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.

Distribution
sea-level to 300 m elevation

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

Biology
Longino (2010) - Megalomyrmex mondaboroides occurs in lowland wet forest habitats in Panama and Costa Rica. Colonies have been collected in the nests of small attines, primarily and. In Costa Rica a worker was collected in a Winkler sample of sifted leaf litter.

Adams et al. (2015) found that workers of Cyphomyrmex costatus, the host of Megalomyrmex mondaboroides and Megalomyrmex silvestrii, react to a sting by Megalomyrmex parasites mainly with submissive behavior, playing dead or retreating. Host submission also followed brief antennal contact. The observed behavior of Cyphomyrmex costatus was similar to that of Cyphomyrmex cornutus, host of Megalomyrmex mondabora, suggesting that the alkaloidal venoms with pyrrolidines from M. mondabora, piperidines from M. mondaboroides, and pyrolizidines from M. silvestrii may function similarly as appeasement and repellent allomones against host ants, despite their different chemical structure. With the use of these chemical weapons, Megalomyrmex thief ants are met with little host resistance and easily exploit host colony resources.

Nomenclature

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

Worker
(holotype): HW 0.718, HL 0.783, SL 0.851, EL 0.231, ML 1.180, CI 92, SI 109.

(n=6): HW 0.605–0.721, HL 0.642–0.788, SL 0.682–0.866, EL 0.188–0.261, ML 0.893–1.180, CI 91–94, SI 106–110.

Palp formula 4,3; mandible with large apical and subapical teeth, 8–10 smaller basal teeth; most basal tooth smaller than adjacent distal tooth, so that juncture of basal and masticatory margin of mandible is rounded; dorsal surface of mandible smooth and shiny; occipital carina narrow, not visible in full-face view, anterior ends extending a short distance onto ventral surface of head, not much beyond level of foramen; face, clypeus, and ventral surface of head smooth and shiny, with a few irregular rugulae on clypeus; mesosoma largely smooth and shiny, with variable development of coarse longitudinal carinae on posterior katepisternum and metanotal groove; foraminal carina an entire semicircle delimiting propodeal foramen, some specimens with a second concentric carina above foraminal carina; petiole and postpetiole smooth and shining, posterior peduncles of both with a few concentric carinulae dorsally; ventral margin of petiole flat, with a very small anterior tooth and almost no development of a ventral keel; ventral margin of postpetiole flat; gaster smooth and shining; all dorsal body surfaces and appendages with abundant flexuous setae; color red brown, with appendages and mandibles lighter brown to a variable degree.

Queen
(n=1): HW 0.813, HL 0.847, SL 0.874, EL 0.317, ML 1.286, CI 96, SI 103.

Palp formula 4,3 or 3,2; general shape, sculpture, and pilosity characters, including mandibular dentition and sculpture, similar to worker; parapsidal lines present, extending from posterior border of mesoscutum to midlength.

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.

Type Material
Holotype worker. PANAMA, Panama: El Llano, 9.27956°N 78.96150°W, 300 m, 30 Mar 2001 (H. Fernandez-Marin#HF010330–50), unique specimen identifier JTLC000015325. Paratypes: Same data as holotype, 1 queen, 1 male MCZ, CASENT0613246, CASENT0613247, 1 worker, CASENT0613228, 1 queen, 1 male, 1 worker , CASENT0613229, 2 workers , USNMENT693033, USNMENT693032, 1 worker , JTLC000015326; discrepancy in paratype CASENT0613230; same data as holotype except (C. Currie#CC010324–50), 2 workers , CASENT0613226, CASENT0613227.

Etymology
The name of this species refers to its similarity to M. mondabora.

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.
 * Longino J. T. 2010. A taxonomic review of the ant genus Megalomyrmex Forel (Hymenoptera: Formicidae) in Central America. Zootaxa 2720: 35-58
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.