Micronecta lumutensis, Chen & Nieser & Lansbury, 2008

Chen, Ping-ping, Nieser, Nico & Lansbury, Ivor, 2008, Notes on aquatic and semiaquatic bugs (Hemiptera: Heteroptera: Nepomorpha, Gerromorpha) from Malesia with description of three new species, Acta Entomologica Musei Nationalis Pragae 48 (2), pp. 269-279 : 270-272

Micronecta lumutensis sp. nov.

( Figs. 1-5 , 7-9 )

Type locality. Indonesia, Kalimantan Timur Province, Pasir on Mount Lumut.

Type material. HOLOTYPE: J ‘ INDONESIA: Kal / Tim [= Kalimantan Timur], Pasir / G.Lumut, 2 km E Rantaulayong / 1°36′36,8″S 115°58′38,7″E / E. Gassó Miracle 24-xi-2005 // GLBA 24-XI-2005 EGM25 / evergreen rain forest along / river; at light ML 19-21 hrs // NNM Leiden’ ( RMNH) . Paratypes: 1 J 2 ♀♀, same data as holotype ( RMNH).

Description. Macropterous specimens; a small greyish Micronecta .

Dimensions (all in mm). Length J 1.48-1.52, ♀ 1.45-1.50; width J 0.69-0.72, ♀ 0.52-0.54; width of head J 0.49-0.51, ♀ 0.52-0.54; synthlipsis J 0.23-0.24, ♀ 0.23-0.24; width of eye J ♀ 0.16; width of pronotum J 0.54-0.57, ♀ 0.56-0.58.

Colour. Dorsally light brown, eyes grey, head yellowish with large brown spot on frons (in one female paratype reduced to two smaller points) and dark brown transverse grooves on rostrum, legs and posterior and lateral margins of pronotum yellowish; ventral side greyish, becoming sordid yellowish caudally. Pronotum shining, unmarked except for lighter posterior and lateral margins. Hemelytra shining with usual hyaline spot basally on clavus, hyaline stripe distally of apex of clavus indistinct; apex of clavus darker brown, darker marks on corium arranged in three interrupted longitudinal stripes, inner angle of corium with a single, variably developed, elongate spot; left membrane hyaline with outer half smoky.

Structural characteristics. Ratio length/width of body: male 2.2-2.5, female 2.1. Head narrower than pronotum, synthlipsis distinctly wider than posterior width of an eye, ocular index: male 1.77-1.78, female 1.59-1.60. Pronotum dorsally convex, about two and a half times as wide as its median length (male 2.7, female 2.4-2.5). Hemelytra appearing smooth at lower magnifications, with very small spines most distinctly on corium where they are arranged in longitudinal rows, and along membranal suture. Spines on lateral sides of abdominal segments as follows: V, 2 short, 1 long; VI, 2-3 short, 1 intermediate, 1-2 long; VII, 3-4 short, 1 intermediate, and 1 or 2 long; VIII, 5 short, 2 very long, bristle-like. Length of fore leg segments (femur: tibia: tarsus, all in mm): 0.19: 0.07: 0.11 in male and 0.20: 0.20 in female; length of middle and hind leg segments (femur: tibia: tarsus: claw): middle leg 0.49: 0.17: 0.24: 0.17, hind leg 0.31: 0.25: 0.26: 0.12: 0.07.

Male. Fore leg ( Fig. 1 ); femur in basal part with two spines and apically with 2-3 small spines; tibia with three spines near distal margin; pala with three long dorsal hairs, palm with about 15 bristles in dorsal and about 16 in ventral row, claw simple, clavate. Abdomen with prestrigilar lobe as in Fig. 7 , strigil ( Figs. 2 and 3 ) small, at a magnification of 400 × without distinct teeth, median lobe of sternite VII short and acute with four bristles (three in paratype on Fig. 8 ). Free lobe of left part of segment VIII ( Fig. 4 ) with rounded apex with 9- 10 bristles; plectrum on right part of segment VIII very finely wrinkled, about 40 thick hairs in a double row along inner margin between plectrum and apex of right part of segment VIII ( Fig. 2 ). Shaft of right paramere ( Fig. 5 ) gradually widened towards apex, left paramere ( Fig. 9 ) apparently with apical impression.

Female. With the same size and general structure as the male except for the usual differences in sexual characteristics.

Brachypterous form unknown.

Differential diagnosis. With the key to West Indonesian males of Micronecta ( NIESER & CHEN 1999) , this species runs to M. skutalis Nieser & Chen, 1999 , from Sabah ( Malaysia) and Palawan (the Philippines) ( NIESER & CHEN 2003). The latter species is of about the same size and, due to a similar hemelytral pattern, looks very similar. Male fore leg and prestrigilar lobe of M. skutalis and M. lumutensis sp. nov. are also very similar. However, the right paramere of the male of M. skutalis is straight with more or less parallel margins, whereas in M. lumutensis sp. nov. it is slightly curved and somewhat widened at the apex ( Figs. 5 and 6 ); the left paramere of M. skutalis is parallel sided, whereas in M. lumutensis sp. nov. it has a widened apex. Most other South East Asian and Malesian species of Micronecta are distinctly larger than M. lumutensis sp. nov. Other species of similar size to M. lumutensis sp. nov. are M. acuta Lundblad, 1933 , from Java, which is slightly smaller (1.1-1.3 mm body length) and lacks a strigil; M. lemnae Nieser, 2000 , from Thailand, West Malaysia and Yunnan ( NIESER et al. 2005) is known only from the brachypterous form, which is slightly smaller (1.2-1.3 mm) and has a characteristic, apically lobed right paramere.

Etymology. Named after its type locality, Mount Lumut.

Bionomics. Collected at light in an evergreen rain forest along a river.

Distribution. Indonesia, Eastern Kalimantan.

Figures

Figs. 1-6. 1-5 – Micronecta lumutensis sp. nov., J (paratype). 1 – fore leg; 2 – apex of abdomen in dorsal view; 3 – strigil; 4 – free lobe of left part of tergite VIII; 5 – right paramere. 6 – Micronecta skutalis Nieser & Chen, 1999, right paramere. Scales = 0.1 mm except Fig. 2 = 0.25 mm.

Figs. 7-13. 7-9 – Micronecta lumutensis sp. nov., J (paratype). 7 – prestigilar lobe; 8 – median lobe of abdominal sternite VII; 9 – left paramere, lateral view. 10-13 – Enithares rinjani sp. nov., J (holotype). 10 – genital capsule; 11 – right paramere, mesal view; 12 – trochanter and femur of middle leg, ventral view; 13 – metasternal xiphus.