Pugs of the tribe Eupitheciini (Lepidoptera, Geometridae): the history of study and distribution over biogeographic regions

Abstract

The World fauna of the tribe Eupitheciini is the most species-rich in the family Geometridae. This tribe includes about 1900 species (almost 3000 species-group names) from 47 genera; about one third of the genera (15) are monotypic. The generic diversity of Eupitheciini is the highest in the Australian (38 genera, 11 of them endemic) and Oriental regions (32 genera, 4 endemic) and the lowest in the Neotropical Region (possibly one genus only). The faunas of different biogeographic regions can be arranged in following order by their species richness: the Palaearctic (487 species), Oriental (397), Neotropical (346), Australian (251), Afrotropical (198), and Nearctic Regions (166 species). Eupithecia is the most species-rich genus in the family Geometridae and the entire order Lepidoptera, and one of the largest genera in the whole World fauna of insects. The greatest number of species of this genus is recorded in the Palaearctic Region (466 species), where Eupithecia accounts for about 95% of the tribe Eupitheciini. The mainland of the Oriental Region (especially the Himalayas) is also very species-rich; however the proportion of the Eupithecia representatives decreases towards Malaysia, Sundaland, and the Australian Region (about 2% of the tribe). The Eupitheciini faunas have the greatest similarity at the generic level between the Oriental and Australian Regions (the Jaccard and Sorensen coefficient values being 0.62 and 0.77, respectively). The Palaearctic fauna is more similar to the Afrotropical and Oriental faunas at the genus-group level. On the whole, the fauna of the Nearctic Region is similar to that the West Palaearctic, with the exception of the fact that representatives of the genera Gymnoscelis and Chloroclystis are absent in North America, although two endemic genera Nasusina and Prorella are present. At the genus-group level, the Nearctic fauna of Eupitheciini is more similar to the Neotropical (the Jaccard and Sorensen coefficients 0.20 and 0.33, respectively) than to the Palaearctic fauna (0.17 and 0.29). The number of synonymies is very high in the tribe Eupitheciini because of the homogeneity of this group, whose species are difficult to identify without the use of elaborate anatomical techniques. Modern revisions, catalogues, surveys, and atlases on Eupitheciini are absent for many countries and large geographic regions. Revisions of pugs of the tribe Eupitheciini for some biogeographic regions are extremely difficult because of fragmentation of entomological collections including the type specimens of many species-group taxa. A large fraction of synonyms is characteristic of parts of the World with the best known faunas: Europe (64% of synonyms) and North America (39%). On the contrary, the lowest levels of synonymy are typical of the less known faunas of the regions situated at the equatorial latitudes, namely the Neotropical (9%) and Afrotropical (8%) ones.