A new subterranean Crematogaster with one ommatidium from Cambodia, based on morphology and DNA (Hymenoptera: Formicidae)

A subterranean myrmicine ant Crematogaster monocula sp. nov. is described based on two worker specimens from Cambodia. This species belongs to the C. biroi group of the subgenus Orthocrema Santschi, 1918, which is characterized by developed subpetiolar process, developed subpostpetiolar process and sculptured mesosoma. The new species is easily distinguished from other species of Crematogaster Lund, 1831 by having only one ommatidium. DNA sequences comprising a 761 bp fragment of the 3’ region of the mitochondrial COI gene were amplified and analyzed for C. monocula sp. nov. and other closely related species from the same group. The interspecific COI divergence is 17.8% for C. monocula sp. nov. and C. reticulata Hosoishi, 2009. This species is unique in having the smallest eye in the genus Crematogaster