Baeus tropaeumusbrevis, Stevens, 2007

Stevens, N. B. & Austin, A. D., 2007, Systematics, distribution and biology of the Australian ' micro-flea' wasps, Baeus spp. (Hymenoptera: Scelionidae): parasitoids of spider eggs., Zootaxa 1499, pp. 1-45 : 38-41

18. Baeus tropaeumusbrevis, Stevens , sp. nov.

(Figs 14A & B, 17A)

Holotype, ♀, Western Australia, ' 15.38S 125.15E, CALM Site 28/3, 4 km W of King Cascade , W.A., 12-16. June.1988, T. A. Weir'; ' Malaise trap with trough, closed forest' ( ANIC).

Paratype: Western Australia: 1 ♀, Marun, Prince Frederick Harbour , 15.00S 125.21E, 6-11.xi.1988, I. D. Naumann ( ANIC) ; Christmas Island: 1 ♀, 10.29S 105.37-38E, nr Central Area Workshop , 13-28.iv.1989, J. Lawrence, flight intercept trap, closed forest, plateau ( ANIC) ; 1 ♀, 10.28S 105.42E, Lily Beach Road , 13-28.iv.1989, J.C. Cardale, malaise trap ( ANIC) ; 1 ♀, 10.27S 105.33E, nr North-West Point , 13-28.iv.1989, J.F. Lawrence, flight intercept trap, closed forest, terrace ( ANIC) ; 1 ♀, 10.30S 105.35-36E, East-West Park Track , 13-28.iv. iv.1989, J.F. Lawrence, flight intercept trap, closed forest, plateau ( ANIC) .

Description. Female. Mean length 0.72 mm (0.69-0.74; n = 2); body and head dark brown, legs and antennae light brown, both slightly darker dorsally; a yellow medial band exists across the head of the Australian type specimens but this is believed to be an artefact of the trap preservative.

Head. 2.27 x as wide as inter-ocular distance and 1.79 x head length; medial ocellus 10 µm in diameter, 70 µm from posterior head margin; lateral ocelli touching or within 5 µm of eye margin, 20 µm from posterior head margin; posterior ocellar line = inter-ocular distance; vertex faintly coriarious, hair processes prominent, pilosity mostly moderately dense, but can be dense posteriorly, of medium length overall; eyes circular, height 0.46 x head height, eye width 0.66 (0.63-0.68) x length, pilosity of medium length; frontal carina reaching 0.53 distance to medial ocellus; lateral cristulations of malar region not reaching to within 10 µm of eye margin; in postero-lateral view, anterior and posterior genal margins parallel medially; anterior genal margin in contact with 0.72 of ventral eye margin length; posterior eye margin not touching hyperoccipital carina, is 10 µm from posterior head margin.

Mesosoma. Length 0.63 (0.59-0.68) x width; mesoscutum and mesoscutellum faintly coriarious, pilosity mostly moderate in density but can be dense in parts, and of medium length overall; posterior margin of mesoscutellum broadly extending to anterior margin of T2, so propodeum not visible medio-dorsally; mesoscutum length 0.50 (0.48-0.52) x width, 0.70 (0.68-0.71) x mesosoma length and 2.28 (2.17-2.40) x mesoscutellum length; sculpturing latero-dorsal mesopleuron and propodeum anterior to spiracle confused, region of latero-dorsal propodeum, posterior of spiracle, bearing short carinae dorsally, each with a long bristle posteriorly, and longer, more distinct carinae ventral of spiracle that are not prominent enough to obviously delineate lateral propodeum from dorsal propodeum; propodeal spiracle opening small and ovoid; posterior margin of metapleuron distinct, straight, and long, ending dorsal to level of antero-lateral margin of T2, posterior region of metapleuron level with anterior region of lateral propodeum; hind femoral spine absent.

Metasoma. T2 length 0.80 (0.77-0.83), sculpturing faintly coriarious anteriorly to smooth posteriorly; pilosity mostly moderately dense, but sparse areas do occur posteriorly, of medium length overall; both T3 and T4 glabrous.

Comments. Baeus tropaeumusbrevis is readily distinguished from most other species by the posterior margin of the mesoscutellum extending over the propodeum dorsally to reach the anterior margin of T2. Only B. tropaeumusdensus and an undescribed Baeus species also possess this distinctive character. However, B. tropaeumusbrevis is distinguished from these by having shorter pilosity, and the lateral ocelli being closer to the eye margin. It is suspected that the trap preservative used to collect this species has caused bleaching to occur, resulting in a yellow band across the head of the Australian type specimens. However, the head is believed to be uniform in colour, similar to the body.

This species is known from two specimens from north western Australia (Fig. 17A) and four specimens from Christmas Island.

It is named after the Latin words tropaeumus, meaning a shield or trophy taken from a battlefield by the victor as a token of a foe's defeat, relating to the extended mesoscutellum, and brevis, meaning short, relating to both its shorter pilosity and the shorter posterior extension of the mesoscutellum over the anterior margin of T2, relative to B. tropaeumusdensus .