Megalomyrmex mondaboroides

Boudinot et al. (2013) - Recently studied in the laboratory, this thief ant species nests separately from their Cyphomyrmex costatus host colony and periodically conducts raids. During raids, the C. costatus workers remain still, hide in the fungal substrate, or flee. The raid is led by M. mondaboroides scouts where several workers follow each other to the garden then quickly graze on the fungus garden and take brood back to their nest. With access to a small host subcolony and brood supplements from Sericomyrmex, Trachymyrmex, and Acromyrmex, a M. mondaboroides colony can live for at least 2 1/2 years in the laboratory. Remarkably this species is also associated with Apterostigma goniodes. In 2001, three queens and ~30 workers were found at the bottom of the host cavity and then continued to nest beside and not within the host garden in the laboratory. Although clearly associated with the fungus-growing ants, it is possible this species forages outside the nest, as two workers have been collected in sifted leaf litter (Costa Rica, Longino 2010; Peru, this study).

Identification
Boudinot et al. (2013) - Worker uniquely identifiable among Central American Megalomyrmex as follows: (1) 8–10 small, subequal denticles subtending large apical two; (2) katepisternum smooth and shining; (3) antennal insertion not encircled by carinulae; (4) scape relatively short (SI < 114). Queen similarly identifiable as worker, alate. MaleIdentifiable by the following two characters: (1) forewing submarginal cell 1 about eight times as long as wide; (2) entire antenna white. Identification supported by the following: (1) forewing 1m-cu present; (2) occipital carina not visible in full-face view.

The male of M. mondaboroides differs from Megalomyrmex mondabora and M. male 01 by the following: (1) antenna entirely white; (2) occipital carina not visible in full-face view; (3) frontal and occipital carina weak. Differing from all other Central American Megalomyrmex by the following combination of characters: small (ML < 2.0 mm, HW < 1.0 mm), crossvein 1m-cu and apical abscissa of M absent.

Workers of Megalomyrmex mondaboroides were observed to have very sparse or no ocular setae, while the male’s compound eyes were glabrous.

Key to Central American Megalomyrmex:
 * workers
 * males

Distribution
sea-level to 300 m elevation

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

Nomenclature

 *  mondaboroides. Megalomyrmex mondaboroides Longino, 2010: 49, figs. 1E, 5B, 5D, 6B, 9AH (w.q.m.) PANAMA.

Male
Boudinot et al. (2013) - (n=2 from Longino 2010): HW 0.72–0.75, HL 0.64–0.66, SL 0.29–0.33, EL 0.35–0.36, ML1.16–1.17, CI 113–114, SI 46–51, EI 48–49.

Head Antenna with 13 antennomeres; antennomere 3 apically kinked; not forming club; scape length less than eye length. Antenna entirely white. Palpal formula 4,3 or 3,3. Mandible triangular; masticatory margin with 10–12 teeth; apical and subapical teeth largest; basalmost tooth offset from juncture of masticatory and basal margins. Dorsal face of mandible smooth and shining, with weak piligerous punctae. Minimum distance between lateral ocellus and compound eye greater than two lateral ocellus lengths. Compound eye glabrous. Occipital carina not visible in full-face view. Mesosoma Mesosoma somewhat attenuate. Notauli absent. Parapsidal lines distinct. Basitarsi tubular. Pterostigma well-developed. Forewing crossvein 1m-cu absent; submarginal cell 1 about one eighth as wide as long; terminal abscissa of M branches distad 2r-rs. Metasoma Basipetiolar carina almost cordate, with rounded posterolateral corners and with posterior margin linear. Ventrolateral longitudinal carina of petiole present. Petiolar spiracle in anterior third. Posterior margins of petiole and postpetiole with girdling carinae. Postpetiolar helcium subcircular. Sternum of postpetiole weakly convex in profile view. Postpetiolar tergum distinctly nodiform, with steeper anterior face and sloping posterior face; apex anterad midlength. Genitalia Abdominal sternum IX broader than long; lateral margins concave, curving abruptly to posterior margin; posterior margin with acute triangular lobe which is about as long as wide at base. Telomere short and bluntly triangular; dorsal margin concave and ventral margin convex; median dentiform process absent; median face not arched; ventral margin without sclerotized denticles. Apical margin of cuspis convex; without apicodorsal process. Digitus narrow basally, rapidly becoming broad; dorsal margin explanate apicodorsally and subapically; ventral margin strongly convex and grading to linear apically; apex triangular; ventral margin only slightly obscuring apicodorsal angle of cuspis. Valviceps less than half as tall as long, subrectangular; dorsal margin linear, curving somewhat abruptly to apex and continuing evenly through ventral margin; ventral margin linear; penisvalvar teeth short and close-set.