Hoplandrothrips samirseni (Varatharajan, Singh & Bala) comb. n., 2024

Okajima, Shûji & Masumoto, Masami, 2024, The genus Hoplandrothrips and its relatives (Thysanoptera: Phlaeothripidae) from Southeast Asia and Taiwan, Zootaxa 5489 (1), pp. 22-91 : 51-52

Hoplandrothrips samirseni (Varatharajan, Singh & Bala) comb. n.

( Figs 43–44 , 233–243 )

Tylothrips samirseni Varatharajan, Singh & Bala, 2015: 7160-7162 .

This species was originally described from Manipur, Northeastern India based on a unique holotype male collected from the fallen leaves of Ureno lobata ( Malvaceae ). The maxillary stylets are relatively long but not reaching the middle of the head capsule and close together medially, and the fore wings are slightly constricted medially with a few duplicated cilia. These character states indicate that this species may not be related to the genus Tylothrips ( Mound 1977, Uzun Yiğit et al. 2021). The original description of samirseni provides only a few important structural details to recognise its taxonomic position, and the measurements also lack accuracy. The published images indicate that the tube is clearly shorter than the head, although it is much longer than the head in the measurements. This is probably because the magnification of the objective lens was incorrect when using the eyepiece micrometer. However, the images and figures in the description are available for this study and suggest that it is very similar to grass-inhabiting Hoplandrothrips species from Southeast Asia. Based on that description it cannot be distinguished satisfactorily from specimens collected in Indonesia, Thailand and Vietnam listed below, especially the smaller males. Therefore, these specimens are here identified as samirseni , but with slight hesitation, because there are some small differences between local populations in addition to the insufficient original description. It undoubtedly belongs to the nobilis - group, and is related to H. basantratus described above. Both of them share some character states as follows: head elongate with a constriction just behind compound eyes, rather short maxillary stylets retracted to basal 1/3 of head, pronotal basantra present at least in specimens from Southeast Asia, and the body bicoloured yellow and brown. However, samirseni differs clearly from basantratus in having the body largely brown mentioned in the key above. Another grass-inhabiting species, H. graminicola , may also be related, but has the body uniformly brown and no prosternal basantra.

The full description of this species is given below based on the specimens from Java, Indonesia, because the original description is insufficient for the present study.

Female (macroptera). Distended body length: 2.0– 2.9mm. The following description is based on a female with 2.3mm body in length. Body largely brown, but partly yellowish; head, thorax, abdominal segments VII–IX and tube brown, abdominal segments II–III yellow, very weakly shaded with brown, segments IV–VI brownish yellow to brown, gradually darkened posteriorly. Antennal segments I–II brown, a little darker than head, segment III yellowish, weakly shaded with brown, segments IV–VIII largely pale brown, bases of IV–VI slightly paler. Femora brown; tibiae and tarsi yellow, tibiae often weakly shaded. Fore wings almost clear. All prominent setae clear. Head ( Fig. 233 ) elongate, 1.45–1.50 times as long as wide, 1.48 times, dorsal surface almost smooth, but weakly sculptured with reticulation at extreme base, postero-lateral portion, just behind eyes and ocellar region. Cheeks weakly rounded, incised just behind eyes, weakly serrated, with some minute setae. Postocular setae shorter than eyes, dilated. Eyes bulged, about 0.3 times as long as head; posterior ocelli close to eyes, distance between posterior ocelli longer than diameter of an ocellus, 25μm apart from one another. Antennae ( Fig. 237 ) 1.8–1.9 times as long as head; segment VIII rather elongate, constricted at base, pedicellate; segment III 1.76 times as long as wide, almost as long as segment IV, with three sense cones. Mouth cone short, maxillary stylets retracted to basal 1/3 of head, not reaching postocular setae, 15–20μm apart from each other, 16μm. Pronotum smooth, but weakly reticulate posteriorly, about 0.5–0.6 times as long as head; five pairs of prominent setae elongate, slender and expanded; am much shorter than aa, pa and epim subequal in length. Prosternal basantra ( Fig. 239 ) present, but small; mesopresternum divided into two lateral large triangle plates and a median circular plate. Metanotum ( Fig. 240 ) weakly sculptured with longitudinal reticulation; median pair of setae acute, about 40–45μm apart from anterior margin, about 70μm apart from one another. Fore tarsal tooth ( Fig. 234 ) minute. Fore wings with 3–5 duplicated cilia; three sub-basal setae ( Fig. 242 ) expanded. Pelta ( Fig. 241 ) hat-shaped, with rather broad lateral wings, distinctly reticulate. Tergite IX S1 setae almost pointed or blunt, shorter than tube, S2 acute, almost as long as tube or a little shorter. Tube ( Fig. 243 ) 0.56 times as long as head, about 2.0 times as long as wide. Terminal setae much longer than tube.

