Solenopsis vinsoni

Workers of S. vinsoni were collected in litter samples, as well as with subterranean baits of Vienna sausage in Costa Rica (600-1200m wet montane cloud forest) and Mexico (10 m tropical forest). Additional specimens were collected from litter extractions in low montane forest, transitional bamboo cloud forest, upper montane and wet cloud forest, montane hardwood forest, Specimens from Colombia were collected in subterranean Viena sausage traps in clay soils in virgin tropical forest. Additionally, S. vinsoni was collected in Guatemala by subterranean bait of Vienna sausage in riparian tropical rain forest in clay soil at 177 m.

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

Pacheco and Mackay (2013) – Minor and Major - This is a dimorphic species in which the majors are slightly larger than the minors (see dimensions in key). The majors can be recognized as the extralateral teeth are moderately developed, but are much smaller than the pair of lateral teeth. The punctures on the head are coarse, greater in diameter than the hairs that arise from them. The dorsum of the head is also nearly covered with poorly defined rugulae. The scapes are relatively short (0.260 in the major, 0.220 mm in the minor), the minor segments of the antenna are relatively short (0.110 in the major, 0.080 in the minor). The eye of the major is relatively large (0.06 mm greatest diameter), almost as long as the distance from the anterior border to the insertions of the mandibles. The top of the mesosoma is mostly covered with punctures and poorly defined rugulae, the side of the pronotum is moderately smooth and shining, the mesopleuron is smooth and glossy (slight sculpturing along the anterior edge), the metapleuron is longitudinally striated, the propodeum mostly smooth and glossy. The petiole and postpetiole are both sculptured with punctures and very fine rugulae.

The minor worker has several additional differences from the major worker. The extralateral teeth are poorly developed, the head is mostly smooth and glossy, with scattered, coarse punctures (much larger in diameter than the width of the hairs arising from them). The eye is relatively small (maximum diameter about 0.03 mm), much smaller than the distance from the anterior border to the insertions of the mandibles. The mesosoma, petiole and postpetiole are mostly smooth and moderately to strongly shiny. Both the majors and the minors are yellow or pale brownish-yellow.

Queen - The gyne is medium brown with lighter brown appendages. The head is elongate with straight sides and is covered in vertical striae. The propodeum is completely covered in thin rugulae with an angulate posterior edge. The petiole and postpetiole are covered in rugulae. A minute tooth is present ventrally on the petiolar peduncle. The gaster of the gyne is noticeably longer than the remainder of the body.

The major worker could only be confused with workers of Solenopsis rugiceps based on the sculpturing of the head. It can be easily separated by the sculptured mesosoma, petiole and postpetiole (predominantly smooth and glossy in S. rugiceps). Additionally the notopropodeal suture is weakly depressed (strongly depressed in S. rugiceps). Although the sculpturing of the head is similar in the two species, they do not appear to be closely related.

The minor workers will key to the fugax species complex. They are unlikely to be confused with any of the other species in the complex, due to their relatively small size and the uniform hairs of 0.03 mm present on the head.

Keys

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

Distribution
Mexico (Tabasco) south to Colombia.

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

Nomenclature

 *  vinsoni. Solenopsis vinsoni Pacheco & Mackay, 2013: 348, figs. 341-346, map 82 (w.q.) MEXICO.

Worker
Pacheco and Mackay (2013) – Major Measurements (n=5). TL 1.68-1.74 (1.70); HL 0.480-0.522 (0.505); HW 0.402-0.456 (0.431); EL 0.048-0.060 (0.050); ED 0.036-0.048 (0.042); SL 0.264-0.282 (0.274); FSL 0.102-0.114 (0.107); CI 83.8-87.4 (85.2); SI 50.6-57.5 (54.2); PL 0.084-0.102 (0.091); PW 0.138-0.156 (0.149); PI 53.8-68.0 (61.4); PPL 0.132-0.138 (0.134); PPW 0.138-0.180 (0.166); PPI 75.9-95.7 (81.8); WL 0.330-0.360 (0.348); PSL 0.030; PSW 0.030.

