Iridothrips lobulatus, Wang & Mound & Tong, 2019

Wang, Zhaohong, Mound, Laurence & Tong, Xiaoli, 2019, Phylogenetic relationships within the Frankliniella genus-group based on morphology, with a revision of Iridothrips (Thysanoptera, Thripidae), Zootaxa 4651 (1), pp. 141-154 : 148-150

Iridothrips lobulatus sp. n.

( Figs 7 , 13, 18 , 21 , 27, 30, 35, 38 )

Female macroptera. Body brown to pale brown; antennal segments I–II and VI–VIII brown, segments III–V pale ( Fig. 27 ); femora brown, tibiae and tarsi pale; fore wing brown with basal 1/5 and clavus pale ( Fig. 30 ).

Head approximately as wide as long, projecting in front of compound eyes, cheeks parallel and as long as eyes; ocellar triangle smooth, 3 pairs of ocellar setae present, pairs I and II small, pair III as long as distance between hind ocelli ( Fig. 7 ); postocular region sculptured with transverse anastomosing striae, 5 pairs of minute postocular setae present, pair II arising posterior of setal row. Antennae 8-segmented, segments III–IV with forked sense cones, usually Y-shaped with a short base; III–VI with sparse microtrichia on both dorsal and ventral surfaces. Pronotum ( Fig. 13 ) sculptured with transverse lines at anterior and posterior margins, all setae situated on margins and no medial discal setae; anterior margin with 3 pairs of setae, submedian pair slightly longer; posterior margin with 4–5 pairs of setae, submedian setae elongate and median minor setae present or absent; posteroangular setae with inner pair longer than outer pair. Mesonotum with median pair of setae near posterior margin. Metanotum sculptured with irregular reticulation, median setae arising well behind anterior margin, campaniform sensilla absent ( Fig. 18 ). Mesosternal endofurca with spinula and metasternal without spinula. Fore wing first vein with 11–12 setae, second vein with 4–6 setae, clavus with 3+1 (rarely 4+1) setae ( Fig. 30 ). Abdominal tergites II–VII sculptured with widely spaced transverse lines, but smooth posterior to median setae; posterior margin with irregular short lobes; tergite I with ciliate microtrichia on lateral lines, tergite VIII with irregular short teeth arising from lobes on posterior margin ( Fig. 21 ); tergite X with complete dorsal split. Sternites sculptured with transverse anastomosing striae, II–VII with short posteromarginal craspeda between posteromarginal setae, sternite VII without craspeda between median setal pair ( Fig. 38 ).

Measurements (holotype female in microns). Distended body length 1420. Head, dorsal length 140, width across eyes 140; ocellar setae III 40; eye length 65. Pronotum length 125, width 175. Fore wing length 570. Antennal segments I–VIII length (width): 17(28), 33(26), 38(17), 34(17), 33(16), 48(17), 10(7), 15(5).

Male macroptera. Similar to female; abdominal tergite IX with tiny teeth on lines near anterior margin and 2 pairs of campaniform sensilla; sternites III–VII each with a small transverse pore plate medially ( Fig. 35 ).

Measurements (male paratype): Distended body length 1130. Head, dorsal length 128, width across eyes 132; eye length 65. Pronotum length 112, width 155. Fore wing length 510. Antennal segments I–VIII length (width): 15(25), 30(24), 37(16), 29(16), 27(15), 40(15), 7(7), 13(5).

Material examined. Holotype female CHINA, Shandong province, Zhangqiu County, Duozhuang Reservoir (36°29'12"N, 117°24'26"E, alt. 340m), collected from base of Themeda sp. ( Poaceae ) by the lake shore, 24.ix.2015, Zhaohong Wang (in SCAU) . Paratypes: 5 females and 1 male, same data as holotype (in SCAU & ANIC).

Etymology. The specific epithet is in reference to the abdominal tergites and sternites with obvious lobes.

Comments. The two species previously placed in Iridothrips were thought to be unrelated ( Mound 2002), but this new species has character states intermediate between the previous two species, thus linking them together. This species is recognizable by obvious craspedal lobes on the postior margin of tergites and sternites. One female among the type series was found to have a transverse pore plate on each of sternites III–VII. Such a character state is unusual for females, but females of several Frankliniella in South America also have one or two pore plates, but only on sternite III ( de Borbon & Zamar 2018), and females of Yaobinthrips also have a pore plate on sternite VI. Females with this condition also are known in a few species of Thrips genus-group, including Thrips knoxi and Stenchaetothrips bambusicola . According to descriptions, the mesosternal spinula is absent in I. iridis but present in I. mariae ; it is variable in I. lobulatus . The paratype female of this latter species in which a mesosternal spinula is not visible has a body considerably paler than the remaining dark specimens of the type series, all of which have an obvious spinula. This raises the possibility that in some species the sclerotization, and thus the visibility, of the mesosternal spinula may be related to maturity, and thus not entirely reliable for use in distinguishing species.

This new species was found living in the basal leaf sheaths of a species of Themeda by a lake shore. The plants were in a wet area during August to December when the lake contains much water, but during January to July there is lower water storage. Thus the plants will be submerged after the summer rainy season, but the land could be relatively dry and cold in early spring. As mentioned above for I. iridis , the instability of body structure may in some way be related to the instability of the habitat.

Figures

FIGURES 2–12. Character states of Frankliniella genus-group. 2–7 head: (2) Fr. insularis; (3) Fr. schultzei; (4) Y. yangtzei; (5) I. mariae; (6) Ps. araucariae; (7) I. lobulatus. 8–12 head and pronotum: (8) Fr. zizaniophila; (9) Fr. williamsi; (10) S. calcaratus; (11) T. physapus; (12) P. achaetus. [see Appendix 1 for character state codes]

FIGURES 13–18. Character states on thorax. 13–15 pronotum: (13) I. lobulatus; (14) Pa. setifer; (15) Fr. tenuicornis. 16–18: meso and metanotum (16) Pa. setifer; (17) I. iridis; (18) I. lobulatus.

FIGURES 19–26. Character states on tergites: (19) Fr. tenuicornis IV–V; (20) Y. yangtzei V–VI; (21) I. lobulatus VII–VIII; (22) Pa. setifer VI–VIII; (23) T. physapus VII–VIII; (24) Ps. achaetus VII–VIII; (25) I. mariae VIII; (26) Fr. schultzei VII–VIII. [see Appendix 1 for character state codes].

FIGURES 27–38. Character states of Frankliniella genus-group. 27–28 antennae: (27) I. lobulatus; (28) I. mariae. 29–30 fore wing: (29) Fr. schultzei; (30) I. lobulatus. 31–33 tergite VIII: (31) Fr. cephalica; (32) Fr. williamsi; (33) K. pisivorus. 34–35 male: (34) Fi. firmus tergites IX–X; (35) I. lobulatus sternites VII–VIII. 36–38 sternite VII: (36) Fr. intonsa; (37) T. physapus; (38) I. lobulatus. [see Appendix 1 for character state codes].