Autapomorphies in the generic classification of Plectrothripini (Thysanoptera, Phlaeothripinae), with a new genus and a new record from Malaysia

466

The thysanopteran genus Chiridurothrips Okajima is known from a single extant species, C. hisakoae Okajima, collected in Japan (ThripsWiki 2019). Occurring on dead leaves and branches of evergreen trees in the subtropical Ryukyu Islands, this species remains known from only five females (Okajima 1981, 2006; also pers. comm. 2018). Within Phlaeothripidae, Chiridurothrips is associated with the tribe Plectrothripini. Species of this sub-group feed on fungal hyphae or the break-down products of fungal attack on decaying plant material (Mound & Ng 2018). They are found mainly under the bark of trees or on dead branches, and they do not seem to inhabit leaf-litter (Okajima 1981). At present, Plectrothripini comprises 60 extant species in 13 genera, with no fossils recorded. Of these species 32 are placed in the genus Plectrothrips Hood, ten in Streptothrips Priesner, and six in Chirothripoides Bagnall, whereas both Menothrips Hood and Mastigothrips Priesner each include only two species. The remaining eight species are all placed in separate monobasic genera (ThripsWiki 2019). Concerning this strongly asymmetric classification, Mound and Ng (2018) suggest that Plectrothripini might be particularly old, with the large number of monobasic genera each representing a relict lineage. An alternative possibility, however, might be an unusual instability in the genes controlling morphogenetic processes, and thus resulting in striking autapomorphies on which each one of these genera is diagnosed (Mound & Ng 2018). Species associated with Plectrothripini share the following character states (Okajima 1981; Mound & Tree 2017): antennae 8-segmented, segment II with the campaniform sensillum situated in the basal half, III–IV with stout sense cones, VIII slender with narrow base; head with posterior ocelli close to compound eyes; pronotum commonly with sclerotized plate eroded or reduced, prosternal basantra week or absent; legs with fore tarsal tooth large; mid and hind tibiae commonly with apical spur-like setae; macropterae with fore wings parallel-sided, usually with duplicated cilia; pelta broad at base, abdominal tergite II eroded laterally; abdominal sternites often with reticulate glandular areas. Regarding the fore wings, it seems worth mentioning that in some members of Plectrothripini the subbasal wing vein is reduced and thus the three subbasal wing setae are lacking (see Plectrothrips tenuis Okajima, Chiridurothrips [c.f. fig. 2], Chirothripoides, Lonchothrips Hood; Bhatti 1998; Okajima 1981). This short vein that is present in (almost all) other macropterous Phlaeothripidae has been interpreted as a plesiomorphic feature that resulted from the reduction of a former well-developed longitudinal first vein of ancestral Tubulifera, the Rohrthripidae (Ulitzka 2018, 2019).

Section: Discussionmentioning

confidence: 58%

A new species of Chiridurothrips Okajima from Miocene amber of the Dominican Republic (Thysanoptera: Phlaeothripidae)

Ulitzka¹

2019

466

“…However, both Turmathrips species have the mesonotum with a complete median longitudinal division. The presence of structurally remarkable autapomorphies, such as the unique tubercle ventrally on the head in Pharothrips, is a frequent problem when considering relationships among Phlaeothripinae (Dang et al 2014;Mound & Ng 2018). Despite this remarkable structure, the genus is possibly related to Drypetothrips, but again molecular data would be needed to consider such a possibility.…”

Section: Drypetothrips Korykis Spn (Figs 2-7)mentioning

confidence: 99%

Two new monobasic thrips genera for a gall-inducing species and its kleptoparasite (Thysanoptera, Phlaeothripinae)

Mound

Wells

2020

454

Drypetothrips korykis gen. et sp.n. is described as inducing leaf-margin galls on a small tree in Australia, Drypetes deplanchei [Putranjivaceae]. This thrips is similar in appearance to the smaller species of the genus Kladothrips that induce galls on Acacia species. The galls are invaded by a phytophagous kleptoparasitic thrips, Pharothrips hynnis gen. et sp.n., females of which have a forked plough-like structure protruding ventrally on the frons that is unique amongst Thysanoptera.

Enigmatic male dimorphism in the Phlaeothripinae (Thysanoptera, Phlaeothripidae), with description of a new genus and species

Okajima

Masumoto

2022