Heligmothrips xanthoskelus, Mound & Tree & Wells, 2022

Mound, Laurence A., Tree, Desley J. & Wells, Alice, 2022, Convoluted maxillary stylets among Australian Thysanoptera Phlaeothripinae associated mainly with Casuarinaceae trees, Zootaxa 5190 (3), pp. 301-332 : 324-326

Heligmothrips xanthoskelus sp.n.

( Figs 59 , 63, 65 )

Female macroptera. Body uniformly brown, tube darkest; all legs much paler, variably yellow to light brown with fore femora darkest; apex of antennal segment II and all of segment III almost yellow, IV–VIII brown with basal third of IV and V paler; major setae shaded but not dark; fore wing pale with base brown. With the character states given in the generic diagnosis, except as follows: head slightly wider than long, genae without prominent setae; postocular setae capitate, extending slightly beyond hind margin of eyes; eyes smaller ventrally than dorsally; hind ocelli not close to eyes; maxillary stylets retracted to eyes ( Fig. 59 ), not crossing over each other, but at level of base of head twisting sharply laterally into figure-of-eight convolutions before entering mouth cone; mouth cone pointed but not extending to prosternal ferna ( Fig. 65 ). Antennal segment III longer than wide, IV with 3 sense cones, V and VI each with ventrolateral apex slightly prolonged. Pronotum transverse, with extensive reticulate sculpture ( Fig. 59 ); major setae short, capitate and weakly shaded. Mesonotal lateral setae capitate. Metanotum strongly reticulate; median setae small and finely pointed ( Fig. 63 ). Prosternal ferna transverse; mesopresternum complete but narrowed medially ( Fig. 65 ). Fore tarsal tooth small. Fore wing with about 8 duplicated cilia. Pelta quadrate with apex truncate ( Fig. 63 ); tergites II–VII each with 2 pairs of wing-retaining setae of which anterior pair on each tergite is small; tergite IX with all 3 major setae long and capitate; tube shorter than head.

Measurements. Body length 2100. Head, length 200; width medially 220; po setae 35. Pronotum, length 160; width 330; major setae – am 35, aa 35, ml 30, epim 45, pa 35. Fore wing length 750; sub-basal setae 35. Tergite IX setae S1 70, S2 50. Tube, basal width 85, length 160. Antennal segments III–VIII length 70, 70, 60, 50, 45, 25.

Male macroptera. Very similar to females but with legs slightly more shaded; largest male with fore femora enlarged, fore tarsal claw about 0.5 as long as tarsal width, and fore tibia with small tubercle at inner apex, smaller males with more slender fore legs. Tergite IX setae S2 slightly shorter than S1; sternite VIII with small circular pore plate medially.

Specimens studied. Holotype female macroptera, New South Wales: Moree 40km north, from Casuarina cristata , 20.v.2022 (Alice Wells) ( LAM6548 ).

Paratypes: New South Wales: 2 females, 3 males taken with holotype .

Comments. The pale legs contrasting with the dark body of this species were noted when it was taken alive together with the dark brown micropterous species, H. eiletus . The maxillary stylets are also distinctive in forming two large rings in a figure-of-eight, and the truncate apex to the pelta is also unusual for species in this genus. The male is unique in the genus for having a small, circular pore plate on sternite VIII.

Figures

FIGURES 51–59. Heligmothrips species heads and stylets. (51) brevidens; (52) erinaceus; (53) gracilior; (54) eiletus; (55) eiletus larva; (56) exallus; (57) macropus; (58) narrabri; (59) xantoskelus.

FIGURES 60–68. Heligmothrips species thorax and antenna. (60) eiletus; (61) narrabri; (62) exallus; (63) xanthoskelus; (64) exallus; (65) xanthoskelus; (66) narrabri; (67) exallus antenna; (68) macropus pronotum.