Acallurothrips Bagnall, 1921

Mound, Laurence A. & Tree, Desley J., 2021, Tubuliferous Thysanoptera inAustralia with an enlarged tenth abdominal segment (Phlaeothripidae, Idolothripinae), including six new species, Zootaxa 4951 (1), pp. 167-181 : 169

Acallurothrips Bagnall

Acallurothrips Bagnall, 1921: 269 .

Type species A. macrurus Bagnall

A full diagnosis of this genus of Idolothripinae was provided by Okajima (2006), but the most important character states are: head short and broad with stylets widely spaced; maxillary palp segment I longer than wide and almost half as long as segment II, terminal sensorium on II large ( Fig. 32 ); antennae 8-segmented but with segments VII–VIII almost completely fused; mesopresternum usually vestigial ( Figs 31–32 ); fore tarsal tooth present in both sexes; fore wings when present without duplicated cilia; tergites shorter than sternites; tube swollen often with convex margins ( Figs 1–4 ).

Among species of Phlaeothripidae the first segment of the maxillary palps is usually scarcely longer than wide, and thus much shorter than the second segment. Only among the species of the Idolothripinae genus Carientothrips is the first maxillary palp segment known to be as long as, or even longer than, the second ( Eow et al. 2014). Howev- er, Acallurothrips species are also unusual in having the first segment considerably longer than wide, and sometimes about half as long as the second segment. Moreover, the sensorium at the apex of segment II is unusually large, approaching the condition found in Allothrips species. Females of Acallurothrips species share a character with many other Phlaeothripidae , in that they have two pairs of minor setae on tergite IX between the major setae S1 and S2. Okajima (1993) refers to these setae as SB1 and SB2 ( Fig. 11a, b ). The setae SB1 are homologous with the setal pair in Apelaunothrips species that were discussed as setae iS by Mound (2013). These setae are also sometimes prominent in related genera ( Dang et al. 2013) such as Hoplandrothrips and Adraneothrips . Contrary to the interpretation by Okajima, and subsequent to examining male paratypes of both Acallurothrips casuarinae and A.spinurus , the males of species of Acallurothrips are considered to lack on tergite IX the setae known as SB 2 in females. Moreover, this pair of (often minute) setae are commonly absent in the males of other Phlaeothripidae . Species differentiation in Acallurothrips here relies largely on the form of this setal pair in females, as well as the shape of the tube.

Currently 22 species are listed in this genus (ThripsWiki 2021), with three further species described below. However, relationships between some of the listed species are not secure. For example, A. judithae (Faure) from South Africa has a well-developed mesopresternum, a structure that is commonly vestigial or absent in members of this genus ( Okajima 2006). The New World genus Diopsothrips is currently considered a synonym of Acallurothrips , but the three species involved have a relatively well-developed pair of ocellar setae in contrast to the species considered here, and antennal segments VII and VIII are fused with no suture between them. Unfortunately, nothing is known of the mesopresternum in the three species placed originally in Diopsothrips . Of the 25 species now placed in Acallurothrips , eight are from the Neotropics, four from the Ethiopian Region, seven from Japan or China, and four from Australia.

Figures

FIGURES 23‒33. Species of Acallurothrips. Neosmerinthothrips, Ozothrips and Pygothrips. Antennae 23‒30: (23) A. darumbali sp.n. (24) A. nogutti. (25) A. erubi sp.n. (26) A. yagara sp.n. (27) N. barrowi sp.n. (28) N. turrbali sp.n. (29) O. meanjini sp.n. (30) P. pygus. Mouth cone & mesopresternum 31-33: (31) A. yagara sp.n. (32) A. nogutti. (33) O. meanjini sp.n.

FIGURES 1‒13. Abdominal segment X variation in shape. Acallurothrips species 1‒4: (1) darumbali sp.n; (2) nogutti; (3) yagara sp.n; (4) erubi sp.n. Neosmerithothrips species 5‒6: (5) barrowi sp.n; (6) turrbali sp.n. (7) Ozothrips meanjini sp.n. Pygothrips species 8‒10: (8) vicinus paratype; (9) rugicauda male; (10) rugicauda female. (11 a, b) Acallurothrips tergites VIII‒X to show setae SB1 and SB2 (from Okajima 1993). (12) Pygothrips rugicauda holotype tergite X dorsal and lateral views (from Hood 1915). (13) Pygothrips pygus tergites IX‒X (from Mound 1974a).