Peltocercyon taylorae 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 : 50-54

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

Figs 27A–G , 28A–E , 37A–E .

Type material examined. Holotype: male ( SYSU), “ China , Yunnan , Honghe Autonomous Prefecture , Luchun County, Sanmeng Village , Huanglianshan Nature Reserve / in fresh cow dung / 22.8966°N 102.3044°E / 1867 m / 29.VII.2022 / Zu-Qi Mai leg.” Paratypes: CHINA: Yunnan: 49 spec. ( SYSU), same data as the holotype ; 1 spec. ( SYSU), “ China, Yunnan, Honghe Autonomous Prefecture , Luchun County, Sanmeng Village , Huanglianshan Nature Reserve / light trap / 22.8953°N 102.3045°E / 1962 m / 31.VII.2022 / Zu-Qi Mai leg.” . LAOS: 1 male, 1 female ( NMP), “LAOS-NE, Houa Phan prov. / 20°13′09–19″N 103°59′54″– 104°00′03″E / 1480–1520 m / PHOU PANE Mt., 2–22.VI.2011, Vit. KubÁň leg. // Primary mountain forest / flight intercept trap. / Laos 2011 Expedition / National Museum Prague, Czech Republic // PELTOCERCYON sp. / det. M. FikÁček ” ; 3 spec. ( NMP), “Laos-NE, Houa Phan prov. / 20°12–13.5’N, 103°59.5’–104°.01’E / Ban Saluei → Phou Pane Mt. , 1340–1870 m, 22.IV–15.Ⅴ.2008, Vit. KubÁň & Lao coll. leg. // Primary mountain forest, intercept trap. / Laos 2008 Expedition National Museum Prague, Czech Republic” 101 spec. ( NMP), “LAOS-NE, Houa Phan Prov., 20°13’09–19’’N 103°59’54’’ – 104°00’03’’E, 1480–1510 m, PHOU PANE Mt., 2–22.VI.2011, Vit. KubÁň leg. // Primary mountain forest, flight intercept trap. / Laos 2011 Expedition / National Museum Prague, / Czech Republic.” 6 spec. ( NHMB), “LAOS-NE, Houa Phan Prov., 20°13’09–19’’N 103°59’54’’ – 104°00’03’’E, 1480–1510 m, PHOU PANE Mt. , 22.IV–14.Ⅴ.2008, Vit. KubÁň leg.” 25 spec. ( NHMB), “LAOS, Phongsaly Prov., 21°41–2’N 102°06–8’E / 28.Ⅴ. –20.VI.2003, PHONGSALY env., / 1500 m, Vit. KubÁň leg.” 20 spec. ( NHMB), “LAOS, Phongsaly Prov., PHONGSALY env., / 6–17.Ⅴ.2004, 1500 m, / 21°41’N 102°06–8’E / Vit. KubÁň leg.” . INDIA: 1 spec. ( NMP), “NE INDIA, ARUNACHAL PR. / ETALIN vicinity, 700 m / 28°36’56’’N 95°53’21’’E / FIT (flight interception trap) / L. Dembický leg., 12–25.Ⅴ.2012 ” ; 63 spec. ( ZFMK), “NE INDIA, ARUNACHAL PR. / ETALIN vicinity. 700 m / 28°36’56’’N 95°53’21’’E / FIT (flight interception trap) / L. Dembický leg. , 12.–25.Ⅴ.2012.

DNA voucher. MF469: 1 spec. ( NMP), “LAOS-NE, Houa Phan Prov., 20°13’09–19’’N 103°59’54’’ – 104°00’03’’E, 1480–1510 m, PHOU PANE Mt., 2–22.VI.2011, Vit. KubÁň leg. // Primary mountain forest, flight intercept trap. / Laos 2011 Expedition / National Museum Prague, / Czech Republic. // DNA isolate: DNA extraction: MF469, DNA extract stored at Department of Entomology , National Museum, Prague ” .

Diagnosis. Length 3.0– 3.7 mm. Head black; pronotum yellowish brown with a narrow longitudinal black median patch widened anteriorly ( Fig. 27A ). Elytron yellowish brown, with a large black triangular patch lateromedially, reaching stria 3 medially. Elytra shiny, spaces between ground punctation smooth. Pronotum with uniform crescent-shape punctures. Mentum with sparse and fine punctures ( Fig. 28A ). Posterior tentorial pits not distinctly depressed ( Fig. 28A ). Prosternum tectiform medially; lateral portion with sparse and fine setae, without ridge; prosternal process finely notched posteriorly ( Fig. 28B ).Antennal grooves moderate in size (Fig. B). Mesoventral plate spindle-shaped ( Fig. 28C ). Arcuate ridge of metaventrite strongly bent backwards and distinct ( Fig. 28D ). Lateral areas of metaventrite without coarse punctures ( Fig. 28D ). First abdominal ventrite without longitudinal sculptures basally. ( Fig. 28E ). Male genitalia ( Fig. 27D–G ): paramere slightly widened subapically and then gradually narrowing towards apex, apex bluntly pointed and straight; inner face of paramere with a fringe of long setae subapically and a few apical setae. ( Fig. 27D ). Median lobe nearly parallel sided, narrowed subapically; apex bluntly pointed ( Fig. 27E ).

