Nipponocercyon shibatai Satô, 1963

Hoshina, Hideto & Fikáček, Martin, 2010, Morphological study and taxonomic revision of the genus Nipponocercyon (Coleoptera: Hydrophilidae: Sphaeridiinae), Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 117-130 : 124-128

Nipponocercyon shibatai Satô, 1963

Nipponocercyon shibatai Satô, 1963: 267 .

Nipponocercyon shibatai oyamanum Nakane, 1968: 86 , syn. nov.

Nipponocercyon monticola Nakane, 1968: 86 (second part of description published in NAKANE (1977: 87)), syn. nov.

Nomenclatorial note. The description of Nipponocercyon monticola was divided into two parts: NAKANE (1968: 86) published the first part of the description containing the information about the colouration and about the morphology of the head and antennae and explicitly indicated that the remaining part of the description will be published later. The second part of the description containing the information about the morphology of remaining head appendages and the rest of the body, the differential diagnosis of the species and the list of type material examined was published nine years later by NAKANE (1977: 87). As the ICZN (1999: Art. 13.1) requires only a description or a definition for species names published before 2000, the name N. monticola is available already from NAKANE (1968).

Type locality. Japan, Honshu, Ôsaka Prefecture, Minoo.

Type material examined. Nipponocerycon shibatai : HOLOTYPE: J ( EUMJ), Minoo, Osaka Pref., Honshu , iv.1959, K. Ueda leg. PARATYPE: 1 spec. ( ZMUC), Kasuga, Nara, 1.xii.1957, T. Shibata leg.

Nipponocerycon shibatai oyamanum: HOLOTYPE: J ( EIHU), Sagami-oyama, Kanagawa Pref., Honshu , 15.iv.1967, K. Masumoto leg.. PARATYPE: 1 spec. ( ZMUC), same data as holotype.

Nipponocerycon monticola : HOLOTYPE: ♀ ( EIHU), Mt. Jônen, Nagano Pref., Honshu , 1.xi.1960, K. Kamimura leg. PARATYPE: 1 spec. ( ZMUC), Mt. Jônen, Nagano Pref., Honshu, 16.x.1960, K. Kamimura leg.

Additional material examined. KYUSHU: FUKUOKA PREF.: 1 spec. ( FEFU), Mt.Hikosan , 31.v.1995, sifting of leaf litter, H. Hoshina leg. ; 1 spec. ( FEFU), same locality and collector, 26.vi.1995, sifting of leaf litter ; 3 spec. ( FEFU), same locality and collector, 20.xi.1995, sifting of leaf litter ; 2 spec. ( FEFU), Mt. Inunaki, 18.xii.1995, sifting of leaf litter, H. Hoshina leg. SHIKOKU: TOKUSHIMA PREF.: 1 spec. ( FEFU), Dosu-tôge, Kisawa-village , 23.–31.v.1998, M. Yoshida leg. ; 1 spec. ( FEFU), Okuyarito, Kisawa-village , 28.–31.v.2004, flight intercept trap, K. Tanaka leg. ; 2 spec. ( FEFU), same locality and collector, flight intercept trap, 31.v.–4.vi.2004 ; 1 spec. ( FEFU), same locality and collector, flight intercept trap, 4.–8.vii.2004, K. Tanaka leg. ; 3 spec. ( FEFU), Mt. Takashiro, Kisawa-village, 29.v.–19.vii.2004, M.Yoshida leg. HONSHU: HYÔGO PREF.: 2 spec. ( FEFU), Mt.Nagusayama , 10.v.1997, sifting of leaf litter, H. Hoshina leg. ; 3 spec. ( FEFU), Tentaki, Ôya-town, 10.v.1997, sifting of leaf litter, H. Hoshina leg. FUKUI PREF.: 4 spec. ( FEFU), Katsumi , Obama-City , 24.–31.v.2007, urea traps, H. Hoshina leg. ISHIKAWA PREF.: 1 spec. ( FEFU), Mt.Hakusan , 18.–31.x.2002, urea traps, H. Hoshina leg. KANAGAWA PREF.: 1 spec. ( FEFU), Tanzawa-ôyama , 14.iv.1973, K. Masumoto leg. ; 2 spec. ( FEFU), Aikawa-town , 20.xi.1994, T. Shimano leg. ; 1 spec. ( FEFU), Inugoeji, Tanzawa , 5.v.1993, Y. Hirano leg. ; 1 spec. ( PJWP): Nishi-Tanzawa , 9.xi.2002, P. Jałoszyński leg.

