Date of this Version
Ślipiński A. 2020. A new species of Euxestoxenus Arrow (Coleoptera: Euxestidae) from Thailand. Insecta Mundi 0838: 1–4.
Michael C. Thomas Festschrift Contribution
A new species of Euxestoxenus Arrow (Coleoptera: Euxestidae), E. thomasi Ślipiński, is described from northern Thailand. The species differs from all Oriental and most of African species of Euxestoxenus by a 10-segmented antenna and glabrous, polished dorsum.
Euxestidae is a small and poorly known family of Coccinelloidea that currently includes 11 genera and about 70 species distributed mostly in the Old-World tropics and subtropics but extending into temperate areas of North America and Australia (Ślipiński 1990). The biology of the Euxestidae is mostly unknown but it appears that all species are fungivores, commonly found in rotten wood, forest litter, in the ant galleries and in the fungus gardens of the fungus growing termites in the genus Odontotermes Holmgren (Jiang et al. 2020).
The first species of Euxestoxenus was described by G.J. Arrow in the family Erotylidae in the volume of the Fauna of British India (Arrow 1925). The specimens of E. striatus Arrow were collected by H.G. Champion in the Northern India (Kumaon, Haldwani District) within the comb of a common termite species Odontotermes obesus (Rambur). Euxestoxenus was later found (John 1968) to be a senior synonym of two African genera, the common and speciose Elytrotetrantus John, 1941 and more obscure and monotypic Tachyoryctidium Jeannel and Paulian, 1945. The African taxa have been collected at light, sifted from decaying litter and fruits, from subterranean mammal nests and from ant nests of the genus Myrmicaria Saunders. The ant-nest inhabiting species have been put into a subgenus Anaulakous John (John 1963) characterised by almost glabrous and irregularly micropunctured elytra.
Interestingly a similar, glabrous Euxestoxenus species has been found among the unidentified Euxestidae from Thailand deposited at the Natural History Museum in Geneva. The new species is the second Oriental species of Euxestoxenus, different from the Indian species, E. striatus, but more similar to the myrmecophilous species from Angola and Democratic Republic of the Congo (John 1964). The species from Thailand was collected by sifting from the “pied d’arbre” [foot of the tree] but the potential association with the ants has not been recorded.
Euxestoxenus is diagnosed by having 8–10 segmented antenna bearing large, asymmetrical 1-segmented club received by concave hypomeron, lightly sculptured elytra and the prosternal process broad and expanded apically (Ślipiński 1990). The taxonomic status of the approximately 60 African species is unclear due to a large number of synonyms created by the late Hans John that remain unrevised.