Baeus scrobiculus, 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 : 35-37

16. Baeus scrobiculus, Stevens , sp. nov.

(Figs 7E, 13A & B, 16D)

Holotype, ♀, Queensland, ' 11.51S 142.38E, 12 km SSE Heathlands , 22.Mar-25.Apr. 1992, T. McLeod, FIT #2'; ' F.I.T., ANIC 1245 , closed forest' ( ANIC).

Paratypes: Queensland: 1 ♀, same data as holotype ( ANIC) ; 2 ♀♀, Bellenden Ker Range, Cableway Base Station , 17.x.-9.xi.1981 ( QDPC) ; 1 ♀, Julatten, Clacherty Rd , 4-25.ii.1983, A. Walford-Huggins ( QDPC) ; 1 ♀, Heathlands Research Reserve , 11.51S 142.38E, 22.iii-25.iv.1992, T. Mcleod ( ANIC) .

Description. Female. Mean length 0.94 mm (0.87-0.98; n = 5); body and posterior vertex dark, red brown, anterior vertex and frons brown, legs and antennae lighter than frons, both with darker markings dorsally.

Head 2.65 (2.50-2.88) x as wide as inter-ocular distance and head length; medial ocellus 20 µm in diameter, 122 (120-130) µm from posterior head margin; lateral ocelli touching eye margin, 20 µm from posterior head margin; posterior ocellar line 1.54 (1.50-1.56) x inter-ocular distance; vertex finely coriarious, pilosity sparse and mostly short, if setae of medium length do occur then only just exceeding 10 µm; eyes are large and ovoid, eye height 0.56 (0.53-0.59) x head height, eye width 0.62 x length, pilosity minute, not visible under a stereo-light microscope; frontal carina broad, prominent but short, reaching 0.42 (0.36-0.48) distance to medial ocellus; lateral cristulations of malar region faint, reaching to within 10 µm of eye margin; in postero-lateral view, anterior and posterior genal margins highly convergent medially; anterior genal margin in contact with 0.40 (0.38-0.42) of ventral eye margin length; posterior eye margin broadly touching hyperoccipital carina.

Mesosoma. Very compact, length 0.31 (0.27-0.33) x width; mesoscutum and mesoscutellum transverse in appearance; mesoscutum finely coriarious, pilosity very sparse, although small patches of medium density can occur, mixture of short and medium length, medium length setae in range of 10-15 µm, not exceeding 20 µm; anterior half mesoscutellum faintly coriarious, posterior half smooth, only one row setae present, short, dense medially, moderately dense laterally; propodeum glabrous medio-dorsally; mesoscutum length 0.23 (0.20-0.26) x width, 0.54 (0.50-0.60) x mesosoma length and 1.73 (1.50-2.25) x mesoscutellum length; mesoscutellum 2.2 (2.0-2.5) x as long as propodeum; sculpturing of entire dorso-lateral mesosoma scrobiculate, except for pronotum and thin glabrous band along posterior margin of propodeum; propodeal spiracle difficult to see within sculpturing laterally, more visible postero-laterally, opening small and ovoid; prominent laterally projecting carina not present on dorso-lateral propodeum (Fig. 13B); posterior margin of metapleuron distinct, curved dorsally and ending ventral to level of antero-lateral margin of T2, ventro-posterior margin elevated from ventro-anterior margin of lateral propodeum; hind femoral spine absent.

Metasoma. T2 length 0.88 (0.77-0.96), faintly coriarious, pilosity sparse and mostly short, if setae of medium length do occur then only just exceeding 10 µm; T3 smooth, bearing one row of short setae; T4 glabrous.

Comments. This species is similar in size, shape, and pilosity to B. arthuri . The genal shape of both species are similar, with the posterior and anterior margins being strongly convergent medially. However, B. scrobiculus is easily identifiable by the extensive scrobiculate sculpturing of the dorso-lateral propodeum.

It is this distinctive feature that the species name is derived from the Latin word scrobiculus, meaning extensive scrobiculation.

Baeus scrobiculus is recorded from northern Queensland, a region that has been extensively sampled(Fig. 16D). However, it has not been commonly collected and is described here from five specimens only.