Solenopsis patagonica

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Solenopsis patagonica
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species complex: fugax
Species: S. patagonica
Binomial name
Solenopsis patagonica
Emery, 1906

Solenopsis patagonica casent0103221 profile 1.jpg

Solenopsis patagonica casent0103220 dorsal 1.jpg

Specimen labels


Solenopsis patagonica was collected in a nest of Linepithema humile in Brazil. This species was collected under rocks in Argentina (Gallardo 1919).


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

Pacheco and Mackay (2013) – Worker - This is a small, shiny, golden yellow to light brown species. The head is quadrate, coarsely punctate and covered in short, suberect hairs. All four clypeal teeth are present and well defined. The minor funicular segments 3-8 are 0.120 mm in length. The eye is small and contains 3-5 ommatidia. Coarse punctures are visible on the pronotum. The propodeum has an angled posterior margin and the propodeal spiracle is large at 0.030 mm maximum diameter. The petiole is wide and much larger than the postpetiole in profile. A well-developed tooth is present on the subpeduncular process as well as ventrally on the postpetiole. Queen - Not seen. Modified from Gallardo (1919), "The female is dark brown with reddish brown appendages. The head is coarsely punctated, longer than wide and wider posteriorly, with the posterior border straight and the posterior lateral corners rounded. The anterior clypeal margin has four well defined teeth. The scape is long reaching the lateral ocelli. The minor funicular segments 3-6 are wider than long, segment 7 is as long as wide and segment 8 is longer than wide. The postpetiole is oval and wider than the postpetiole." Male - The male is small and golden brown in color. The anterior margin of the clypeus is nearly straight with no visible tooth or bump present. The eyes are large. The antennae are long and pale yellow in color. The three ocelli are large and clear. Coarse punctures are present on the head, pronotum and first tergite of the gaster. There are thin rugulae present on the propodeum. The petiolar node is angulate.

This species is similar to Solenopsis tetracantha, with well-developed lateral and extralateral teeth, but can be distinguished by its wider petiole compared to the more slender node of S. tetracantha (as seen in profile). Solenopsis patagonica is similar to Solenopsis westwoodi, based on the coarsely punctate head, but can be distinguished as S. westwoodi is dark brown in coloration and much smaller in total length. It is possible that S. patagonica is dimorphic as Solenopsis thoracica, but we have not seen the major.

The male resembles the male of Solenopsis goeldii, but can be distinguished as S. goeldii lacks striae on the lower half of the propodeum and S. goeldii has less pronounced angles on the upper portion of the petiole. This species was considered to be a synonym of S. thoracica (by Kusnezov 1960b), however the male of S. thoracica is approximately 5.00 mm in length while the S. patagonica male barely exceeds 3.00 mm in length and we regard S. patagonica as valid. The workers of Solenopsis patagonica medeis are identical to the nominal and is synonymized.

Keys including this Species


Distribution based on Regional Taxon Lists

Neotropical Region: Argentina (type locality), Brazil (type locality), Chile.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb




The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • patagonica. Solenopsis patagonica Emery, 1906c: 132, fig. 14 (w.) ARGENTINA. Gallardo, 1919b: 246 (q.m.). Senior synonym of medeis: Pacheco & Mackay, 2013: 252. See also: Kusnezov, 1949b: 281.
  • medeis. Solenopsis patagonica r. medeis Forel, 1912g: 10 (w.m.) BRAZIL. Junior synonym of patagonica: Pacheco & Mackay, 2013: 252.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Pacheco and Mackay (2013) - Measurements (n=5). TL 1.56-1.62 (1.59); HL 0.420-0.480 (0.446); HW 0.360-0.420 (0.379); EL 0.036; ED 0.030; SL 0.264-0.300 (0.285); FSL 0.072-0.120 (0.099); CI 80.0-87.5 (85.2); SI 58.7-69.4 (64.1); PL 0.078; PW 0.120-0.138 (0.128); PI 56.5-65.0 (60.9); PPL 0.120; PPW 0.132-0.150 (0.141); PPI 80.0-90.9 (85.5); WL 0.288-0.360 (0.346); PSL 0.030-0.036 (0.031); PSW 0.024-0.030 (0.029).

