Okajimathrips borealis, Okajima & Masumoto, 2025

Okajima, Shûji & Masumoto, Masami, 2025, Some Poaceae-inhabiting Phlaeothripinae (Thysanoptera, Phlaeothripidae) in East Asia, with descriptions of six new genera and 18 new species, Zootaxa 5726 (1), pp. 1-68 : 28

publication ID	https://doi.org/10.11646/zootaxa.5726.1.1
publication LSID	lsid:zoobank.org:pub:894F9D4B-2A99-4AC1-8C9A-828006840831
DOI	https://doi.org/10.5281/zenodo.17869643
persistent identifier	https://treatment.plazi.org/id/03E28781-243F-5040-64C5-FF65AB22FF24
treatment provided by	Plazi
scientific name	Okajimathrips borealis
status	sp. nov.

Treatment

Okajimathrips borealis sp. nov.

( Figs 94–104 View FIGURES 94–107 , 254 View FIGURES 254–257 )

Female (macroptera). Distended body length: 2.5–2.7mm. Body largely yellow ( Fig. 94 View FIGURES 94–107 ); anterior half of head and apex of tube brown, but rarely abdominal segment IX and tube brown; the rest of body and legs yellow. Antennal segment I brown, segments II – VI yellow, segments VII – VIII scarcely shaded with brown. Fore wings scarcely shaded, major body setae pale. Head about 1.3 times as long as wide ( Fig. 96 View FIGURES 94–107 ), 1.33 times in holotype , scarcely protruded in front of eyes, widest across cheeks at a level of postocular setae, dorsal surface almost smooth. Cheeks rounded, almost smooth. Postocular setae shorter than eyes, expanded, situated near cheeks, 175µm apart from each other, 32–33µm apart from eyes in holotype. Eyes relatively small, about one-fourth of head length, ommatidia separated from each other. Ocelli small, posterior ocelli almost as large as ommatidium, about 80µm apart from each other. Antennae ( Fig. 104 View FIGURES 94–107 ) about 1.6 times as long as head; segment VIII pedicellate, distinctly constricted at base, a little longer than segment VII; segment III 1.85 times as long as wide in holotype . Maxillary stylets 14µm apart from each other in holotype; maxillary bridge somewhat weak, a little narrower than one-fifth of head width. Pronotum 0.94 times as long as head and 1.03 times as wide as long in holotype, almost smooth. Prosternum and mesopresternum very similar to those of the type-species ( Fig. 101 View FIGURES 94–107 ). Mesonotum almost smooth, lateral pair of setae short and acute. Metanotum almost smooth at middle; median pair of setae short, 72–73µm apart from anterior margin, 65µm apart from each other in holotype. Fore wing sub-basal setae short and pointed. Pelta weak. Tergites II – VIII S2 setae: II short, but weakly expanded, III, IV and VIII expanded, V – VII finely pointed. Tergite IX S1 and S2 setae shorter than tube, pointed, S1 much shorter than S2. Tube ( Fig. 102 View FIGURES 94–107 ) 0.77 times as long as head, 2.47 times as long as wide in holotype .

Measurements ( holotype female in µm). Body length 2670 (distended). Head length 248, from anterior margin of eyes 220, width across eyes 170, maximum width across cheeks 187; eyes length 63; diameter of posterior ocelli 8–10; postocular setae 35–40. Maxillary bridge width 35. Antenna total length 395, segments III–VIII length (width) as follows: 50 (27), 55 (30), 50 (27), 50 (25), 43 (20), 45 (15). Pronotum length 233, width 240. Setae on prothorax: aa about 20, pa 25, epim 52–53. Fore wing length 850. Sub-basal wing setae: S1 17, S2 15, S3 17. Pelta length?80, width 132. Tergite IX setae: S1 45 –50, S2 150–155. Tube length 190, maximum width 77; terminal setae about 200.

Male (macroptera). Distended body length: 2.0– 2.2mm. Very similar to female in color and structure. Head a little shorter than 1.3 times as long as head; tube about 0.7 times as long as head. Pore plates on sternite VIII are very similar to those of the type-species ( Fig. 103 View FIGURES 94–107 ).

Measurements ( paratype male in µm). Body length 2140 (distended). Head length 208, from anterior margin of eyes 184, width across eyes 150, maximum width across cheeks 162; diameter of posterior ocelli 7–9; postocular setae about 35. Maxillary bridge width 30. Antenna total length 360, segments III–VIII length as follows: 47, 48, 43, 43, 37, 45. Pronotum length 200, width 202. Setae on prothorax: aa 20–22, pa 20–25, epim 45–47. Fore wing length 740. Sub-basal wing setae: S1 11 –15, S2 15 –20, S3 15 –16. Pelta length 78, width 103. Tergite IX setae: S1 43 –45, S2 40 –45. Tube length 150, maximum width 61; terminal setae 190.

Type material. Holotype: macropterous female, Thailand, nr. Chiang Mai, Doi Suthep , on bamboo, 1.ix.1991, TN & SO . Paratypes: Thailand, 31 females and 11 males, collected together with holotype; same locality and habitat as in holotype , 4 females, 3.ix.1991, 27 females and 10 males, 24.viii.1992, TN & SO, 1 female, 2.ix.1992, SO; 4 females, nr. Chiang Mai, Ka Jan , on bamboo, 3.ix.1992 , SO; 2 females, nr. Chiang Mai, Hong kai, on bamboo, 4.ix.1991 , TN & SO; 2 females, Chiang Mai, on bamboo, 2.ix.1991 , TN & SO; 2 females, nr. Chiang Mai, Doi Inthanon , on bamboo, 29.viii.1992 , TN & SO.

Non-paratypic specimens. Thailand, 4 females and 1 male, nr. Chiang Mai, Ka Jan , on bamboo, 3.ix.1992, SO .

Comments. This species has the body largely yellow ( Fig. 94 View FIGURES 94–107 ), although O. kentingensis has the body sharply bicolored brown and yellow ( Fig. 105 View FIGURES 94–107 ). Previously, this species has been considered as a color form of kentingensis , but it appears to have several differences in structure, and it can be distinguished from kentingensis by the key above. Therefore, caution should be exercised because this species is mixed in the specimens collected from Thailand that Okajima has identified as ‘ O. kentingensis ’ in the past. Incidentally, Fig. 133 View FIGURES 125–133 in Dang et al. (2014) is likely to be this species, not kentingensis , based on the aspect ratio of the head and the condition of the maxillary stylets. Four females and one male listed in the non-paratypic specimens may represent this species, but these have the head largely pale brown ( Fig. 97 View FIGURES 94–107 ), and abdominal segment IX and tube largely brown ( Fig. 95 View FIGURES 94–107 ). These specimens were collected together with four females that show the typical color pattern of borealis , and the two color forms are indistinguishable in structure. This species and O. kentingensis are ectopically distributed, but the boundary is not clear at this time.