Measurements (female in μm). Body length about 2290 (distended). Head length 242, from anterior margin of eyes 212, width across eyes 150, maximum width across cheeks 163; eyes length 70, width 48; diameter of posterior ocelli 13–17; postocular setae 50-52. Antenna total length 450, segments I–VIII length (width) as follows: 50 (40), 50 (33), 60 (34), 62 (33), 62 (28), 52 (24), 50 (21), 41 (13). Pronotum length 135, width 225. Setae on prothorax: am 15–20, aa 35–40, ml 40–45, pa 52–53, epim 52–55, cox about 40. Fore wing length 800. Sub-basal wing setae: S1 45 –47, S2 52 –55, S3 50 –52. Tergite IX setae: S1 110–112, S2 130–132. Tube length 135, maximum width 67; terminal setae 200.

Male (macroptera). Distended body length: 1.7–2.4mm. Abdominal segments usually darker than female, segments I and II yellowish brown, remaining segments gradually darkened towards tube, pale brown to dark brown; mid femora yellowish, apical 1/5–1/3 of fore femora and basal 1/3 of hind femora often yellowish, mid and hind tibiae often weakly shaded with brown. Pronotal am setae reduced, less than 15μm. Large male: pronotal aa setae elongate, much longer than pa; fore coxa with some stout setae on posterior margin; fore femur ( Fig. 236 ) swollen, with a ventro-apical tubercle, fore tibia with a sub-basal inner tubercle, but without apical tubercle, fore tarsal tooth stout, wide-based; fore wing with 6 duplicated cilia. Small male: pronotal aa setae almost as long as pa, or a little shorter; fore femur ( Fig. 235 ) without apical tubercle, fore tibia without sub-basal tubercle, fore tarsal tooth small as in female. Abdominal sternite VIII without pore plate; tergite IX S2 setae about 1/2 length of S1, S1 almost as long as tube. Tube 0.47–0.52 times as long as head.

Measurements (large/small males in μm). Body length about 2340/1720 (distended). Head length 245/222, from anterior margin of eyes 220/195, width across eyes 150/130, maximum width across cheeks 160/140; eyes length 80/63, width 50/40; postocular setae 65–68/40. Antenna total length 405/385, segments I–VIII length as follows: 50/43, 50/45, 63/50, 63/52, 65/52, 53/45, 47/42, 42/40. Pronotum length 180/125, width 260/195. Setae on prothorax: am about 10/about 10, aa 85–90/35–40, ml 75–80/38–40, pa 60/40–45, epim 68–75/40–45, cox 55–60/ about 30. Fore wing length 870/680. Sub-basal wing setae: S1 45 /33, S2 65–68/43, S3 60 –65/40. Tergite IX setae: S1 120–123/about 100, S2 58 –60/50–52. Tube length 125/105, maximum width 71/55; terminal setae 195/155.

Specimens examined. Indonesia, Java, Malang, Wono-koyo , ca 1150m alt., 34 females and 15 males, on grass, 23.viii.2005, SO . Thailand, nr. Chiang Rai, Pha Yao , 4 females and 1 male, on grass, 5.ix.1992, SO; 2 females, data very similar to above, but on dead leaves and branches; foot of Doi Inthanon, 1 female, on grass, 20.viii.1992, TN & SO; Pha Hean, 1 female and 2 males, 3.ix.1992, TN & SO; Doi Pui, 1 female, on grass, 1.ix.1992, SO ; Saraburi, Farm of Kasetsart University , 2 males, on grass, 20.viii.1991, TN & SO ; Chiang Mai, 1 female, in paddy field, 7.v.1978, K. Yasumatsu ; Phuket Is., Phuket Hill , 1 male, 9.ix.1992, SO . Vietnam, Lam Dong Province, Bao Loc, Dam Bri , 1 male, on bamboo, 27.xii.2001, SO .

Figures

FIGURES 43–55. Hoplandrothrips and Phlaeothrips species. H. samirseni comb. n. 43–44: (43) female; (44) large male. H. sapae sp. n. 45–47: (45) female; (46) small male; (47) large male. H. sulawesi sp. n. 48–50: (48) female; (49) large male; (50) small male. H. thailandicus sp. n.: (51) female. P. annamensis sp. n. 52–53: (52) small male; (53) large male. P. tonkinensis sp. n. 54–55: (54) female; (55) male.

FIGURES 233–243. Hoplandrothrips samirseni comb. n. (233) Head and prothorax, female; (234) fore leg, female; (235) fore leg, small male; (236) fore leg, large male; (237) antennal segments III–VIII, female; (238) antennal segments III–IV, female; (239) prosternum and mesopresternum, female; (240) metanotum, female; (241) pelta, female; (242) sub-basal wing setae, female; (243) tube, female.