Adelomyrmex brenesi

A montane endemic, known only from the peak of Volcan Barva, Costa Rica

Identification
Longino (2006) - A large montane version of Adelomyrmex 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.

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Biology
This species is still only known from the material reported in Longino (2006). It is a montane endemic, known only from the peak of Volcan Barva. This is a forested mountaintop of relatively small area in the Cordillera Volcánica Central of Costa Rica. Adelomyrmex brenesi is restricted to a narrow elevation range at the very top of the peak, around 2000 m, and does not occur at lower elevations (Longino & Colwell 2011). In a quantitative inventory at this site, it occurred in 13 of 150 miniWinkler samples. This is a species clearly in danger of mountaintop extinction due to climate change (Colwell et al. 2008).

Nomenclature

 *  brenesi. Adelomyrmex brenesi Longino, 2006b: 132, figs. 1-3 (w.) COSTA RICA.

Worker
Holotype: HL 0.814, HW 0.698, SL 0.519, MeL 0.822.

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.

Type Material
Holotype worker: Costa Rica: Heredia Prov., 6 km ENE Vara Blanca (10° 11' N, 84° 07' W), 2000 m elevation, 13. III.2002, leg. Project ALAS, specimen code JTLC00000 3382.

Paratypes: 4 workers, same data as holotype, specimen codes INB0003223968, INB0003223966 , INB0003223953 , INB0003223935.

Etymology
Named for Danilo Brenes M., Project ALAS Parataxonomist from 1992 to 2006.