Simopelta oculata

The type series formed a column about 30-150 cm above the ground in vegetation in deep shade. The nest was in a hollow, dead twig 1.5 cm in diameter and 33 cm long, suspended vertically by a dead vine about 1.5 m above the soil surface. The column was carrying larvae, pupae and workers of a medium-size species of Pheidole, which was the dominant ant genus in the area. Partly eaten pieces of prey were found in the twig. The nest contained at least several hundred workers, plus a female and brood. The workers ran rapidly, holding their antennae in a similar fashion to the workers of Ecitoninae. Workers are able to sting, which feels something like a mosquito bite (Gotwald and Brown, 1966).

Identification
Mackay and Mackay (2008) - The large eyes would separate this species from most other species. Simopelta andersoni also has relatively large eyes, but can be separated by the four-toothed mandibles (S. oculata has a three-toothed mandible). Occasionally, the eyes of Simopelta paeminosa are moderately large, and in these cases the partially smooth and shiny mesopleuron would separate the two species (mostly coarsely sculptured in S. paeminosa). It would not be confused with Simopelta pergandei due to its larger size and wider petiole as seen from the side. The large eyes would also separate this species from those that occur in South America, such as Simopelta fernandezi, in which the dorsum of the head has transverse striae.

Distribution
Atlantic slope, Costa Rica and Panama.

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

Habitat
Various middle elevation forest sites on the Atlantic slope.

Nomenclature

 * . Simopelta oculata Gotwald & Brown, 1967: 267, figs. 1-14 (w.q.l.) COSTA RICA.
 * Type-material: holotype worker, 42 paratype workers, 1 paratype queen.
 * Type-locality: holotype Costa Rica: Limon Prov., nr Guapiles, nr bridge over Rio Toro Amarillo (N. Scott & W.L. Brown); paratypes with same data.
 * Type-depositories: MCZC (holotype); CASC, MCZC, MZSP, NHMB (paratypes).
 * Combination in Belonopelta: Baroni Urbani, 1975b: 300 (in key);
 * combination in Simopelta: Bolton, 1995b: 383.
 * Status as species: Kempf, 1972a: 230; Baroni Urbani, 1975b: 300 (in key); Brandão, 1991: 331; Bolton, 1995b: 383; Mackay & Mackay, 2008: 314 (redescription).
 * Distribution: Costa Rica.

Mackay and Mackay (2008):

Worker
The worker is a small (total length 3.5 mm), black ant, with dark brown appendages. The mandible has 3 teeth, and the anterior margin of the clypeus is broadly rounded or only slightly angulate. The relatively large eye (maximum diameter ~ 0.1 mm), which is located less than two eye diameters from the anterior margin of the head, characterizes this species. The dorsum of the mesosoma is broadly concave. The petiole is thick when viewed in profile, with well-developed spiracular horns and a poorly developed subpetiolar process.

The head is covered with punctures, as is the dorsum of the pronotum. The lower half of the side of the pronotum is smooth and shining, the mesonotum and propodeum have transverse, poorly defined striolate, most of the side of the mesopleuron is smooth and shiny, and the sides of the propodeum have longitudinal, poorly defined striae. Most of the side of the petiole is moderately smooth and glossy, the dorsum has transverse, poorly defined striolae, the dorsum of the first tergum is mostly smooth and shiny.

Queen
The female is wingless and has a large, protruding scutum and scutellum, as well as a large propodeum, and a wide petiole (when viewed from above).

Type Material
Worker, female, Costa Rica: Limón: Río Toro Ama-rillo near Guapiles.

References based on Global Ant Biodiversity Informatics

 * Baroni Urbani C. 1975. Contributo alla conoscenza dei generi Belonopelta Mayr e Leiopelta gen. n. (Hymenoptera: Formicidae). Mitt. Schweiz. Entomol. Ges. 48: 295-310.
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Fernández F., and T. M. Arias-Penna. 2008. Las hormigas cazadoras en la región Neotropical. Pp. 3-39 in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano, F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Gotwald W. H., Jr., and W. L. Brown, Jr. 1967. The ant genus Simopelta (Hymenoptera: Formicidae). Psyche (Camb.) 73: 261-277.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * 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.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Mackay W. P., and E. E. Mackay. 2008. Revision of the ants of the genus Simopelta Mann. Pp. 285-328 in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano, F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.