Solenopsis abjectior

Known only from the type material. The type series was collected in the nest of Pheidole taurus Emery (but in a separate chamber) (Forel1909).

Identification
A New World thief ant that is a member of the molesta species complex. (Key to New World Solenopsis Species Complexes)

Pacheco and Mackay (2013) – Worker - This species is concolorous yellow, with a densely and coarsely punctate head. The shape of the petiole is very distinct, with the anterior and posterior faces being nearly parallel. The minor funicular segments 3-8 are short (0.09mm).

The densely and coarsely punctate head separates it from the species allied to Solenopsis decipiens, which also occurs in Buenos Aires. Additionally, the shape of the petiole is very distinct, with the anterior and posterior faces being nearly parallel. It appears to be more closely related to the pollux subgroup, with shorter funicular segments. The semi-coarsely punctate head also distinguishes this taxon from all of the others that are related to Solenopsis pollux.

Distribution
Known only from the type locality of Buenos Aires, Argentina.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina.

Castes
Known only from the worker caste.

Nomenclature

 * . Solenopsis abjectior Pacheco & Mackay, 2013: 105, figs. 22, 23 (w.) ARGENTINA (Buenos Aires).
 * Type-material: holotype worker, 5 paratype workers.
 * Type-locality: holotype Argentina: Buenos Aires (J. Richter); paratypes with same data.
 * Type-depository: MHNG.
 * [First available use of Solenopsis decipiens subsp. abjecta var. abjectior Forel, 1909a: 266 (w.) ARGENTINA; unavailable (infrasubspecific) name. As unavailable (infrasubspecific) name: Forel, 1912g: 9; Bruch, 1914: 223; Emery, 1922e: 199; Ettershank, 1966: 139; Kempf, 1972a: 235. Declared as unavailable (infrasubspecific) name: Bolton, 1995b: 386.]
 * Distribution: Argentina.

Worker
Measurements (n=6). TL 1.31-1.32 (1.31); HL 0.384-0.396 (0.391); HW 0.318-0.330 (0.326); EL 0.036; ED 0.030; SL 0.240-0.258 (0.251); FSL 0.090-0.096 (0.094); CI 81.5-84.6 (83.4); SI 62.5-66.2 (64.2); PL 0.084-0.090 (0.089); PW 0.120-0.126 (0.124); PI 66.7-75.0 (71.8); PPL 0.114-0.120 (0.117); PPW 0.126; PPI 90.5-95.2 (92.9); WL 0.282-0.300 (0.297); PSL 0.018-0.024 (0.019); PSW 0.018.

Small; concolorous yellow; lateral clypeal teeth well developed, extralateral teeth absent; eye small with only three ommatidia; anterior medial clypeal margin concave; lateral teeth extend past anterior border of clypeus by 0.018 mm; head elongate (longer than wide), covered with coarse, dense punctures, similar to members of fugax and pygmaea groups; petiole somewhat rectangular-shaped, with two faces nearly parallel with well-developed tooth present on subpeduncular process.

Most body parts covered with short (0.04 mm), bristly hairs, all approximately same length.

Type Material
Argentina, Buenos Aires (Richter) (Holotype worker and 5 paratype workers ).