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

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

Methods
This study is based on examination of 342 workers and 38 gynes, with measurements taken from 130 specimens: 107 workers and 23 gynes. We compared three species that are most likely to be confused with each other: Temnothorax ambiguus, T. curvispinosus, and T. caryaluteus sp. nov. All measurements and morphological observations in thus study were performed at a maximum magnification of 160X using a Leica M205C stereomicroscope, a movable stage equipped with orthogonal digital micrometers, and an ocular graticule. 

Means of raw morphological measurements and indices of Temnothorax ambiguus, T. curvispinosus, and T. caryaluteus sp. nov. were compared with the pairwise Wilcoxon test, and an overall significance of each set of comparisons was calculated using the Kruskal-Wallis test.