Peltocercyon kouwenkaii Mai, Jia, Ryndevich

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 : 24-27

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-FF95-6B36-FF2C-2394B581EA8C
treatment provided by	Plazi
scientific name	Peltocercyon kouwenkaii Mai, Jia, Ryndevich
status	sp. nov.

Treatment

Peltocercyon kouwenkaii Mai, Jia, Ryndevich , Angus & Fikáček sp. nov.

Figs 3B, D, E View FIGURE 3 , 4A, B View FIGURE 4 , 11A–G View FIGURE 11 , 12A–F View FIGURE 12 .

Type material examined. Holotype: 1 male ( SYSU), “ China: Xizang, Nyingchi City (= Linzhi ), Medog County / Forest behind the Renqingbeng Temple (仁ª崩*后Ɯ) / 2104 m / 29.3086°N, 95.3471°E / 18.VI.2023 / Zuqi Mai & Wenkai Kou leg. // Primary forest , flight intercept trap with rotten jackfruits, bamboo shoots and human dung around // DNA isolate: DNA extraction: MZ22” GoogleMaps Paratypes: 2 females ( SYSU) , 2 males, 1 female ( NMP) , male ( SYSU), “ Xizang, Nyingchi City (= Linzhi ), Medog County / Forest behind the Renqingbeng Temple (仁ª崩*后 Ɯ) / 2104 m / 29.3086°N, 95.3471°E / 18.VI.2023 / Zuqi Mai & Wenkai Kou leg. // Primary forest , flight intercept trap with rotten jackfruits, bamboo shoots and human shit around” GoogleMaps ; 1 female ( IZCAS) , “ Xizang, Motuo County, Beibeng Village, Jiangxin Road , in a triangular pool / 13.VII.2019 / D2 / 750 m // 29.24045°N 95.17053°E / Hong- Bin Liang & Yuan Xu leg. // IOZ(E)22446086” GoogleMaps

DNA voucher. MZ22: Holotype.

Diagnosis. Length 2.8–3.2 mm. Head and pronotum reddish brown, darker in the middle; dark reddish brown on the disc, light yellow brown on humeral angles and in the posterior third, ( Fig. 11A View FIGURE 11 ). Punctation on pronotum consisting of two sizes of punctures, the finer punctures crescent-shaped, the coarser punctures rounded ( Fig. 12A View FIGURE 12 ). Elytra shiny, spaces between ground punctation smooth ( Figs 4A, B View FIGURE 4 , 12B View FIGURE 12 ). Mentum with transverse microsculpture and coarse punctures ( Fig. 12C View FIGURE 12 ). Posterior tentorial pits slightly concave, not distinctly depressed ( Fig. 12C View FIGURE 12 ). Prosternum tectiform medially; middle portion of prosternum rugulose; lateral portion without ridge, shagreened; prosternal process deeply notched posteriorly ( Fig. 12D View FIGURE 12 ). Antennal grooves narrow ( Fig. 12D View FIGURE 12 ). Mesoventral plate spindle-shaped ( Fig. 12E View FIGURE 12 ). Arcuate ridge of metaventrite strongly bent backwards and distinct; lateral area of metaventrite without coarse punctures ( Fig. 12E View FIGURE 12 ). First abdominal ventrite with short longitudinal sculptures basally ( Fig. 12F View FIGURE 12 ). Male genitalia ( Fig. 11D–G View FIGURE 11 ): Paramere distinctly expanded and obliquely truncate apically; inner face of paramere without fringe of setae ( Fig. 11F View FIGURE 11 ). Median lobe widest in basal third and bluntly pointed apically ( Fig. 11E View FIGURE 11 ).

Description. Form and Colour ( Fig. 11A–C View FIGURE 11 ). Total length 2.8–3.2 mm; maximum width 1.6–1.7 mm. Body broadly oval, not parallel-sided in the middle, moderately convex. Dorsum shiny, head and pronotum reddish brown, paler laterally; elytra dark reddish brown on the disc, light yellow brown on humeral angles and in posterior third. Maxillary and labial palpi yellowish brown; antennae yellowish brown with club darker. Ventral surface yellowish brown to dark reddish black; hypomeron and epipleuron yellowish brown, meso- and metaventrite dark reddish black. Legs yellowish brown.

