Neusterensifer stysi, 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 : 275-278

Neusterensifer stysi sp. nov.

( Figs. 14-18 )

Type locality. Papua New Guinea, East Sepik Province, Passam near Wewak.

Type material. HOLOTYPE: J (micropterous), PAPUA NEW GUINEA: SEPIK: ‘P.N.G. E. Sepik / P. R. Prior // Passam 400m / village S. Wewak on / Sepik hghwy. 30.xi. / 1995 ’ ( OXUM) . PARATYPES: 1 J 1 ♀ (micropterous), same data as holotype ( OXUM).

Description. Micropterous specimens.

Dimensions (all in mm). Length J 1.90-2.01, ♀ 2.18; width J 0.83-0.88, ♀ 0.89.

Colour ( Fig. 14 ). Ground colour dull dark greyish brown to blackish. Head: rostrum yellowish to light brown with darker median stripe, apical segment shining black; bucculae yellowish; clypeus shining black and mostly covered with silvery pubescence; a band of silvery pubescence from clypeus to inner angle of eye; antennal sockets and eyes castaneous; vertex dull grey brown to dark grey, median groove black. Pronotum: anterior quarter medially half dark greyish brown, second quarter medially yellowish brown, lateral parts of anterior half covered by thick silvery pubescence; posterior half dull dark grey, concolorous with metanotum; anterolateral angles of metanotum with silvery pubescence. Tergites II-VI dull grey, VII and VIII medium brown to grey; tergites II-VIII laterally with patches of variable size of silvery pubescence, which are nearly absent on tergite IV. Connexiva medium to dark brown. Venter dark grey, medially variably medium brown.Antennae and legs yellowish with infuscated stripes and apices of segments.

Structural characteristics. Body dorsally covered with appressed golden brown pilosity and sparse longer semi-erect brownish setae. Width of head 1.3 times its length (0.90 / 0.62); width of eye about half the width of interocular space (0.15 / 0.27). Lengths of antennal segments I: II: III: IV equal to 0.31: 0.22: 0.37: 0.47, with short and not striking pilosity except for 1-3 longer setae on segment I and 1-2 on segment II. Pronotum covering mesonotum ( Fig. 14 ), its width 2.3 times its median length (0.81 / 0.35), with transverse groove about halfway its length, anterior half covered by very thick pilosity obscuring the underlying pits, posterior half of pronotum and metanotum with well visible pits; lateral margins of prothorax rounded, humeri not developed. Median length of metanotum 0.27. Median length of tergites II-VII equal to 0.15: 0.13: 0.11: 0.12: 0.13: 0.25. Lengths of leg segments (femur: tibia: tarsus I: tarsus II), foreleg 0.53: 0.48: 0.24, middle leg 0.73: 0.68: 0.15: 0.24, hind leg 0.80: 0.99: 0.19: 0.25.

Male. Fore tibia with a subapical indentation ( Figs. 14 and 17 ); tibial comb 0.57 times as long as tibia (0.27 / 0.47). Abdomen: ventrites IV-VI and anterior half of ventrite VII with median groove becoming deeper posteriorly; ventrite VI in posterior half, adjacent to the median groove with a pair of tumescences each bearing a dense tuft of short black setae ( Fig. 15 ); ventrite VII medially with a large tumescence about half as wide as the ventrite, its caudal half with transverse impression anteriorly and posteriorly demarcated by a rim; ventrite VIII flattened.

Female. Connexiva IV-VII dorsally with double row of long erect bristles. Gonocoxae expanded with broad basal and narrow apical part ( Fig. 18 ).

Macropterous form unknown.

Differential diagnosis. Neusterensifer is a very speciose genus in New Guinea and adjacent islands ( POLHEMUS & POLHEMUS 1994, 2000a,b, 2004). Males are identified primarily by the process of proctiger and the abdominal venter. The new species is very similar to N. cyclops J. Polhemus & D. Polhemus, 1994 , with a nearly identical pattern of silvery hairs on the thoracic and abdominal dorsum and the identical structure of ventrite VII and process of proctiger in the male. However, the male of N. cyclops is slightly smaller (1.87 mm long), the ratio of antennal segments is different (0.21: 0.19: 0.33: 0.40), the fore femur is without subapical indentation and, according to one of the peer reviews, the tibial comb on the foreleg is 0.50 tibial length in N. cyclops and 0.57 in N. stysi sp. nov., and the raised patches on ventrite VI have a more ovate shape in N. cyclops than in N. stysi sp. nov. Neusterensifer sepik , which occurs in the same area as N. stysi sp. nov., has a somewhat similar process of proctiger in the male. However, males of N. sepik have a distinct row of black bristles on the fore femur which are lacking in N. stysi sp. nov. Females of N. sepik have the apex of connexiva pointed whereas it is rounded in N. stysi sp. nov.

Etymology. With pleasure we dedicate this species to our colleague and friend, Prof. Pavel Štys, for his extensive and great contributions to heteropterology.

Distribution. Northern Papua New Guinea.

Figures

Fig. 14. Neusterensifer stysi sp. nov., J (paratype), habitus, body length 1.90 mm.

Figs. 15-18. Neusterensifer stysi sp. nov. 15-17 – J (paratype). 15 – apex of abdomen, ventral view, segment IX and proctiger removed; 16 – process of proctiger; 17 – fore leg. 18 –♀ (paratype), apex of abdomen, lateral view. Scales: Figs. 15 and 17 = 0.25 mm, Fig. 16 = 0.1 mm, Fig. 18 = 0.5 mm.