Small, golden yellow to brown; head longer than wide, coarsely punctate; clypeal lateral and extralateral teeth well developed; clypeal carinae well defined; scape does not reach posterior lateral corner of head; eye small, 3-5 ommatidia; pronotum coarsely punctate, smooth and shiny between punctures; mesopleuron and propodeum smooth and shiny; notopropodeal suture weakly depressed; posterior propodeal margin angulate; petiole wide compared to postpetiole (viewed laterally); petiolar node rounded, peduncle with well-developed tooth ventrally; petiolar node oval, with well-developed tooth ventrally.

Abundantly hairy; hair covering all body surfaces; head, mesosoma, petiole, postpetiole and gaster heavily pilose with erect and suberect hairs.


Pacheco and Mackay (2013) - Not seen. Translated and modified from Gallardo (1919), "Large (6.00 mm TL); dark brown; head coarsely punctated, longer than wide; clypeal carinae well defined; clypeallateral and extralateral teeth well developed; scape long, reaching lateral ocelli; mesosoma convex, finely punctated; basal face of epinotum quadrate forming obtuse angle with declivitous face that is also longer; petiole node scale-like, wider than long, with anterior face parted medially; postpetiole oval, slightly wider than petiole."

From Gallardo (1919), "Moderately hairy, erect and suberect hairs scattered on all body surfaces; short pubescence on head, mesosoma, petiole and appendages."


Pacheco and Mackay (2013) - Measurements (n=3). TL 3.00-3.12 (3.08); HL 0.396-0.420 (0.412); HW 0.384-0.420 (0.400); EL 0.216-0.240 (0.224); ED 0.180; MOL 0.060; MOD 0.090; SL 0.162-0.180 (0.174); FSL 1.02; CI 91.4-100 (97.1); SI 40.9-42.9 (42.2); PSL 0.066; PSW 0.054-0.060 (0.058); PL 0.120; PW 0.192-0.210 (0.204); PI 57.1-62.5 (58.9); PPL 0.180; PPW 0.240; PPI 75.0; WL 0.840.

Small, concolorous golden brown; head wider than long, smooth and shiny except for roughened area posterior to medial ocellus; anterior clypeal margin straight with no visible teeth or bumps; eyes relatively small; antennae long; pale yellow; ocelli large, clear; head, pronotum and first tergite of gaster coarsely punctate; pronotum and mesopleuron smooth and shiny; propodeum entirely rugose; petiole wider than postpetiole viewed laterally; petiolar node angulate, peduncle lacking tooth or flange ventrally; postpetiolar node rhombus, lacking tooth or flange ventrally.

Abundantly hairy; erect and suberect hair prevalent on all body surfaces; nearly all punctures with suberect hair.

Type Material

Pacheco and Mackay (2013) - Argentina, Puerto Madryn, Chubut, (Silvestri) (lectotype worker and 1 paralectotype worker [here designated], Museo Civico di Storia Naturale, Genoa). Solenopsis patagonica medeis, Brazil, Rio de Janeiro (Goeldi) (lectotype worker, 2 paralectotype workers and 3 paralectotype males [here designated], Musee d'Histoire Naturelle Genève).


References based on Global Ant Biodiversity Informatics

  • Cheli G. H., J. C. Corley, O. Bruzzone, M. Brío, F. Martínez, N. M. Roman, and I. Ríos. 2010. The ground-dwelling arthropod community of Península Valdés in Patagonia, Argentina. Journal of Insect Science 10:50 available online:
  • 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.
  • Goetsch W. and C. Menozzi. 1935. Die Ameisen Chiles. Konowia 14: 94-102
  • Goetsch, W., and C. Menozzi. "Die Ameisen Chiles." Konowia 14 (1935): 94-102.
  • Kempf W. W. 1970. Catálogo das formigas do Chile. Papeis Avulsos de Zoologia (São Paulo) 23: 17-43.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1949. Sobre la reproducción de las formas sexuales en Solenopsis patagonica Emery (Hymenoptera, Formicidae). Acta Zoologica Lilloana 8: 281-290.
  • Kusnezov N. 1960. La fauna de hormigas en el oeste de la Patagonia y Tierra del Fuego. Acta Zoologica Lilloana 17: 321-401.
  • 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.
  • Santschi F. 1923. Solenopsis et autres fourmis néotropicales. Revue Suisse de Zoologie 30: 245-273.
  • 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).