The Milliped Genus Scytonotus in Eastern North America, with the Description of Two New Species

Abstract

The examination of recently acquired material reveals that the milliped genus Scytonotus is represented in eastern North Amer- ica by four species, two of them previously undescribed. On the basis of several taxonomic characters of the body form and male genitalia, two subgeneric groups can be recognized: a Granulatus Group including the common and widespread S. granulatus (Say) and S. australis, n. sp., from north Georgia, and a Virginicus Group with S. virginicus (Loomis) and S. michauxi, n. sp., from North Carolina. A key is provided for identification of these four species, and the gonopods are illustrated. Scytonotus cavernarum Bollman is added to the synonymy of S. granulatus, and the status of this and some other junior synonyms discussed. The ranges of the four eastern species are, so far as known, entirely allopatric, and no two species have been found at any locality. S. granu- latus is apparently a specialized and successful form with a wide range; the other three species have limited distributions. Locality records are shown on a spot map. During the decade which has elapsed since publication of my short paper (1950) on the two forms of Scytonotus occurring in Vir- ginia, I have accumulated a considerable quantity of material, which includes representatives of two undescribed members of the genus. Eight collections from the mountains of North Carolina and Tennessee include a scytonotid obviously related to S. virginicus (Loomis) - a localized species endemic to the Blue Ridge in central and northern Virginia. But since prolonged search indicates that the ranges of the two populations are widely separated, and since conspicuous and constant differences in the gonopods readily separate the two forms, I recognize the southern population as a full species, the third member of the genus now known in eastern North America. Specimens from northern Georgia are somewhat similar to S. granulatus (Say) in shape of the gonopods, but differ sufficiently in the details of these appendages as well as in external body form to warrant designation as a distinct species. This form is now the south- ernmost known member of the otherwise characteristically sub-boreal. genus. In addition to the proposal of the new specific names, I include additional locality records for S. virginicus and a discussion of the distribution and synonymy of the widespread S. granulatus, so that the present paper constitutes a short synopsis of Scytonotus in the eastern part of its range. The genus is represented elsewhere by