Nebrioporus indicus ( Sharp, 1882 )

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 : 65-68

Nebrioporus indicus ( Sharp, 1882)

Figs 32, 60

Deronectes indicus Sharp (1882: 413) (orig. descr.); Branden (1885: 198).

Hydroporus (Deronectes) indicus (Sharp) ; Régimbart (1899: 198).

Deronectes (Potamodytes) indicus Sharp ; Zimmermann (1919: 189; 1920: 127).

Potamonectes (s.str.) indicus (Sharp) ; Guignot (1959b: 10).

Potamonectes indicus (Sharp) ; Vazirani (1970: 126); Brancucci (1979a: 199); Zeng (1989: 3).

Nebrioporus (s.str.) indicus (Sharp) ; Nilsson & Angus (1992: 288); Nilsson (1995b: 56; 2001: 172; 2003: 66). Nebrioporus indicus (Sharp) ; Toledo (1998: 86); Hajek & Fery (2004: 37).

Potamonectes manii Vazirani (1970: 124) (orig. descr.); Angelini (1978: 387); ( Zeng 1989: 3).

Nebrioporus (s.str.) manii (Vazirani) ; Nilsson & Angus (1992: 288); Nilsson (1995b: 56); Toledo (1998: 86) (synonymy of indicus Sharp ); Nilsson (2001: 172) (idem).

? Potamonectes laeviventris ( Reiche & Saulcy, 1855) ; Guignot (1958b: 29).

? Potamonectes kashmirensis ( Régimbart, 1899) ; Vazirani (1970: 123) (partim).

Type locality. D. indicus : N. India. P. manii : India > Kashmir> Haichin.

Type material. Deronectes indicus :? Holotype ♂ ( MNHN) labelled "Northern India type 267 [=287? Hw. Sharp], coll. Wehncke ". In Sharp's original description, the single type specimen has the indication "type 287 in coll. Bonvouloir ". It is not clear whether the specimen in MNHN is the real holotype or not. Three specimens in BMNHL (2 ♂♂ and 1 ♀) labelled " India 67-56 \ D. (Potamonectes) indicus Sharp, J. Balfour- Browne det." were incorrectly considered syntypes by Vazirani (1970).

Potamonectes manii : Holotype ♂ ( MNHN), dissected, "Kashmir, Haichin, 22.IX.1954 \ Holotype Potamonectes (s. str.) manii n. sp. T. G. Vazirani det".

Additional material examined. Afghanistan: Nengrahar Prov. , 2 km SW Jalalabad, 600 m, 18.III.1966, leg. Povolný & Tenora (2 exs. IRSNB, MMBC) ; Janny–Chel [ Jani Kheyl ? About 60 km North of the border with Pakistan's Baluchistan], 2100 m, 23.VII.1964 (1 ex. MMBC) .

India: Uttaranchal Pradesh : Missourie, Mossy Falls, 22.III.1932, H.G. Champion (2 exs. BMNH) ; Thalari , 24.VII.1994, leg. M. Snizek (30 exs. MTP, PMB) ; Bhimtal , Kumaon Kalees, 5.VI.1978, Rig. Bisht , CH 6, C.I.E.A. 10788 (1 ex. BMNH) ; Barkot , 1100–1200 m, 5–12.VI. 1981, leg. M. Brancucci (3 exs. GWW) ; Janak , Chatti, 2575 m, Jamuna riv., stream, 10.X.1997, J. Šťastný leg. (2 exs. in MTP) ; Uttarkashi , 1185 m, Bhaghirathi river, 21.X.1997, J. Šťastný leg. (1 ex. MTP) ; Himachal Pradesh : Monali, 2000–2300 m, 15.V.1977, leg. Wittmer & Brancucci (1 ex. GWW) ; Nainital District , spring brook ca. 50 cm wide, right tributary of Gigerani, flowing from steep rocky cliff, ca. 1 km S Chapi village, ca. 5 km N Bhim Tal village ;

1200 m a.s.l.; 29°22'05''N / 79°34'30''E, (28), 16.XI.2006, leg. M.A. Jäch (5 exs. NMW) .

