Bactrothrips luteus Ananthakrishnan, 1973

Okajima, Shûji & Masumoto, Masami, 2025, Two idolothripine genera, Bactrothrips and Megalothrips (Thysanoptera, Phlaeothripidae), from Asia between India and Taiwan, with descriptions of two new species, Zootaxa 5696 (4), pp. 491-516 : 503-504

Bactrothrips luteus Ananthakrishnan

( Figs 57–67 )

Bactrothrips luteus Ananthakrishnan, 1973: 81–84 .

Bactrothrips brevitubus zhamanus Han & Zhang, 1981: 298–299 . Syn. nov.

This species was described based on seven females and 126 males taken from dry sal ( Shorea robusta , Dipterocarpaceae ) leaves in Bhowali, Nainital district, North India, and is recorded here from Nepal and North Thailand for the first time. It is characterized by the following features: antennal segments III–VI sharply bicolored, yellow in pedicels, brown in club heads ( Figs 59 & 60 ); hind tibiae largely yellow, tinged with brown sub-basally; postocular setae pair II usually shorter than interocellar setae; male tubercles on tergite VI almost straight, or scarcely curved inwards, largely yellowish with dark brown base ( Fig. 61 ); abdominal tergite VII with a pair of distinct lateral small tubercles at least in medium to large male; antennal segment III 0.60–0.65 times as long as head in female, 0.63–0.67 times in male; sense cones on antennal segment III shorter than one-third of the segment length; setae on tube short and sparsely scattered in male ( Fig. 65 ), usually about 40µm long, at most 50µm, but longer in female ( Fig. 64 ). The female Bournier’s Apparatus is developed and somewhat similar to that of B. quadrituberculatus (Fig. 9), with well-developed tufted area and stout hilt ( Fig. 66 ). The male subgenital plate tongue-shaped, but rather variable in shape, often narrowed towards base ( Fig. 67 ). Moreover, each of abdominal segments II–VIII with a pair of lateral ‘faded windows’ (see B. honoris , cf. Fig. 39 ). Presumably, when alive, this species has red spots on both sides of abdomen, like B. honoris and B. pictipes (cf. Figs 1 & 2 ).

Haga and Okajima (1989) considered that B. brevitubus zhamanus described from Xizang (= Tibet), China, was not distinguishable from brevitubus s. str. judged from the original description ( Han & Zhang 1981). However, this judgement was incorrect, because the male tubercles on the tergite VI of zhamanus are different from brevitubus s. str. in color and structure. Subsequently, Dang and Qiao (2012) examined the holotype male of zhamanus and treated it as a synonym of B. pictipes without any morphological consideration, although the characteristics of zhamanus in the original description are clearly different from pictipes in several structures. Moreover, the priority under the International Code of Zoological Nomenclature is in the name zhamanus, not pictipes , and this treatment is thus unacceptable. According to the original description as well as additional information of zhamanus by Han (1997), it appears to be more similar to B. luteus than pictipes in having the antennal segment III longer with brown club-head, the cephalic interocellar setae longer, male tubercles on tergite VI bicolored, and tergite VII with a pair of distinct lateral tubercles. Moreover, it was specified that the setae on the tube are sparse and fewer in the original description, and this condition is also found in the male of luteus but not in pictipes . In addition, the type locality of zhamanus is closer to the distribution range of luteus than that of pictipes . Therefore, B. brevitubus zhamanus is newly synonymized here with B. luteus . However, females have not been recorded, and the condition of the female Bournier’s Apparatus of zhamanus is unknown.

Specimens examined. Thailand, nr. Chiang Mai, Doi Suthep , 1100m alt., on dead leaves, 1 male, 11.viii.1976, 1 female and 1 male, 13.viii.1976, SO; 1 female, Doi Suthep, nr. Meo Village , 22.v.1979, W. Suzuki. India, 2 paratype males, Bhowali (U.P.), dry sal leaves, 18.x.1970, T. N. Ananthakrishnan. Nepal, 7 females and 5 males, Kathmandu Valley, Godavari , 11.vi.1981, W. Suzuki.

Figures

FIGURES 57–67. Bactrothrips luteus from Thailand: (57) head, female; (58) head, male; (59) antennal segments III & IV, female; (60) antennal segments V–VIII, female; (61) abdominal segments VI & VII, male; (62) pelta, female; (63) pelta, male; (64) setae on tube, female; (65) setae on tube, male; (66) Bournier’s Apparatus, female (a: tufted area, b: hilt); (67) subgenital plate, male.

FIGURES 27–43. Bactrothrips honoris. Hind tibia, female 27–33: (27–29) Taiwan; (30) Java; (31) Peninsular Malaysia; (32) Mindanao Is., the Philippines; (33) S. Sulawesi. Mid tibia, female 34–38: (34) Taiwan; (35) Java; (36) Peninsular Malaysia; (37) Mindanao Is., the Philippines; (38) S. Sulawesi. (39) Abdominal segments VI and VII, female (arrows indicate ‘faded windows’), female from Java. Male subgenital plate 40–41: (40) Taiwan; (41) Java. Female Bournier’s Apparatus 42–43: (42) Java; (43) Peninsular Malaysia.

FIGURES 1–2. Bactrothrips species: (1) B. honoris, male; (2) B. pictipes, female.