Nipponocercyon satoi Fikáček, Jia & Ryndevich, 2015, sp. nov.
Creators: name: Fikáček, Martin
name: Jia, Fenglong
name: Ryndevich, Sergey
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydrophilidae
Nipponocercyon
Nipponocercyon satoi

description: Nipponocercyon satoi sp. nov.
(Figs. 1–21)
Type material. Holotype: male (SYSU): CHINA: Zhejiang Prov. Tianmushan Mt., bamboo garden, sifted from leaf litter on the ground, 4.vi.2013, Ma Gu-de lgt. (labelled in English and Chinese). Paratypes: 1 female (SYSU): CHINA: Jiangxi prov., Jinggangshan Mts., Xiangzhou (forested valley S of the village), 26°35.5′N, 114°16.0′E, 374m, 26.iv.2011; F.-L. Jia lgt.; 1 female (NMPC): “ CHINA: Jiangxi prov. [MF04] / Jinggangshan Mts., Xiping / 26°33.7ʹN 114°12.2ʹE, / 915 m, 24.iv.2011 / Fikáček, Hájek, Jia & Song // sifting: moist leaf litter / accumulted above the / banks of a stream in a sparse / tree-bamboo bush // DNA isolation: MF533 / isolated by D. Vondráček / ix.2013, isolate deposited in / National Museum, Prague”.
Description. Body widely oval, widest in anterior third of elytra. Body length of the holotype: 2.0 mm. General coloration of dorsal surface dark brown to black, anterior and anterolateral margins of clypeus and lateral portions of frontoclypeal suture reddish, anterior and lateral margins of pronotum and lateral margins of elytra narrowly reddish. Ventral surface dark brown to black, mouthparts reddish brown. Maxillary palpi, antennae reddish brown, legs reddish brown except for brown to dark brown meso- and metafemora.
Head. Clypeus rounded laterally, straight mesally, constricted above antennal bases, with very distinct marginal bead. Clypeus and frons with uniform punctuation consisting of semicircular punctures, bearing a very fine seta each (seen only under SEM), interstices without microsculpture. Frontoclypeal suture apparent only laterally as a non-sculptured stripe directing mesad. Eyes moderately large but not much exposed dorsally, isolated by 9.5× the width of one eye in dorsal view. Mentum with sparsely arranged fine setiferous punctures, those situated on lateral margin and close to it with stouter and longer setae; interstices with strong scale-like microsculpture. Antennal club with distinct groups of peg-like sensilla situated ventrally on distal margin of antennomeres 7 and 8 and in two oval closely adjacent groups in apical third of antennomere 9, the sensilla are intermixed with surrounding setae, not placed in a deep cavity. Maxilla of male with sucking disc ventrally.
Prothorax. Pronotum with sparsely arranged fine setiferous semicircular punctures, larger punctures along posterior margin absent; interstices without microsculpture. Lateral portions of pronotum largely deflexed, but only very narrowly seen in ventral view. Prosternum with well defined median plate 2.1× wider than long, bearing strong rugose sculpture with sparsely intermixed moderately coarse rounded setiferous punctures; the plate without median carina. Anterolateral corners of prosternum (at contact with hypomeron) with small but distinct tooth (Fig. 11, prt). Antennal grooves moderately large, not reaching lateral margin of hypomeron. Profemur with a shallow depression on a large portion of ventral surface. Protibia angulate on outer margin in distal third, rounded distally.
Mesothorax. Scutellar shield with few fine semicircular punctures, without microsculpture. Elytra with 10 series of punctures, series 1–2 reaching from elytral base to apex, remaining series very irregular and only reaching subbasally; all series not impressed and consisting of large but very shallow punctures, and hence elytral series very indistinct; elytral intervals flat, interval punctation sparse, consisting of minute V- or Y-shaped punctures, each bearing fine seta; interstices without microsculpture; lateral portions of elytra strongly deflexed laterally (hence, largely visible in ventral view); epipleuron present throughout elytral length, but very narrow in apical half. Mesoventrite with subpentagonal posteromedian elevation, 1.3× wider than long, with rugose setiferous sculpture.
Metathorax. Anteromedian process with very distinct short longitudinal ridges (Fig. 16, mtr), postcoxal ridge widely diverging from posterior margin of mesocoxal cavity forming a wide elevated rim behind mesocoxal cavities; median portion of metaventrite not distinctly elevated, bearing sparsely arranged small setiferous punctures; lateral portions of metaventrite with intermixed large and moderately large setiferous punctures; whole surface of metaventrite without microsculpture on interstices. Hind wings well developed.
Abdomen. Abdominal ventrite 1 carinate medially, with dense and coarse punctation; ventrites 2–5 without median carina, bearing sparsely arranged fine punctuation; interstices of all ventrites with fine microsculpture.
Male genitalia. Aedeagus 0.67 mm long. Parameres slender, 1.6× longer than phallobase. Median lobe robust, very wide basally, gradually narrowing apicad, apex rounded; gonopore situated at midlength of median lobe.
Etymology. The species is dedicated to the Japanese specialist on Hydrophilidae and other aquatic beetles Masataka Satô (1937–2006), who discovered and described the genus Nipponocercyon.
Biology. Terrestrial species. Both female specimens from Jinggangshan Mts. were sifted from leaf litter in the forest close to a small stream, in one case with many bamboo plants. The holotype was sifted from the leaf litter in bamboo undergrowth.
Distribution. Known from two mountain systems in Southwest China situated ca. 640 km from each other: Tianmushan Mts. in Zhenjiang Province, and Jinggangshan Mts. in Jiangxi Province (Fig. 21). It may be more widely distributed in the mountains of SW China, but seems to be generally rare on the localities based on our intensive field work in Jinggangshan Mts.
N. satoi sp. nov. N. shibatai N. sichuanicus Differential diagnosis. The new species may be easily recognized as a member of Nipponocercyon based on the presence of two short ridges on anteromedian portion of the metaventrite (i.e. on metaventral process, Fig. 16: mtr), which is unique for the genus within the Megasternini. In addition, it bears a subpentagonal mesoventral plate (Figs. 2, 16), mesoventral grooves for reception of procoxae reaching to mesocoxal cavities (Fig. 16: grp) and prosternum with differentiated median plate and anterolateral corner projecting into a “tooth” (Fig. 11, prt). It differs from the remaining two species of the genus on the first view by the small highly convex body and the absence of impressed elytral series (Figs 1–3, 21). For a detailed comparison of the three species, see Table 1.
By the general habitus, i.e. small shiny globular body seemingly without distinct elytral series, N. satoi is easily confused with the megasternine genera Megasternum and Pacrillum (both also occurring in China / Japan) rather than with other species of Nipponocercyon. Both genera differ from N. satoi by large antennal grooves reaching to lateral portion of hypomeron, absence of ridges on the metaventral process, absence of a profemoral depression and anepisternum 3 narrowing from base and hence extremely narrow anteriorly. Pacrillum also differs e.g. by the rhomboid strongly carinate prosternal plate and mesoventral plate longer than wide. Megasternum differs e.g. by hexagonal ecarinate prosternal plate which is as wide as long, mesoventral plate wider than long and anterolaterally excised protibiae.
description: Published as part of Fikáček, Martin, Jia, Fenglong & Ryndevich, Sergey, 2015, A new aberrant species of Nipponocercyon from the mountains of southeastern China (Coleoptera: Hydrophilidae: Sphaeridiinae), pp. 572-580 in Zootaxa 3904 (4) on pages 573-579, DOI: 10.11646/zootaxa.3904.4.6, http://zenodo.org/record/239881