Siamothrips initium, Mound, L. A., 2015

Mound, L. A., 2015, Genera of the Scirtothrips genus-group (Thysanoptera, Thripidae) with a new species of Siamothrips from Malaysia, Zootaxa 4021 (2), pp. 387-394 : 392

Siamothrips initium sp.n.

( Figs 8–17 )

Female macropterous. Body pale to brown, anterior margin of head brown; pronotum uniformly pale; femora, tibiae and tarsi pale, tarsi slightly shaded at extreme apex; antennal segments I–III pale, IV–V shaded in apical half, VI–VIII uniformly shaded ( Fig. 12 ); fore wing brown at base including clavus, and middle areas ( Fig. 15 ); abdominal tergites pale; all abdominal sternites pale including antecostal ridges.

Head wider than long; ocellar setae I present; II situated outside ocellar triangle, III arising on tangent between anterior margins of hind ocelli; two pairs of postocular setae; mouth-cone not extending beyond posterior margin of pronotum, maxillary palps 3-segmented; compound eyes without pigmented ommatidia. Antennae 8-segmented, segment I without dorsal apical setae, II without CPS and mid dorsal setae, with four rows of microtrichia dorsally; III and IV with sense cones forked; III–VI with three to four rows of microtrichia on both dorsal and ventral surfaces. Pronotum trapezoidal with about 30 fine setae, transverse striae at margins but striae irregular medially; no long posteroangular setae, 2 or 3 pairs of posteromarginal setae ( Fig. 10 ). Mesonotum with irregular transverse striae with inner markings; no anterior CPS, median and submedian setae arranging in a transverse line. Metanotum sculpture irregular reticulate medially with inner markings, lateral area with longitudinal lines, median and submedian setae situated at anterior margin, without CPS. Mesosternum with about 23 long and fine setae, endofurca with spinula. Metasternum with about 12 long and fine setae ( Fig. 14 ), endofurca with spinula. Fore wing first vein with 3 + 2 setae on basal half, 5 setae with distinct gap on apical half; second vein without setae; clavus with three veinal and one discal setae; posteromarginal fringe cilia weakly wavy. Tarsi 2-segmented; abdominal tergites II–VII with closely spaced rows of small microtrichia on lateral thirds, S1 setae arising close together; tergite VIII with rows of microtrichia extending across segment on anterior half, with complete posteromarginal comb ( Fig. 16 ); tergite IX with no CPS or microtrichia. Sternites II–VII with rows of discal microtrichia across median area, at least on posterior halves, posterior margin with fringe of microtrichia; segment II with 2 pairs of long posteromarginal setae, III–VII with 4 pairs of long posteromarginal setae ( Fig. 17 ), on VII median pair arising in front of margin.

Measurements of holotype (in microns). Distended body length 870. Head, length 57; width across cheeks 88; vertex length 8–12. Pronotum median length 100; width 126. Metascutal median setae 11; submedian setae 16. Fore wing length 430. Antennal segments I–VIII length (width): 11 (20), 28 (21), 31 (16), 35 (15), 26 (13), 39 (13), 9 (6), 11 (5).

Male unknown.

Material studied. Holotype female: MALAYSIA, Perak, Pulau Pangkor, on Commersonia sp., 2–7.v.2009 (Ng, Y.F.) (in CISUKM). Paratypes: 5 females collected with holotype (in CISUKM and ANIC).

Etymology. This species was first recognised in 2009 during a visit by the first author to the laboratory of Laurence Mound at CSIRO, Canberra. The species name initium , meaning “beginning’, is in reference to that commencement of our collaborative studies.

Comments. The colour of this new species is clearly different from that of Siamothrips argus . In contrast to the uniformly pale colour of that species, initium has several brown markings including the anterior margin of the head, the posterior area of the mesoscutum, the entire metascutum, and the base and middle area of the fore wing. Moreover, the arrangement of the metascutal median and submedian setae in a transverse straight line, and the inner markings to the reticulation on the meso- and metascutum are different from argus .

Figures

FIGURES 8 – 17. Siamothrips initium sp. n: (8) Head, (9) frons; (10) Pronotum; (11) Mesonotum and metanotum; (12) Antenna; (13) Abdominal tergites VI – X; (14) Mesosternum and metasternum; (15) Fore wing; (16) Abdominal tergites VII – IX (close up); (17) Abdominal sternites VI – VII.