Megalomyrmex brandaoi

The only known collections of this species are from the Barva Transect in Costa Rica. The type series was nesting in a dead stick in leaf litter, while other partial colonies or strays have been collected via Winkler. Males have been collected via malaise and Winkler sifting; the latter probably due to leaf litter nesting. (Boudinot et al. 2013)

Identification
Boudinot et al. (2013) - Uniquely identified among Central American Megalomyrmex by the following combination of characters: (1) disc of katepisternum smooth and shining; (2) occipital carina not visible in full-face view; (3) first gastric tergum with at most 4 short appressed setae; (4) setae coarse; (5) foraminal carina absent. Queen Identifiable similarly to worker, alate. Male Differing from all known Central American Megalomyrmex by the following combination: (1) lateral ocellus greater than three of its lengths from the compound eye; (2) pedicel swollen (i.e. with convex sides); (3) antenna without any kinked antennomeres; (4) scape short (SI 30); (5) eyes short, relative to head length (EI 28). Among the Central American species examined, M. brandaoi has the smallest genitalia, and most reduced penisvalvar dentition.

Megalomyrmex brandaoi is strikingly setose. Although other Megalomyrmex species have far more setation—such as the mondabora complex and the leoninus group— M. brandaoi is easily distinguished from other drifti complex species by its fiercely hirsute facies.

The following characters are unique to M. brandaoi among species of the drifti complex: (1) setae coarse; (2) first gastric tergum with at most four short, appressed setae, though usually without; (3) portion of clypeus between antennal insertions wider than maximum width of scape; (4) antennal club shorter than combined length of antennomeres 2–9; (5) metanotal sulcus shallow (vs. deeply incised). Supporting characters for the separation of M. brandaoi from drifti complex species include: (1) mandible with five comparatively large, almost evenly-spaced teeth (vs. variable, often with small denticles); (2) basal and masticatory margins distinct; (3) the three longitudinal carinae crossing metapleural gland bulla wide-set (vs. dense); (4) foraminal carina absent.

Distribution
Costa Rica, Ecuador; sea-level to 500 m elevation.

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

Nomenclature

 *  brandaoi. Megalomyrmex brandaoi Boudinot, Sumnicht & Adams, 2013: 28, figs. 7, 36, 39, 47, 54, 69, 84, 102–105, 179, 194, 209, 224, 238 (w.q.m.) COSTA RICA.

Worker
(holotype): HW 0.52, HL 0.58, SL 0.50, OMD 0.09, EL 0.15, ML 0.71, CI 89, SI 85, EI 29, OMI 62.

Measurements (n=6): HW 0.49–0.54, HL 0.55–0.60, SL 0.47–0.52, OMD 0.09–0.10, EL 0.13–0.16, MK 0.67–0.76, CI 88–90, SI 85–88, EI 27–31, OMI 60–72.

Head Palpal formula 3,2. Basal and masticatory margins of mandible distinct, demarked by an angle with a small tooth. Mandible with 5–6 teeth; apical two teeth largest; apical tooth slightly less than twice as long as subapical; 3–4 basal teeth small, widely-spaced. Dorsal surface of mandible smooth and shining, interrupted by weak piligerous punctae. Clypeus truncate in profile view, with median seta often raised on a small tubercle. Clypeal carinae present, often weak; diverging anteriorly. Clypeus, between antennal insertions, broader than maximum diameter of scape. Antennal fossa encircled by 2–3 complete carinulae. Malar area roughened in anterior half, smooth posteriorly. Compound eye with 1–5 ocular setae. Occipital carina short, distinct; obscured by vertex in full-face view; extending anteroventrally less than one eighth distance to hypostomal margin. MesosomaKatepisternum and promesonotum smooth and shining; propodeum smooth and shining excluding 3 wide-set metapleural carinulae. Metapleural carinulae do not reach meso-metapleural suture. Propodeum with dorsal and posterior faces meeting at a blunt angle; propodeum dorsolaterally marginate only at angle; dorsal margin concave in profile view. Foraminal carina absent. Meso- and metabasitarsi tubular. Metasoma Petiole and postpetiole predominantly smooth and shining, except for fine carinulae or rugae around posterior bases, the anterior petiolar base, and the ventrolateral longitudinal carina of petiole. Subpetiolar process a truncate denticle. Postpetiolar sternum finely bidentate anteriorly. Lancets of sting apparatus weakly spatulate. Setation Coarse; head dorsum with long, somewhat dense subdecumbent to suberect setae and medium appressed setae which are most abundant on gena; setae on scape appressed to subdecumbent; promesonotum with about 16 erect setae on each lateral half, most setae very long, about 5 or 6 shorter; first gastric tergum with dense, long, subdecumbent to suberect setae, with 0–4 very sparse short appressed setae. Head, meso- and metasoma burnt caramel brown, mandibles, antennae, and legs deep honey yellow.

