Chironius scurrula, the correct nomen for Chironius scurrulus (Squamata, Serpentes, Colubridae), with a list of the correct spellings of specific epithets currently in use in this genus

The correct epithet of the snake species so far known as Chironius scurrulus Wagler in Spix, 1824 is shown to be scurrula, as it is not an adjective but a noun in apposition to the generic substantive, therefore invariable. This case prompted us to review the grammatical status of the epithets of the 23 species currently considered valid in the genus Chironius Fitzinger, 1826. Only about 56.5 % of these epithets turned out to be adjectives agreeing in gender with the generic nomina with which they are combined. Although this proportion will be very variable from one zoological genus to another, it is likely that in genera with a high number of species (10‒20 or more), some epithets will not agree in gender with the genus nomina. In order to avoid subsequent corrections in the spellings of epithets (and therefore ‘nomenclatural instability’), taxonomists are therefore encouraged to pay attention to this question. As a consequence of this survey, we also provide new information on a few miscellaneous questions: the author of the type species designation for Chironius; the author, date, type specimen and type locality of the nominal taxon Chironius flavolineatus; and the etymology and status of the epithets of the bionomina Chironius foveatus and Chironius leucometapus.