The variegated mud-loving beetles (Coleoptera: Heteroceridae) of Mississippi and Alabama, with discussion and keys to the species occurring in the southeastern United States

We review the variegated mud-loving beetle fauna of the southeastern United States (Coleoptera: Heteroceridae), with an emphasis on Mississippi and Alabama. A key is presented to all species known to occur in the southeastern US, and includes several extra-limital species. Descriptions, illustrations and distribution maps are presented for each species. One new species, Tropicus nigrellus, is described and a lectotype is designated for Heterocerus schwarzi Horn. Our molecular data suggest that many previously recognized generic concepts are unnatural. As a result, the following generic synonymies are proposed: Culmus Pacheco 1964, Damfius Pacheco 1964, Efflagitatus Pacheco 1964, Erus Pacheco 1964, Filiolus Pacheco 1964, Gradus Pacheco 1964, Lanternarius Pacheco 1964, Lapsus Pacheco 1964, Neoheterocerus Pacheco 1964, Olmedous Pacheco 1964 and Peditatus Pacheco 1964 are synonyms of Heterocerus Fabricius; the genera Centariatus Pacheco 1964, Explorator Pacheco 1964, and Microaugyles Pacheco 1964 are synonyms of Augyles Schiödte. New combinations proposed and used in this paper include: Augyles auromicans (Kiesenwetter 1851, Heterocerus), Heterocerus parrotus (Pacheco 1964, Lanternarius), Heterocerus sandersoni (Pacheco 1964, Neoheterocerus) and Heterocerus selanderi (Pacheco 1964, Efflagitatus), Heterocerus texanus (Pacheco 1964, Peditatus). Other new combinations for North American species formed as a result of these generic reconfigurations, but not used in this paper, include: Heterocerus inciertus (Pacheco 1964, Damfius), Heterocerus longilobulus (Pacheco 1964, Neoheterocerus), Heterocerus sinuosus (Pacheco 1964, Lanternarius), Augyles canadensis (Fall 1920, Heterocerus), Augyles compactus (Fall 1937, Heterocerus), Augyles moleculus (Fall 1920, Heterocerus) and Augyles mundulus (Fall 1920, Heterocerus). New combinations for South American species suggested by molecular data, all originally described in the genus Efflagitatus, include: Heterocerus boliviensis (Pacheco 1964), Heterocerus freudei (Pacheco 1973), Heterocerus furmidus (Pacheco 1964), Heterocerus ingeniosus (Pacheco 1964), Heterocerus meridianus (Pacheco 1975), Heterocerus reticulatus (Pacheco 1964), Heterocerus solitarius (Pacheco 1973), Heterocerus splendidus (Pacheco 1964), Heterocerus tortuosus (Pacheco 1973), Heterocerus woodruffi (Pacheco 1975). No new combinations involving synonymy within the genera Culmus, Erus, Filiolus, Gradus, Lapsus, and Olmedous were proposed because all included species were originally described as Heterocerus