Xestioplexia, Gyulai, Peter, Ronkay, László & Saldaitis, Aidas, 2015

Gyulai, Peter, Ronkay, László & Saldaitis, Aidas, 2015, Xestioplexia gen. n. with the description of a new species from China (Lepidoptera: Noctuidae), Zootaxa 4007 (1), pp. 131-137 : 131-132

Xestioplexia gen. n.

Type-species: Xestioplexia albicollis sp. n., here designated.

Diagnosis. The new genus belongs to the subfamily Noctuinae , tribe Noctuini , displaying the closest affinity with the genus Xestia (s. l.). Xestioplexia is represented by two, externally rather similar, medium-sized species (wingspan 34–40 mm) having black or dark brown ground colour of forewings, generally Xestia (Pachnobia) — like noctuid pattern and clear white hindwings. Xestioplexia differs externally from the members of Xestia (Pachnobia) by the more angular forewings, the somewhat Anaplectoides -like forewing pattern with conspicuous black intercellular patches, sharply defined orbicular and reniform stigmata and cross lines, the whitish frons, vertex and collar (which is best visible in the freshly emerged females), and the white hindwings. The bipectinate antennae of the males are present in certain speciesgroups of Xestia , but this gracile, shortly and finely pectinated type of the male antenna is typical of this lineage. The members of the new genus are somewhat similar also to the taxa of the genus Neurois Hampson , especially N. cadioui Hreblay & Ronkay, 1998 and N. atrovirens (Walker, 1865) but have more robust body, finely pectinated male antennae (those of the Neurois species are filiform), broader forewings with different markings; the detailed comparisons see under the diagnoses of the two Xestioplexia species.

The genitalia structures basically indicate the closer affinity of Xestia , with a number of striking differences. The most prominent apomorphy of the new genus is the unusual configuration of the harpe–ampulla complex: it is a flattened and basally slightly bilobed plate, with long, spine-like, ventro-apical process in X. colorata and X. albicollis , resembling mostly to that of certain Oroplexia , especially O. euplexina ( Draudt, 1950) . Another diagnostic features of Xestioplexia are the evenly thin and long uncus, the entire lack of pollex, the rather short, curved aedeagus with conspicuously strongly sclerotised carinal appendages (the ventral plate is strongly serrated), and the large, ample vesica bearing medium-long, tubular medial diverticulum terminated in fine, acute cornutus. The vesica of almost all Xestia s.l. species is tubular, most often without cornutus.

The configuration of the female genitalia of Xestioplexia is also unique. The females of the new genus have large, strongly sclerotised calyculate antrum and more or less similarly shaped and sized, also strongly sclerotised posterior section of ductus bursae. These two sclerotised areas form a double trapezoidal configuration; this structure differs conspicuously from those of the main lineages of Xestia and very distinctive from all of the externally somewhat similar species. The anterior section of ductus bursae, the appendix bursae and the sacculiform corpus bursae are membranous in X. albicollis , corresponding to those of certain Xestia species, e. g. X. (Pachnobia) borealis (Nordström) .

Etymology. The name Xestioplexia is created from the generic names “ Xestia ” and “ Oroplexia ” due to the resemblance of the male clasping apparatus to both genera.