocercyon

Based on morphology, we define two species groups ( P. splendidus group and P. vagus group) that undoubtedly consist of closely related species. The monophyly of the P. splendidus group was confirmed by our DNA analyses. Additional DNA data are needed to properly understand the relationships of the remaining species, hence we leave the remaining species without species group assignment for the moment.

Species not assigned to a species group:

Peltocercyon basirugosus sp. nov. China (Hainan, Yunnan) , Laos (Bolikhamsai, Phongsaly, Luang Prabang) .

Peltocercyon carnarius sp. nov. Indonesia (West Sumatra, East Kalimantan), Philippines (Mindanao), Malaysia (Sabah, Sarawak).

Peltocercyon coomani d'Orchymont, 1925 View in CoL . China (Hainan,Yunnan), Indonesia (West Sumatra), Laos (Khammouane, Xiangkhouang, Luang Prabang, Bolikhamsai, Houaphanh), Vietnam (Hoa Binh), Thailand (Mae Hong Son, Surat Thani), Malaysia (Selangor, Sarawak), Indonesia (West Sumatra).