Trichromothrips formosus, Masumoto, Masami & Okajima, Shûji, 2005

Masumoto, Masami & Okajima, Shûji, 2005, Taiwan, with descriptions of four new species and a review of the Trichromothrips group of genera, Zootaxa 1082, pp. 1-27 : 11-17

Trichromothrips formosus sp. nov.

( Figs. 6–14 )

Trichromothrips sp. 1: Okajima, 2000: 103.

Female. Distended body length 1.2–1.7 mm. Body strongly bicoloured, without internal red pigment but often with a small red area near the ovipositor. Head dark brown with cone­like pale area medially on posterior margin ( Fig. 6 ). Antennal segments I to II dark brown, III yellowish white with apex shaded and often with basal third shaded including pedicel, IV to V yellowish white with distal third brown, VI brown with basal half yellowish white, VII to VIII brown. Pronotum with dark brown lateral stripes, large median triangular area yellowish white ( Fig. 6 ); pterothorax yellowish white with tegula shaded; fore wing uniformly dark brown with a small pale area near base; all legs yellowish white. Abdominal segments I to VI yellowish white, tergum VI often slightly shaded at middle along antecostal line ( Fig. 9), segments VII to IX dark brown, segment X dark brown with apex slightly pale. Prominent body setae shaded.

Head 1.0–1.2 times as long as wide, dorsal surface distinctly sculptured with transverse anastomosing striae on basal third, strongly produced in front of fore ocellus, strongly constricted behind compound eyes with cheeks rounded ( Fig. 6 ). Compound eyes almost as long as length of cheeks, without pigmented ommatidia. Ocellar setae II about half length of setae III, setae III situated between hind ocelli and 2.5–5.3 times as long as distance between their bases ( Fig. 6 ). Antennal segment IV usually the longest, often subequal to segment VI; sense­cone of segments III and IV usually reaching at least to basal third and nearly to basal half of next segment, each 0.5–0.9 times and 0.6–0.8 times as long as their segments ( Fig. 7 ). Antennal segments I to VIII length/width: 0.8–1.2, 1.3– 1.6, 2.9–4.2, 3.1–4.5, 2.5–4.0, 3.3–4.5, 1.0–1.7, 3.0–4.5.

Pronotum 1.3–1.8 times as wide as long, almost smooth on pale area, sculptured with widely spaced indistinct anastomosing striae at lateral dark areas, with 14–20 discal setae; median pair of setae near anterior margin slightly longer; posteroangular setae I 1.0–1.5 times as long as setae II and 0.5–0.7 times as long as pronotal median length ( Fig. 6 ).

Mesonotum almost smooth anteromedially; median pair of setae situated in front of submedian pairs; anteromedian campaniform sensilla absent ( Fig. 8 ). Metascutum smooth medially; median pair of setae situated near anterior margin and 0.3–0.4 times as long as metascutal median length, slightly shorter than submedian pairs; campaniform sensilla absent ( Fig. 8 ). Metaepimeron usually without setae, rarely one seta on only one side (only left in holotype). Fore wings with 22–30 setae on costal vein (left 30, right 26 in holotype), usually with 6 (rarely 5 or 7) basal setae on first vein, with 12–22 setae on second vein (15 in holotype).

Abdominal terga VI to VIII with B4 setae minute ( Figs. 9–10); tergum IX with posterior pair of campaniform sensilla, SB2 setae present ( Fig. 10); sterna without discal setae; sternum II with three pairs of posteromarginal setae; sternum VII with all posteromarginal setae in front of posterior margin. Ovipositor 2.1–2.7 times as long as pronotal median length.

Measurements of female holotype (in m). Body length 1725. Head, dorsal length 145, across cheeks 125, width behind compound eyes 113; compound eye dorsal length (width) 83 (50); ocellar setae III length (interval) 38 (13). Pronotum median length (width) 118 (183); posteroangular setae I length 62, setae II length 54. Metascutum median length 93; median setae length 30. Fore wing length 845. Abdominal tergum IX median length 118; tergum X median length 73. Ovipositor length 285. Antenna length 360; segments I–VIII length (width): 35 (33), 43 (28), 63 (20), 68 (18), 50 (18), 70 (20), 10 (10), 23 (5); segments III and IV sense­cone length 45 and 55.

Male. Macropterous. Distended body length 1.1–1.5 mm. General structure and colour similar to female. Abdominal tergum IX with 1 pair of drepanae on posterior margin ( Figs. 11–12 ); sterna III to VIII each with 5 glandular areas (paired circles laterally and 1 oblong medially) ( Fig. 13 ). Parameres of genitalia with two projections on dorsal surface ( Fig. 14 ).

