Scirtothrips frondis, 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 : 20-21

Scirtothrips frondis sp. nov.

[ Figs 11 , 50 , 53 , 60 ]

Female macroptera. Colour: Pale yellow, antecostal ridges on tergites III­VIII weakly shaded across full width of segments, sternites III­VII with weak shading; forewings uniformly weakly shaded; antennal segment I pale, II pale to weakly shaded, III mainly pale, V – VIII uniformly dark.

Structure: Vertex closely striate, ocellar triangle with reticulate pattern; bases of ocellar setae pair III closer together than length of these setae, arising between midpoints of posterior ocelli; two pairs of post­ocellar setae each at least 0.75 as long as ocellar setae pair III. Pronotum with transverse striae irregular and widely separated; with 2­7 anterior marginal setae, 9­16 discal setae; 4 pairs of posteromarginal setae, seta II sometimes longer than seta I, but often similar in length to I, seta III never longer than I and II. Metanotum equiangular reticulate; median setae well behind margin. Forewing scale usually with 4 marginal setae; first vein setae 3­4+1­4+1+1+0­1+0­1+0­1; second vein 4 setae; posteromarginal fringe cilia wavy. Tergite I median setae usually extend beyond posterior margin of tergite, III­V with bases of median setae separated at least 2.25 times the length of these setae; tergal microtrichial fields with 3 discal setae; VIII with posteromarginal comb of microtrichia complete, no discal microtrichia medially; tergite IX without discal microtrichia. Sternites with lateral microtrichial fields extending mesad of S2 marginal setae.

Measurements of holotype female. Body length 1100. Head, length 100; width 135; p.o. S1 13. Pronotum, length 85; width 150; posteromarginal setae S1 25, S2 28. Forewing length 650. Antennal segments III – VI, 45, 38, 45, 47.

Male macroptera. Similar in colour and sculpture to female, but smaller; sternites commonly with one transverse row of microtrichia close to antecostal ridge; abdominal segment IX with a pair of dark drepanae ventrolaterally with pointed apices curving dorsally; aedeagus without either lateral arrays of spines or terminal spines.

Holotype female. Australian Capital Territory, Tidbinbilla, from young fronds of Dicksonia Antarctica [ Dicksoniaceae ], 20.xi.2002 (LAM 4229). Paratypes: 6 females collected with holotype; New South Wales, Nimmitabel, 8 females, 2 males, and 4 instar II larvae, from tree fern (? Dicksonia sp.), 19.iii.1999 (LAM 3676); Mt. Dromedary, 8 females, 5 males from Dicksonia sp. young fronds, 20.iii.1999 (LAM 3679); Monga, 7 females, 2 males, and 7 instar II larvae from Dicksonia antarctica young fronds, 13.i.1999 (LAM 3659), same site and plants, 20 females 3 males, 23.xi.2002 (LAM 4232), same site and plants, 16 females 6 males, 30.iv.2003 (LAM 4309­12); 20km west of Kiama, Jamberoo Mt Road, 9 females from young fronds of Cyathea sp. [ Cyatheaceae ], 3.xi.2002 (LAM 4207).

Comments. This species breeds on newly emerged fronds of tree ferns, and the larvae are similar in appearance to those of S. dobroskyi ( Figs 60, 63 ). Although it has been found commonly on Dicksonia antarctica , one sample was taken from very young fronds of a Cyathea species. Tree ferns of the genus Dicksonia are widespread and abundant from sheltered gullies within dry sclerophyll forest to rainforest. It is the most common of the tree ferns accounting for 95% of this group in southeast Australia. Four females recorded by Palmer and Mound (1983) from tree ferns in Victoria as being close to S. pan Mound & Walker from New Zealand, presumably represent S. frondis . The New Zealand species differs from S. frondis in having ocellar setae III anterior to the tangent joining the anterior margins of the posterior ocelli, antennal segment III is brown, and the setae on abdominal tergite I are not long enough to reach the posterior margin of this tergite. The pronotal transverse striae of this species are more widely separated than in any other Australian member of the genus.

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.

FIGURES 51 ­ 56. Scirtothrips abdominal sternites. 51, australiae V­VII; 52, dorsalis IV­VII; 53, frondis V­VII; 54, aurantii sternites V­VII; 55, albomaculatus sternites IV­VI; 56, quadriseta IV­ VII; 57, drepanofortis male tergites VIII­IX.

FIGURES 58 ­ 63. Scirtothrips second instar larvae, head and pronotum. 58, aurantii; 59, dorsalis; 60, frondis; 61, helenae; 62, tenor; 63, dobroskyi.