Abstract
The enigmatic millipede assassin bug genus Xenorhyncocoris Miller, 1938 is revised. Previously known species, X. caraboides Miller, 1938, X. princeps Miller, 1949 and X. schoenitzeri Putshkov & Bérenger, 1999, are diagnosed and photographed. A new species, X. attractivus sp. nov., is described based on male and female specimens from northeastern Borneo. The male of Xenorhyncocoris is reported for the first time, revealing the extreme sexual dimorphism present in the genus. The diagnosis of Xenorhyncocoris is extended in order to make it applicable to the new discovery, and a female-based key to species of the genus is updated. Relationships among Xenorhyncocoris and Vilius Stål, 1863, Neozirta Distant, 1919 and Schottus Distant, 1902 are briefly discussed.
Highlights
Millipede assassin bugs have been treated as a separate subfamily Ectrichodiinae since Amyot & Audinet-Serville (1843), but were recently reduced to the tribe Ectrichodiini based on a phylogenetic study combining morphological and molecular data (Forthman & Weirauch 2017)
A new species from northeastern Borneo is described, of which we discover the macropterous male in addition to the micropterous female
Xenorhyncocoris – Cook 1977: 64, 70. — Maldonado Capriles 1990: 78. — Putshkov & Bérenger 1999: 92. This genus can be recognized within Ectrichodiinae by the following combination of characters: macropterous or micropterous; head club-shaped, subapically widened, distinctly longer than pronotum; ventral surface of anteocular part flat; antenniferous tubercle surrounded by lump-form process laterally; antennae four-segmented, with basiflagellomere shorter than other segments; labial segment II longest and dorsoventrally flattened, segment III inflated, segment IV flattened laterally; apex of prosternum acute, distinctly surpassing fore coxae; metathoracic gland evaporatorium invisible in lateral view; femora not thickened; apexes of tibiae bulbous; fossula spongiosa present on fore and mid tibiae; abdominal tergite II with three longitudinal ridges
Summary
Millipede assassin bugs have been treated as a separate subfamily Ectrichodiinae since Amyot & Audinet-Serville (1843), but were recently reduced to the tribe Ectrichodiini based on a phylogenetic study combining morphological and molecular data (Forthman & Weirauch 2017) This group, comprising about 670 species in 120 genera, is generally circumtropical in distribution, with only a few species reaching temperate regions (Maldonado Capriles 1990; Swanson 2019). Despite the high species diversity among Ectrichodiini, many taxa of this group are described based on only a few specimens of a single sex, which, coupled with the prevalence of sexual dimorphism within the group, can sometimes cause difficulty with matching the conspecific males and females and can even cause taxonomic confusions (e.g., Rédei & Tsai 2012; Rédei et al 2012) Such taxonomic problems impede our knowledge concerning the actual biodiversity and evolutionary relationships of millipede assassin bugs. Thanks to recent advances in DNA sequencing, molecular data can be effectively obtained and utilized, together with morphological and distributional information, to associate sexually dimorphic individuals and different life stages, which has already been successfully applied in Reduviidae (e.g., Zhang & Weirauch 2011; Forthman et al 2016; Weirauch et al 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
