Squamothrips, Okajima & Masumoto, 2025

Okajima, Shûji & Masumoto, Masami, 2025, Some Poaceae-inhabiting Phlaeothripinae (Thysanoptera, Phlaeothripidae) in East Asia, with descriptions of six new genera and 18 new species, Zootaxa 5726 (1), pp. 1-68 : 55-56

Squamothrips gen. nov.

Small-sized phlaeothripine species possibly belonging to the Phlaeothrips -lineage; body somewhat thick and distinctly reticulate, with one pair of wing-retaining setae on abdominal tergite VIII and major body setae thick and distinctly dilated. Head almost as long as wide ( Fig. 213 ), distinctly sculptured with raised polygonal reticulation, with a pair of postocular setae. Cheeks with several stout setae. Eyes and ocelli normal. Antenna eight-segmented; segment VIII conical ( Fig. 220 ), widely joined to segment VII; segments III–VI pedicellate; segments III and IV each with (1+1) sense cones. Mouth cone rather long and pointed; maxillary stylets long and close together at middle, maxillary guide well-developed, maxillary bridge absent. Prothorax with five pairs of major setae; notopleural suture complete. Basantra absent ( Fig. 214 ); prospinasternum transverse. Pterothorax a little wider than long; mesonotum entirely reticulate; metanotum with a pair of stout median setae. Mesopresternum transverse, but narrow. Metathoracic sternopleural sutures present ( Fig. 217 ). Fore wing scarcely constricted at middle ( Fig. 219 ), with duplicated cilia. Fore tarsus unarmed at least in female. Pelta irregularly shaped ( Fig. 216 ). Abdominal tergites II–VII each with two pair of wing-retaining setae, which are rather stout and close together ( Fig. 221 ); tergite VIII with a pair of simply curved wing-retaining setae at middle (may well be homologous with anterior pair). Posteromarginal setae S1and S2 on tergite IX much shorter than tube, intermediate setae between S1 and S2 minute. Tube straight-sided, tapering, shorter than head; terminal setae shorter than tube.

Type-species. Squamothrips crassus sp. nov.

Comments. This genus is somewhat similar in appearance to some genera included in the Liothrips -lineage, e.g. Eurhynchothrips and Psephenothrips , in having the body slightly thickened, maxillary stylets long and close together and the prosternal basantra absent. But Squamothrips probably belongs in the Phlaeothrips -lineage, because it has two sense cones on both antennal segments III and IV. Moreover, it is characterized by having the anterior pair of wing-retaining setae on abdominal tergite VIII. Usually, the wing-retaining setae are present on tergites II to VII and only rarely on tergite VIII in Phlaeothripinae . These unusual wing-retaining setae on tergite VIII are found only in a few genera, such as Andrethrips , Lizalothrips , Phylladothrips , Propesolomonthrips and Solomonthrips , and usually two pairs are present, but two Lizalothrips species and Phylladothrips bispinosus have only the anterior pair of these setae. In addition, one Oriental Terthrothrips species, T. strasseni , also has the anterior pair on tergite VIII. However, Squamothrips does not appear to have a close relationship with any of these genera, because there are no important features in common with these genera other than wing-retaining setae. The distinctly reticulate body and distinctly dilated stout body setae of this genus are somewhat similar to those of Azaleothrips and its relatives ( Okajima & Masumoto 2014). Moreover, Azaleothrips similarly has both right and left wing-retaining setae situated rather close together (cf. Fig. 221 ) and often has short and simply curved anterior pair of wing-retaining setae on tergite VIII. These two genera, Squamothrips and Azaleothrips , may have a common ancestor. From Azaleothrips , it can easily be distinguished by the postocular setae arising near the cheeks.

The genus name is derived from the Latin ‘ squama ’ meaning scales. The type-species has scale-like sculptures on the surface of the body. Gender: masculine.

Figures

FIGURES 212–221. Squamothrips crassus gen. et sp. nov., female. (212) whole body; (213) head, prothorax and fore legs; (214) prosternum and mesopresternum; (215) meso- and metanota; (216) pelta; (217) metathoracic sternopleural suture; (218) tube; (219) fore wing; (220) antennal segments III–VIII; (221) tergite III.