Differential diagnosis. See the differential diagnosis of the genus.

Redescription. Body widest in anterior third of elytra. Body length: 2.1–2.7 mm (holotype: 2.25 mm); body width: 1.3–1.5 mm (holotype: 1.35 mm).

Colouration. Head brown with reddish anterior margin of clypeus and small reddish spot in front of each eye. Pronotum dark reddish to brown, lateral portions paler, reddish to dark reddish. Scutellar shield brown. Elytron bicolored, reddish with rather sharply limited dark brown to black lateral triangular spot arising from ca. midlength of elytral interval 3 and reaching basalmost part of series 9 and posterior fourth of elytral interval 9 (= ‘large lateral spot’); additional small spots situated at posterior third of elytral interval 1 (‘small sutural spot’, sometimes joint with large lateral spot through otherwise completely pale interval 2) and at the bases of intervals 2–4 (‘small basal spot’, obsolete in some specimens); lateralmost elytral interval pale; pseudepipleuron and epipleuron pale. Ventral surface dark brown except for slightly paler posterior and lateral portions of abdominal ventrites. Legs and head appendages reddish, antennal club brown.

Head. Clypeus with moderately dense punctation consisting of rounded setiferous punctures; interstices without microsculpture. Frons with punctation similar to that on clypeus, punctures of same shape medially and laterally; interstices without microsculpture. Surface of mentum flat, bearing moderately dense punctation consisting of rounded punctures without longer setae, anteromedian portion lacking punctation; intestices with or without microsculpture (see Variability).

Thorax. Pronotum with dense punctation consisting of rounded punctures similar to those on head; all punctures similar in size, slightly coarser towards lateral margins; interstices with or without weak mesh-like microsculpture (see Variability). Elevated median portion of prosternum 1.45 times as wide as long, median carina slightly concave in lateral view. Scutellar shield bearing moderately dense rounded punctures lacking setae; interstices without microsculpture. Punctures of elytral series moderately large and rather dense, elytral series not impressed or weakly impressed (see Variability); elytral intervals flat near scutellar shield, becoming slightly convex laterad and posteriad; punctation sparse, consisting of fine irregularly arranged scar-like setiferous punctures; interstices with more or less developed mesh-like microsculpture. Preepisternal plate of mesothorax 1.2–2.2 times as long as wide (see Variability), central portion weakly convex in some specimens; surface with moderately dense punctures bearing long setae, interstices smooth. Median portion of metaventrite with coarse and dense punctation lacking setae; interstices without microsculpture.

Abdomen. Ventrites 2–4 with moderately dense and coarse punctation bearing short setae; interstices with distinct mesh-like microsculpture.

Male genitalia. Aedeagus 0.95–1.00 mm long (holotype: 0.95 mm). Parameres 2.1 times as long as phallobase, slender, continually narrowing from base to apex or slightly expanded apically (see Variability); phallobase 1.75 times as long as wide. Median lobe slightly longer than parameres, continually narrowing from base to apex; corona situated in basal 0.4 of median lobe.

Variability. Considerable variability was observed in the proportions of the preepisternal elevation of the mesothorax, in the development of intersticial microsculpture on the mentum, pronotum and elytra and in the shape of the basal portions of the elytral series. While specimens from one locality are identical or vary only very slightly, specimens from different localities may considerably differ in these characters ( Table 1). Male genitalia are identical in all examined specimens, showing only slight variability in the shape of the apical portions of the parameres (these may be either slightly expanded apically or continually narrowing apicad). In contrast to the remaining variable characters, the shape of parameres varies even within the same population and may differ among specimens in the same sample (e.g., in the specimens from Fukuoka Prefecture). Observed variability of elytral colouration (see the description above) does not seem to correlate with geographical distribution.

Biology. The collecting circumstances are known only for the specimens collected by the first author: they were sifted from leaf litter in evergreen laurel forest with Cinnamomum spp. , Machilus spp. and other species of Lauraceae (Fukui Prefecture), and in deciduous beech (with Fagus crenata ) and oak (with Quercus spp. ) forests (Ishikawa, Fukuoka and Hyôgo Prefectures). Other specimens were collected by sifting leaf litter or using flight intercept traps and urea traps.

Distribution. Endemic to Japan and known from the islands of Kyushu, Shikoku and Honshu.