Strepterothrips verruculus, Mound, Laurence A. & Tree, Desley J., 2015

Mound, Laurence A. & Tree, Desley J., 2015, Fungus-feeding Thysanoptera: Phlaeothripinae of the Idiothrips genus-group in Australia, with nine new species, Zootaxa 4034 (2), pp. 325-341 : 340

Strepterothrips verruculus sp.n.

( Figs 4 , 16 , 29, 35 , 39, 40 )

Female aptera: body dark brown with much internal red pigment; legs and antennae brown, antennal segment III slightly paler at extreme base, head with paired longitudinal submedian paler areas, pterothorax sometimes paler laterally, metanotum sharply yellow on posterior third; major setae all pale.

Head longer than wide ( Fig. 29 ); cheeks weakly convex with several weakly curved, broadly blunt setae; dorsal surface strongly reticulate particularly medially with small tubercles within each reticle, mid-dorsal setae not elongate; eyes with about 18 facets dorsally and 5 ventrally; postocular setae short, broadly capitate. Antennae 7- segmented ( Fig. 4 ), III with one small sense cone, IV with 2 larger sense cones; segments with strong sculpture lines, II with 2 pairs of broadly blunt setae. Pronotum finely tuberculate ( Fig. 39 ), anterolaterally with paired groups of about 25–30 small spatulate setae; major setae short, broadly capitate, but pa setae not developed; posteromedially with 2 pairs of short capitate setae; notopleural sutures incomplete. Mesonotum finely tuberculate, with one pair of capitate lateral setae. Metanotum finely tuberculate, with less than 10 setae on anterior two-thirds, but posterior third with narrow transverse band of 20–30 setae ( Fig. 40 ). Prosternal basantra not developed; ferna transverse, not meeting medially; mesopresternum reduced to pair of small lateral triangles, mesoeusternum anterior margin complete ( Fig. 16 ). Pelta transverse, with irregular reticulate sculpture of small tubercles but no discal setae ( Fig. 40 ); tergites finely tuberculate, with transverse row of 4–6 small pointed discal setae; II–VII with pair of broadly capitate posteromarginal setae; setae S1 on IX capitate, S2 finely acute.

Measurements (holotype female in microns). Body length 1510. Head, length 200; width 175; po setae 15. Pronotum, length 125; width 250; major setae, am 20, aa 20, ml 20, epim 30, pa?. Tergite IX setae S1 40; S2 80. Tube length 135; basal width 55; anal setae 100. Antennal segments III–VII length, 50, 43, 40, 38, 63.

Male aptera: similar in colour, sculpture and chaetotaxy to female, but highly variable in body size; small males similar to small females with normal small hamus on fore tarsus; largest males with head longer, projecting in front of eyes and narrowed to base ( Fig. 35 ); fore femora swollen sub-basally on inner margin, fore tibia with small apical tubercle, fore tarsal hamus greatly enlarged and claw-like.

Material studied. Holotype female aptera. Australia, Norfolk Island, Prince Philip Drive, from dead Lagunaria branches, 26.xi.2014 (LAM 6084), in ANIC.

Paratypes, all apterae from Norfolk Island; 4 females, 5 males taken with holotype, also 4 females, 4 males at same site, 29.xi.2014; 21 females, 18 males from dead branches on various dates between 27.xii.2012 and 24.xi.2014, at many localities including, 100 Acre Reserve, Mt Bate, Highland Lodge, Palm Glen, Bird Rock Track, and Mission Road Forest.

Comments. This species, together with its bright red larvae, is common and widespread on dead branches across Norfolk Island where it is presumably endemic ( Mound & Wells 2015). It is one of only two Strepterothrips in which the anterior margin of the mesoeusternum is known to be transverse and entire. In structure and colour, verruculus is closely similar to tuberculatus that is widespread across Australia, differing particularly in the sculpture and arrangement of setae on the pronotum and metanotum. In contrast to that species, no macropterae have been found, but the males show a similar diversity of form depending on the body size.

Figures

FIGURES 1 – 8. Idiothrips genus-group from Australia. Antennae 1 – 4: (1) Idiothrips bellus from Iran; (2) Azaleothrips lixinae; (3) Stictothrips namadji; (4) Strepterothrips verruculus. Azaleothrips lixinae 5 – 8: (5) head; (6) pelta and tergites; (7) tergites VII – IX and tube; (8) pronotum and metanotum.

FIGURES 16 – 26. Strepterothrips species from Australia. Mesoeusternal anterior margin 16 – 19: (16) verruculus; (17); arake; (18) orientalis; (19) parvulus. Antennae 20 – 26: (20) arake; (21) barbatus; (22) moffati; (23) okajimai; (24) orientalis; (25) parvulus; (26) tuberculatus.

FIGURES 27 – 35. Strepterothrips species from Australia. Head 27 – 29: (27) moffati, (28) tuberculatus; (29) verruculus. Head and pronotum 30 – 32: (30) okajimai; (31) parvulus;; (32) arake. Metanotum, pelta and tergites 33 – 34: (33) okajimai; (34) akake. (35) Male verruculus.

FIGURES 36 – 45. Strepterothrips species from Australia. Metanotum and pelta 36 – 37: (36) apterus; (37) barbatus. Pronotum 38 – 39: (38) barbatus; (39) verruculus. (40) verruculus metanotum and pelta. (41) tuberculatus thorax and pelta. (42) moffati metanotum, pelta and tergites. Apical abdominal segments 43 – 45: (43) arake; (44) okajimai; (45) orientalis.