Head. Dorsal surface with uniform dense and coarse crescent-shaped punctures; interstices between punctures smooth. Anterior margin of clypeus with a marginal bead. Eyes of moderate size, separated by ca. 5× the width of one eye. Mentum subtrapezoid, ca. 1.7× as wide as long, slightly depressed anteromedially; anterior margin of mentum slightly concave; with transverse microsculpture and coarse punctures ( Fig. 12C View FIGURE 12 ). Posterior tentorial pits without distinct depressions ( Fig. 12C View FIGURE 12 ). Antennae with 9 antennomeres; antennal club (antennomeres 7–9) compact and densely pubescent. Maxillary palpomere 2 strongly swollen in apical half, longer than palpomere 3; palpomere 4 almost symmetrical, slightly longer than palpomere 3. Each maxilla with a sucking-disc shaped appendage in male.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad; punctation on pronotum consisting of two sizes of punctures, the finer punctures crescent-shape, the coarser punctures rounded ( Fig. 12A View FIGURE 12 ). Lateral margins of pronotum narrowly rimmed, the rim overlapping anterior and posterior corners, anterior and almost all of posterior margin without rim. Prosternum gradually raised at middle portion and tectiform medially, with sharp median carina; middle portion of prosternum rugulose; lateral portion of prosternum without ridge; depressed lateral portion of prosternum shagreened; prosternal process deeply notched posteriorly ( Fig. 12D View FIGURE 12 ). Antennal groove narrow, outer lateral margin moderately convex ( Fig. 12D View FIGURE 12 ). Mesoventral plate spindle-shaped and elongate, surface slightly convex and shining; ca. 5× as long as wide, posterior apex overlapping the anterior ridge of metaventrite in a single point ( Fig. 12E View FIGURE 12 ). Scutellar shield triangular, longer than wide, with punctures finer than those on pronotum. Elytra widest at anterior third; each elytron with 10 rows of punctate striae, striae moderately impressed; striae 6, 8 and 9 not reaching anterior margin of elytron; stria 10 short, only ending at posterior third of elytron; intervals of striae flat, with fine punctures, intervals between punctures smooth. Epipleuron wedge-shaped and strongly oblique at anterior half of elytron. Central area of metaventrite uniformly punctate and bare, lateral areas of metaventrite densely pubescent, without coarse punctures; anterior ridge of metaventrite strongly bent backwards at anterolateral corner and forming an arcuate ridge; metaventrite with complete femoral lines crossing the anterolateral arcuate ridges and reaching anterolateral corners of metaventrite ( Fig. 12E View FIGURE 12 ). Anterior ridge of metaventrite continuous with the arcuate ridge at the crossing point of femoral line ( Fig. 12E View FIGURE 12 ).

Legs. Profemora bare ventrally, with very fine punctures; mesofemora with coarser setiferous punctures than those on metafemora. Tibiae with small lateral spines. Tarsi with sparse gold ventral setae, first metatarsomere about as long as metatarsomeres 2–3 combined.

Abdomen. Abdominal ventrites densely pubescent. First ventrite sharply carinate medially, with a series of very short longitudinal sculptures basally ( Fig. 12F View FIGURE 12 ).

Male genitalia. Paramere widest basally, slightly narrowed medially; distinct expanded and obliquely truncate apically; inner face of paramere without fringe of setae ( Fig. 11D, F View FIGURE 11 ). Phallobase much shorter than parameres; nearly parallel sided, manubrium gradually narrowed and asymmetrical at the base ( Fig. 11D, F View FIGURE 11 ). Median lobe widest in basal third, bluntly pointed apically; gonopore triangular, situated subapically ( Fig. 11E View FIGURE 11 ). Median projection of sternite 9 gradually narrowed anteriad; lateral struts slightly longer than median portion ( Fig. 11G View FIGURE 11 ).

Biology. ( Fig. 38A, B View FIGURE 38 ) Inhabits forests above 1000 m a.s.l. We found living specimens in rotting bamboo shoots and jackfruits.

Etymology. This species is named after Mr. Wen-kai Kou, one of the collectors of type specimens.

Remarks. This new species is similar to P. vividus and P. rugosipennis sp. nov. It can be distinguished from P. vividus by elytra paler on humeral angles and in the posterior third ( Fig. 11A View FIGURE 11 ) (dorsum uniformly reddish brown in P. vividus , Fig. 19A View FIGURE 19 ), and pubescent lateral area of metaventrite without coarse punctures ( Fig. 12E View FIGURE 12 ) (with coarse punctures in P. vividus , Fig. 20C View FIGURE 20 ). It can be distinguished from P. rugosipennis sp. nov. by shiny elytra (Figs A, B) (elytra with very dense and tiny dots between ground punctures and hence dull in P. rugosipennis sp. nov., Figs A, B), and the arcuate ridge of the metaventrite strongly bent backwards and distinct laterally (Fig. D) (almost transverse at the anterolateral corner of metaventrite and less distinct laterally in P. rugospennis sp. nov., Fig. 19D View FIGURE 19 ).