Queen
(n=1): HW 0.59, HL 0.62, SL 0.53, OMD 0.09, EL 0.20, ML 0.88, CI 95, SI 85, EI 33, OMI 44.

Similar to worker, but with alate-condition mesosoma, coarser sculpturation, and more numerous setae on mesosoma. Wing venation as in male.

Male
(n=2): HW 0.55–0.56, HL 0.52–0.54, SL 0.16, EL 0.28–0.29, ML 0.86–0.89, CI 104–107, SI 30, EI 51.

Head Antennae with 13 antennomeres, none of which are kinked; not forming a club; scape length shorter than eye length; entire antenna brown. Palpal formula 3,2. Mandible subfalcate; masticatory margin with four triangular teeth, decreasing in size from apical tooth. Dorsal surface of mandible roughened and weakly striate. Minimum distance between lateral ocellus and compound eye distinctly greater than two lateral ocellus lengths. Compound eye with few, sparse ocular setae. Occipital carina not visible in full-face view. Mesosoma Mesosoma robust. Notauli weakly indicated by indistinct sulci with transverse carinulae. Parapsidal lines weak. Foraminal carina absent. Metasternum without a process. Basitarsi tubular. Pterostigma well-developed. Forewing crossvein 1m-cu present; submarginal cell 1 length about twice width; terminal abscissa of M branching from Rs+M at 2r-rs. Metasoma Basipetiolar carina arc-shaped. Ventrolateral longitudinal carina of petiole present. Petiolar spiracle in anterior third. Petiolar and postpetiolar posterior margins without distinct girdling carinae. Postpetiolar helcium approximately circular. Postpetiolar spiracle placed at about the first one third of the lateral tergal margin. Sternum of postpetiole concave with a weak median bulge in profile view. Postpetiolar tergum shallowly but evenly convex; apex at midlength; not bilobed. Genitalia Abdominal sternum IX lateral margins tapering to base of apical triangle, which is produced ventrally somewhat; apical triangle neither keeled nor with a distinct degree of sclerotization; apical process narrowly triangular, pointed. Telomere short, triangular, bluntly rounded; medial dentiform process absent; medial face of telomere not arched; ventral margin without sclerotized denticles. Cuspis apicodorsally and apicoventrally produced; apical margin concave. Digitus thin; dorsal margin parabolic, ventral margin unevenly arched, with basal half more strongly arched than the nearly linear posterior half; ventral margin slightly obscuring posteroapical angle of cuspis. Valviceps height subequal to length, ovate; basal half of dorsal margin slightly flattened, while the distal half curved continuously through the apical margin to the ventral margin; ventral margin weakly convex; penisvalvar teeth miniscule.

Type Material
Holotype worker. COSTA RICA, Heredia: 10 km SE La Virgen, 10.33333°N 84.08333°W ±2 km, 500 m, 9 Nov 2002, wet forest, nest in dead stick in litter (J. Longino#JTL4856) [CASENT0630943, ].

Paratype worker: (9) Same collection as holotype. [CASENT0630939, ; CASENT0630940, ; CASENT0630941, ; CASENT0630942, ; JTLC000003329, ; CASENT0630944, ; CASENT0630945, ; CASENT0630946, ; CASENT0630947, ].

Paratype queens: (2) Same collection as holotype [JTLC000003329, JTLC; CASENT0630948, MCZ]

Paratype males: (3) Same collection as holotype [JTLC000002912, ; CASENT0630949, MCZ; CASENT0630950, MZSP].

Etymology
Named after Dr. Roberto Brandão for his valuable contributions to the taxonomy of this genus.

References based on Global Ant Biodiversity Informatics

 * Boudinot B. E., T. P. Sumnicht, and R. M. M. Adams. 2013. Central American ants of the genus Megalomyrmex Forel (Hymenoptera: Formicidae): six new species and keys to workers and males. Zootaxa 3732(1): 1-82.