Cercyon (Clinocercyon) hanseni Jia, Fikáček & Ryndevich, 2011, sp. nov.
Creators: name: Jia, Feng-Long
name: Fikáček, Martin
name: Ryndevich, Sergey K.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Hydrophilidae
Cercyon
Cercyon hanseni

description: Cercyon (Clinocercyon) hanseni sp. nov.
(Figs. 1–10)
Type material. Holotype: male, “Jiangxi, Shangrao, Sanqingshan Mt., 15-20.iv.2007 [transcribed from Chinese]” (SYSU). Paratypes: 23 exs., same the data as the holotype (SYSU, NMPC); 1 male, 33 exs., “ CHINA: Jiangxi prov., Jinggangshan Mts., Xiping, 26°33.7ʹN 114°12.2ʹE, 915 m, 24.iv.2011, Fikáček, Hájek, Jia & Song // cow excrements at the farm” (NMPC, BMNH, CSR, KSEM, NHMW, ZMUC); 9 spec., “ CHINA: Jiangxi prov., Jinggangshan Mts., Jingzhushan, 640 m, 25.iv.2011, 26°31.0ʹN 114°05.9ʹE, Fikáček, Hájek, Jia & Song // cow excrements on the forest clearing” (NMPC); 4 exs., “ CHINA: Jiangxi prov., 26.iv.2011, Jinggangshan Mts., Xiangzhou (forested valley S of the village), 26°35.5ʹN 114°16.0ʹE, 374m, Fikáček, Hájek, Jia & Song // cow excrements on the trail + straw bedding with old excrements from cattle shelter” (NMPC); 1 male “ China, W Guizhou prov., Leigongshan, Xijiang, 29 May-2 Jun 1997, 1200-1900 m, Bolm lgt.” (NHMB).
Differential diagnosis. Head black; pronotum black with narrowly yellow lateral margins; each elytron with black sutural interval and black triangular spot in anterior two thirds of intervals 7–10 (Figs. 1–3); interval punctures on elytra rather coarse and dense; preepisternal plate narrowly elongate, ca. 5.5–7.5× as long as wide; metaventrite without femoral lines, with moderately coarse and dense punctation; parameres slightly longer than phallobase, with large dorsal and small ventral portions, wide subapically; median lobe widest subapically, obtusely pointed at apex, gonopore large, subapical.
The new species may be distinguished from several similar undescribed species occurring in China especially by the combination of narrowly yellow lateral margins of pronotum (in contrast to widely yellow margins or largely yellow pronotum with a small dark median spot in similar Chinese species), the yellowish elytra with dark sutural interval and relatively small but distinctly triangular dark spot anterolaterally on each elytron (elytra of similar species lack dark sutural interval, bear differently shaped lateral spot or totally different dark pattern), and characteristic aedeagus with paramere wide subapically and bearing a largely exposed dorsal portion (parameres narrow subapically and/or the dorsal portion of the paramere is largely covered by ventral portion in similar species). The color pattern of the new species also resembles the coloration of numerous species of the genus Peltocercyon Orchymont, 1925, which can be easily distinguished from C. hanseni sp. nov. by the distinct femoral line of the metaventrite intersecting the anterolateral ridge.
Description. Form and Color. Body elongate oval (Fig. 1), length 2.7–2.9 mm, width 1.6–1.7 mm. Head, pronotum, scutellum and extreme base of elytra very dark brown, lateral margins of pronotum narrowly pale (Figs. 1– 2). Each elytron yellowish brown, with black sutural interval and a black triangular spot laterally in anterior two thirds of intervals 6–10 (sometimes only 7–10), the inner corner of the spot usually reaching fifth stria in anterior third. Elytral striae dark. Elytral epipleura yellow. Maxillary palpomeres 1–3 reddish yellow, palpomere 4 slightly darkened, sometimes even palpomere 3 of same color as palpomere 4. Antennae reddish yellow except for dark club. Ventral surface dark brown to black, posterior margins of abdominal ventrites yellowish. Legs yellow to rufous, tarsi rufotestaceous.
Head. Clypeus with dense, moderately coarse punctures, interstices without microsculpture. Anterior margin of clypeus narrowly rimmed. Frontoclypeal suture undetectable. Frons without microsculpture on interstices. Eyes small, somewhat protruding, interocular distance ca. 5× as wide as one eye in dorsal view. Mentum glabrous, ca. 1.5× as wide as long, densely and coarsely punctate, strongly depressed anteromedially. Antennae with 9 antennomeres, scapus ca. 1.3× as long as antennomeres 2–5 combined, club compact. Maxillary palpomere 2 strongly swollen, palpomere 4 almost symmetrical, equal to palpomere 3 in length.
Thorax. Pronotum ca. 2.0–2.1× as wide as long. Pronotral punctation similar to that on head. Lateral margins narrowly rimmed, the rim not overlapping anterior and posterior corners, anterior and posterior margin of pronotum without rim. Prosternum with strong longitudinal carina medially; antennal groove distinct, medium large, rounded laterally. Preepisternal plate narrowly elongate, ca. 5.0–7.5× as long as wide, widest in anterior third, gradually narrowing posteriad to pointed posterior apex; surface with a few coarse and sparse punctures (Fig. 9). Metaventrite with raised glabrous, strongly punctate median pentagonal area; femoral lines absent. Elytra with 10 punctate striae, striae 1–5 slightly impressed and reaching base, striae 6–10 consisting or coarser punctures than striae 1–5; striae 6, 8 and 9 abbreviated anteriorly. Ground punctures on intervals very fine and somewhat obscure. Humeral bulge distinct. Apical portion of pro- and mesocoxae with stout, golden setae. Femora with sparse and strong punctures ventrally, with distinct tibial groove. Tarsi with densely arranged white setae ventrally, first metatarsomere about as long as metatarsomeres 2–3 combined.
Abdomen. Abdomen with five exposed ventrites, first abdominal sternite distinct longer than other sternites, with distinct median longitudinal carina, fifth sternite arcuate, not emarginate apically.
Male genitalia (Figs. 4–8). Median projection of sternite 9 narrowly rounded apically, bearing two long subapical setae, median portion shorter than lateral struts (Fig. 8). Phallobase slightly shorter than parameres, asymmetrical basally. Paramere rather wide subapically, with large dorsal and narrow ventral portions, strongly convex on outer margin, narrowly rounded apically (Figs. 4–5). Median lobe widest subapically, strongly narrowing apicad (Figs. 6–7), apex obtusely pointed; gonopore large, situated subapically.
Variation. The species varies largely in the proportion of the preepisternal plate, which ranges between 5.0–7.5× even in specimens from a single sample (see Figs. 9–10 for the examples of the variation). Observed variation corresponds with that known for several other Cercyon species and the shape moreover varies even between the specimens from a single sample. Thus, we consider all examined specimens as conspecific and include all of them in the type series.
Etymology. The species is dedicated to the late Michael Hansen in order to commemorate his massive contribution to the systematics of the Hydrophiloidea.
Biology. All type specimens were collected in cow excrements.
Distribution. China (Jiangxi, Guizhou).
description: Published as part of Jia, Feng-Long, Fikáček, Martin & Ryndevich, Sergey K., 2011, Taxonomic notes on Chinese Cercyon: description of a new species, new synonyms, and additional faunistic records (Coleoptera: Hydrophilidae: Sphaeridiinae), pp. 41-56 in Zootaxa 3090 on pages 42-44, DOI: 10.5281/zenodo.279052