Nebrioporus Régimbart, 1906

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 : 7-9

Nebrioporus Régimbart

Nebrioporus (subgenus of Hydroporus ) Régimbart (1906: 237) (orig. descr.); Zimmermann (1920: 133).

Nebrioporus Régimbart (1906) ; Guignot (1946: 15; 1959a: 463); Nilsson & Angus (1992: 276); Nilsson (1992: 81); Angus et al. (1992: 287); Nilsson (1995b: 55); Nilsson & Holmen (1995: 83); Hendrich & Mazzoldi (1995: 1); Pederzani (1995: 39, 66) (partim); Fery et al. (1996: 306); Nilsson (2001: 170; 2003: 65).

Potamodytes (subgenus of Deronectes ) Zimmermann (1919: 186) (orig. descr.); Zimmermann (1920: 121); Feng (1933: 104); Takizawa (1933: 176); Alfieri (1976: 34).

Potamonectes (subgenus of Deronectes ) Zimmermann (1921: 87) (replacement name for Potamodytes Zimmermann); Zimmermann (1933: 1).

Potamonectes Zimmermann (1921) (as valid genus); Guignot (1933: 462; 1941: 57; 1947: 143; 1959a: 439); Zaitzev (1953: 205); Omer-Cooper (1965: 140, 201); Vazirani (1970: 120); Franciscolo (1979: 446); Guéorguiev (1981: 409; 1987: 86); Angelini (1984: 77; 1993: 5); Machado (1987: 45); Rico et al. (1990: 110); Shirt & Angus (1992: 109); Nilsson & Angus (1992: 276) (synonym of Nebrioporus Régimbart ); Pederzani (1995: 41, 66) (valid genus, partim).

Rhabdonectes Houlbert (1934: 68) (orig. descr.).

Zimmermannius (subgenus of Potamonectes ) Guignot (1941: 59) (orig. descr.) syn.n.; Guignot (1959a: 442); Machado (1987: 45); Nilsson & Angus (1992: 287) (subgenus of Nebrioporus ); Nilsson (2001: 173; 2003: 67) (subgenus of Nebrioporus ).

Bistictus (subgenus of Potamonectes ) Guignot (1941: 59); Guignot (1959a: 441); J. Balfour-Browne (1944b: 186) (synonym of Zimmermannius Guignot ).

Type species of Nebrioporus Régimbart , by monotypy: Hydroporus kilimandjarensis Régimbart (1906) .

Type species of Potamonectes Zimmermann , as designated by Guignot (1941): Dytiscus elegans Panzer (1794) .

Type species of Rhabdonectes Houlbert , by original designation: Hydroporus carinatus Aubé (1838 a) .

Type species of Zimmermannius Guignot , by original designation: Hydroporus canariensis Bedel (1881) .

Type species of Bistictus Guignot, by original designation: Hydroporus dubius Aubé (1838b) .

Diagnosis. Following the diagnosis of Nilsson & Angus (1992), the genus Nebrioporus is distinguished from other Deronectes -group genera by the following combination of characters: apex of parameres with sclerotised hook; ventral surface of body normally dull from fine and dense punctuation or from reticulation between coarse punctures, if ventral surface glossy, elytron with subapical spine; median lobe of aedeagus symmetrical; dorsal surface of elytra with fine and dense punctuation, without larger punctures except for the longitudinal series; in most species a lateral subapical spine on each elytron is visible; dorsum yellow or reddish-yellow with darker markings.

Description. Length 3.6–7.8 mm, width 2.3–3.9. Body oval to elongate, flat to almost convex; angle between pronotum and elytron from remarkably pronounced and obtuse, to tenuous or almost invisible. Lateral sides of pronotum from rounded to almost straight, usually bordered; scutellum concealed (partially exposed in N. kilimandjarensis ). Dorsal colouration yellow or reddish-yellow with head and pronotum usually maculate and elytra maculate or vittate; in some species the colouration could be almost completely dark.

Head dorsally visibly reticulated, usually together with more or less dense punctures; underside densely punctate in some species, without a visible postocular ridge; in other species microreticulate, with postocular ridge clearly visible. Epistome rounded or somewhat truncate, with two shallow depressions on clypeus. Dorsal surface yellow or reddish-yellow, normally with dark markings, in some species completely dark or almost so, in some others completely rufo-testaceous. Ventral face reddish or dark, gula and mouthparts reddish.

Pronotum transverse to almost cordiform (cordiform in N. kilimandjarensis ). Lateral sides bordered or not, from rounded to almost straight; in the latter case the sides are usually convergent inward and in few species they are subparallel or convergent backward. Hind angles acute or rounded. Posterior margin strongly or moderately sinuate. Upper surface with a fine and dense punctuation, plus larger and scattered punctures, mostly concentrated along the inner and the hind sides; reticulation scarcely visible. Colouration yellow or reddish-yellow, mostly with dark inner and fore margins; in some species completely dark or almost so. Ventral surface densely punctate, dark or reddish in colouration. Prosternal process lanceolate or triangular, bordered and elevated in the middle, more or less sinuate in lateral view (except for N. kilimandjarensis and N. vagrans where the prosternal process is completely flat and smooth, at least in the apical half).

Elytra elongate, with lateral margins varying from rounded to partially straight. In most species the subapical denticle is present on each elytral apex, although they may be of variable prominence. Dorsal surface covered with short sparse hairs and a fine, dense punctuation, plus three longitudinal series of larger punctures that are not always visible. In some species carinae or elevations are visible. Colouration yellow or reddish-yellow, with dark maculae or vittae developed to varying extents; in some species the dark colour is prevalent.

Surface of metaventrite and abdominal sternites dull, rarely shining, normally covered by a fine, dense punctuation with reticulation not or barely visible (in N. kilimandjarensis and N. melanogrammus , the ventral surface is glossy and covered by large and sparse punctures together with barely visible reticulation). Interlaminar bridge of metacoxae concealed. Colouration black, dark brown or reddish.

Ventral face of metafemora with a longitudinal row of setiferous punctures, densely punctate in most of the species, with reduced punctuation and almost glossy in some others. External face of metatibiae with or without additional punctures whether in rows or irregularly distributed, between the two normal series of spiculiferous punctures.

Males: pro and mesotarsi slightly or obviously more laterally expanded than in females; in most species the protarsal claws are modified but this modification may be variable in extent between species. Male antennal segments slightly more elongate than the females in some species. Parameres with apical sclerotised hook. Median lobe of aedeagus symmetrical, more or less elongate.

Females: dorsal surface generally duller than males and often with differentiation possible through the differently shaped pronotal margins and hind angles. In some species the subapical spines on elytra are more developed in females and the elytral apex more or less produced.

Distribution. Mostly Palaearctic, with the majority of the species in the Mediterranean and Middle East. A number of species occur in North and Central Europe, Siberia, China, Japan, the Himalayan Region, Arabian Peninsula. Some species are Afrotropical, confined to the highlands of eastern Africa and in southern Africa. Three species occur in boreal North America.

Sixty one species and three subspecies were previously known for this genus ( Nilsson 2001). Fifty seven species and four subspecies of Nebrioporus have been recognised in the present revision.