Costa Rica: Volcan Barva, 2000m.
Worker: Mandible shining, coarsely striate, with five teeth on masticatory margin, masticatory margin meeting basal margin at obtuse angle, basal margin with stout triangular tooth at base near mandibular insertion; median lobe of clypeal plate a single blunt projection or slightly emarginate medially; lateral teeth of clypeal plate pronounced, triangular, interlocking with basal mandibular tooth when mandibles closed; anterior and medial face with striae mixed with large, widely-spaced foveae, grading posteriorly to area of large foveae separated by smooth, shiny interspaces, with foveae becoming sparser and smaller toward vertex margin; eye composed of 5-12 ommatidia, variably fused; hypostomal margin with small tooth; promesonotum smooth and shiny with sparse, shallow, piligerous foveae; mesopleuron and propodeum with large rugae, rugae widely spaced with smooth and shiny interspaces, rugae on dorsal face and upper half of posterior face of propodeum transverse, lower half of posterior face smooth and shining; promesonotum forming single convexity, dropping step-like to flat dorsal face of propodeum; propodeal spines triangular, acute, about as long as wide; petiolar and postpetiolar dorsa smooth except for piligerous puncta, shining; anteroventral margin of petiole lacking tooth, with at most a narrow longitudinal lamella; anteroventral margin of postpetiole with a strongly projecting transverse flange that appears as an acute tooth in side view; gaster smooth except for piligerous puncta, shining; mandibles, scapes, face, sides of head, femora, tibiae, petiolar and postpetiolar nodes, and gaster covered with abundant, long, subdecumbent pilosity; promesonotum covered with similar but somewhat more erect pilosity; dorsal face of propodeum with two long setae inclined forward, otherwise pilosity sparse; color dark red brown.
Measurements (holotype): HL 0.814, HW 0.698, SL 0.519, MeL 0.822.
Named for Danilo Brenes M., Project ALAS Parataxonomist from 1992 to 2006.
This species is a montane endemic, known only from uppermost limits of ant distribution on the Barva Transect in Braulio Carrillo National Park. It is known only from the type specimens, which occurred in four miniWinkler samples (leaf litter sifted from a 1 m2 forest floor patch) from one of the Project ALAS Winkler transects (http://purl.oclc.org/alas). It appears to be patchy in its local distribution: it occurred in only one of five Winkler transects at the site. Each transect was 250 m long, and the four occurrences of A. brenesi were widely separated along the transect in which it occurred.
In Fern‡ndez (2003) this species keys to A. foveolatus. It is a large montane version of A. foveolatus, differing in the much larger size and the step-like juncture of promesonotum and propodeum. In A. foveolatus the mesosoma forms a single arched convexity.
Fern‡ndez C., F. 2003. Revision of the myrmicine ants of the Adelomyrmex genus-group (Hymenoptera: Formicidae). Zootaxa 361:1-52.
Longino, J. T. 2006. New species and nomenclatural changes for the Costa Rican ant fauna (Hymenoptera: Formicidae). Myrmecologische Nachrichten 8:131-143.
Found most commonly in these habitats: 2 times found in cloud forest, 3 times found in montane wet forest
Collected most commonly using these methods or in the following microhabitats: 6 times Mini Winkler, 2 times MiniWinkler
Elevations: collected at 2000 m