Argothrips, Mound, Laurence A. & Tree, Desley J., 2017

Mound, Laurence A. & Tree, Desley J., 2017, Two new Australian fungus-feeding thrips in two new Plectrothripini genera (Thysanoptera, Phlaeothripinae), Zootaxa 4273 (3), pp. 443-446 : 446

Argothrips gen.n.

Diagnosis. Head as long as maximum width, but sharply narrowed to base such that basal width only 0.6 of maximum width ( Figs 7, 8 ); cheeks extending slightly around external margins of compound eyes; eye facets more numerous ventrally than dorsally, but one posterodorsal facet enlarged and separated; anterior margin of head and first ocellus overhanging first antennal segment, posterior ocelli close to compound eyes; postocular setae no longer than minor setae; maxillary stylets retracted to eyes and close together medially. Antennae 8-segmented ( Fig. 13 ), all segments pedicellate; segment II with campaniform sensillum placed medially; III almost spherical with one short stout sense cone; IV with 3 similar sense cones, V with 2 but VI with only one such sense cone; VIII elongate. Pronotum strongly eroded, at anterior and lateral margins, also epimera; only epimeral setae longer than discal setae ( Fig. 11 ); metanotum with no sculpture medially. Prosternal sclerites and anterior margin of mesosternum eroded, only ferna present ( Fig. 12 ); minute setae present in position of basantra. Fore tarsus without tooth; mid and hind tibiae without stout setae (fore wing not seen). Pelta very broadly triangular, tergite II eroded laterally ( Fig. 10 ); II–VII with no sculpture lines and no wing-retaining setae; VIII and IX with posteroangular setae long and finely pointed; tube much shorter than head, lateral margins weakly concave ( Fig. 9 ). Sternites without reticulate areas.

Type species Argothrips ommatos sp.n.

Comments. The campaniform sensillum on the second antennal segment is placed almost medially, rather than in the basal half of the segment, and the sternites lack glandular areas. However, the species shares the following character states with typical Plectrothripini species: antennal segment VIII elongate; sense cones on III and IV short and stout; posterior pair of ocelli close to compound eyes; pronotum strongly eroded; second abdominal tergite strongly eroded laterally. In the key to genera ( Okajima 1981) this new genus progresses to the last couplet involving Menothrips and Plectrothrips . However, the maxillary stylets are longer and closer together than in species of either of those genera, the fore tarsus lacks a tooth, and the structure of the eyes is unique amongst Phlaeothripidae . It is not unusual in various unrelated Thysanoptera species for a few ventral eye facets to be enlarged, but the condition in this species of a single enlarged dorsal facet is unique. Although the fore tarsus lacks a lateral tooth, the hamus is well-developed on the ventrolateral external margin of the tarsus.

Figures

FIGURES 7 – 13. Argothrips ommatos sp. n. (7) head, dorsal; (8) head, ventral; (9) tergite IX and tube; (10) pelta and tergite II; (11) pronotum; (12) prosternites; (13) antenna.