Sibirhelus corpulentus ( Reitter, 1900 )

Hisamatsu, Sadatomo, 2011, A review of the Japanese Kateretidae fauna (Coleoptera: Cucujoidea), Acta Entomologica Musei Nationalis Pragae 51 (2), pp. 551-585 : 572-574

Sibirhelus corpulentus ( Reitter, 1900)

( Figs. 2D , 9 )

Heterhelus corpulentus Reitter, 1900: 231 , tab. II, fig. 7. Type locality: [ Russia:] Irkutsk.

Heterhelus corpulentus: GROUVELLE (1913: 15) [catalogue].

Sibirhelus corpulentus: KIREJTSHUK (1989: 147) [redescription]; KIREJTSHUK (1992: 214) [in key]; HISAMATSU (2003: 14) [note]; JELÍNEK & AUDISIO (2007: 458) [catalogue].

Material examined. JAPAN: IWATE: 1J 1 ♀, Kouyanotutumi, Kanegasaki-chô, Iwasa-gun, 9.v.2007, Y.Takahashi leg. TOCHIGI: 2JJ 4♀♀, Watarase-yûsuichi,Fujioka-chô, 2.v.1992, H.Ohkawa leg., by sweeping of Carex dispalata ;

10 JJ 2 ♀♀, Watarase-yûsuichi, Fujioka-chô, 24.–25.iv.2010, S-T. Hisamatsu leg.; 4JJ 5♀♀, Watarase-yûsuichi,

Fujioka-chô, 24.iv.2010, T. Kurihara leg. ( EUM).

Diagnosis. Body coloration fully luteous to dark brown ( Fig. 2D ); antennae almost moniliform ( Fig. 9G ). Medial tuft of setae on abdominal sternites III ( Fig. 9K ) in Japanese specimens, on abdominal sternites III–V in Russian specimens. Male protibiae ( Fig. 9I ) strongly medially arcuate.

Redescription. Length 2.7–3.6 mm.

Male. Body ( Fig. 2D ) elongate oval, strongly convex, feebly shining; dorsal disc with a long, yellowish setae. Coloration fully luteous or rarely dark brown.

Head densely punctate, each puncture larger than eye-facet, separated by <1 diameter; interspaces finely reticulate or smooth. Frontoclypeal suture incomplete, distinctly visible. Front margin of clypeus with medial arcuate emargination. Labrum broadly notched at middle. Mandibles slightly bent inward. Antennae ( Fig. 9G ) 1.16 times longer than HW (n = 2), appearing moniliform, without club; approximate ratio of each segment (n = 1) is 2.00: 1.14: 1.43: 1.14: 1.14: 1.00: 1.00: 1.00: 1.14: 1.29: 2.14.

Pronotum strongly convex, 1.35 times as wide as long (n =1); lateral margins narrowly explanate, arcuately rounded, widest at mid-length; anterior corner not prominent; posterior corner obtusely angulate; anterior margin nearly straight or with slight curvature, clearly bordered; basal margin gently arcuated, slightly sinuated at mid-width, distinctly bordered; punctures on disc larger than those on head, separated by <1 diameter; interspaces finely reticulate.

Elytra conjointly 1.03 times as long as wide (n = 1), 1.75 times as long as pronotum (n = 1), subparallel-sided; punctures on disc larger than those on pronotum, extremely dense, separated by <1 diameter; interspaces smooth. Abdominal tergite VI partially obscured by elytra. Abdominal tergite VII fully exposed, apex arcuately emarginate. Abdominal tergite VIII externally visible.

Prosternum (excluding prosternal process) rather long, 0.56 times as long as mesoventrite (n = 1), 0.40 times as long as metaventrite (n = 1); prosternal process slightly converging towards apex. Mesoventrite depressed below the level of the metaventrite, apical margin between inter-mesocoxa straight. Metaventrite convex, strongly shining, metathoracic discrimen in basal 1/2; disc with sparse punctures, separated by 1 or 2 diameter(s) at the middle; punctures becoming denser laterally. Inter-mesocoxal distance separated by 1.67 times width of inter-procoxal distance. Inter-metacoxal distance separated by 2.50 times width of interprocoxal distance. Abdominal sternites III ( Fig. 9K ) with medial tuft of setae; approximate ratio of length of abdominal sternites III–VII (n = 1) is 3.00: 1.00: 1.00: 1.90: 3.00. Legs slender and long, protibiae ( Fig. 9I ) strongly medially arcuate; claws ( Fig. 9E ) more or less expanded at the base.

Male genitalia sclerotized; tegmen ( Fig. 9A ) with parameres asymmetrical, bearing long setae; interparameral lobe broadly rounded; median lobe ( Fig. 9C ) abruptly bent inward near apex in lateral aspect.

Female. Apical margin of abdominal tergite VII rounded. Ovipositor ( Fig. 9D ) deeply bifid, with extremely short styli.

Variability. Russian specimens have medial tuft of setae on abdominal sternites III–V (Kirejtshuk, pers. comm.), but Japanese specimens have these tufts on abdominal sternite III only. The tarsal claws were described as ‘subdentatis’ in the original description ( REITTER 1900), and as ‘dentate’ in KIREJTSHUK (1992). However, in the Japanese specimens examined so far, the base of the tarsal claws is more or less expanded at the base with no apparent tooth or denticle.

Bionomics. Twelve specimens of S. corpulentus were collected from flowers of Carex dispalata Boott (Cyperaceae) , in Watarase-yûsuichi, Tochigi Pref. No additional information is available.

Distribution. Japan (Honshû) – first recorded by HISAMATSU (2003); Russia (Irkutsk and Primorsky Kray) ( KIREJTSHUK 1992).

Figures

Fig. 2. Habitus and labels of Kateretidae spp. A–B – Heterhelus (Heterhelus) morio (Reitter, 1878): A – lectotype, male; B – ditto, labels; C – Heterhelus (Boreades) solani (Heer, 1841), male (Hokkaido); D – Sibirhelus corpulentus (Reitter, 1900), male (Iwate Pref.); E – Brachypterus urticae (Fabricius, 1792), male (Hokkaido); F–G – Brachypterolus shimoyamai Hisamatsu, 1985: F – holotype, male; G – ditto, labels. Scale bars = 1.0 mm.

Fig. 9. Sibirhelus corpulentus (Reitter, 1900).A – tegmen (ventral view); B – median lobe (ventral view); C – median lobe (lateral view); D – ovipositor; E – tarsal claw of right foreleg; F – left maxillary palpus; G – male right antenna; H – female right protibia; I – male right protibia; J – pronotum; K – abdominal sternites. A–K = Tochigi Pref., Watarase-yûsuichi,