A Taxonomic Revision of the New World Genus Discoderus LeConte, 1853 (Coleoptera: Carabidae: Harpalini)

The New World genus Discoderus LeConte, 1853 is revised to include 23 species, four of which are described as new herein. The character states of three external structures (tarsi, anal setation, and mesotibial dentition) in adult males provide the basis for three subgenera and the identification of species. Added to subgenus Discoderus (sensu stricto) LeConte are Discoderus circulus Messer and Raber, new species and Discoderus pueblaensis Messer and Raber, new species. Added to Paraselenalius Messer and Raber, new subgenus (type species: Selenophorus beauvoisii Dejean, 1829) are Discoderus nonarcuatus Messer and Raber, new species and Discoderus shpeleyi Messer and Raber, new species. The monobasic subgenus Selenalius Casey retains Discoderus cordicollis Horn. Transferred from Selenophorus Dejean are Discoderus curvipes (Putzeys), new combination and Discoderus valgus (Bates), new combination. Discoderus amblyderus (Bates), status restored is removed from synonymy with Discoderus arcuatus (Putzeys). Nineteen new synonyms are proposed: Discoderus aequalis Casey senior to Discoderus congruens Casey, Discoderus dallasensis Casey, Discoderus longicollis Casey, Discoderus peregrinus Casey, and Discoderus texanus Casey, new synonyms; Discoderus amblyderus (Bates) senior to Discoderus pulvinatus Bates, new synonym; Discoderus cordicollis Horn senior to Discoderus parilis (Casey), new synonym; Discoderus crassicollis Horn senior to Discoderus dislocatus Bates, new synonym; Discoderus crassiusculus (Putzeys) senior to Discoderus crassiusculus var. nigrescens (Bates) and Discoderus pinguis Casey, new synonyms; Discoderus curvipes (Putzeys) senior to Discoderus hepburni (Bates), new synonym; Discoderus difformipes Bates senior to Discoderus distortus Bates and Discoderus piger Bates, new synonyms; Discoderus impotens (LeConte) senior to Discoderus papagonis Casey and Discoderus symbolicus Casey, new synonyms; Discoderus parallelus (Haldeman) senior to Discoderus tenebrosus (LeConte), new synonym; Discoderus robustus Horn senior to Discoderus melanthus Bates, Discoderus robustus piceus Casey, and Discoderus subviolaceus Casey, new synonyms. Discoderus acinopoides Bates is treated as species inquirenda. New state records (USA), new country records, geographic distribution maps, photographs of habitus and phallic median lobes, and a separate species identification key for each sex are provided. Anatomic similarities to other harpaline genera are discussed.