Spelaeogammarus quilombola sp. nov. (Amphipoda: Bogidielloidea: Artesiidae): a New Stygobitic Amphipod for Brazil, with a Supplementary Description of Spelaeogammarus bahiensis Da Silva Brum, 1975.

A new stygobitic amphipod species of the genus Spelaeogammarus is described from a cave in the municipality of Morro do Chapéu, in Bahia, northeastern Brazil, increasing the total number of species in the genus to eleven. Spelaeogammarus quilombola sp. nov. shares similarities primarily with Spelaeogammarus spinilacertus, S. bahiensis, and S. trajanoae, but can be distinguished from its congeners by specific morphological and morphometric traits. An updated comparative table highlighting the diagnostic characteristics of Spelaeogammarus species are also provided. Additionally, we offer a supplementary description of S. bahiensis da Silva Brum, 1975, the type species of the genus. Finally, we discuss the habitat characteristics and the threats facing both species addressed in this study. Given its high endemism, this new species holds particular significance for biogeographical and conservation studies.