Camponotus vagulus Forel 1908 b. NEW STATUS.

Camponotus fastigatus subsp. vagulus Forel 1908b: 403. [w syntypes examined, MHNG; São Paulo, Brazil (v. Ihering)]

Camponotus (Myrmaphaenus) fastigatus subsp. vagula Forel. Emery 1925: 155. Camponotus (Myrmaphaenus) fastigatus vagulus Forel. Kempf 1972: 46.

Camponotus fastigatus has been interpreted broadly by Forel, Emery, and Santschi, who each named subspecies based on forms that are distinct from C. fastigatus in head shape, mesonotal structure, and pilosity. It is unlikely that any of these subspecies, including Forel’s C. vagulus, are truly conspecific as they maintain their differences in broad sympatry in southern South America.

With minor workers approaching only 3mm in length, Camponotus vagulus is one of the smallest Camponotus in the region. This ant co-occurs with C. fastigatus throughout eastern Paraguay and shows similar associations with open or edge habitats. Both ants share a robust build, a strong medial clypeal carina, and short antennal scapes that in repose fall well short of the posterior cephalic margin. However, differences between the two are numerous. In full face view, the head of the major of C. vagulus is rectangular, over 1.1x longer than broad, with sides straight and subparallel, while the head of C. fastigatus is rounded, about as long as broad, with the sides clearly convex. The integument of C.vagulus over most of the body has little microsculpture, giving the ant a characteristic shiny appearance, while that of C. fastigatus is opaque. The pubescence of C. vagulus is shorter and more difficult to see than that of C. fastigatus, and the head of both worker castes in C. vagulus is lighter in color near the mandibular insertions. In light of the numerous differences in sympatry between the forms, the case for raising C. vagulus to species is unambiguous.