Peltocercyon basirugosus 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 : 13-16

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-FF8E-6B23-FF2C-23C4B202EBC8
treatment provided by	Plazi
scientific name	Peltocercyon basirugosus Mai, Jia, Ryndevich
status	sp. nov.

Treatment

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

Figs 5A–G View FIGURE 5 , 6A–E View FIGURE 6 , 40A–D View FIGURE 40 .

Type material examined. Holotype: male ( SYSU), “ Yunnan , Dehong Dai and Jingpo Autonomous Prefecture , Longchuan County, Husa village , Banggunjianshan Mt. / in rotten bamboo shoots / 24.3619°N 97.8316°E / 1387 m / 12–15.VIII.2022 / Yu-Chen Zheng, Yue-Zheng Tu & Zu-Qi Mai leg.” GoogleMaps Paratypes: CHINA: Yunnan: 1 male ( SYSU) , 1 male ( NMP), same data as the holotype GoogleMaps ; 1 male ( SYSU), “ Yunnan, Dehong Dai and Jingpo Autonomous Prefecture, Tongbiguan , Xima Town , Hulukou , Xingyun Secondary power station (AE云二ãDzü) / in rotten bamboo shoots / 24.7759°N 97.6582°E / 1021 m / 18–20.VIII.2022 / Yu-Chen Zheng, Yue-Zheng Tu & Zu-Qi Mai leg.” GoogleMaps ; 1 female ( SYSU), “ Yunnan, Luchun County, Sanmeng Village, Huanglianshan Nature Reserve / in rotten banana trunk / 22.8952°N 102.3045°E / 1898 m / 28.VII.2022 / Zu-Qi Mai leg.” GoogleMaps ; 21 spec. ( SYSU), “ Yunnan Prov., Baoshan City, Baihualing / 25°10′N 98°16′E / 1516 m / 18.IV.2015 / Renchao Lin & Yudan Tang leg. // PARATYPE // Peltocercyon basirugosus sp. nov. Det. Fenglong Jia ” GoogleMaps ; 2 spec. ( SYSU), “ Manfei / Nabanhe Conv. / Yunnan Prov. / 10.Ⅰ.2004 / Li & Tang leg.” Hainan: 12 spec. ( SYSU, NMP), “ Hainan, Baisha County, Hongkan Waterfall Scenic / in rotten banana trunk / 435 m / 19.0985°N 109.5170°E / 435 m / 3.Ⅴ.2022 / Zhuo-Yin Jiang leg.” GoogleMaps 1 female ( SHNU), “ Hainan Prov. / Lingshui County / Diaoluoshan Mt. / Winding Road / 18°42′N, 109°52′E // alt. 600–1000 m / 26.IV.2012 / PENG & DAI leg.” GoogleMaps 1 male ( SYSU), “ Hainan, Bawangling East fifth district / 8.Ⅴ.2011 / Shuang Zhao leg.” 1 female ( SYSU), “ Hainan, Wuzhishan City, Shuimanxiang Town, Wuzhishan Nature Reserve / in rotten banana trunk / 788 m / 18.9061°N 109.6827°E / 8.II.2023 / Zu-Qi Mai leg.” GoogleMaps . LAOS: 4 spec. ( NHMB) , 1 spec. ( NMP), “LAOS, 1–18.Ⅴ.2001. / Bolikhamsai prov. / 18°21’N 105°08’E / Ban Nape (8 km NE), 600 m, Vit. KubÁň leg.” GoogleMaps ; 1 female ( NHMB), “LAO, Phongsaly Prov., 21°41–2’N 102°06–8’E / 28.Ⅴ–20.VI.2003. / PHONGSALY env., / 1500 m, Vit. KubÁň leg.” ; 1 spec. ( NHMB), “LAOS-N (Louangphrabang), 11–21.Ⅴ.2002 / 19°35’N 101°58’E / THONG KHAN, 750 m, Vit. KubÁň leg.” GoogleMaps

DNA voucher. MZ108: 1 male ( SYSU) “ Yunnan, Dehong Dai and Jingpo Autonomous Prefecture , Longchuan County, Husa village , Banggunjianshan Mt. / in rotten bamboo shoots / 24.3619°N 97.8316°E / 1387 m / 12– 15.VIII.2022 / Yu-Chen Zheng, Yue-Zheng Tu & Zu-Qi Mai leg. // DNA extraction: MZ108” GoogleMaps