Nepal ("dark specimens"): W– Nepal, Silghari-Doti, Kali Gandaki 30.VII.1953, J.B. Tyson (1 ex. BMNH) ; Pokhara lake 25.VII.85, leg. Preuler (1 ex. NMW) ; Mustang, Jomson, Dumba lake , 21.XI.1993, leg. Moog et. al. (2 exs. NMW) ; Mustang Distr., Kaligandaki nr. Marpha , 1.IV.1996, leg. Graf et al. (1 ex. NMW) ; Mustang Distr., Manang, Pisang , 3350 m, 25.XI.1987, leg. Pasang (11 exs. NMW) ; Mustang Distr., Jharkot, Muktinath , Khola , 19.XI.1993, leg. Sharma (1 ex. NMW) ; Mustang Distr., Jharkot , 1985 leg. Preuler (9 exs. NMW, HF) ; Mustang distr., Syang, Syang riv. 2700 m, 18.XI.1993 leg. S. Sharma (1 ex. NMW) ; Kathmandu Valley , 2.II.1981, leg. M. Jäch (5 exs. NMW) ; Kathmandu Valley , 25.II.1981, leg. M. Jäch (1 ex. NMW) ; Kathmandu Valley , 2.XI.1981, leg. M. Jäch (3 exs. NMW) ; Godawari , 16–17.V.1992, leg. I. Jenis (5 exs. NMW) ; Karnali prov., Jumla, Tatapani, Tila river , 2200 m, 24.V.1995, leg. A. Weigel (1 ex. ASS) ; Mahakali distr., Darchula, env. of Makarighar , village side, 1380 m, 29°47’38”N, 80°50’51”E, 3.VI.2005, leg. M. Hartmann & A. Weigel (4 exs. ASS) .

Nepal ("pale specimens"): Prov. Kabrepalanchowk, Cha Khola, Dolalghat , 7.XI.1993, leg. Moog et al. (S 10) (1 ex. NMW) ; C. Nepal, Godawari , 16–17.V.92, leg I. Jenis. (4 ex. NMW) ; Kathmandu Valley , 2.II.1981, M. Jäch leg. (9 exs. NMW) ; Kathmandu Valley, Gokarneswor , Bagmati riv., leg. B. Pradhan (B 68) [without date] (2 exs. NMW) ; Kathmandu Valley, Sundarimai, Nagmati riv., leg. B. Pradhan (B 28) [without date] (1 in NMW) ; Kathmandu Valley, Budhanilkanth, Mahadev riv., leg. B. Pradhan (B 34) [without date] (1 ex. NMW) ; Kathmandu Valley., Sundarimai, Nagmati riv., leg. B. Pradhan (B 28) [without date] (1 ex. NMW) ; Kathmandu Valley, Narayanthan, Dhobi riv., leg. B. Pradhan (B 25) [without date] (2 exs. NMW) ; Kathmandu Valley, Narayanthan, Bishnumati riv., leg. B. Pradhan (B 24) [without date] (1 ex. NMW) ; Kathmandu Valley, Gangobu, Bishnumati riv., leg. B. Pradhan (B 25) [without date] (2 exs. NMW) ; Kathmandu Valley, 25 km SE Sankhu, Salinadi Khola , leg. B. Pradhan (B 52) [without date] (1 ex. NMW) ; Kathmandu Valley, Gokarna , Bagmati riv., leg. S. Sharma (133) [without date] (5 exs. NMW) ; Kathmandu Valley, Chisini vill., Bishnumati riv., leg. B. Pradhan (B 32) [without date] (5 exs. NMW) ; Kathmandu Valley, Matathirt, Matathirt riv., leg. B. Pradhan (B 71) [without date] (1 ex. NMW) ; Kathmandu Valley, Mahadev Khola bei Balaju , 1350 m, 2.I–6.V.1996, leg. B. Pradhan (B 51) (5 exs. NMW) ; Kathmandu Valley, Budhanilkantha, Bishnumati riv., leg. S. Sharma (151) [without date] (2 exs. in NMW) ; Kathmandu Valley, Budhanilkantha, Dhobi riv., leg. S. Sharma (150) [without date] (1 ex. NMW) ; Kathmandu Valley, Nayapati , Bagmati riv., leg. B. Pradhan (B 67) [without date] (4 exs. NMW) ; Kathmandu Valley, Gokharna, Mahadev riv., 27.III.1996, leg. B. Pradhan (3 exs. NMW) ; Kathmandu, Pashupatinath , Bagmati river, 1350 m, 27°43’N, 85°21’E, 15.IV.2000, leg. A .

Weigel & A. Skale (2 exs. ASS); Kabhre distr. , Bebar, Bebar Khola, 1514 m, 27°35'00"N 85°29'50"E, 1.XII.1999, leg. S. Khanal (6) (2 exs. NMW) .

