Stenchaetothrips hullikali, Tyagi, Kaomud & Kumar, Vikas, 2008

Tyagi, Kaomud & Kumar, Vikas, 2008, Two new species of Stenchaetothrips (Thysanoptera: Thripidae) from India, Zootaxa 1851, pp. 58-64 : 59-61

Stenchaetothrips hullikali sp. n.

Female macroptera. Body bicoloured; head, thorax and abdominal segment I yellow, segments II-X brown. Antennal segment I-III yellow, IV-VII brown. Fore wings yellow in basal ¼, and distal ¼, brown in middle ½. Legs yellow.

Ocellar seta pair III slightly longer than or subequal to pair II, pair II placed near lateral margins of antennal sockets, pair III arising between fore and hind ocelli outside ocellar triangle. Postocular setae I smaller than III in size, II subequal to IV and shorter than I and III.

Pronotum with few transverse lines of sculpture. Mesonotum with anterior pair of campaniform sensilla; median pair of setae placed far ahead of posterior margin; with weak, nearly imperceptible lines of sculpture between and behind anterior pair of campaniform sensilla. Metanotum without campaniform sensilla, with closely spaced longitudinal lines of sculpture converging a little posteriorly at middle; median setae back to anterior margin. Meso and metathoracic spinula absent. Fore wing costal vein with 21 setae; second vein with 11 setae.

Abdominal tergites I-VII with a few, small, laterally directed teeth at side of posterior margin, VII with teeth also at middle. Tergite IX with two pairs of campaniform sensilla; sternite I with a pair of minute setae apically at middle; median pair of primary setae on VII usually inserted just ahead of posterior.

Male macroptera. Body bicoloured as in female. Abdominal tergites I-IV with small teeth laterally on posterior margin; tegites V-VIII with small teeth all along posterior margin; tergite VIII posterior margin without comb; sternites III-VII with transverse glandular areas somewhat contracted at middle.

Measurements (holotype female in microns): Total body length 1280. Head length 130, width at eyes 125, at cheeks 123. Ocellar seta pair II length 18, pair III seta length 20. Postocular setae I length 18, setae III length 25. Total antennal length 245, Length (width) of antennal segments I 25 (25), II 33 (23), III 43 (17), IV 38 (17), V 35 (15), VI 45 (17), VII 15 (7). Pronotum length 118, width 145. Posteroangular inner setae length 73, outer setae length 72. Fore wing length 630, width at middle 50. Fore femur width 48; hind tibia length 142. Ovipositor length 220.

Male total body length 1130. Length (width) of glandular areas on sternites III-VII 80 (10), 80 (10), 80 (10), 73 (10), 65 (8). Fore wing length 560, width at middle 38.

Material Studied: Holotype Female, India: Karnataka (Udupi: Hullikal ghat), on Oryza sativa , 14-x-2006 (Kaomud Tyagi). Paratypes: 2 females 1 male with same data as holotype.

Etymology: This species name refers to the place of the collection.

Comments: According to the key to Indian species ( Bhatti 1982), this new species is closely related to S. bicolor (Ananthakrishnan. & Jagadish) . It can be differentiated from bicolor by the lack of campaniform sensilla on the metanotum. Further, bicolor has a very sparse comb of microtrichia on abdominal tergite VIII, whereas hullikali has a well-developed comb on this tergite.

The male of bicolor has the median pair of metanotal setae placed far back from the anterior margin of this sclerites, and tergite VIII bears a complete comb of microtrichia. In contrast, in hullikali these setae are placed just near to the anterior margin of the metanotum, and tergite VIII lacks a comb of microtrichia. Moreover, the glandular areas on abdominal sternites III-VII of bicolor are small, rounded and even rudimentary on sternite VII, but in hullikali these areas are well-developed and transverse although somewhat constricted at the middle on abdominal sternites III-VII.

Within the biformis group of species this new species is very close to the Taiwan species S. undatus Wang , in having the body bicoloured, setae poIII and poI subequal in length, campaniform sensilla absent on the metanotum, and tergite VIII with a complete comb of microtrichia. However, in hullikalli the fore wing distal quarter is yellow whereas it is brown in undatus and postocular setae I is smaller than III. Males of hullikalli lack a comb on the posterior margin of abdominal tergite VIII and have transverse glandular areas somewhat contracted at the middle on abdominal sternites III-VII, whereas undatus has a stout complete comb on tergite VIII and elliptical glandular areas on sternite III-VII.

S. caulis is the only other species in Stenchaetothrips with ocellar setae pair III subequal to pair II. However, this species can be differentiated from hullikalli in having unshaded forewings, a pair of campaniform sensilla on the metanotum, spinula on mesosternum, and metanotal setae inserted back of anterior margin.

The rice thrips , S. biformis , is one of the highly variable Stenchaetothrips species and also shares the host plant with this new species. However, hullikalli can be distinguished from biformis by having yellow tibiae, ocellar setae pair III longer or sub equal to pair II, two pairs of campaniform sensilla on abdominal tergite IX and the metanotal setae placed close to the anterior margin.

FIGURES 1–7. S. hullikalli 1. Head & Pronotum Female, 2. Meso- & Metanotum Female, 3. Abdominal tergites VI–X female, 4. Abdominal tergites I–V male, 5. Abdominal sternites III–VII male, 6. Meso- & Metasternum male. 7. Fore wing female.