Solenopsis parva

We found S. parva in creosote bush scrub in the deserts of Argentina and in shrub lands and collected it in pitfall traps in January (summer) in light brown fine sandy soils. (Pacheco and Mackay 2013)

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

Pacheco and Mackay (2013) – Worker - This is a concolorous yellow to brown species with smooth, glossy sculpturing. The head is nearly quadrate with the anterior portion rounded while the posterior is angled at the edges. The lateral clypeal teeth are poorly developed and angu1ate. The eyes are moderately large with approximately 5-8 ommatidia and often kidney-shaped. Both the mesopleuron and metapleuron are horizontally striated. The peduncle is relatively long and extends 0.100 mm from the propodeum. The postpetiole is nearly quadrate viewed dorsally. Queen - The queen is moderately large and concolorous brown in color. What is striking about the queen is the thick scape (maximum diameter 0.096 mm) which is thicker basally and tapers distally towards the minor segments. The propodeum is striated basally.

Solenopsis parva is easily recognized by having reduced angulate clypeal teeth and a moderately large, kidney-shaped eye. The eye separates this species from all other smaller yellow thief ants of the molesta species complex.

Keys

 * Key to New World Solenopsis Species Complexes
 * Key to Solenopsis molesta species complex / Clave a las obreras del complejo Solenopsis molesta

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

Castes
Males have yet to be collected.

Nomenclature

 *  parva. Solenopsis parva Mayr, 1868b: 175 (w.) ARGENTINA. Senior synonym of angulata, dolichops, huasanesis, mendozensis, gallardoi: Pacheco & Mackay, 2013: 248.
 * angulata. Solenopsis angulata Emery, 1894g: 393 (footnote) (w.q.) BRAZIL. Combination in S. (Diplorhoptrum): Santschi, 1925e: 161; in S. (Oedaleocerus): Creighton, 1930b: 146. [Misspelled as angustata by Santschi, 1912e: 526.] Junior synonym of parva: Pacheco & Mackay, 2013: 248.
 * dolichops. Solenopsis angulata var. dolichops Emery, 1906c: 123 (w.q.) ARGENTINA. Junior synonym of parva: Pacheco & Mackay, 2013: 248.
 * huasanensis. Solenopsis angulata r. huasanensis Forel, 1912g: 8 (w.) ARGENTINA. Junior synonym of parva: Pacheco & Mackay, 2013: 248.
 * mendozensis. Solenopsis angulata r. mendozensis Forel, 1914d: 277 (w.) ARGENTINA. [First available use of Solenopsis angulata r. carettei var. mendozensis Forel, 1913l: 223; unavailable name.] Junior synonym of parva: Pacheco & Mackay, 2013: 248.
 * gallardoi. Solenopsis (Diplorhoptrum) gallardoi Santschi, 1925e: 160, fig. 5 (w.) ARGENTINA. Junior synonym of parva: Pacheco & Mackay, 2013: 248.

Worker
Pacheco and Mackay (2013) - Measurements (n=7). TL 1.56-1.62 (1.58); HL 0.420-0.456 (0.443); HW 0.378-0.408 (0.389); EL 0.060-0.078 (0.070); ED 0.048-0.060 (0.053); SL 0.270-0.360 (0.314); FSL 0.120-0.138 (0.126); CI 82.9-93.2 (87.9); SI 61.6-78.9 (70.9); PL 0.066-0.078 (0.072); PW 0.084-0.096 (0.090); PI 73.3-86.7 (79.9); PPL 0.120; PPW 0.126-0.144 (0.134); PPI 83.3-95.2 (89.7); WL 0.300-0.360 (0.343); PSL 0.024; PSW 0.024.

Small; concolorous yellow to brown; head quadrate, longer than wide, finely punctate; lateral clypeal teeth poorly developed, angulate, extralateral teeth absent; clypeal carinae well defined; scape long, reaches 3/4 length of head; minor funicular segments moderately long; eyes black, large, kidney shaped, approximately 5-8 ommatidia; pronotum smooth and shiny; metapleuron horizontally striated, especially basally; notopropodeal suture well depressed, groove breaks sculpture of mesosoma; posterior edge of propodeum slightly angulate; propodeal spiracle small, round; metapleuron horizontally striated; peduncle relatively long; petiolar peduncle lacking tooth or flange ventrally, wider than postpetiole viewed laterally; postpetiole nearly quadrate viewed dorsally, larger than petiole.

Sparsely to moderately pilose, pilosity yellow to light brown; erect and suberect hairs scattered on all body surfaces.

Queen
Pacheco and Mackay (2013) - Measurements (n=2). TL 3.96-4.80 (4.38); HL 0.690-0.720 (0.705); HW 0.660-0.720 (0.690); EL 0.204-0.210 (0.207); ED 0.132-0.156 (0.144); MOL 0.054; MOD 0.054; SL 0.480-0.510 (0.495); FSL 0.270-0.282 (0.276); CI 95.7-100 (97.8); SI 69.6-70.8 (70.2); PSL 0.060; PSW 0.060; PL 0.120; PW 0.270-0.276 (0.273); PI 43.5-44.4 (43.9); PPL 0.240; PPW 0.390-0.402 (0.396); PPI 59.7-61.5 (60.6); WL 0.900.

Moderately large; concolorous brown; head quadrate, semi-coarsely punctate; lateral clypeal teeth angulate, extralateral teeth present as bumps; clypeal carinae well defined; frontal lobes weakly striated; scape long, reaching 3/4 length of head, thickened basally, tapered towards minor segments; minor funicular segments 3-8 long; eyes large, oval, extend 0.054 mm past sides of border of head; medial ocellus small, without pigment; pronotum semi-coarsely punctate, smooth and shiny between punctures; posterior edge of propodeum slightly angulate; propodeal spiracle large, round; metapleuron striated basally below spiracle; petiolar peduncle with minute, thin flange ventrally; postpetiole lacking tooth or flange ventrally.

Abundantly hairy, pilosity yellow to light brown; erect and suberect hairs of various lengths (0.090-0.240 mm) covering all body surfaces; scape with numerous suberect hairs (0.150 mm), especially basally; most hairs on mesosoma, petiole, postpetiole and gaster curve posteriorly.