Temnothorax caryaluteus sp. nov. (Hymenoptera: Formicidae): a new ant species from the eastern United States

Abstract. Although the ant genus Temnothorax is broadly distributed, extremely diverse, and contains multitudes of undescribed species, discovering new Temnothorax species in the eastern United States is rare due to the high concentration of taxonomic effort on this region. Here, we recognize and describe a new species that has consistently been misidentified in museum collections as Temnothorax ambiguus, a common inhabitant of acorn shells and leaf litter. Unlike T. ambiguus, T. caryaluteus sp. nov. nests primarily in arboreal microhabitats, especially within dead branches on live Carya and Quercus trees. We compare the morphology of T. caryaluteus sp. nov. against the congeners with similar appearance T. ambiguus and T. curvispinosus, and delineate diagnostic characters for T. caryaluteus sp. nov. Moreover, we provide an updated key to the Temnothorax species of the eastern United States.