Syngaster (Marsh, 1988)

Iqbal, M., Austin, A. D. & Belokobylskij, S. A., 2006, Systematics of the Australasian endemic wasp genus Syngaster Brullé (Hymenoptera: Braconidae: Doryctinae), Journal of Natural History 40 (13 - 14), pp. 819-853 : 846-847

Syngaster steIJensi sp. nov.

( Figures 4a , 6 f–h, 7a)

Male

Length. 8.25 mm.

Colour. Head brown-yellow with dark brown band on face. Antennae dark brown to black. Palps pale yellow. Mesosoma red-brown except dorsal propodeum which is dark brown to black. Fore and mid legs brown-yellow, hind legs dark brown with coxae black. Wings faintly infuscate, pterostigma dark brown. First tergite of metasoma milky white with dark brown medio-dorsal patch in posterior half, rest of tergites black, tergites 3–6 with wide milk-white bell-shaped posterior area.

Head. Width 1.5 times its median length, 1.1 times width of mesoscutum. Head behind eyes weakly convex. Transverse diameter of eye 1.1 times as long as temple in dorsal view. Ocelli medium size, in triangle with base 1.1 times its sides, POL 1.1 times OD, 0.13 times OOL. Frons short and weakly convex. Diameter of antennal sockets two times distance from socket to border of eye. Eyes glabrous, 1.26 times as high as broad. Malar space height 0.47 times height of eye, almost equal to basal width of mandible. Face width almost equal to height of eye and 1.2 times height of face and clypeus combined. Clypeus with narrow lower flange, clypeal suture distinct laterally, almost absent dorsally. Hypoclypeal depression round, its width 0.73 times distance from edge of depression to eye, 0.4 times width of face. Occipital carina present. Hypostomal keel wide. Head below eyes convexly narrowed. Maxillary palps about 1.7 times as long as height of head. Antennal flagellum slender, 50-segmented, first segment length 3.75 times width. Scape with maximum length including lobe 3.3 times maximum width.

Mesosoma. Length 1.76 times its height. Pronotum short. Mesoscutum highly and almost perpendicularly raised above pronotum. Notauli deep and crenulated. Prescutellar depression rather short, more or less deep, smooth, with three strong carinae, 0.3 times as long as scutellum. Scutellum slightly convex, its maximum width 1.16 times median length. Metanotum with very small median tooth. Subalar depression shallow and wide. Sternaulus shallow, straight, smooth, running along entire lower length of mesopleuron. Metapleural lobe wide. Metapleuron separated from propodeum by distinct punctate suture; propodeal and metapleural surfaces continuously rounded, not angled along suture line. Propodeum with lateral tubercles, distinctly roundly narrowed from base to apex (lateral view). Fore tibia with very small spines arranged almost in single row. Tarsal segment of middle leg not elongate; basitarsus 2.8 times as long as wide, 2.8 times as long as second segment, fourth segment subsquare. Hind coxa without basoventral tooth, 1.33 times as long as wide. Hind femur 4.3 times as long as wide. Inner spur of hind tibia 1.3 times as long as outer spur, 0.2 times as long as basitarsus. Hind tarsus 0.95 times as long as hind tibia, basitarsus 0.8 times as long as second to fifth segments combined, second segment 0.3 times as long as basitarsus, 0.75 times as long as fifth segment (without pretarsus).

Wings. Length of fore wing 3.61 times its maximum width. Pterostigma 4.2 times as long as wide, 0.7 times as long as R1. 3RSa two times r, 0.18 times 3RSb, 0.66 times 2RS. Second submarginal cell 1.86 times as long as wide, 0.6 times as long as first subdiscal cell. Hind wing about four times as long as wide, C+Sc+R almost equal to SC+R.

Metasoma. Metasoma 1.2 times as long as head and mesosoma combined. First tergite distinctly and almost linearly widened basally, weakly narrowed apically, with short and wide basolateral processes, with very small dorsope, without spiracular tubercles, length of tergite 1.4 times its maximum width, 1.7 times its apical width, apical width 0.8 times its maximum width. Second tergite with wide and convex medially basal semicircular area, separated by deep crenulate furrow, median length of area 0.66 times maximum length of tergite, maximum length 0.8 times its basal width, 0.57 times length of third tergite, second suture weakly and distinctly undulate. Third tergite with straight transverse crenulate furrow in basal one-third. Remaining tergites smooth and lacking any surface features except for unusual colour pattern.

Sculpture and pubescence. Vertex, frons, and temple entirely smooth. Vertex with rather long semi-erect sparse hairs. Face rugulose with sparse puncturation. Sides of pronotum, mesoscutum, and scutellum puncturate. Mesopleuron smooth in most part. Metapleuron rugulose. Propodeum almost entirely smooth medially, with sparse puncturation laterally. Mesoscutum entirely with dense short semi-erect hairs. Hind coxa rugulose. Hind femur almost smooth with puncturation. Hind tibia with very short, dense, and semi-erect hairs. First metasomal tergite smooth with sparse puncturation, rest of metasoma almost smooth.

Female

Unknown.

Material examined

Holotype: male, Papua New Guinea, 5 ° 32 9 S, 144 ° 09 9 E, Baiyer River , 1100 m, 25 January to 6 February 1979, J. Sedlacek ( AEIC).

Comments

This is a very distinct species based on the black patch on the first metasomal tergite, and the bell-shaped pale white area on the posterior of metasomal tergites 3–6. There is a possibility that it represents the male of one of the species already described from New Guinea, if the metasomal colour pattern ( Figure 7a ) is sexually dimorphic and does not occur in the female sex. However, this character is so unusual that we have elected to describe the species as new so that it can be more easily recognized in the future. It is named after Nick Stevens in thanks for his help with this revision of Syngaster .

Figures

Figure 4. (a) Distribution map of Syngaster species in New Guinea: (m) S. crypticus; (´) S. hirtus; (*) S. neoguineensis; (w) S. quadricolor; (&) S. steυensi; (>) S. tricolor; (S) S. υariegatus. (b) Distribution map of Syngaster species in Australia: (>) S. lepidus; arrow, S. polychromus. Map for S. lepidus modified from Austin et al. (1994).

Figure 6. (a) Syngaster polychromus sp. nov., female, propodeum and metasoma (lateral view). (b–e) Syngaster quadricolor (Cameron), female: (b) head and mesosoma (lateral view); (c) head (anterior view); (d) propodeum and first tergite to third tergite (dorsal view); (e) body (lateral view). (f–h) Syngaster steυensi sp. nov., male: (f) head (dorso-lateral view); (g) head (frontal view); (h) propodeum and metasomal tergites 1–2 (lateral view). Scale bars: 2 mm (a, c); 1 mm (b, d–h).

Figure 7. (a) Syngaster steυensi sp. nov., male, metasomal tergites 3–6 (dorsal view). (b–e) Syngaster tricolor sp. nov., female: (b) head (frontal view); (c) head (dorso-lateral view); (d) head and mesosoma (dorsal view); (e) metasoma (dorsal view). (f–h) Syngaster υariegatus (Szépligeti), female: (f) head (anterior view); (g) head, mesosoma and first metasomal tergite (lateral view); (h) metasomal tergites 1–4 (dorso-lateral view). Scale bars: 1 mm (a–c, f–h); 2 mm (d, e).