Octostruma megabalzani

Octostruma megabalzani is a montane species. The lowest elevation record is 950 m in Panama, and the highest record is 2000 m in southern Peru. It has been collected most often in mature cloud forest and montane oak forest habitats, but has also been collected in litter beneath cultivated coffee. All collections are from Berlese and Winkler samples of sifted litter and rotten wood from the forest floor. (Longino 2013)

Identification
Differing from Octostruma balzani as follows (O. balzani characters in parentheses): petiole with a pair of erect setae (typically lacking); postpetiole with 2–4 erect setae (0–2); first gastral tergite with 16–22 erect setae, more or less evenly distributed on tergite, gastral setae stiff, flattened, but nearly linear, very weakly clavate (first gastral tergite with 4–16 erect setae, these clustered posteriorly, relatively more broadened apically); color dark brown (red brown); HW 0.61–0.66 (HW 0.50–0.63). (Longino 2013)

Key to Octostruma workers

Distribution based on Regional Taxon Lists
Neotropical Region: Bolivia, Panama, Peru.

Biology
The Andean and Central American specimens of O. megabalzani appear identical. Both occur in elevational parapatry with lowland Octostruma balzani. Whether the Andean and Central American populations are members of one montane clade or convergently evolved montane forms is an open question.

Nomenclature

 *  megabalzani. Octostruma megabalzani Longino, 2013: 42, figs. 1E, 3D, 5B, 9B, 31, 42 (w.q.) PANAMA.

Worker
HW 0.61–0.66, HL 0.56–0.61, WL 0.60–0.66, CI 107–111 (n=7). Similar in most respects to Octostruma balzani except for the characters in the diagnosis (see the identification section above).

Queen
HW 0.67, HL 0.62, WL 0.84, CI 108 (n=1). Labrum, mandible, scape, antennal scrobe, and head sculpture similar to worker; face with 8 erect setae distributed symmetrically around lateral and posterior margins of head, a seta on low ridge in front of each compound eye, 6 setae across vertex between compound eyes; ocelli distinct; compound eye large, multifaceted, about 12 ommatidia in longest row.

Mesosoma with queen-typical alar sclerites; sculpture like workers; anepisternum and katepisternum separated by strong sulcus; posterodorsal propodeum concave; propodeal spines pronounced, in the form of flattened perpendicular plates, acute in profile; pronotum with 4 erect setae, mesoscutum with 10, axilla with 1, scutellum with 2, metanotum with 2, petiolar node with 2, postpetiole and gaster missing from single queen available for examination. Other characters similar to worker.



Type Material
Holotype worker: Panama, Chiriquí: 24 km W El Hato del Volcan [8.833, -82.754, ±10 km], 1160 m, 26 Jun 1976, cloud forest, ex sifted leaf litter (A. F. Newton), unique specimen identifier MCZ-ENT00511006]. Paratype queen, worker: same data MCZ, MCZ-ENT00511004;, MCZ-ENT00511005.