The Melanoplus scudderi species group, when erected by Blatchley, contained six species. The revision of the group presented here describes 21 new species and establishes the Carnegiei group and Davisi groups. Most of these new species are associated with grasslands in the southeastern United States. Analysis of DNA barcoding data, suggests that the technique does not adequately delineate species based on well-established morphological concepts. However, analysis of the barcode data did produce three broad mitochondrial DNA clades that correspond to the Apalachicola and Mississippi River discontinuity phylogeographic pattern, which is displayed by several other organisms in the southeastern United States and is attributed to vicariant events resulting from Pleistocene glaciation. Keys to the groups and species along with a hypothetical evolutionary history of the groups are presented.
southeastern United States