Ctenothrips Franklin, 1907

Wang, Zhaohong, Li, Yajin, Tong, Xiaoli & Mound, Laurence, 2020, Phylogenetic analysis of the Taeniothrips genus-group, with revision of the species of Ctenothrips and Vulgatothrips (Thysanoptera, Thripinae), Zootaxa 4750 (3), pp. 301-327 : 307

Ctenothrips Franklin

Ctenothrips Franklin, 1907: 247 . Type species: C. bridwelli Franklin.

This genus was erected for a single species based on five females from a site just north of Boston in North America, and about 20 years later a second species was described based on a single short-winged female that was taken just West of Boston ( Moulton 1929). We conclude below that these two represent a single species that is widespread in the area between New Hampshire, Tennessee and Alberta. In contrast, the other 13 species currently listed in this genus are all from Eurasia (ThripsWiki 2019). One is widespread across the Palaearctic, one is known only from alpine Japan, three are from the Himalayan mountain areas in Nepal and India, and eight are from China. Unfortunately, most of these species were described by authors without personally examining specimens of previously described species. Many descriptions were based on few specimens (see Table 1 ), and some were damaged when mounted onto slides ( Figs 53–57 , 64–66 ). However, useful taxonomy of phytophagous thrips needs to be based on adequate samples, together with reliable host-plant records. Xie et al. (2011) drew attention to the resultant confused situation by producing a key to 12 species, of which information concerning 10 species was drawn solely from published literature. The structure of that key revealed the weakness of several character states that had been used to diagnose several species, including pronotal surface sculpture and varying shades of yellowish-brown on antennal segments. Given the lack information concerning the identity of the plant species on which these insects live, and the inadequate morphological distinctions used, there is good reason to query the taxonomic significance of some of the species described in Ctenothrips .

According to the analysis results above, three names should be transferred to Vulgatothrips , 13 names are now left in Ctenothrips (clade 2 in Figure 1 ). Although most species were known from limited specimens with weak host plant information, study of the extensive available slide collections (Appendix 1) suggests some possible host associations. Ctenothrips bridwelli is associated with leaves of certain Liliaceae and Orchidaceae ; the Palaearctic species, C. distinctus , is associated with Convallaria majalis (Asparagaceae) , another lily-like plant; a new species from China is described below from another member of the Liliales , Paris yunnanensis (Liliaceae) ; and nonnae from Japan was known from Paris japonica . Although the other nine species were taken from unrelated plants, yangi was described as breeding on various different plants, Bryophyllum (Crassulaceae) , Oxalis (Oxalidaceae) , Glycine (Leguminosae) , Pilea (Urticaceae) , Mentha (Lamiaceae) and also Paris . This polyphagous feeding habit may be related to the variation in structural characters that we record below among the available samples of adult Ctenothrips specimens.

Diagnosis: Macropterous or micropterous. Head longer than wide or as long as wide, constricted behind eyes; maxillary palps 3-segmented; eyes without pigmented facets and not longer than length of cheek; ocellar setae I absent. Antennae 8-segmented, segment I without paired dorso-apical setae, III and IV with forked sense cones. Pronotum wider than long; two pairs of long posteroangular setae, one or two pairs of posteromarginal setae present. Mesonotum reticulate, median pair of setae situated near middle; campaniform sensilla present anteromedially. Metanotum reticulate; median setal pair behind anterior margin; campaniform sensilla present ( Fig. 22 ). Fore wing vein setal rows complete or first vein with short gaps; clavus with five veinal and one discal setae; posterior fringe cilia wavy ( Fig. 31 ). Prosternal ferna not divided; basantra membranous, without setae; prospinasternum broad and transverse. Mesosternum without sternopleural sutures, meso- and metasternal endofurca without spinula ( Fig. 24 ). Tarsi 2-segmented. Abdominal tergites reticulate, III–VII posterior margin without ctenidia or craspeda ( Fig. 44 ); VIII with complete posteromarginal comb; IX with two pairs of campanifom sensilla; X with median split com- plete. Sternites reticulate, III–VII with three pairs of posteromarginal setae, II with two pairs posteromarginal setae, VII with S1 and S2 far from margin ( Fig. 50 ). Pleurotergites without discal setae. Male similar to female; sternites III–VIII each with oblong pore plate ( Fig. 45 ).

Figures

FIGURE 1. Strict consensus of four most parsimonious trees. (Tree generated from morphological phylogenetic analysis, unambiguous apomorphies mapped on branches, black circles indicate nonhomoplastic changes; bremer support values and bootstrap mapped near the nodes below and above branches respectively).

FIGURES 53–62. Ctenothrips. (53) bridwelli (Holotype of frosti). 54–59 kwanzanensis: (54) paratype female of taibaishanensis; (55) paratype male of taibaishanensis; (56) paratype of leionotus; (57) paratype of cornipennis; (58) paratype of guizhouensis; (59) paratype of nonnae. (60) transeolineae. 61–62 parisae: (61) female; (62) male.

FIGURES 64–67. Vulgatothrips. (64) paratype of dissimilis; (65) paratype of shennongjiaensis; (66) shennongjiaensis; (67) male of smilax.

FIGURES 16–31. Characters on thorax. 16–19 pronotum: (16) C. distinctus; (17) C. distinctus; (18) C. transeolineae; (19) C. parisae. 20–23 Meso-and metanotum: (20) V. shennongjiaensis; (21) C. distinctus; (22) Ta. eucharii; (23) C. parisae. 24–26 Meso-and metasternum: (24) C. distinctus; (25) Ta. eucharii; (26) V. smilax. 27–28 Hind leg: (27) C. bridwelli; (28) C. distinctus. 29–31 Fore wing: (29) Ta. orionis; (30) C. parisae; (31) C. distinctus.

FIGURES 39–52. Characters on abdomen. 39–40 Tergites: (39) Ta. orionis tergites III–IV; (40) Ta. eucharii tergites IV–VI; (41) V. shennongjiaensis tergite VIII; (42) Te. frici tergites VI–X; (43) C. kwanzanensis tergites V–VII; (44) C. distinctus VII–IX. 45–46 Male sternites: (45) C. parisae; (46) V. shennongjiaensis. 47–49 Male tergites IX: (47) C. kwanzanensis; (48) C. parisae; (49) C. transeolineae. 50–52 Sternites: (50) C. bridwelli; (51) Ta. picipes; (52) V. shennongjiaensis.