Psilothrips Hood, 1927

Minaei, Kambiz & Mound, Laurence, 2015, Thysanoptera disjunct distribution between western America and the Mediterranean with a new Psilothrips species (Thripidae) from Iran, Deutsche Entomologische Zeitschrift 62 (1), pp. 1-7 : 1

Psilothrips Hood, 1927

Psilothrips Hood, 1927: 198. Type species Psilothrips pardalotus Hood, 1927, by monotypy.

Remarks.

Members of this genus can be distinguished from other Thripinae by the lack of a comb of microtrichia on the posterior margin of tergite VIII, and the presence of a particularly long pair of setae arising in a unique position on the antecostal ridges of tergites III-VII (Figs 11, 13). Only one other genus shares these two character states, Apsilothrips Bhatti & de Borbon, 2008 from western Argentina (Mendoza and Jujuy). The single species placed in that genus could equally well be interpreted as an unusual species of Psilothrips , but is weakly distinguished by the presence of small cilia on the anterior margin of the fore wing and complete absence of sternal discal setae. In contrast, other Thripinae taxa in which the median tergal setae are unusually long have these setae arising just posterior to the antecostal ridge; they also usually have a comb on tergite VIII, and cilia present on the anterior margin of the fore wing. A generic definition of Psilothrips was provided by O’Neill (1960), but that failed to mention several important character states, including the number of ocellar setae, the presence of six prominently pigmented facets ventrally on each compound eye, and the presence of a prominent spinula on both the meso and metafurca. The number of ocellar setae is particularly important because of the failure of earlier workers to note the presence of ocellar setae pair I in front of the first ocellus, including O’Neill’s failure to illustrate these setae (see her Fig. 1/6). This led Bhatti (1967) to refer to an “additional” pair of anteocellar setae when describing Psilothrips indicus as a new species. This pair of setae is often very small, and is difficult to see due to the curvature of the head except when a specimen is very well cleared or the head crushed (Figs 1, 2).

Generic diagnosis.

Macropterous Thripinae . Antennae 8-segmented (Fig. 9), segment I with no dorso-apical setae, II with no long setae, sense cones on III-IV forked, III-VI with rows of microtrichia. Head transverse, with 3 pairs of ocellar setae, pair III near anterior margins of triangle (Figs 1, 2); maxillary palps 2-segmented; compound eyes with 6 pigmented facets (Fig. 2). Pronotum transverse (Figs 3, 4, 5, 6), weakly sculptured, discal setae small; with 4 pairs of posteromarginal setae, of which one posteroangular pair sometimes longer than other pairs. Meso- and metafurca with spinula. Mesonotal anterior campaniform sensilla absent, median pair of setae distant from posterior margin. Metanotal sculpture irregularly reticulate, median setae arise medially; no campaniform sensilla (Figs 6, 7, 8). Tarsi 2-segmented. Fore wing costa with setae but no cilia (Fig. 10); first vein with 3 widely spaced setae on distal half; second vein with continuous, widely spaced, row of setae; clavus with 4 veinal setae and one discal seta; posterior fringe straight. Tergites with weak transverse reticulation, posterolaterally these lines bear small microtrichia; II-VIII with setae S1 (median pair) elongate (Figs 11, 12, 13), on III-VII arising on antecostal ridge; V-VII with setae S2 unusually elongate, almost as long as S1; tergites without ctenidia, VIII with no posteromarginal comb; tergite IX with one pair of campaniform sensilla (Fig. 12), without discal microtrichia (except Psilothrips priesneri ), X with no median split (Fig. 12); pleurotergites with or without discal setae; sternites III-VII with 3 pairs of marginal setae (lateral pair on VII sometimes absent), discal setae varying in number from zero to eight. Male with sternal pore plates present or absent.

Key to species of Psilothrips

1	Pronotum with 1 pair of posteroangular setae as long as, or longer than, width of antennal segment II (Figs 5, 6); pleurotergal discal setae absent	2
-	Pronotum with no elongate setae, posteroangular setae less than 0.5 times as long as width of antennal segment II (Figs 3, 4); pleurotergal discal setae present or absent	3
2	Metanotum posterior third with concentric sculpture lines (Fig. 6); major setae on pronotum setiform; western USA	pardalotus
-	Metanotum posterior third with equiangular reticulation (Fig. 8); major setae on pronotum longitudinally grooved; Iran	zygophylli sp.n.
3	Metanotum posterior third with many complex markings within each reticle (Fig. 7); tergite IX anterior third with prominent transverse band of microtrichia (Fig. 12); western USA	priesneri
-	Metanotal reticles with few or no internal markings; tergite IX with no prominent microtrichia	4
4	Head and body uniformly brown (in life with bright red internal pigment); macropterae and micropterae; Canary Islands	minutus
-	Head and pronotum yellow with brown areas, tergites II-VII yellow posterolaterally (in life with orange pigment in pterothorax); only macropterae known; Morocco, Egypt, Yemen, Israel, India, China	bimaculatus