Scirtothrips pilbara, Hoddle, Mark S. & Mound, Laurence A., 2003

Hoddle, Mark S. & Mound, Laurence A., 2003, The genus Scirtothrips in Australia (Insecta, Thysanoptera, Thripidae), Zootaxa 268, pp. 1-40 : 27-28

Scirtothrips pilbara sp. nov.

[ Figs 17 , 45 ]

Female macroptera. Colour: Yellow, compound eyes with 4 ommatidia weakly to deeply shaded; tergites II – VIII brown medially, ocellar triangle and anterior half of mesonotum sometimes brown; antecostal ridges on tergites III­VIII dark medially but paler laterally; sternal antecostal ridges on III­VII dark; forewings uniformly weakly shaded; antennal segment 1 pale, II variable, III – IV pale with apex shaded, V ­ VIII dark.

Structure: Vertex closely striate, ocellar triangle with transverse lines; bases of ocellar setae pair III usually separated by at least the length of these setae, arising well anterior of tangent to anterior margins of posterior ocelli toward margins of ocellar triangle; three pairs of post­ocular setae at least as long as ocellar setae pair III; mouth cone long, extending to mesosternum. Pronotum with anastomosing transverse striae closely spaced; 6­8 anteromarginal setae, 12­20 discal setae; 5 pairs of posteromarginal setae, S2 about twice the length of S1, S1 subequal to S3 and both longer than S4 and S5. Metanotal sculpture transversely reticulate anteriorly and longitudinally reticulate posteriorly; median setae close to margin. Forewing scale with 4­5 marginal setae; first vein setae 3­14+1­9+1­2+0­ 1+0­1; second vein 4­6 setae; proximal posteromarginal fringe cilia straight. Bases of median tergal setae on segments III­V almost in­line with tergal discal setae, separated by no more than 0.75 times the length of these setae; tergal microtrichial fields with 3 discal setae; VIII with a few discal microtrichia anteromedially, posteromarginal comb interrupted medially; tergite IX with microtrichia on posterior half. Sternites III­VI with 3 pairs of posteromarginal setae; microtrichia reduced, scarcely extending mesad of S3.

Measurements of holotype female. Body length 1300. Head, length 75; width 175; p.o. S1 20. Pronotum, length 125; width 190; posteromarginal setae S1 13, S2 30. Forewing length 750. Antennal segments III – VI, 52, 47, 35, 47.

Male macroptera. Similar in colour and sculpture to female, but smaller; abdominal segment IX without paired drepanae, anterior margin convex and extending into segment VIII; aedeagus without paired array of spines laterally, but with group of small spines at apex.

Holotype female. Western Australia, 20 km west of Millstream, from Acacia xiphophylla [Leguminosae], 23.ix.1995. (LAM 2810). Paratypes: 7 females and 1 male collected with holotype; 40 km southwest of Yalgoo, 3 females from Acacia ramulosa , 26.iv.1997 (LAM 3237);

Material excluded from type series: Western Australia, 50 km south east of Wittenoom, 9 females from? Crotalaria flowers, 24.ix.1995 (LAM 2823); 170 km south of Carnarvon, 1 female from Acacia grasbyi 25.iv.1997 (LAM 3219); 75 km southwest of Yalgoo, 1 female collected from Acacia sp. 26.iv.1997 (LAM 3239); 100 km west of Paraburdoo, 1 female collected from Acacia sp. 23.iv.1997 (LAM 3207); Queensland, 15 km west of Mt Glorious, 3 females and 3 males collected from Acacia bipinnate sp., 19.iii.2002 (LAM 4127); Australian Capital Territory, Casuarina Sands , 1 female collected from Acacia mearnsii , 6.xii.1994 (LAM 2606).

Comments. The three paratypes from Acacia ramulosa have a clearly defined brown area medially on the tergites, whereas the females taken with the holotype have this area with weak and diffuse shading. The non­paratypic females listed above from Crotalaria flowers near Wittenoom are all considerably darker than the type series. They not only have the tergites extensively brown, but the forewing second vein bears 8 – 12 setae, and ocellar setae pair III arise further apart close to the anterior margins of the ocellar triangle. In contrast, the specimens from Mt Glorious, Queensland, are considerably smaller and clear yellow, with ocellar setae III separated by no more than the diameter of the first ocellus. Moreover the males in this sample have a paired array of slender spines laterally on the aedeagus. The pattern of variation amongst these specimens excluded from the type series of S. pilbara is such that it is not possible to conclude how many species might be involved. Even the single female taken from near Canberra cannot be distinguished with confidence from the Western Australian specimens. Presumably this species­group, in which the mouth cone usually extends to the mesosternum, is associated with various species of Acacia .

Figures

FIGURES 11 ­ 20. Scirtothrips heads and pronota. 11, frondis; 12, inermis; 13, kirrhos; 14, longipennis; 15, litotes; 16, moneres; 17, pilbara; 18, tenor; 19, quadriseta; 20, solus.

FIGURES 45 ­ 50. Scirtothrips abdominal tergites. 45, pilbara VI­VIII; 46, quadriseta VI­IX; 47, solus VI­IX; 48, litotes VI­IX; 49, tenor IV­VI; 50, frondis IV­VII.