A new species of harvester ant of the genus Pogonomyrmex (Hymenoptera: Formicidae) from México [Una especie nueva de la hormiga cosechadora del género Pogonomyrmex (Hymenoptera: Formicidae) de México]

Abstract

We describe a new species of harvester ant, Pogonomyrmex humerotumidus from the state of Michoacán, México. The worker of this species is easily recognized, as the psammophore is poorly developed, the mandibles have only 5 teeth, the pronotal shoulders are swollen into protuberances, and the propodeum lacks teeth. The worker is ferrugineous red. The female and male are unknown. It also differs from similar North American species such as P. huachucanus Wheeler, 1914, P. imberbiculus Wheeler, 1902 and P. pima Wheeler, 1909 in lacking propodeal spines. It can be distinguished from P. laevinodis Snelling, 1982, which also lacks spines on the propodeum, as the side of the petiolar node is sculptured, not smooth as in the latter species. It is similar to P. guatemaltecus Wheeler, 1914, which also lacks propodeal spines, but differs in being larger (total length ∼ 8 mm, vs. ∼ 6 mm in P. guatemaltecus). The pronotal angles of P. guatemaltecus are slightly swollen, but do not form protuberances as they do in P. humerotumidus. In morphology this species is closely related to the Argentinean P. inermis Forel, 1914, which can be distinguished as it has 6 mandibular teeth, and lacks the angulate subpeduncular process