Description. Form and Colour ( Fig. 27A–C ). Total length 3.0– 3.7 mm; maximum width 1.9–2.3 mm. Body broadly oval, slightly parallel-sided in the middle, moderately convex.Dorsum shiny.Head black.Pronotum yellowish brown with a longitudinal black patch medially that widened anteriorly and almost paralleled laterally; with two tiny spots on each side of longitudinal black patch basally. Elytron yellowish brown, interval of stria 1 black throughout, interval of striae 1–3 without black patch; elytron with a large black triangular patch lateromedially, reaching stria 3 medially. Maxillary palpi and labial palpi yellowish brown; antennae yellowish brown with club black. Prosternum, mesoventral plate, epipleura and legs yellowish brown, other portion dark yellowish brown to black.

Head. Dorsal surface with uniformly dense and coarse crescent-shape 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. 1.5× as wide as long, slightly depressed anteromedially; anterior margin of mentum slightly concave; with very sparse and fine punctures ( Fig. 28A ). Posterior tentorial pits not distinctly depressed. Antennae with 9 antennomeres; antennal club (antennomeres 7–9) compact and densely pubescent. Maxillary palpomere 2 moderately 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 crescent-shape punctures as 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; prosternum pubescent, without ridge; prosternal process finely notched posteriorly ( Fig. 28B ). Antennal groove in moderate size, outer lateral margin moderately convex ( Fig. 28B ). Mesoventral plate narrowly elongate, surface slightly convex and shining; ca. 7–8× as long as wide, posterior apex overlapping the anterior ridge of metaventrite in a single point ( Fig. 28C ). Scutellar shield in shape of equilateral triangle, longer than wide, with crescent-shape punctures as 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 glabrous. 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 a distinct arcuate ridge; metaventrite with complete femoral lines crossing the arcuate ridges and reaching anterolateral corners of metaventrite; anterior ridge of metaventrite continuous with the arcuate ridge at the crossing point ( Fig. 28D ).

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, without short longitudinal sculptures basally ( Fig. 28E ).

Male genitalia. Paramere widest basally, gradually narrowing towards apical fourth and slightly widen subapically, then gradually narrowing towards apex; apex of paramere bluntly pointed, slightly curved inwards; inner face of paramere with a fringe of long setae subapically and two apical setae ( Fig. 27D, F ). Phallobase slightly shorter than parameres; nearly parallel sided, manubrium gradually narrowed and asymmetrical at the base ( Fig. 27D, F ). Median lobe widest in the middle, parallel-sided, narrowed subapically, apex bluntly pointed ( Fig. 27E ). Median projection of sternite 9 gradually narrowed anteriad and rounded basally; lateral struts slightly longer than median portion ( Fig. 27G ).

Biology ( Fig. 37A–E ). Adults occur in fresh cow excrement in mountain forests, and are sometimes attracted by light at night.

Etymology. The species is named after Christine Taylor, one of the previous curators of aquatic beetles in the Natural History Museum, London.

Remarks. This new species can be distinguished from other species of the Peltocercyon splendidus group by pronotum mostly yellowish brown, with a median narrow black patch widened anteriorly and almost paralleled laterally. It can be distinguished from P. splendidus sp. nov. and P. medogensis sp. nov. by apex of median lobe bluntly pointed (median lobe with an obtuse or rounded apex in P. splendidus sp. nov. and P. medogensis sp. nov.)

Distribution ( Fig. 42 ). China (Yunnan), Laos (Houaphanh), India (northeast India).

Figures

FIGURE 27. Peltocercyon taylorae sp. nov. (holotype) A–C: habitus. D–G: male genitalia. A: dorsal view. B: lateral view. C: ventral view. D: aedeagus. E: median lobe. F: tegmen, G: sternite 9. Scale bars 0.5 mm.

FIGURE 28. SEM photos of Peltocercyon taylorae sp. nov. A: ventral view of head. B: ventral view of prothorax. C: mesoventral plate and central area of metaventrite. D: right portion of metaventrite. E: first abdominal ventrite.

FIGURE 37. Habitats of Peltocercyon taylorae sp. nov. A: Huanglianshan Mt. in Yunnan, China. B: fresh cow excrement under forest. C, D: alive adults in cow excrement. E: alive adult attracted by light.

FIGURE 42. Distribution map of species in Peltocercyon splendidus group.