Myrmelachista meganaranja

This species occurs in mature wet forest in the southern highlands of Costa Rica. At Wilson Botanical Gardens it occurs in a variety of plant species, nesting in live stems. I found a large aggregation of workers in the terminal two internodes of a Cecropia insignis sapling. A nest in a 2–3m tall Ocotea contained only workers, brood, and males, even though I entirely dissected the tree. A 10m tall Guarea rhopalocarpa tree contained a colony scattered in live stems throughout the crown. All the shoot tips contained cavities excavated by beetle larvae prior to entrance by ants. Many of the branches contained alate queens. The nests contained Pseudococcidae on the inner stem walls. (Longino 2006)

Identification
Longino (2006) - Worker with antenna 9-segmented, maxillary palpus 6-segmented, color yellow orange. Queen with orange head, HW 1.28–1.36mm. Male with pygostyles present, basiparamere lobes and parameres very long and thin, digitus broadening apically to paddle-shaped apex.

Distribution
Costa Rica. Southern highlands, at Wilson Botanical Gardens near San Vito and at Las Alturas.

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

Nomenclature

 *  meganaranja. Myrmelachista meganaranja Longino, 2006a: 36, figs. 1, 6, 12, 13 (w.q.m.) COSTA RICA.

Worker
HL 0.830–0.970, HW 0.824–0.991, SL 0.457–0.527, EL 0.149–0.159, CI 99–102 (n=5).

Antenna 9-segmented; maxillary palpus 6-segmented; dorsal surface of mandible coarsely punctatorugose; clypeus and face smooth and shining; in full face view, with abundant short subdecumbent setae projecting from rear margin and sides of head; ventral surface of head with abundant short subdecumbent setae, occasional longer setae; scapes with abundant erect to subdecumbent setae, longer setae subequal to width of scape; outer surface of hind tibia with abundant subdecumbent short setae, occasional longer erect setae about 2/3 width of tibia; color uniformly orange.

Queen
HL 1.450–1.509, HW 1.277–1.358, SL 0.646–0.673, EL 0.315–0.326, OW 0.092–0.094, OD 0.185–0.203, CI 88–90, OI 24–25, OcI 6–6 (n=2).

Antenna 9-segmented; maxillary palpus 6-segmented; labrum short, bilobed, not covering mouthparts; dorsal surface of mandible with dense, large, piligerous puncta; face and clypeus smooth and shining, with some larger puncta on anterior malar spaces; in full face view, with abundant short subdecumbent setae projecting from rear margin and sides of head; ventral surface of head with abundant somewhat longer appressed to suberect setae; scapes with abundant erect to suberect setae, longer setae subequal to width of scape; outer surface of hind tibia with abundant erect to subdecumbent setae, longer setae about 1/2 to 2/3 width of tibia; color orange with infuscated bands on gastral terga.

Male
Antenna 10-segmented; maxillary palpus 6-segmented; pygostyles small but present, distinctly sclerotized, setose; basiparamere lobe and paramere very elongate, thin; cuspis a thin spiniform processed fused to inner surface of paramere, distant from digitus; digitus elongate, paddle-shaped, broadening distally; apodeme of penial valve curving into dorsal margin at obtuse angle; ocelli relatively large.

Type Material
Holotype alate queen: Costa Rica, Prov. Puntarenas, Wilson Botanical Garden, 4km S San Vito, 8°47’N, 82°58’W, 1200m, 23 Mar 1990 (J. Longino#2623), specimen code JTLC000006225.

Paratypes: workers and queens, from same nest as holotype, specimen codes JTLC000006226-JTLC000006230, distributed to, , , ,.

Etymology
The name refers to the large size and orange coloration of the workers.

References based on Global Ant Biodiversity Informatics

 * Longino J. T. 2006. A taxonomic review of the genus Myrmelachista (hymenoptera: Formicidae) in Costa Rica. Zootaxa 1141: 1-54