Adelomyrmex laevigatus

Longino (2012) - This species occurs in mature cloud forest leaf litter. It is found from 800–1500 m elevation, apparently in all the cordilleras of Costa Rica and western Panama. It is usually a lower density species than the sympatric Adelomyrmex tristani. At a 1000 m site on the Volcan Barva transect in Costa Rica, it was found in 18 of 150 miniWinkler samples, while it was not found at adjacent 500 m and 1500 m sites with similar sampling intensity (Longino & Colwell 2011).

Identification
Adelomyrmex laevigatus can be separated from the other species in the genus as the promesonotum is nearly completely smooth and shiny, with only a few rugulae on the sides. No other species of Adelomyrmex possesses this characteristic, except A. micans, in which the entire head is also smooth and glossy. Additionally, the sculpture of the head is distinctive, with a mixture of rugae and foveae. The first tergite is notably concave when viewed from above. The hypostomal teeth are large, robust, much more than any other species in the genus. The numbers of ommatidia ranges from 5–6 up to 12. (Fernández 2003)

Adelomyrmex laevigatus appears to be an upland version of Adelomyrmex microps, with A. laevigatus being darker, more robust, and with shorter pilosity. Although they occur on the same mountain slope (Volcan Barva in Costa Rica), so far they have not been found together, with A. laevigatus only known from 800 m elevation and above, A. microps below 500 m. (Longino 2012)

Key to Adelomyrmex of the New World mainland

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

Castes
Known only from the worker caste.

Nomenclature

 *  laevigatus. Adelomyrmex laevigatus Mackay, W.P., in Fernández & Mackay, 2003: 600, figs. 4-7 (w.) PANAMA. See also: Fernández, 2003b: 19.

Worker
Posterior border of head nearly straight. Mandibles with 5 teeth, the three apical-most larger. Anterior margin of clypeal plate concave. Eye with about 5 to 12 ommatidia. Hypostomal tooth large, stout. Promesonotum evenly convex and higher than propodeum. Metanotal groove well marked. Propodeal dorsum short. Propodeal teeth longer than wide. In dorsal view, anterior margin of first tergum clearly concave. Head with rugae and foveae confluent. Dorsum of promesonotum largely smooth and shining, with trace of longitudinal rugulae on the sides. Most of side of pronotum smooth and shining. Propodeum with transverse rugae. Dorsum of petiole and postpetiole smooth and shining, laterally with some oblique rugae. Pilosity on dorsum of body moderately long, scattered. Body dark brown, antennomeres lighter.