Myrmelachista skwarrae

The types were collected from two bromeliad (Tillandsia) species.

Identification
Worker with nine antennal segments. See Longino's comments regarding Myrmelachista of southern Mexico.

Distribution based on Regional Taxon Lists
Neotropical Region: Guatemala, Honduras, Mexico.

Nomenclature

 *  skwarrae. Myrmelachista skwarrae Wheeler, W.M. 1934g: 192, fig. 2 (w.q.m.) MEXICO. Current subspecies: nominal plus laeta, picea.

Worker
Length 2-2.5 mm.

Head large, rectangular, as broad as long, slightly narrower in front than behind, with straight sides and posterior border, flattened dorsally and ventrally. Eyes small, flat, near the middle of the sides of the head. Mandibles convex, 5-toothed, the median tooth small. Clypeus convex, its anterior border with a minute, acute, median denticle. Frontal carinae short, subparallel, somewhat farther apart than their distance from the lateral borders of the head. Antennae rather stout; scapes extending a distance equal to their greatest diameter beyond the posterior orbits; first funicular joint large, fully twice as long as broad; joints 2-5 small, the second nearly as long as broad, 3-5 much shorter; club stout, its two basal joints as long as broad, together shorter than the swollen terminal joint. Thorax short and stout though considerably narrower than the head; promesonotum convex, subhemispherical; mesonotum transversely rounded-rectangular, one and one-half times as broad as long; mesoepinotal constriction short and shallow dorsally, pronounced laterally; epinotum lower and shorter than the promesonotum, somewhat longer than wide, narrowed anteriorly, with rounded sides; base and declivity subequal in profile, the former feebly convex, the latter sloping and somewhat concave posteriorly. Petiole rather short, as high as long; scale scarcely inclined forward, narrow, with rather thin, acute, very feebly sinuate superior border. Gaster large, oval; first segment rounded anteriorly, the tip pointed. Legs rather stout, fore femora distinctly enlarged.

Smooth and shining, with sparse piligerous punctures. Mandibles obscurely punctate-striate; clypeus, anterior borders of cheeks and neck reticulate.

Hairs glistening white, bristly, moderately long on the head, thorax and gaster, partly erect and partly shorter and appressed. Scapes and funiculi with numerous erect or suberect hairs, legs with short, sparse suberect hairs.

Black; neck, tips of coxre, trochanters, bases and tips of femora, tibiae, scapes and basal joints of funiculi brownish yellow or yellowish brown; mandibles, mouthparts and anterior borders of cheeks reddish brown.

Queen
Length 3-4 mm.

Slender; head rectangular, one and one-third times as long as broad, flattened above and below, with rounded posterior corners, straight subparallel sides and feebly sinuate posterior border. Mandibles large and convex, with strong teeth. Clypeus convex, its anterior border with a small median tooth. Eyes rather small, flat, a little in front of the middle of the sides of the head; ocelli small, widely separated. Antennae as in the worker, but scapes reaching only to the posterior orbits. Thorax elongate oval, about two and one-third times as long as broad, broader than the head; mesonotum very flat above, decidedly longer than broad; epinotum small and short, feebly rounded in profile, without distinct base and declivity. Petiole broader than in the worker, scale more inclined forward, with the superior border transverse, straight and entire or feebly sinuate in the middle. Gaster large, elongate-elliptical, fully as long as the remainder of the body. Legs rather stout, with somewhat enlarged femora. Wings long, measuring 4 mm., with well-developed venation; marginal cell closed; discoidal cell absent.

Sculpture, pilosity and color as in the worker, but mandibles and cheeks more distinctly punctate-rugulose. Wing-membranes faintly brownish; veins and pterostigma pale brown.

Male
Length 2.5-2.7 mm.

Head through the eyes broader than long, convex and semicircularly rounded behind, with short, slightly convex, anteriorly converging cheeks. Eyes large and prominent; ocelli moderately large. Mandibles narrow, geniculate at the base, bidentate apically, the terminal tooth small and acute, the basal tooth in the form of a rounded lobe. Clypeus very convex, its anterior border rounded, without distinct median denticle. Antennae 10-jointed; scapes fully six times as long as broad; first funicular joint large, twice as long as broad; joints 2-5 small, the second as long as broad; 3-5 broader than long, the three basal joints of the club not longer than broad, subequal, together longer than the somewhat broader terminal joint. Thorax robust, much broader than the head, oval, less than twice as long as broad; mesonotum as broad as long, dorsally flattened, anteriorly convex and projecting above the very short pronotum; epinotum small, shaped like that of the female. Petiolar scale like that of the worker but inclined more forward, its superior border thicker, when seen from behind straight, transverse and entire. Gaster elliptical; genitalia very large and exserted. Legs slender. Wings broad.

Sculpture, pilosity and color as in the worker and female, but the pilosity less conspicuous and the body more piceous black; antennal clubs less infuscated; mandibles sub opaque, densely punctate. Wings slightly paler than in the female, but their veins and pterostigma of the same color.

Type Material
Described from numerous workers, seven females and six males (762) taken by Dr. Skwarra at Cuautla, Morelos (type-locality) in Tillandsia circinata, a number of workers belonging to several colonies (770, 771, 772, 777, 783a and 786) taken at Cuernavaca, Morelos in the same plant, and several workers (Z 208a) at Mirador, Vera Cruz in T. valenzuelana.

Longino (2006) -,  (USNM syntype worker examined).

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Rojas P., C. Fragoso, and W. P. MacKay. 2014. Ant communities along a gradient of plant succession in Mexican tropical coastal dunes. Sociobiology 61(2): 119-132.
 * Vasquez-Bolanos M. 2011. Checklist of the ants (Hymenoptera: Formicidae) from Mexico. Dugesiana 18(1): 95-133.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133