Measurements of male paratype (in m). Body length 1080–1530. Head, dorsal length 100–147, across cheeks 85–103, width behind compound eyes 95–115; compound eye dorsal length (width) 53–73 (38–40); ocellar setae III length (interval) 28–40 (8–10). Pronotum median length (width) 65–113 (130–170); posteroangular setae I length 48–79, setae II length 38–60. Metascutum median length 50–80; median setae length 15–30. Fore wing length 303–463. Antenna length 253–323; segments I–VIII length (width): 23–35 (25–30), 30–40 (23–28), 38–58 (13–18), 45–63 (15–18), 38–50 (13–18), 48–65 (13–18), 8– 10 (8), 15–20 (5); segments III and IV sense­cone length 18–35 and 23–40.

Type series. Holotype (female): Japan, Tokyo, The Imperial Palace Grounds, Fukiage­gyoen, on leaves of Aucuba japonica [ Cornaceae ], 26­v­1999, S. Okajima. Paratypes Japan: 1 female and 2 males collected together with the holotype. 4 females, collected at same place with the holotype, Cinnamomum camphora [ Lauraceae ], 16­x­ 1996, S. Okajima. 1 female, Kanagawa Pref., Hayama­machi, Mt. Futago­yama, on leaves of Cinnamomum japonicum [ Lauraceae ], 25­v­2002, M. Masumoto. 59 females, Kanagawa Pref., Yokohama City, Kanazawa­shizenkouen park, on leaves of Machilus thunbergii [ Lauraceae ], 26­v­2002, M. Masumoto. 3 females, Kanagawa Pref., Yokosuka City, Kannonzaki, on leaves of Pleioblastus chino [ Poaceae ], 15­vi­2002, M. Masumoto. 7 females, Kanagawa Pref., Yokosuka City, Kannonzaki, on leaves of Machilus thunbergii , 29­vi­2002, M. Masumoto. 2 females and 1 male, Kanagawa pref., Yokosuka City, Kannonzaki, on leaves of Polystichum polyblepharum [ Aspidiaceae ], 19­vi­2005, M. Masumoto. 30 males, Kanagawa Pref., Yokohama City, Tomioka­sogokouen park, on leaves of Polystichum polyblepharum , 30­vi­2002, M. Masumoto. 3 males, Kanagawa Pref., Yokohama City, Tomioka­sogokouen park, on leaves of Polystichum polyblepharum , 27­vii­2003, M. Masumoto. 18 females, Kanagawa Pref., Yokohama City, Kanazawashizenkouen park, on leaves of Machilus thunbergii , 27­vi­2004, M. Masumoto. 1 female, Kanagawa Pref., Yokohama City, Tomioka­sogokouen park, on leaves of Polystichum polyblepharum , 10­vii­2004, M. Masumoto. 105 females and 5 males, Hiroshima Pref., Hiroshima City, Higashi­ku, Ushita­yama, on leaves of Machilus thunbergii , 25­x­1994, S. Okajima. 21 females, Nagasaki Pref., Kitamatsuura­gun, Tabira­cho, Ogitamen, on leaves of Machilus thunbergii , 27­x­1994, S. Okajima. 2 females and 1 male, Nagasaki Pref., Kitamatsuura­gun, Tabira­cho, Motoyama­rindou, on leaves of Quercus glauca [ Fagaceae ], 28­x­1994, S. Okajima. 18 females, Nagasaki Pref., Kitamatsuura­gun, Tabira­cho, Motoyama­rindou, on leaves of Machilus thunbergii , 28­x­1994, S. Okajima. 36 females and 2 males, Nagasaki Pref., Kitamatsuura­gun, Tabira­cho, Yakiyama, on leaves of Machilus thunbergii , 28­x­1994, S. Okajima. 1 female, Fukuoka Pref., Fukuoka City, Johan­ku, Abura­yama, on leaves of Quercus glauca , 30­x­1994, S. Okajima. The holotype and most paratypes are deposited in Laboratory of Insect Resources, Faculty of Agriculture, Tokyo University of Agriculture, Atsugi, Kanagawa Pref., Japan.

