The identity of Canthydrus testaceus (Boheman, 1858) and a new faunistic record of Sternocanthus indicus (Wehncke, 1876) (Coleoptera: Noteridae)

During the recent revision of the Asian species of the genus Canthydrus Sharp, 1882 (Toledo & Negri 2024) it was not\r\npossible to ascertain the identity of Hydrocanthus testaceus Boheman, 1858 described from “China”, because the insect\r\ncollection of the Swedish Museum of Natural History in Stockholm, where the type material of this taxon is housed, was\r\ntemporarily inaccessible.\r\nAccessibility to the collections has now been restored, and the examination of what is presumably the only available\r\nsyntype of Hydrocanthus testaceus reveals that it is a female of a small, uniformly pale Canthydrus. To ensure taxonomic\r\nstability, the syntype is here designated as the lectotype of Hydrocanthus testaceus Boheman, 1858. Although no male\r\ngenitals are available for a more precise diagnosis, the external morphology clearly shows that it belongs to the species\r\ncurrently named Canthydrus ritsemae (Régimbart, 1880), which has already been recorded for southern China (Toledo\r\n& Negri 2024). The synonymy of these two species-names was already hypothesized by Toledo (2003). According to\r\nthe ICZN (1999: Article 23), the species-name testaceus Boheman, 1858 has priority over ritsemae Régimbart, 1880.\r\nTherefore, Hydrocanthus ritsemae Régimbart, 1880 syn. nov. becomes a junior subjective synonym of Hydrocanthus\r\ntestaceus Boheman, 1858. Consequently, Canthydrus javanus Wehncke, 1883 and C. pseudoflavus Rocchi, 1986, so\r\nfar junior synonyms of C. ritsemae, now also become synonyms of C. testaceus. For full bibliography of all concerned\r\nspecies, see Nilsson (2011) and Toledo & Negri (2024).