Pakistan: Baltistan , Skardou , Indus Riv., Karakorum, 2300 m, 2.VII.1976, leg. Osella (3 exs. MSNV) ; same data, 20.VII.1976 (1 ex. MSNV) ; same data, Karakorum , 3000-3300 m, 12.VII.1976 (1 ex. MSNV) ; Swat , SE Minora, Karakar, 1100 m, 25.V.1978, leg. C. Holzschuch (2 exs. GWW) ; Swat , Jowar, 1100 m, 19.V.1983, Besuchet-Löbl (3 exs. MHNG) ; Shishi Valley , 20 km NE Drosh, 11.VII.1998, J. Rejsek leg. (5 exs. MTP) .

Description. TL: 4.7–5.5 mm; MW: 2.4–2.8 mm. Oval to slightly elongate, somewhat flat, poorly shining. Angle between pronotum and elytra obsolete. Colouration yellow with more or less extensive dark markings on pronotum and elytra.

Head yellow or reddish-yellow, usually with a very thin, dark postocular band. Punctuation moderately deep and close, together with few, larger scattered punctures. Antennae testaceous, slightly darkened at the apex of the last 5-6 segments. Mouthparts reddish-yellow. Maxillary palpi testaceous, darkened apically.

Pronotum quite narrow, with maximum width at base. Lateral sides straight or almost so, with lateral border normally strong, specially in apical side. Posterior angles acute.

Elytra oval with maximum width at about the middle of the length. Sides regularly rounded. Surface covered by a fine and impressed punctuation. Discal and sutural rows of punctures usually visible. Subapical denticle distinct.

Dorsal colouration ( Fig. 32a–d): pronotum reddish-yellow, with a variably developed dark band on anterior and posterior borders and two discal spots, more or less extended; elytra yellow, with dark brown or black longitudinal vittae (see under "variability" below).

Underside black, shining, regularly covered by a dense punctuation; traces of fine reticulation are barely visible between the punctures. Apical combs of setae on metasternites visible. Epipleuron testaceous.

Legs uniformly reddish-yellow.

Male: Protarsi slightly dilated. Anterior claws as in Fig. 32e–g. Mesotarsal claws unmodified. Median lobe of aedeagus ( Fig. 32j) thick, slightly sinuate apically; parameres ( Fig. 32h,i) wide, visibly sinuate dorsally.

Female: Similar to male, sometimes a little duller.

Variability. As far as I have seen, specimens from Nepal are inconsistent in colouration and body shape when compared to typical examples from Afghanistan, Pakistan and, of course, Northern India, the habitus of which is shown in Fig. 32a. This is furthermore complicated by the fact that Nepalese populations can be divided into two morphological forms, which tend to be geographically distinct, although not strictly divided: i) the first ("dark specimens") is more elongate and robust in appearance than the specimens of indicus from India and Pakistan and, frequently, with the angle between pronotum and elytra more visible; the dark patterns on pronotum and elytra of these beetles are more extended and, often, the black colouration is prevalent: the elytral vittae are thick and mostly fused together leaving, virtually, only postbasal, submedial and subapical yellow markings; the pronotum is dark on most of the disc’s surface ( Fig. 32b). This form is common in the District of Mustang and perhaps in the whole of western Nepal. Nevertheless, I have also seen specimens from Kathmandu and nearby areas with similar habitus. The holotype of Potamonectes manii from Kashmir ( Fig. 32c) looks quite similar to these Nepalese indicus , but is paler and lacks the same robustness. ii) The second form ("pale specimens") is paler and with a generally wider and more convex body. Dark patterns on elytra and pronotum are less developed, even less so than in typical indicus ( Fig. 32d): discal markings of pronotum are normally reduced to elongate spots, and elytral markings tend towards isolated vittae, not fused together: a kind of pattern quite similar to N. formaster . I have seen specimens of this form only from the valley of Kathmandu, where it seems to be abundant. In spite of their morphological and geographical differentiation, it is difficult to affirm whether these two Nepalese forms should have systematic value or not.

Habitat. N. indicus lives in streams and rivers as do most of the species of this genus. In Pakistan (Baltistan) this species has been collected in the valley of Indus in a temporay pool on a river bed at 2300 m, warmed by the sun [Dr. B.G. Osella, personal comunication].

Distribution ( Fig. 50). A mainly Himalayan species, so far known with certainty from Eastern Afghanistan (Hindukush and northern Sulaiman Range), Pakistan (Karakorum), Kashmir, Northern India (Himachal Pradesh, Uttaranchal Pradesh) and Nepal. In China Zeng (1989: 3) recorded Potamonectes indicus and Potamonectes manii for Tibet and Yünnan, but this has yet to be examined and therefore confirmed as I have been unable to see any Chinese examples (see Toledo 1998); nevertheless the presence of this species in Tibet is at least probable, while in Yünnan these data could be attributed to N. melanogrammus (see below).