Solenopsis pygmaea nests underground and was collected in soil in Selva Avacohite. This species was collected in tropical rain forest by subterranean baits at 11 m in elevation in clay and 69 m in elevation in rocky loam soil in Guatemala.
Pacheco and Mackay (2013) – Worker - The workers are small (usually less than 1.00 mm in total length), pale yellow ants, in which the minor segments of the funiculus are short in total length. The lateral clypeal teeth are well developed and the extralateral teeth are absent. The punctures on the head are moderately large, larger than the hairs that arise from them. Queen - The queen is large (about 5 mm total length). It is medium brown with a lighter brown gaster (due in part to the lighter intersegmental membranes of the distended gaster) to black. The eye is relatively small (maximum diameter 0.180 mm), extending about 1/3 of the length of the side of the head. The dorsum of the head is covered with coarse punctures. The scapes and tibiae are covered with suberect hairs. Both the petiole and postpetiole are thickened, robust and have rugulae.
The workers of this species are nearly identical to those of Solenopsis tennesseensis, differing in being slightly smaller and more abundantly covered with erect hairs. The hairs on the dorsum of the first tergum are all short (up to 0.030 mm, few up to 0.040 mm), abundant (more than 20) and approximately equal in length. The similar hairs of S. tennesseensis are longer (many 0.050 mm), sparse (fewer than 20) and are somewhat unequal in length. Specimens from Mexico appear to be identical to specimens from Puerto Rico, but are not associated with queens.
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Males have yet to be collected.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- exigua. Solenopsis exigua Forel, 1893g: 395 (w.) ANTILLES. Junior secondary homonym of exigua Buckley, above.] Replacement name: pygmaea: Forel, 1901e: 345.
- pygmaea. Solenopsis pygmaea Forel, 1901e: 345. [Originally misspelled as pygmaca; justified emendation to pygmaea by Forel, 1915c: 354.] Replacement name for exigua Forel, 1893g: 395. [Junior secondary homonym of exigua Buckley, 1867: 342.]
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=6). TL 0.960-1.08 (0.996); HL 0.342-0.360 (0.350); HW 0.240-0.276 (0.255); EL 0.018-0.030 (0.024); ED 0.012-0.024 (0.019); SL 0.204-0.222 (0.211); FSL 0.060-0.066 (0.064); CI 70.2-76.7 (72.8); SI 58.3-64.9 (60.3); PL 0.060-0.066 (0.063); PW 0.072-0.090 (0.081); PI 66.7-84.6 (78.2); PPL 0.078-0.090 (0.082); PPW 0.102-0.108 (0.103); PPI 76.5-88.2 (79.6); WL 0.240-0.360 (0.260); PSL 0.018-0.030 (0.024); PSW 0.018-0.024 (0.020).
Small, concolorous pale yellow; head elongate, longer than wide, posterior border straight, semi-coarsely punctated; lateral clypeal teeth well developed, extralateral teeth absent; clypeal carinae weakly defined, nearly absent; scape does not reach posterior border of head; minor segments of funiculus 3-8 short, less than 0.070 mm total length; eyes small, 1-3 ommatidia; pronotum coarsely punctate, smooth and shiny between punctures; mesopleuron smooth and shiny; metapleuron with faint, thin striae; posterior propodeal margin rounded; petiole wider than postpetiole viewed laterally; petiolar node round, somewhat triangular, lacking tooth or flange ventrally; postpetiolar node oval viewed laterally and dorsally.
Abundantly hairy; pronotum with numerous erect hairs, of different lengths; hairs on posterior tibiae usually slightly raised from cuticular surface; erect and suberect hairs on first tergum of gaster similar to those on pronotum, but tend to be equal in length (0.036 mm); hairs on remaining terga longer and coarser.
Pacheco and Mackay (2013) - Measurements (n=1). TL 4.92; HL 0.648; HW 0.600; EL 0.180; ED 0.150; MOL 0.066; MOD 0.072; SL 0.420; FSL 0.240; CI 92.6; SI 64.8; PSL 0.072; PSW 0.066; PL 0.138; PW 0.282; PI 48.9; PPL 0.180; PPW 0.324; PPI 55.6; WL 0.960.
Large, medium brown with lighter brown to black gaster; head longer than wide, coarsely punctated; clypeal lateral teeth well developed, extralateral teeth angulate; clypeal carinae weakly defined; eye relatively small, extending about 1/3 length of side of head; medial ocellus small; scape yellow, does not reach posterior border of head; minor segments of funiculus long; mesosoma, petiole, postpetiole and first gastral tergum coarsely punctated; pronotum and mesopleuron smooth and shiny between punctures; propodeum striate; petiole robust, wider than postpetiole (viewed laterally); petiole rugose, node triangular, peduncle with tooth or flange ventrally; postpetiolar node globose, lacking tooth or flange ventrally.
Abundantly hairy; erect and suberect hairs covering all body surfaces; erect hairs on pronotum nearly equal in length (~0.120 mm); scapes and tibiae covered with suberect hairs; hairs on petiole and postpetiole curve posteriorly.
Pacheco and Mackay (2013) - (lectotype worker [here designated], Forel Coll. Musee d'Histoire Naturelle Genève), Antilles Is., St. Vincent.
- Bernard, F. 1950a . Notes sur les fourmis de France. II. Peuplement des montagnes méridionales. Ann. Soc. Entomol. Fr. 115: 1-36 (page 15, worker described)
- Bernard, F. 1978a . Révision des Diplorhoptrum de France, fourmis plus différenciées par l'écologie que par leurs formes (Hym. Formicidae). Ann. Soc. Entomol. Fr. (n.s.) 13: 543-577 (page 571, queen, male described)
- Ettershank, G. 1966. A generic revision of the world Myrmicinae related to Solenopsis and Pheidologeton (Hymenoptera: Formicidae). Aust. J. Zool. 14: 73-171 (page 144, Replacement name: tertialis)
- Forel, A. 1893j. Formicides de l'Antille St. Vincent, récoltées par Mons. H. H. Smith. Trans. Entomol. Soc. Lond. 1893: 333-418 (page 395, [Junior secondary homonym of exigua Buckley, 1867: 342.])
- Forel, A. 1901j. Variétés myrmécologiques. Ann. Soc. Entomol. Belg. 45: 334-382 (page 345, Replacement name for exigua)
- Forel, A. 1905f. Ameisen aus Java. Gesammelt von Prof. Karl Kraepelin 1904. Mitt. Naturhist. Mus. Hambg. 22: 1-26 (page 21, worker described)
- Forel, A. 1915c. Formicides d'Afrique et d'Amérique nouveaux ou peu connus. IIe partie. Bull. Soc. Vaudoise Sci. Nat. 50: 335-364 (page 354, Replacement name: marxi)
- Pacheco, J.A. & Mackay, W.P. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, New York. 501 pp.