Neptosternus circumductus Régimbart, 1899

Hájek, Jiří, 2006, The westernmost record of Neptosternus circumductus, and a review of Dytiscidae (Coleoptera) of Baluchistan (Iran, Pakistan), Acta Entomologica Musei Nationalis Pragae 46, pp. 43-56 : 45-46

Neptosternus circumductus Régimbart, 1899

( Figs. 1, 3 )

Neptosternus circumductus: RÉGIMBART (1899) : 83 (original description; Genji, South Arkot [Tamil Nadu, India]);

VAZIRANI (1953): 424 (description of variability; Madras [Tamil Nadu], Madhya Pradesh); VAZIRANI (1963): 16

(Bihar); (1969a): 251 (Maharahstra, Orissa, Uttar Pradesh); HOLMEN & VAZIRANI (1990): 20 ( India); HENDRICH

& BALKE (1999): 60 ( India); HENDRICH & BALKE (2000): 1286 (Madhya Pradesh, Maharastra, Orissa, Tamil

Nadu, Uttar Pradesh).

Type locality. ‘l’Inde anglaise. Genji (South Arkot)’ [Province Tamil Nadu, southern India].

Type material. LECTOTYPE: 3, by present designation ( MNHN), labelled: ‘ INDE ANGLAIS, Maindron 1881 / MUSEUM PARIS, COLL. MAURICE REGIMBART, 1908 [printed] / TYPE [red label, printed] / Neptosternus circumductus Rég. n. sp. typ. [hw], Régimbart det. 1896 [printed] / LECTOTYPUS 3, NEPTOSTERNUS circumductus Régimbart, 1899 , Jiří Hájek des. 2002 [red label, printed]’. 2 paralectotypes ( MNHN), labelled: ‘MUSEUM PARIS, INDE ANGLAISE, ARKOT NORD, GENJI, M. MAINDRON 1881 / Genji (South Arkot), Inde anglaise, Janvier 1881 / circumductus Rég. , Inde (typ. museum) [hw]’ and the respective paralectotype labels. I herein designate the lectotype to fix the identity of this species, as available taxonomic works do not allow unambiguous identification of specimens.

Additional material examined. INDIA: 13 1♀, ‘S-India, Tamil Nadu, Nilgiri Hills, 15 km SE Kotagiri, Kunchappanai , 900 m, 76°56′E 11°22′E, 17-28.11.1993, leg. Boukal & Kejval’ ( NMW) ; 4 ex, ‘ C India, MP [Madhya Pradesh], Panna National Park , VIII.1988, C. Werner leg.’ ( LHCB, NHMB, NMPC) ; IRAN: 84 exs., ‘IRAN, 11.- 12.IV.2000, Sistan va Baluchestan Prov., Pir Sohrab env., 100 m, (25°44′N, 60°50′E)’, ‘ Iran 2000 Czech Biological Expedition, J. Hájek & M. Mikát leg.’ ( LHBC, NMPC) .

Redescription. Large, elongate species; body arched in lateral view. Head and pronotum testaceous, elytra brown with variable yellowish pattern ( Fig. 1 ). Ventral parts and appendages testaceous.

Measurements. Total length of beetle 3.6-3.9 mm (lectotype 3.7 mm); length without head 3.3-3.5 mm (lectotype 3.3 mm); maximum width of beetle 1.9-2.1 mm (lectotype 2.0 mm).

Head. Coloration testaceous. Reticulation composed of slightly impressed polygonal meshes, but medially densely punctate. Mouthparts testaceous.

Pronotum. Coloration testaceous, with thin brown stripe along posterior margin, darker anteriorly along the row of large punctures, and in some specimens also with median brown spot along anterior margin. Reticulation similar to that on head but more impressed. Surface densely punctate; basomedially, along anterior margin and laterally with some larger punctures.

Elytra. Blackish brown, with uninterrupted lateral yellow margin and two variable, sometimes confluent yellowish spots on disc of each elytron; lateral margin dilated apically towards suture in form of a triangle ( Fig. 1 ). Microreticulation consisting of slightly transverse polygonal meshes. Large punctures sparse on disc. Three rows of serial punctures perceptible (cf. HENDRICH & BALKE 1997): discal and first lateral row distinct, second lateral row perceptible only in second third of elytral length, sutural row not present.

Ventral side. Venter testaceous and microreticulated. Abdominal sternites with several large setigerous punctures.

Legs. Completely testaceous. Male tarsomeres of fore and middle legs not dilated. Claws simple and equal.

Male genitalia. Shape of median lobe as in Fig. 3 .

Female. Similar to male. Last abdominal sternite narrowed apically.

Affinities. According to the elongate shape of body and elytral coloration, N. circumductus stands relatively solitary within the Indian and Oriental species of the genus. Habitually, it is more similar to the African species arranged by OMER- COOPER (1970) in species group I ( N. ornatus -species group). At present, this group contains 14 species occurring in southern and central Africa and Madagascar.

Habitat. The Iranian specimens of N. circumductus were collected in a small pool of an almost dry river bed (around 5 metres in diameter and 1 meter in depth). The bottom consist- ed of sand and few larger stones ( Figs. 5-6 ). All specimens were collected with a dip net at night.

Distribution. India and Iran (Sistan va Baluchestan province). Presence in Pakistan is likely.

Figures

Figs. 1-4. 1, 3: Neptosternus circumductus Régimbart, 1899. 1 – habitus (a – aberrant specimen from Baluchistan; b – lectotype from India); 3 – median lobe of aedeagus (a – apex of median lobe in ventral view; b – median lobe in lateral view). 2, 4: Laccophilus inefficiens (Walker, 1859). 2 – habitus; 4 – median lobe of aedeagus in lateral view. Scale bars: 2 mm (Figs 1-2); 0.25 mm (Fig. 3); 0.5 mm (Fig. 4).

Figs. 5-6. Locality ‘Pir Sohrab’, 100 m a.s.l., 12.iv.2000, Sistan va Baluchestan Province, Iran. Photo author.