Nebrioporus melanogrammus ( Régimbart, 1899 )

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 : 69-70

Nebrioporus melanogrammus ( Régimbart, 1899)

Figs 31, 61

Hydroporus (Deronectes) melanogrammus Régimbart (1899: 197) (orig. descr.).

Deronectes (Potamodytes) melanogrammus (Régimbart) ; Zimmermann (1919: 189; 1920: 128).

Potamonectes (s. str.) melanogrammus (Régimbart) ; Guignot (1959b: 11) (synonym of indicus Sharp ); Vazirani (1970: 126) (synonym of indicus Sharp ).

Nebrioporus melanogrammus (Régimbart) ; Toledo (1998: 84) (valid species); Nilsson (2001: 172; 2003: 66).

Potamonectes satie Vazirani (1980: 28) (orig. descr.).

Nebrioporus (s.str.) satie (Vazirani) ; Nilsson & Angus (1992: 288); Toledo (1998: 84) (synonymy of melanogrammus Régimbart ).

Type locality. H. melanogrammus : India > Ragpore> Moradabad; P. satie : India > Himachal Pradesh> Sirmour.

Type material. Hydroporus melanogrammus : Lectotype ♂ ( MNHN, coll. Régimbart), here designated. This specimen is glued on a card with a lateral indention to make part of its underside visible, and it is labelled: " India or \ Mehradabad [hw?, yellow label, the first letters of "Mehradabad" almost illegible]; melanogrammus Rég. [hw Régimbart]". A label " Lectotype " [long red label, printed text, no name of author and date] was added in more recent times. A second ♀ specimen in MNHN (coll. Régimbart) labelled: " India or. \ Rangpore [hw?, yellow label, the first letters of "Rangpore" almost illegible]" plus the following labels added by Wewalka "Co-Typus Hydroporus melanogrammus Reg. Wewalka ‘73 [hw Wewalka] \ nicht melanogrammus Reg [hw Wewalka] \ Potamonectes indicus Sharp , det. G. Wewalka ‘74" [hw Wewalka in part] should be considered as syntype of N. melanogrammus , although it belongs to another species ( N. indicus ) and was cited in Regimbart’s original description of H. melanogrammus .

Potamonectes satie : Holotype ♂ ( NZSI) " India, Himachal Pradesh, Sirmour , 29.VII.1972, M. Chandra, Reg. No 8443/H4A", 1 paratype "Reg. No 8444/H4A" same locality as holotype.

Additional material examined. Bhutan: Punhaka Prov. , ca. 2 km NW Punhaka, Mo Chhu, ca. 1230 m, 27°35’45"N 89°51’19"E, 28.XI.2005, leg. M. J. Jäch (35) (1 ex. NMW) .

China: Yünnan, 100 km W Baoshan, Gaoligongshan Nat. Res. , 14-21.VI.1993, leg. E. Jendek & O. Šauša (1 ex. NMW) .

India: Uttaranchal Pradesh: "Hardwar, Ganges, Potamonectes melanogrammus (Rég.) , det. G. Wewalka, 1984" (4 exs. BMNH, GWW) ; Rhisikesh , 23.X.1997, J. Šťastný leg. (4 exs. JSL, MTP) ; Uttarkashi , 1158 m, Bhaghirathi riv., 21.X.1997, J. Šťastný lgt. (1 ex. JSL) .

Nepal: Chitwan, Narayanghat , Narayani riv., 170 m, 12.XI.1993, leg. Moog & Pradhan. (5 exs. NMW) ; 20 km NW Pokhara, Lumle , 1600 m, 2.V.1984 (N 2) (2 exs. GWW) ; Dahran. Umg. [?Dahran Bazar], 13.II.1987, leg. M. Jäch, N 12 (4 exs. NMW) ; Helambu, upper Chipling 2200–2400 m, 29–30.VIII.1997, leg. S. Fabrizi & D. Ahrens (4 exs. ASS) .

Description. TL 4.8–5.3 mm; MW 2.4–2.7 mm. Widely oval, flat, dorsal and ventral surface shiny. Angle between pronotum and elytra obsolete. Testaceous, with poorly developed dark markings on head and pronotum, elytra vittate.

Head yellow with a very thin, dark, postocular band. Dorsal surface with moderately deep and close punctuation, together with a few, larger, scattered punctures. Antennae completely testaceous. Mouthparts reddish-yellow.

Pronotum narrow, maximum width at its base. Lateral sides more or less straight, bordered. Posterior angles acute. Dorsal surface covered by a fine punctuation, not very dense on the disc, together with few larger punctures on anterior and posterior margins.

Elytra oval; maximum width at about the middle of the length. Sides regularly rounded. Discal series of punctures usually visible, the other two often obsolete. Subapical denticle invisible or almost so.

Dorsal colouration ( Fig. 31a,b): pronotum yellow or reddish-yellow, with a thin, dark band on anterior and posterior borders, the latter extends into two small expansions; elytra yellow, with five longitudinal dark lines plus two - three lateral maculae.

Underside almost smooth, with very large, deep and well spaced punctures on lateral expansions of metaventrite, metacoxal plates and first two sternites; smaller and finer punctures on metacoxal process, medial portion of metaventrite and the other sternites ( Fig. 3); a fine reticulation of transverse meshes is visible in the medial part of sternites. Apical comb of setae almost completely reduced. Colouration pitchblack, paler on prosternal process. Epipleuron testaceous.

Legs uniformly yellow.

Male: Subapical denticle not visible ( Fig. 31c). Protarsi slightly dilated. Anterior claws ( Fig. 31d) blunt, with the inner shorter than the outer, this latter sharply acuminate and not flattened. Mesotarsal claws unmodified. Median lobe of aedeagus ( Fig. 31e–g) bent downward apically; parameres elongate ( Fig. 31 h,i).

Female: Slightly duller. Subapical angles on elytra hardly visible, but always present ( Fig. 31c). Lateral sides of pronotum less clearly bordered.

Variability. As suggested by Toledo (1998), the Chinese population could represent a separate subspecies, due to its apparent geographical isolation and for some morphological differences seen in the only Chinese specimen so far known (Yünnan). Nevertheless , one specimen is insufficient for a definitive diagnosis .

Habitat. Specimens of N. melanogrammus were collected in Uttaranchal Pradesh (Uttarkashi and Rhishikesh) in small sand and gravel pools without vegetation, on the recent river terraces near main streams. The pools were shallow (about 30–50 cm) with layers of fine glacier powder on the bottom. In Uttarkashi the species was collected together with Nebrioporus indicus and Hyphydrus renardi Severin. In Rhishikesh it was collected in association with Copelatus sp. [Jaroslav Šťastný, personal communication, 1999].

Distribution ( Fig. 50). A strictly Himalayan species, which does not seems to extend into the higher elevations: Northern India (Uttaranchal Pradesh, Himachal Pradesh), Nepal, Bhutan, China (Yünnan). Apparently rare. First record of Nebrioporus for Bhutan.