Non­paratypic specimens. Japan: 4 males, Fukuoka Pref., Mt. Tachibana, collected by yellow pan trap, 14­x­1978, K. Yamagishi. 3 males, Tsushima Is., collected by yellow pan trap, 13­vi­1979, T. Goto & K. Ogata. 6 females, Kagoshima Pref., Amami­ohshima Is., Uken­son, Fureainomori, on Machilus thunbergii , 23­iii­1990, S. Okajima. 3 females, Kagoshima Pref., Amami­ohshima Is., Uken­son, Fureainomori, on leaves of? Machilus sp., 1­vii­2000, M. Masumoto. 1 female, Okinawa Pref., Okinawa­hontou Is., Urazoe City, on leaves of Lygodium japonicum [ Lygodiaceae ], 12­v­2004, K. Minoura. 2 males, Okinawa Pref., Ishigaki­jima Is., Mt. Banna­dake, on bamboograss, 31­viii­1989, T. Nonaka. 1 female, Okinawa Pref., Ishigaki­jima Is., Mt. Banna­dake, on leaves of Fraxinus griffithii [ Oleaceae ], 16­i­1991, S. Okajima. 1 female, Okinawa Pref., Ishigakijima Is., Mt. Banna­dake, on leaves of Machilus thunbergii , 17­i­1991, S. Okajima.

Taiwan: 13 females and 1 male, Nantou­hsien, Nanshanchi, on leaves of Liquidambar formosana [ Hamamelidaceae ], 3­iv­1993, T. Nonaka & S. Okajima. 1 female, nr. Taipei, Yangmingshan, on Osmanthus fragrans [ Oleaceae ], 27­iii­1993, T. Nonaka & S. Okajima. 1 female, Chiai­hsien, Kuantzulin, 1­vi­1993, T. Nonaka & S. Okajima. 1 female, Pintung Hsien, Kenting Nat. Park, on dead leaves, 18­iii­1984, S. Okajima. 1 female and 1 male, Pintung Hsien, Kenting Nat. Park, on dead leaves, 19­iii­1984, S. Okajima. 1 female and 1 male, Nantou Hsien, Nanshanchi, on bush, 25­iii­1984, S. Okajima.

Comments. This new species is vivid pale greenish yellow at the pale areas when alive. In general structure and coloration this species is similar to the Indian species T. alis , according to its original author ( Bhatti, 1967, 2000). Among Thripidae , these two species shares an unusual feature in that the base of antennal segment III is shaded. T. alis is known only from the holotype female, and we have not been able to study this specimen in the collection of the Zoological Survey of India, Kolkata. However , we sent slides of the Japanese species collected at Yokohama to Dr. Bhatti who compared these with notes from when he last studied the holotype of T. alis in 1963. The Japanese species seems to differ from alis in having longer sense cones of antennal segments III and IV, and different pronotal sculpture and chaetotaxy. The published illustrations ( Bhatti, 2000: figs, 11, 32– 34, 77) appear to support this: in alis , the sense cones of antennal segments III and IV reach the extreme base or at most the basal fourth of the next segments, many pronotal sculpture lines are distinct laterally, the pronotal posteroangular outer setae are almost the same length as the inner setae, and abdominal tergum IX lacks campaniform sensilla (only from fig. 77). In contrast, in the new species the sense cones of antennal segments III and IV reach the basal third of the next segments, pronotal sculpture lines are indistinct, the pronotal posteroangular outer setae are distinctly shorter than the inner setae, and tergum IX has a posterior pair of campaniform sensilla (although Taiwanese specimens often lack campaniform sensilla or have only one sensillum).

The characteristics of the female of this new species distinctly indicate relationships to the bellus section. However, the male has drepanae on abdominal tergum IX and five glandular areas on the sterna, whereas males of the other species in the bellus section ( Bhatti, 2000) lack drepanae on tergum X and have numerous scattered glandular areas on the sterna.

According to Laurence Mound (personal communication), two females collected from the tip of Cape York in Northern Australia appear to be this species.

Etymology. In the reference vivid body colour of this species when it alive.

Figures

FIGURES 6 – 8. Trichromothrips formosus n. sp. (female): (6) Head & pronotum (median pale areas on head and pronotum indicated by dotted lines); (7) Antennal segments I – VIII (right); (8) Mesonotum & metascutum. Scale bar = 0.04 mm.

FIGURES 11 – 14. Trichromothrips formosus n. sp. (male). Abdominal segments: (11) Terga IX – X; (12) Tergum IX (left­dorsal aspect); (13) Sternum VI; (14) Genitalia (left aspect). hy = hypomere; pa = paramere. Scale bar 0.04 mm.