Nebrioporus dubius ( Aubé, 1838 )

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 : 98-99

Nebrioporus dubius ( Aubé, 1838)

Fig. 42

Hydroporus dubius Aubé(1838b: 51) 7 (orig. descr.).

Deronectes dubius (Aubé) ; Sharp (1882: 794); Branden (1885: 49) (synonymy of vigilans Wollaston ).

Deronectes (Potamodytes) dubius (Aubé) ; Zimmermann (1919: 188; 1920: 128) (synonymy of vigilans Wollaston ). Deronectes (Potamonectes) dubius (Aubé) ; Zimmermann (1933: 155).

Potamonectes (Bistictus) dubius (Aubé) ; Guignot (1941: 59; 1959a: 441); Régil Cueto & Valladares Díez (1983: 659). Potamonectes dubius (Aubé) ; Balke & Hendrich (1989: 63).

Nebrioporus (Zimmermannius) dubius (Aubé) ; Nilsson & Angus (1992: 287); Nilsson (2001: 173; 2003: 67). Hydroporus vigilans Wollaston (1854: 84) (orig. descr.); Régimbart (1895: 15).

Deronectes vigilans (Wollaston) ; Sharp (1882: 425); Branden (1885: 49); Falkenström (1938:10).

Type locality. H. dubius . Africa [may be mislabelled]. H. vigilans : Portugal > Madeira island.

Type material. Hydroporus dubius : Syntypes ( MNHN) not studied .

Hydroporus vigilans : Syntypes not found in BMNH, only Sharp’s "type mihi"(see below).

Additional material examined. Portugal, Madeira: " Hydroporus vigilans Woll. (♂), 9nd auth., type mihi D. S., Madeira [Sharp hw.], Madeira, Sharp Coll. 1905-313, type 248 Hydroporus vigilans " (1 ex. BMNH) ; " Hydroporus vigilans Woll. (♀)" same data except for " type 248" label (1 ex. BMNH) ; additional specimens with same data of Sharp’s “ type mihi” with the following label added " Potamonectes dubius Aubé det. B.- Browne" ( BMNH) ; " Madeira, Deronectes vigilans Woll. compared with the type G.J.A." (2 exs. ♀♀ BMNH) ; " Madeira 99-103, Hydroporus vigilans Woll. det. Regimbart, Potamonectes dubius Aubé det. B.- Browne " (2 exs. BMNH) ; Curral do Frejas, 600 m, Ribeira do Socorridos , 24– 30.7.1986, leg. Balke & Hendrich (15 exs. MTP, HF, PMB) .

Spain: "Canary Is., Sharp Coll. 1905-313, Potamonectes canariensis Bedel [sic!] J. Balfour-Browne det." (1 ex. ♀ BMNH) .

Description. TL 5.1–5.8 mm; MW 2.4– 2-7 mm. Elongated oval, quite depressed. Angle between pronotum and elytra well visible. Dorsal colouration reddish-yellow, with dark-brown patterns on elytra and pronotum not well defined.

Head reddish-yellow or brownish, vaguely darkened around the eyes. Antennae reddish-yellow, with last segments slightly darkened apically. Ventral face of head pitch-black, smooth and shiny just behind the eyes, without visible punctuation or microreticulation; this area is delimitated by the postocular ridge, which is almost completely developed. Mouthparts reddish-yellow.

Pronotum narrowed near the base, with maximum width at the middle of its length. Lateral sides regularly rounded, with a clearly visible lateral border. Surface covered by a fine and diffuse punctuation, together with larger punctures along anterior and posterior margins with some longitudinal, shallow grooves. Angle between pronotum and elytra well defined in both sexes.

Elytra elongated, with maximum width just behind the middle of the length, covered by a short, hardly visible pubescence and a fine punctuation. At least two series of longitudinal rows of punctures are clearly visible, each one in a groove deeper than in N. canariensis . Subapical spines absent, with the exception of a sinuation hardly visible in some female specimens.

Dorsal colouration ( Fig. 42a) dark-yellow or reddish-yellow; dark patterns on pronotum and elytra brown, very extended and from distinct to completely indistinct; on pronotum they form two large discal maculae, on elytra longitudinal vittae.

Underside pitch-black, proepisterna, hypomera, epipleuron, prosternal and metacoxal process and apex of last four sternites reddish-yellow. Surface shiny, covered by a fine, poorly impressed and diffuse punctuation. Prosternal process flat and smooth, not carinate, laterally with two series of large punctures. Sternites without a visible apical comb of setae.

Legs reddish-yellow, with pro and mesotarsi often slightly darkened. Metafemora covered by a dense, shallow, punctuation. Anterior face of metatibiae with supplementary punctures arranged in a long row.

Male: Protarsi slightly dilated. Anterior claws ( Fig. 42b,c) almost unmodified, although a little more robust than in females. Median lobe of aedeagus ( Fig. 42e) wider than in N. canariensis and more abruptly bent downward at the tip; parameres broader ( Fig. 42d).

Female: Duller than males. Larger punctures on pronotum less deeply impressed.

Distribution ( Fig. 55). Madeira Island. The record for the Canary Islands is very doubtful. The specimen in BMNH "Canary Isl." is a probable mislabelling.