Nebrioporus anchoralis ( Sharp, 1884 )

Toledo, Mario, 2009, Revision in part of the genus Nebrioporus Régimbart, 1906, with emphasis on the N. laeviventris-group (Coleoptera: Dytiscidae), Zootaxa 2040, pp. 1-111 : 35-37

Nebrioporus anchoralis ( Sharp, 1884)

Fig. 25

Deronectes anchoralis Sharp(1884: 442) (orig. descr.); Severin (1892: 473).

Hydroporus (Deronectes) anchoralis (Sharp) ; Régimbart (1899: 196).

Deronectes (Potamodytes) anchoralis Sharp ; Zimmermann (1919: 189; 1920: 122); Takizawa (1933: 176).

Deronectes (Potamonectes) anchoralis (Sharp) ; Zimmermann (1933: 168 footnote).

Potamonectes anchoralis (Sharp) ; Zaitzev (1953: 213).

Nebrioporus (s.str.) anchoralis (Sharp) ; Nilsson & Angus (1992: 287); Mori & Kitayama (1993: 85); Hendrich & Mazzoldi (1995: 2); Nilsson (2001: 170; 2003: 66).

Type locality. Japan > Honshu> Chiuzenji [Shuzenji, Shizuoka Pref.] .

Type material. Lectotype ♂ ( BMNH), here designated, glued together with a ♀ on same card, on which is written [Sharp hw.] " Deronectes anchoralis types D.S. Chinzenji japan G. Lewis 23.8.1881 " bearing BMNH circular, red bordered " Type " label, and labelled " Japan Lewis \ Sharp Coll. 1905-313" plus BMNH circular, blue bordered " Lectotype " label, added by me and my red designation label . Paralectotypes ( BMNH): 4 ♂♂ and 5 ♀♀ same locality , 1 ♀ glued together with lectotype. They all bear BMNL circular, yellow bordered "Cotype" label, plus BMNH circular, light-blue bordered " Paralectotype " label, added by me and my red designation label.

Additional material examined. Japan: " Japan, G. Lewis, 1910-820" (8 exs. BMNH) ; Yakeyama Path , 1400 m, Makioka T., Yamanashi, 6.VII.1988, leg. Y. & T. Abe (12 exs. GWW, PMB, MTP) ; Komagome riv., Aomori City , 23.V.1985, leg. H. Sawada (1 ex. HF) ; Tobira Spa, Matsumoto City , Nagano, 26.VIII.1987, leg. T. Abe & A. Sasai (13 exs. HF, MTP) .

Description. A remarkable species for size, colouration and male characters. TL 5.5–5.8 mm; MW 2.7–2.8 mm. Oval, more convex than other species of the depressus -group. Angle between pronotum and elytra obtuse but clearly visible. Colouration reddish-yellow, with extended and well defined dark pattern on head, pronotum and elytra.

Head reddish-yellow with a large dark, postocular band, usually extended around the eyes. Antennae reddish-yellow, with widely darkened articles, except for the first 3–4. Mouthparts reddish. Last article of maxillary palpi black.

Pronotum wide, with maximum width near the middle of its length. Lateral sides regularly rounded, bordered. Posterior angles rounded.

Elytra oval, not elongate. Maximum width at about the middle of the length. Sides regularly rounded. Longitudinal rows of punctures visible, except for the sutural one which is often obsolete. Subapical denticle well visible.

Dorsal colouration ( Fig. 25a,b) reddish or reddish-yellow: pronotum with a large, black band on the anterior border and a thinner band along the posterior border, which extends into two large discal spots; elytra with five, wide, longitudinal dark lines, plus 2-3 lateral maculae.

Underside dull, due to the impressed and deep punctuation. Colouration reddish-brown or blackishbrown, slightly faded on metaventrite, metacoxal process and prosternal process.

Legs reddish-yellow, with dark tarsi.

Male: Protarsi clearly widened. Anterior claws ( Fig. 25c,d) extremely long: the inner straight, almost three times the length of 5th protarsomere; the outer shorter and more curved, flattened laterally. Mesotarsal claws unmodified. Median lobe of aedeagus and parameres as in Figs 25e,f.

Female: duller, at least the pronotum. Lateral sides of pronotum usually more regularly rounded and less visibly bordered.

Distribution ( Fig. 53). Japan (Honshu, Kyushu).