Megalomyrmex nocarina

Megalomyrmex nocarina occurs in mature wet forest habitats of the Atlantic slope of Costa Rica. It occurs from near sea level to 1110 m elevation. It is known exclusively as isolated workers in Winkler samples of forest floor litter. The nesting and feeding habits of nocarina remain to be discovered, but the similarity to Megalomyrmex mondabora and Megalomyrmex mondaboroides suggest that nocarina, too, might be a specialized predator or social parasite of Attini. (Longino 2010)

Identification
Boudinot et al. (2013) - Worker Uniquely identifiable among Central American Megalomyrmex by the following combination of characters: (1) mandible with 7–10 minute denticles subtending two large apical teeth; (2) katepisternum smooth and shining; (3) occipital carina visible in full-face view; (4) foraminal carina usually absent; (5) postpetiole extremely robust, weakly compressed anteroposteriorly; (6) postpetiolar sternum bulging, minutely dentate anteriorly.

Specimens from Panama have a foraminal carina, contradicting the namesake diagnostic character state. The species is additionally separated from other species in the mondabora complex by its long, thin, posterior clypeal portion.

Longino (2010) - This species is very easy to confuse with Megalomyrmex mondabora and Megalomyrmex mondaboroides, but the lack of a strong foraminal carina is reliably diagnostic. Also, the basal mandibular teeth are slightly larger and fewer in number.

Distribution
sea-level to 1200 m

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

Nomenclature

 *  nocarina. Megalomyrmex nocarina Longino, 2010: 51, figs. 5A, 5C, 10A, 10B (w.) COSTA RICA.

Worker
(holotype): HW 0.701, HL 0.830, SL 0.822, EL 0.234, ML 1.217, CI 84, SI 99.

(n=9): HW 0.662–0.706, HL 0.799–0.859, SL 0.786–0.876, EL 0.222–0.259, ML 1.159–1.253, CI 82–85, SI 98–102.

Palp formula 3,2; mandible with large apical and subapical teeth, 7–9 smaller basal teeth of uniform size and spacing; dorsal surface of mandible smooth and shiny; clypeus convex, bulging medially but not obscuring anterior clypeal margin in full-face view; anterior clypeal margin projecting and somewhat angular; occipital carina forming a distinct rim 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, piligerous puncta very small, resulting in overall smooth and highly polished appearance; mesosoma smooth and shiny throughout, with a few short, coarse carinae on posterior margin of katepisternum, a few longitudinal carinae over metapleural gland; foraminal carina absent, dorsal metapleural lobe curves slightly onto posterior face of propodeum but ends abruptly; petiole and postpetiole smooth and shining; ventral margin of petiole flat, with a low transverse flange anteriorly that forms a blunt tooth in lateral view, a few faint transverse costulae variably present immediately posterior to anterventral tooth; ventral margin of postpetiole with a thin transverse costa anteriorly, a shallowly convex lobe, and 2–3 transverse costulae posteriorly; gaster smooth and shining; all dorsal body surfaces and appendages with abundant flexuous setae; color dark red brown.

Boudinot et al. (2013) - (n=7, plus 9 from Longino 2010): HW 0.66–0.72, HL 0.80–0.88, SL 0.78–0.90, OMD 0.09–0.11, EL 0.22–0.27, ML 1.16–1.34, CI 81–85, SI 97–103, EI 34–38, OMI 34–45.

Type Material
Holotype worker. COSTA RICA, Heredia: Estación Biológica La Selva, 10°26'N 83°59'W, 40–125 m, 16 Sep 2005 (Proyecto TEAM AMI–1–W–044–03), unique specimen identifier INB0003678142]. Paratypes: Same data as holotype, except 4 Sep 2007 (Proyecto TEAM AMI–1–W–091–04), 1 worker, INB0003695485; 12 Jun 2006 (Proyecto TEAM AMI–1–W–080–04), 1 worker , INB0003694200; 7 km SW Pto. Viejo, 10°24'14"N, 084°02'22"W, 160 m, 20 Jan 2006 (Proyecto TEAM AMI–2–W–059–03), 1 worker, INB0003680680; same except 24 Oct 2006 (Proyecto TEAM AMI–2–W–105–06), 1 worker , INB0003697094; same except 23 Apr 2007 (Proyecto TEAM AMI–2–W–131–10), 2 workers , CASENT0613301; , INB0003699639; 16 km SSW Pto. Viejo, 10°19'03"N, 084°02'56"W, 500 m, 16 Oct 2006 (Proyecto TEAM AMI–3–W–100–09), 1 worker MCZ, INB0003696577; Cantarrana, 11 km ESE La Virgen, 10°20'43"N, 084°03'28"W, 300 m, 26 Feb 2007 (Proyecto TEAM AMI–4–W–123–09), 5 workers CAS, CASENT0613296; LACM, CASENT0613297; MCZ, CASENT0613298; USNM, CASENT0613299;, CASENT0613300; INBC, INB0003646495.

Etymology
The name of this species refers to the lack of a foraminal carina. It is a noun in apposition and invariant.

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., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.