Solenopsis macrops

Santschi (1917) states that he observed Oxypomyrmex and the workers stop at the opening of their nest before emerging entirely to observe a 'vast visual sector" (Emery 1930). It appears that the eye of S. macrops allows it to view underneath its head.

Identification
A New World thief ant that is a member of the nigella species complex.

Pacheco and Mackay (2013) – Worker - This is small dark brown species that can be easily recognized by its large (about 35 ommatidia), peculiar kidney-shaped eye that extends ventrolaterally and nearly reaches the mandibles. The lateral clypeal teeth are angulate and the extralateral teeth are absent. The frontal lobes have thin vertical striae. The mesopleuron and the metapleuron have horizontal striae.

This species may be confused with Solenopsis nigella but can be easily recognized by its peculiar eye. No other species of the nigella complex has such a long, elongate eye that extends ventrolaterally, except Solenopsis photophila. This species is very similar to S. photophila and it is obvious that they are sister taxa. They are extremely similar but the eye is smaller in S. photophila and this species has punctate/roughened sculpturing while S. macrops is more smooth and shiny on the mesopleuron and propodeum.

Distribution
Known only from type locality in Argentina, Buenos Aires, Tandil.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina.

Castes
Known only from the worker caste.

Nomenclature

 *  macrops. Solenopsis macrops Santschi, 1917f: 280 (w.) ARGENTINA. Combination in S. (Euophthalma): Creighton, 1930b: 120.

Worker
Pacheco and Mackay (2013) - Measurements (n=2). TL 1.37-1.44 (1.40); HL 0.462-0.468 (0.465); HW 0.390-0.408 (0.399); EL 0.156-0.162 (0.159); ED 0.072-0.084 (0.078); SL 0.276; FSL 0.108-0.120 (0.114); CI 84.4-87.2 (85.8); SI 58.9-59.7 (59.4); PL 0.054; PW 0.078-0.084 (0.081); PI 64.3-69.2 (66.8); PPL 0.09; PPW 0.12; PPI 75.0; WL 0.330-0.336 (0.333); PSL 0.024; PSW 0.018.

Small, concolorous, dark brown; eye large (about 35 ommatidia), kidney-shaped, extends ventrolaterally nearly reaching mandibles; head quadrate, widest near eyes, with fine punctures; lateral clypeal teeth angulate, extralateral teeth absent; clypeal carinae well developed; frontal lobes with vertical striae; scape does not reach posterior border of head, slender at only 0.048 mm at widest point; minor funicular segments 3-8 relatively long; notopropodeal groove breaks sculpture of mesosoma; mesopleuron and metapleuron have horizontal striae; coxa of front legs robust compared to other coxae; petiolar node sharp, triangular with sharp apical face, small tooth present on subpeduncular process, petiole wider than postpetiole viewed laterally.

Not very pilose; short appressed hairs on head, scape, gaster; mesosoma, petiole and postpetiole with very few appressed hairs.

Type Material
Argentina, Buenos Aires Tandil (Bruch), Sammlung, Dr. F. Santschi, Kairouan (lectotype worker and 1 paralectotype worker [here designated] ).