Moderately small; head heart-shaped, concave posterior-medially, covered in rugulae, follow contour of head, coarsely punctate; lateral clypeal teeth well defined, extralateral teeth reduced, angulate; clypeal carinae well defined; frontal lobes vertically striated; eyes moderately large, 5-8 ommatidia; scapes yellowish brown, short, barely surpass midpoint of head; minor funicular segments 3-8 short; dorsum of pronotum with rugulae, coarsely punctate; mesopleuron smooth and shiny; notopropodeal suture well depressed, notch-like, groove breaks sculpture of mesosoma; posterior propodeal face angulate viewed laterally; propodeal spiracle small, round; metapleuron horizontally striated; anterior and posterior faces of petiole nearly straight, node with rugulae, small tooth present ventrally on subpeduncular process; postpetiole globose, rugose.

Abundantly hairy, pilosity light brown to yellow; uniform length, erect hairs on head (0.060 mm); hairs of various lengths on dorsum of mesosoma viewed laterally (0.030-0.120 mm); hairs on petiole, postpetiole and gaster curved posteriorly.

Minor Measurements (n=5). TL 1.14-1.26 (1.19); HL 0.348-0.360 (0.353); HW 0.300-0.318 (0.306); EL 0.030-0.036 (0.034); ED 0.030; SL 0.216-0.240 (0.222); FSL 0.084; CI 83.3-89.7 (86.7); SI 60.0-66.7 (62.9); PL 0.060-0.066 (0.064); PW 0.102; PI 58.8-64.7 (62.4); PPL 0.090-0.108 (0.097); PPW 0.120; PPI 75.0-90.0 (81.0); WL 0.258-0.270 (0.268); PSL 0.024; PSW 0.024.

Small; concolorous golden yellow to brown; head quadrate, longer than wide, coarsely punctate; lateral clypeal teeth well developed, extend 0.024 mm past anterior clypeal margin, extralateral teeth reduced, angulate; clypeal carinae well defined; frontal lobes vertically striated; scapes short, barely surpass midpoint of dorsum of head; minor funicular segments 3-8 short; eyes small, 3-5 ommatidia; pronotum coarsely punctate, smooth and shiny between punctures; mesopleuron smooth and shiny; notopropodeal suture well depressed, notchshaped, groove breaks sculpture of mesosoma; posterior propodeal margin viewed laterally angulate, posteropropodeum sloped; propodeal spiracle small, round; anterior and posterior faces of petiolar node straight, node mostly smooth and shiny, minute tooth ventrally on peduncular process; postpetiolar node globus, horizontally rugose, lacking tooth or flange ventrally.

Abundantly hairy, pilosity light brown, yellow; erect and suberect hairs of various lengths covering all body surfaces; uniform hairs on head (0.030 mm in total length); hairs on dorsum of petiole (0.060-0.090 mm); hairs on petiole, postpetiole and gaster curve posteriorly.

Queen
Pacheco and Mackay (2013) - Measurements (n=3). TL 3.72-3.84 (3.76); HL 0.522-0.528 (0.526); HW 0.420; EL 0.162; ED 0.132-0.138 (0.136); MOL 0.036; MOD 0.042; SL 0.300; FSL 0.156-0.162 (0.158); CI 79.5-80.5 (79.9); SI 56.8-57.5 (57.0); PSL 0.036-0.042 (0.040); PSW 0.036-0.042 (0.038); PL 0.132; PW 0.198; PI 66.7; PPL 0.180; PPW 0.234; PPI 76.9; WL 0.66.

Moderately small; concolorous medium brown with lighter brown appendages; head elongate, sides straight, coarsely punctate; lateral clypeal teeth well developed, extralateral teeth reduced, angulate; clypeal carinae well defined; frontal lobes vertically striated; scape yellow, reaches medial ocellus; medial ocellus without pigment; pronotum coarsely punctate, smooth and shiny; propodeum sculptured with rugulae, posterior margin angulate (viewed laterally); propodeal spiracle small, round; petiole and postpetiole sculptured with rugulae; petiole with small subpeduncular tooth, postpetiole with flange ventrally; gaster large, longer in length than remainder of body.

Abundantly hairy, pilosity yellow and light brown; erect hairs of various lengths (0.030-0.120 mm) on dorsum of head; hairs on dorsum of mesosoma (0.060-0.120 mm); hairs on petiole, postpetiole and gaster curve posteriorly.

Type Material
Holotype unknown symbol (MCZC), 5 paratype unknown symbol and 54 paratype workers, Costa Rica, Guanacaste, Lorna Barbudal, 3-vi-1989, S. B. Vinson # 12039; 1 paratype queen , Panama, P. Pelon Rd. Quebabra Juan GrandeFIT 19-v-95, R. Anderson, Chaboo, Hayford Jolly # 17849.