Micronecta (Micronecta) janssoni, Nieser & Chen & Yang, 2005

Nieser, Nico, Chen, Ping-ping & Yang, Chang Man, 2005, A New Subgenus And Six New Species Of Nepomorpha (Insecta: Heteroptera) From Yunnan, China, Raffles Bulletin of Zoology 53 (2), pp. 189-209 : 194-195

Micronecta (Micronecta) janssoni , new species

( Figs. 12-21 )

Material examined. – Holotype ( CAS) - macropterous male, CHINA: Yunnan, Xishuangbanna, 119 km from Jinghong to Mengla , rocky stream, 1 Jun.2002, coll. C. M. Yang & P. Chew, YCM310.

Paratypes, same data as holotype, 14 males, 19 females ( CAS, ZRC), 6 males, 6 females ( NCTN); in addition, 31 larvae were collected. Yunnan, Xishuangbanna, Mengla, 55th stream, 30 May.2002, coll. C. M. Yang & P. Chew, YCM303 ( ZRC); Yunnan, Xishuangbanna, waterfalls near Mengyuan, 1 Jun.2002, coll. C. M. Yang & P. Chew, YCM309, 1 male ( ZRC); Yunnan, Xishuangbanna, Menglun, Man- Er stream, 11 Jul.2001, coll. H. M. Liu, ME3-004F, 1 female ( ZRC); Mengla, river by Jing Meng Yuan village near Mengyuan, 24 May.2000, coll. L. Cheng, LC033, 1 male, 5 females ( ZRC). All macropterous .

Description. – Macropterous form, based on specimens in alcohol. In dorsal view, generally a medium reddish brown, medium sized, broadly ovate species with its greatest width at the level of the caudal apex of claval commissure.

Dimensions. Length, male <x> 2.03, s 0.047 {2.03}, female <x> 2.02 s 0.051; width, male <x> 1.02, s 0.044 {1.01}, female <x> 1.02, s 0.023; width of head, male <x> 0.78, s 0.014 {0.78}, female <x> 0.78, s 0.011; synthlipsis, male and female <x> 0.38; posterior width of an eye, male and female <x> 0.22; width of pronotum, male <x> 0.84, s 0.021, female <x> 0.83, s 0.011; ocular index, male <x> 1.86, s 0.058 {1.90}, female <x> 1.91, s 0.099.

Colour. Dorsally generally medium reddish brown; head yellowish with an orange to reddish spot placed medially between eyes, eyes castaneous, rostrum dark brown to blackish. Pronotum unicolorous medium brown except for caudolateral angles and posterior margin narrowly yellow; scutellum reddish. Hemielytra medium reddish brown to light brown in distal part of corium, with poorly differentiated slightly darker patches as follows: one to three on clavus, one proximally on corium, a zigzag band halfway corium and one proximally on right membrane. Distal part of right membrane transparent, smoky, with closed hemielytra blackish due to underlying left membrane; embolium reddish, near inner margin with a thin blackish stripe, which may be interrupted; no brown patches at costal margins; hyaline mark at base of clavus short, about 0.12 long, V-shape obscured by reddish marking. Thorax and abdomen ventrally dark brown to greyish black. Legs pale yellowish with some small dark brown to blackish marks, notably in distal half of pala, distal edge of middle tarsus, and the fringe of swimming hairs and claws of hind tarsus.

Structural characteristics. Length two times width (length/ width males 2.03/1.02, females 2.02/1.02). Head slightly narrower than pronotum, synthlipsis 1.7 times as wide as the posterior margin of an eye. Pronotum well developed, dorsally convex with well developed lateral margins, 2.5 times as wide as long (W/L: male 0.84/0.33, female 0.83/0.33). Hemielytra beset with numerous spinules, especially dense and distinct in distal half of corium. Spines laterally on abdominal segments: VI two short, two long ( Fig. 18 ); VII three or four short, two long; VIII five short two very long hair-like. Pala ( Fig. 13 ) with three dorsal bristles; upper row of palm with about 16 bristles which are gradually becoming larger distally; ventral row with about 20 bristles, the distal 12 much larger than the proximal ones. Leg measurements as in table 1.

Male. Fore leg ( Fig. 13 ): femur with two apical spines, one in apical third and two in basal half; tibia with three spines in apical third; palar claw a simple clavate flap ( Fig. 14 ). Prestrigilar lobe ( Fig. 21 ) well differentiated, apical part tongue-like, obtusely rounded; strigil ( Figs. 18, 19 ) oval, with a distinct stalk and one comb with about 90 densely packed teeth. Mediocaudal lobe of seventh abdominal sternite ( Fig. 15 ) short, with an acute apex and four rather weak bristles on its surface. Free lobe of left part of segment eight ( Fig. 20 ) elongate, gradually broadening towards apex, apical margin sinuate; with about 17 bristles in latero-apical part. Right paramere ( Fig. 16 ) with a broad shaft and a hooked apex, beset with three tooth-like structures, basal process with about 40 stridulatory ridges. Left paramere ( Fig. 17 ) rather broad with a small notch halfway the shaft and about three faint transverse grooves.

Female. Fore leg with the same set of spines as male; palar claw bristle-like, distinctly more strongly developed than the bristles in the palmar rows. Receptaculum seminis urn-shaped ( Fig. 12 ).

Brachypterous form unknown.

Etymology. – This species is named in honour of the late Dr. Antti Jansson for his outstanding contributions to the taxonomy and biology of Corixoidea.

Comparative notes. – This species does not run in the key to continental SE Asian species ( Nieser, 2000) because of the claw of the intermediate leg being about half as long as its tibia (couplet 15). The right paramere with its toothed apical part distinguishes this species from all other Asian Micronecta species. The following characters place this species in subgenus Micronecta : four bristles on the median lobe of seventh abdominal sternite, the shape of the left paramere, and the relatively large, clavate, palar claw of the male.

Figures

Figs. 12-15. Micronecta janssoni, new species, paratypes, 12) female, receptaculum seminis; 13) male, foreleg; 14) apex of male pala; 15) male, mediocaudal lobe of sternite VII. Scale: 0.1 mm.

Figs. 16-21. Micronecta janssoni, new species, paratype, male; 16) right paramere; 17) left paramere; 18) right part of tergite VI; 19) strigil, scale: 0.05 mm; 20) free lobe of left part of tergite VIII; 21) prestrigilar lobe. Figs. 16-18, 20-21, scale: 0.1 mm.