Solenopsis joergenseni

Solenopsis joergenseni was collected under a rock as well as with surface baits (wieners) in Mato Grosso, Brazil. Additionally, this species was collected in leaf litter and foraging in the Humid Chaco in Paraguay.

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 is a moderately large concolorous yellow species. The head is rectangular-shaped and longer than wide. The anterior clypeal border generally has four teeth, with a medial bump present in some specimens giving the appearance of a 5th tooth. The eye is relatively large with 8-10 ommatidia. The basal portion of the mesopleuron and metapleuron have horizontal striae.

Solenopsis joergenseni is similar to the widely distributed Solenopsis clytemnestra in coloration, form and both species have large propodeal spiracles. Solenopsis joergenseni can be separated in that it has horizontal striae present on both the meso-and metapleurae, a character only present on the metapleuron of S. clytemnestra. Solenopsis joergenseni may also be confused with Solenopsis orestes (Brazil and Argentina) as it is similar in pilosity and number of ommatidia, but can be distinguished from S. orestes as the head of this species is nearly quadrate while it is rectangular in S. joergenseni. Additionally, S. orestes lacks horizontal striae on the mesopleuron.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Paraguay.

Castes
Known only from the worker caste.

Nomenclature

 *  joergenseni. Solenopsis joergenseni Santschi, 1919f: 42 (w.) ARGENTINA. Senior synonym of cuspisior, edentula, trihasta: Pacheco & Mackay, 2013: 190.
 * cuspisior. Solenopsis joergenseni var. cuspisior Santschi, 1923c: 254 (w.) ARGENTINA. Junior synonym of joergenseni: Pacheco & Mackay, 2013: 190.
 * edentula. Solenopsis (Diplorhoptrum) joergenseni var. edentula Santschi, 1933e: 115 (w.) ARGENTINA. Junior synonym of joergenseni: Pacheco & Mackay, 2013: 190.
 * trihasta. Solenopsis trihasta Santschi, 1923c: 252, fig. 2 (w.) ARGENTINA. Junior synonym of joergenseni: Pacheco & Mackay, 2013: 190.

Worker
Pacheco and Mackay (2013) - Measurements (n=9). TL 1.80-2.16 (1.94); HL 0.528-0.576 (0.550); HW 0.420-0.480 (0.461); EL 0.060-0.072 (0.065); ED 0.042-0.048 (0.046); SL 0.318-0.390 (0.361); FSL 0.150-0.198 (0.175); CI 79.5-88.9 (83.9); SI 55.8-70.0 (65.6); PL 0.090-0.102 (0.101); PW 0.144-0.162 (0.155); PI 62.5-68.0 (64.9); PPL 0.120-0.150 (0.143); PPW 0.180-0.198 (0.187); PPI 66.7-83.3 (76.5); WL 0.360-0.438 (0.415); PSL 0.036-0.042 (0.039); PSW 0.036-0.042 (0.038).

Concolorous yellow species; head quadrate, longer than wide; anterior clypeal border with four teeth (some specimens with medial bump), lateral well developed, extralateral teeth present as angles or bumps; clypeal carinae well developed; cephalic punctures fine; eye relatively large with 8-10 ommatidia; scape reaches 3/4 length to posterior lateral corner of head; funicular segments long; metanotal groove breaks sculpture of mesosoma; horizontal striae present basally on mesopleuron; horizontal striae present on metapleuron; propodeal spiracle small; petiole wider than postpetiole viewed laterally; postpetiole oval in profile.

Moderately hairy with setae on all body surfaces; long suberect hairs present basally on scape; erect and sub erect hairs of various lengths present on mesosoma, petiole, postpetiole and gaster.

Type Material
Argentina, Formosa, Santschi, 990, Sammlung, Dr. F. Santschi Kairouan (lectotype and 4 paralectotypes [here designated], ); BRAZIL, ill. G. Pizefora (pirapora?), M.C.Z. Type, 2-4 20946 (E. Gorbe) (3 ); Wm. M. Wheeler, M.C.Z. Type, 1 20946. (MCZC). Solenopsis trihasta Argentina, Cordoba, M.C.Z. 1- 20948, Santschi 1928 (lectotype [here designated] MCZC). Solenopsis joergenseni var. cuspisior Argentina, Cordoba, La Granja, Sammlung, Dr. F. Santschi Kairouan (lectotype [here designated], ). Solenopsis (Diplorhoptrum) joergenseni var. endentula Argentina, Charrata Chaco. Bosq., Sammlung, Dr. F. Santschi Kairouan (lectotype and 1 paralectotype [here designated], NHMB).