Solenopsis major

Solenopsis major was collected from leaf litter extractions in wet cloud forest habitat in Costa Rica.

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 relatively large, golden yellow species with a somewhat elongate head. The clypeal margin between the lateral teeth (tips) is relatively wide at 0.090 mm and the lateral teeth are poorly developed and are present solely as angles that protrude slightly past the anterior margin as extensions of the well-developed clypeal carinae. The scape is long and nearly reaches the posterior margin of the head. The eye contains 8-10 ommatidia. Queen - The female is large and concolorous brown. All four clypeal teeth are well developed and the anterior margin between the lateral teeth is concave. The scape is thick basally and thins as it reaches the funicular segments. The ocelli are very small. The basal portion of the propodeum is finely and extends laterally past the propodeal spiracle.

Solenopsis major is similar to Solenopsis basalis (Colombia south to Argentina, Caribbean), but is consistently larger in total length with a wider head and is easily distinguished from S. basalis by the wider space on the anterior clypeal margin between the lateral teeth.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Costa Rica.

Nomenclature

 *  major. Solenopsis basalis var. major Forel, 1913l: 220 (w.q.) ARGENTINA. Raised to species: Pacheco & Mackay, 2013: 219.
 * delfinoi. Solenopsis tenuis r. delfinoi Forel, 1913l: 222 (w.) ARGENTINA. Forel, 1914d: 278 (q.). Junior synonym of major: Pacheco & Mackay, 2013: 219.

Worker
Pacheco and Mackay (2013) - Measurements (n=6). TL 2.07-2.46 (2.20); HL 0.510-0.576 (0.539); HW 0.426-0.480 (0.455); EL 0.054-0.060 (0.059); ED 0.036-0.048 (0.043); SL 0.348-0.396 (0.369); FSL 0.138-0.180 (0.155); CI 80.6-92.9 (84.5); SI 62.4-76.5 (68.6); PL 0.09; PW 0.132-0.162 (0.149); PI 55.6-68.2 (60.8); PPL 0.12; PPW 0.150-0.174 (0.165); PPI 68.9-80.0 (72.9); WL 0.420-0.480 (0.440); PSL 0.048-0.054 (0.049); PSW 0.042.

Small, concolorous golden yellow (sometimes with brownish gaster) with a somewhat elongate head; body smooth and shiny; clypeal margin between lateral teeth tips relatively wide at 0.090 mm, lateral teeth poorly developed, present as angles that protrude slightly past anterior margin as extensions of well-developed clypeal carinae; scape long, nearly reaches posterior margin of head; eye moderately large (approximately 8-10 ommatidia); notopropodeal suture well depressed, groove breaks sculpture of body; thin horizontal striae present on metapleuron, absent on mesopleuron; propodeal spiracle large (0.05 mm maximum diameter); petiole thickened, larger than postpetiole viewed laterally; postpetiole oval, viewed dorsally.

Hair present on all body surfaces; head and scape with numerous sub erect hairs, many extend past 0.060 mm in length; few long (0.060-0.120 mm) hairs present on mesosoma (with majority present on the pronotum), petiole, postpetiole and gaster.

Queen
Pacheco and Mackay (2013) - Measurements (n=3). TL 3.84-4.20 (4.04); HL 0.660-0.780 (0.700); HW 0.600-0.792 (0.672); EL 0.180-0.240 (0.202); ED 0.120-0.180 (0.146); MOL 0.048; MOD 0.054-0.060 (0.056); SL 0.420-0.480 (0.460); FSL 0.240-0.252 (0.244); CI 90.9-101.0 (95.7); SI 61.5-72.7 (65.9); PSL 0.054-0.066 (0.062); PSW 0.054-0.060 (0.056); PL 0.126-0.138 (0.132); PW 0.252-0.282 (0.264); PI 48.9-51.2 (50.0); PPL 0.228-0.252 (0.240); PPW 0.300-0.324 (0.310); PPI70.4-82.4 (77.6); WL 0.840-0.900 (0.860).

Large; concolorous brown; lateral and extralateral teeth well developed; anterior margin between lateral teeth concave; head quadrate; scape thick basally, thins distally; frontal lobes with vertical striae; eyes large; ocelli small; metapleuron finely striated, striae extend posteriorly past propodeal spiracle; propodeal spiracle large; petiole wider than postpetiole viewed laterally, pyramidal node; postpetiole globose, rounded, wider than petiole viewed dorsally.

Hairy; scape covered with suberect hairs, longer basally; suberect hairs covering all body structures, shorter on petiole and postpetiole.

Type Material
Argentina, La Plata, les Bruch, 10.9.12, det. Forel, M.C.Z. Cotype 29400 (lectotype worker [here designated] ). Solenopsis tenuis delfinoi, Argentina, Santa Fe, 24 Rosano, (Bruch). 3 Canals, Cordoba, Weiser legit 280 (lectotype worker and 4 paralectotype workers [here designated] ) S. tenuis delfinoi, (3 paralectotype queens [here designated] ).

References based on Global Ant Biodiversity Informatics

 * Bruch C. 1914. Catálogo sistemático de los formícidos argentinos. Revista del Museo de La Plata 19: 211-234.
 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
 * Forel A. 1913. Fourmis d'Argentine, du Brésil, du Guatémala & de Cuba reçues de M. M. Bruch, Prof. v. Ihering, Mlle Baez, M. Peper et M. Rovereto. Bulletin de la Société Vaudoise des Sciences Naturelles. 49: 203-250.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
 * Pacheco J. A., and W. P. Mackay. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Lewiston, New York: Edwin Mellen Press, 501 pp.
 * Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466
 * Vittar, F., and F. Cuezzo. "Hormigas (Hymenoptera: Formicidae) de la provincia de Santa Fe, Argentina." Revista de la Sociedad Entomológica Argentina (versión On-line ISSN 1851-7471) 67, no. 1-2 (2008).