Costa Rica south throughout tropical South America, Galapagos, West Indies (except Cuba and Bahamas). Distribution in Costa Rica: common in lowlands throughout.
This species appears to be more tolerant of dry conditions than many other Odontomachus species. Throughout its range it often extends further than other neotropical species into seasonally dry or semiarid habitats (Brown 1976).
Nests of O. bauri that I have observed in Costa Rica have almost all been under epiphytes in the canopy (I once observed an aggregation of workers in a rotten log on the forest floor, but there was no brood). On the Pacific side of Costa Rica bauri is a very common forager on the ground, and appears to be the most common Odontomachus species in most habitats. On the Atlantic side, nests are common in the canopy, but workers are rarely seen at ground level. Thus, to the typical ground-based ant collector, bauri appears to be very rare on the Atlantic side. At the time of Brown's (1976) revision, he knew of only a single specimen from the Atlantic lowlands, an alate queen collected near Guapiles. I think this is a collector bias, because the species is quite common in the canopy. Brown's Guapiles queen was the northernmost record of the species in Central America at the time of his revision. I expect that the true range of the species extends farther northward in Atlantic lowland rainforest.
bauri. Odontomachus bauri Emery, 1892d: 561 (diagnosis in key) (w.) ECUADOR (Galapagos Is). Emery, 1893d: 90 (w.); Wheeler, W.M. 1919c: 267 (q.m.). Subspecies of haematodus: Emery, 1911d: 115. Revived status as species: Taylor & Wilson, 1962: 142. Senior synonym of microcephalus, notata, paucidens, pubescens, rugisquama, sericeus: Brown, 1976a: 102. See also: Brown, 1976a: 129.
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