Taxonomic revision of the pygmy devils (Tetrigidae: Discotettiginae) with online social media as a new tool for discovering hidden diversity

Abstract

Pygmy grasshoppers (Tetrigidae) are family of small grasshoppers inhabiting humid aras, where thy feed on detritus, algae and mosses, that sometimes grow on their body. Pygmy devils (Discotettiginae) are a group of genera characterized by widened subapical antennal segments. Taxonomy and biogeograpy of all the members are reviewed by examination of large series of museum material and additional photo material found in social networks (Flickr, Facebook). In total 887 specimens of (after revision) 70 species within 9 genera (1 new genus, 34 new species) were examined. Widened antennal segments are homoplastic character. They occur in separate evolutionary and geographic groups. Genera Discotettix, Kraengia and Zvierckia Skejo et al. gen nov. belong to the tribe Scelimenini (Discotettigini syn. nov. – Scelimeninae with Discotettiginae syn. nov.), genera Arulenus and Disconius Skejo et al. gen nov. are members of Scelimeninae, but not the tribe Scelimenini. Genus Rosacris is Metrodorinae member without tribal placement, while genus Ophiotettix belongs to the tribe Ophiotettigini Tumbrinck et Skejo trib. nov. Genera Hirrius and Phaesticus are left without subfamily placement. Photos found on social networks can provide first photographic records of living specimens for the species known only from collections or descriptions lacking drawings, new data on distribution, variability of species, new information on morphology of unknown sex or nymph, and discovery of new species. New species should not be described without physical types.