Senithrips, Mound, Laurence A. & Minaei, Kambiz, 2006

Mound, Laurence A. & Minaei, Kambiz, 2006, New fungus­feeding thrips (Thysanoptera Phlaeothripinae) from tropical Australia, Zootaxa 1150, pp. 1-17 : 9-10

Senithrips gen. n.

Minute apterous Phlaeothripinae , lacking ocelli and wing sclerites. Head longer than wide, cheeks convex but constricted at basal neck ( Fig. 13 ), vertex rounded and slightly overhanging antennal bases, dorsal surface reticulate with three rows of small setae; compound eyes each reduced to 6 facets; maxillary stylets retracted to eyes and closely parallel medially, mouthcone short and rounded. Antennae 6­segmented ( Fig. 14 ), III small without sense cones, IV with 2 sense cones, VI–VIII fused with no trace of sutures. Pronotum transverse, all setae minute, notopleural sutures apparently fused. Mesometanotal suture apparently fused, metanotum broader at posterior, all setae small. Prosternal basantra absent, ferna transversely oval, mesopraesternum eroded medially but forming two transverse sclerites ( Fig. 12 ), mesoeusternum with median longitudinal division; meso­metathoracic sternopleural sutures not developed. Pelta broad but slender, reticulate with submarginal line ( Fig. 13 ); tergites II–VII finely sculptured, with transverse row of more than 12 small setae, posterior margin with one pair of small curved setae laterally, and one pair of curved posteroangular setae; tergite IX setae S1 capitate, S2 blunt, S3 acute; tube short with short terminal setae. Male similar to female; no sternal glandular areas; tergite IX setae S2 stout.

Type species Senithrips psomus sp.n.

Comments

The antennae of the type species of this new genus, with segments VI–VIII fused into a single unit, are similar in structure to the antennae of Hexadikothrips dalbyi Crespi, Morris & Mound (2004) . However, the male of H. dalbyi has a well developed fore tarsal tooth as well as a small glandular area on the eighth sternite, neither of which characters are present in the new species. Moreover, in both sexes of the new species the pelta occupies at least 80% of the anterior margin of tergite II instead of scarcely 60%, the meso­metanotal and the prothoracic notopleural sutures appear to be fused, the prosternal ferna are large, the mesopraesternum eroded medially and forming two transverse sclerites, the metathoracic sternopleural sutures not developed, and the tergites have only one pair of very small marginal setae. Thus Hexadikothrips and this new genus are considered not closely related, and their general similarities are probably due to the small body size and consequent reduction of many structural features. A further species that is similar in appearance is Adurothrips atopus Mound (1995a) . This species is also minute and wingless with the terminal three segments of the antennae fused, but the hind coxae are wider apart than the mid coxae as in Urothrips Bagnall and related genera ( Mound, 1972), the pelta is trilobed, the maxillary stylets wide apart in the head, and the second antennal segment bears an apical flange surrounding the base of the third segment.

Figures

FIGURES 9 – 14. Majerthrips and Sennithrips species. (9) M. barrowi micropterous female, ventral; (10) M. barrowi micropterous female, dorsal; (11) M. barrowi apterous female, metanotum and tergites I – II; (12) S. psomus, ventral; (13) S. psomus, dorsal; (14) S. psomus antenna. [ns = prothoracic notopleural suture; ss = metathoracic sternopleural suture]