Thrips korbuensis, Ng & Mound, 2020

Ng, Y. F. & Mound, L. A., 2020, Character state variation among species of Thrips genus (Thysanoptera) in Malaysia, with one new species and two new records, Zootaxa 4852 (2), pp. 239-245 : 240-242

Thrips korbuensis sp. n.

( Figs 1–12 )

Female macroptera. Body bicoloured, abdominal segments VIII–X uniformly brown ( Fig. 4 ), segments II–VII with median area largely brown; legs pale; antennal segments I–II and IV–VIII brown, segment III and apex of II pale ( Fig. 2 ); fore wing basal and apical areas pale, median area largely brown ( Fig. 10 ); major setae on pronotum and metanotum dark. Antennae 8-segmented, segments VII–VIII small ( Fig. 2 ). Head wider than long; with faint irregular striations in front of first ocellus but ocellar area smooth; vertex with fine transverse striations ( Fig. 1 ); ocellar setae III outside anterior margins of ocellar triangle; postocular setae arising in a row parallel to eye margin, seta I largest, seta II minute. Pronotum wider than long, with faint transverse striations or almost none medially, fine transverse lines at posterior margin; with more than 20 small scattered discal setae; 2 pairs of long posteroangular setae, posterior margin with 3 pairs of short setae. Mesonotum with fine transverse striations, but no sculpture lines close to anteromedian CPS ( Fig. 3 ). Metanotum transversely striate on anterior half, with longitudinal but more widely spaced striations on posterior half; median pair of setae stout, at anterior margin, arising closer to lateral pair than to each other, with a pair of CPS ( Fig. 3 ). Fore wing first vein with about 10–12 setae on basal half, 3–4 widely spaced setae on distal half; second vein with 14–17 setae ( Fig. 10 ); fore wing clavus with 4–5 veinal setae and one discal seta, with subapical veinal seta longer than apical seta ( Fig. 11 ). Abdominal tergite I transversely reticulate, CPS close to posterior margin; tergite II with 4 lateral marginal setae ( Fig. 6 ); tergites II–VII with 1 or 2 faint transverse lines anteriorly, but almost no sculpture medially; tergite VIII posteromarginal comb complete but microtrichia unusually small ( Figs 8 & 9 ); tergite IX with 2 pairs of CPS, median pair of setae (S1) not extending beyond apex of X. Pleurotergites without discal setae. Sternites III–VII with about 10 discal setae, II with a pair of discal setae and 3 pairs of marginal setae; sternite VII posteromarginal setae long, S1 arising in front of posterior margin ( Fig. 5 ).

Measurements (holotype female in microns). Body length 1525. Head, length 120; width across eyes 155; ocellar setae III length 22. Pronotum, length 130, width 220; posteroangular setae 70–80; posteromarginal setae 15–28. Metanotum median setae 55. Fore wing, length 760; distal setae on first vein length 40–60. Tergite X length 130. Antennal length 310; segments III–VIII length 58, 55, 41, 63, 6, 10.

Male unknown.

Specimens studied. Holotype female: MALAYSIA, Perak, Gunung Korbu (4°69’N, 101°21’E), asl 850 meter, from flowers of Rubiaceae plant, 1–7.vii.2019 (Ng, Y.F.) (in Centre for Insect Systematics, UKM, Malaysia) . Paratypes: 4 females all collected with holotype (in CISUKM; Australian National Insect Collection, Canberra, Australia) .

Comments. This new species runs to couplet 13 in the key to the species of Thrips genus recorded from Peninsular Malaysia ( Mound & Azidah 2009). Most of the morphological character states of this new species are shared with the complex of species in “Group V” of Palmer (1992: 20). Using the key in that paper this new species can be tracked to more than one species. If the fore wing first vein setal row ( Fig. 10 ) is interpreted as not having a distinct gap (couplet 75 in Palmer 1992: 14), then this species tracks to T. samoaensis . However, that Pacific Island species is described as having a uniformly light brown body. Alternatively, the new species tracks to T. florum or even to T. coloratus . It shares with T. florum the absence of sculpture lines around the mesonotal campaniform sensilla, also the minute size of postocular setae pair II, and moreover it has the sub-apical seta on the fore wing clavus slightly longer than the apical seta. However, it has more numerous setae on the fore wing first vein than T. florum both on the basal half and the distal half, and tergite X is unusually long. It is similar to T. coloratus , and to most specimens of T. florum , in having only seven antennal segments. However, it differs from T. coloratus in having the fore wing more sharply pale at the base, and the distal part of the fore wing increasingly pale ( Fig. 10 ). Moreover, T. coloratus has lines of sculpture around the mesonotal campaniform sensilla, and the fore wing clavus apical seta is clearly longer than the sub-apical ( Fig. 12 ). The new species is also distinguished by having antennal segments I–II pale brown instead of yellow, abdominal segments VIII–X uniformly dark, and tergite VIII with the microtrichia of the posteromarginal comb unusually small. Another member of this group that was described from various different flowers in Peninsular Malaysia is Thrips razanii . This is also similar to T. florum in having no sculpture lines around the mesonotal campaniform sensilla, and postocular setal pair II minute, but the fore wing is uniformly dark and not paler at the base, antennal segment III is brown not yellow, the metanotal median setae are closer to each other than to the lateral pair, and the metanotal sculpture is irregular medially.

Figures

FIGURES 1–12. Thrips korbuensis sp.n. Female (1) Head; (2) Antennal segments I–VIII; (3) Meso- and metanotum; (4) Abdominal tergites VII–X; (5) Sternites V–VII; (6) Tergite II; (8) Tergite VIII (close up of Holotype); (9) Tergite VIII (close up of Paratype); (10) Fore wing; (11) Fore wing clavus. Thrips coloratus (7) Tergite II; (12) Fore wing clavus.