Diagnosis. Length 2.9–3.4 mm. Head and pronotum dark reddish brown; elytra dark reddish brown to black ( Fig. 5A View FIGURE 5 ). Pronotum with uniform crescent-shaped punctures. Elytra shiny, spaces between ground punctation smooth. Mentum with dense microsculptures and coarse punctures ( Fig. 6A View FIGURE 6 ). Posterior tentorial pits small, not distinctly impressed ( Fig. 6A View FIGURE 6 ). Prosternum tectiform medially; middle portion of prosternum rugulose; lateral portion without ridge, depressed lateral portions smooth; prosternal process deeply notched posteriorly ( Fig. 6B View FIGURE 6 ). Antennal grooves of moderate size ( Fig. 6B View FIGURE 6 ). Mesoventral plate spindle-shaped ( Fig. 6C View FIGURE 6 ). Arcuate ridge of metaventrite strongly bent backwards and distinct ( Fig. 6D View FIGURE 6 ). Lateral areas of metaventrite with scattered coarse punctures ( Fig. 6D View FIGURE 6 ). First abdominal ventrite with longitudinal sculptures basally ( Fig. 6E View FIGURE 6 ). Male genitalia ( Fig. 5D–G View FIGURE 5 ): Paramere distinctly expanded and obliquely truncate apically; inner face of paramere without fringe of setae ( Fig. 5D, F View FIGURE 5 ). Median lobe widest in basal third, bluntly pointed apically ( Fig. 5E View FIGURE 5 ).

Description. Form and Colour ( Fig. 5A–C View FIGURE 5 ). Total length 2.9–3.4 mm; maximum width 1.7–2.1 mm. Body broadly oval, not parallel-sided in the middle, moderately convex. Dorsum shiny, head and pronotum dark reddish brown; elytra reddish brown to black. Maxillary palpi and labial palpi yellowish brown; antennae yellowish brown with club darker. Ventral surface dark reddish black, legs dark reddish 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 moderately large, separated by ca. 5× the width of one eye. Mentum subtrapezoid, ca. 2.0× as wide as long, slightly depressed anteromedially; anterior margin of mentum slightly concave; with dense transverse microsculpture and coarse punctures ( Fig. 6A View FIGURE 6 ). Posterior tentorial pits small, not depressed ( Fig. 6A View FIGURE 6 ). 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, with finer and sparser crescent-shaped punctures than those on head. 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 smooth; prosternal process deeply notched posteriorly ( Fig. 6B View FIGURE 6 ). Antennal groove of moderate size, outer lateral margin moderately convex ( Fig. 6B View FIGURE 6 ). Mesoventral plate spindle-shaped and elongate, surface slightly convex and shining; ca. 4× as long as wide, posterior apex overlapping the anterior ridge of metaventrite in a single point ( Fig. 6C View FIGURE 6 ). 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 ground 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, and with scattered 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. 6D View FIGURE 6 ). Anterior ridge of metaventrite discontinuous with the arcuate ridge at the crossing point of femoral line ( Fig. 6D View FIGURE 6 ).

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 short longitudinal sculptures basally ( Fig. 6E View FIGURE 6 ), more rough than other ventrites.

Male genitalia. Paramere widest basally, slightly narrowed medially; distinctly expanded inwards and obliquely truncate apically; inner face of paramere without fringe of setae ( Fig. 5 D, F View FIGURE 5 ). Phallobase much shorter than parameres; nearly parallel sided, manubrium gradually narrowed and asymmetrical at the base ( Fig. 5D, F View FIGURE 5 ). Median lobe widest in basal third, bluntly poined apically; gonopore triangular, situated subapically ( Fig. 5E View FIGURE 5 ). Median projection of sternite 9 gradually narrowed anteriad; lateral struts slightly longer than median portion ( Fig. 5G View FIGURE 5 ).

Biology ( Fig. 40A–D View FIGURE 40 ). Occurs in forests. Adults live inside rotten banana trunks, sometimes attracted by decaying bamboo shoots in forest.

Etymology. The specific name is derived from Latin basalis (= basal) and rugosus (= rugged), referring to the first abdominal ventrite that is coarsely ridged basally.

Remarks. This new species is similar to Peltocercyon vividus and P. kouwenkaii sp. nov. in form and colour. It can be distinguished from P. vividus by the smooth depressed lateral portions of prosternum ( Fig. 6B View FIGURE 6 ) (with shagreen in P. vividus , Fig. 20B View FIGURE 20 ), paramere distinctly expanded apically ( Fig. 5D View FIGURE 5 ) (slightly expanded apically in P. vividus , Fig. 19D View FIGURE 19 ). It can be distinguished from P. kouwenkaii by the punctation of the pronotum consisting of punctures of single size (consisting of two sizes of punctures in P. kouwenkaii , Fig. 12A View FIGURE 12 ), and lateral area of metaventrite with scattered coarse punctures ( Fig. 6D View FIGURE 6 ) (without distinct coarse punctures in P. kouwenkaii , Fig. 12E View FIGURE 12 ).