Pseudomyrmex pallidus

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Pseudomyrmex pallidus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Pseudomyrmecinae
Genus: Pseudomyrmex
Species: P. pallidus
Binomial name
Pseudomyrmex pallidus
(Smith, F., 1855)

Pseudomyrmex pallidus casent0103890 profile 1.jpg

Pseudomyrmex pallidus casent0103890 dorsal 1.jpg

Specimen Label

A common and widespread species that opportunistically nests within a wide range of cavities, from dead stalks of herbaceous plants to dead twigs in trees.

At a Glance • Polygynous  



Ward (1985) - This is the most common and widespread member of the pallidus group. P. pallidus shows considerable geographical variation in size, sculpture, and body proportions (note wide ranges of some metrics). However the workers are consistently orange-brown in color, with contiguous frontal carinae (MFC < 0.025), moderately long eyes (REL2 > 0.52), and (at least weakly) coriarious-punctulate sculpture on the vertex. No other Nearctic species possesses this combination of characters. Specific differences between P. pallidus and other orange Pseudomyrmex (Pseudomyrmex apache, Pseudomyrmex leptosus, Pseudomyrmex seminole and Pseudomyrmex simplex) are discussed under those species.

Keys including this Species


Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).
Neotropical Region: Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Cuba, Greater Antilles, Guatemala, Honduras, Mexico, Paraguay, Trinidad and Tobago, Uruguay.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Ward (1985) - P. pallidus exhibits diversity in its choice of nesting sites. While it shows a preference for dead stalks or culms of herbaceous plants, it will also nest in dead twigs or branches of shrubs and trees in some localities.

By state, the Nearctic nest-site records are from the following plants (based on personal observations or on museum material which I have examined):

Florida: Ambrosia artemisiifolia, Andropogon, Bidens, Cladium jamaicense, Uniola paniculata.

Georgia: Callicarba.

Texas: Baccharis, Heterotheca subaxillaris, Iva ciliata, Melia azedarach, Prunus, Ptelea trifoliata, Uniola paniculata.

Arizona: Gossypium thurberi, Quercus emoryi, Q. oblongifolia.

California: Acacia greggii, Hyptis emoryi.

The number of functional queens in a colony varies widely. The majority of P. pallidus nests which I dissected from Texas and Florida were queenless or monogynous, but sometimes larger numbers of mated, dealate queens cohabited (up to a maximum of 22). Since P. pallidus colonies are often polydomous, the number of queens per colony may be higher.

P. pallidus alates have been collected in every month of the year, indicating that mating occurs in more than one season.

Koch et al. (2018) sampled this species in Caryocar barsiliense trees, in southeastern Brazil cerrado, as part of a study examining species interactions in ant-plants.

This species is a host for the ant Pseudomyrmex seminole (a temporary parasite) (Ward, 1985).






The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • pallidus. Pseudomyrma pallidus Smith, F. 1855c: 160 (w.) U.S.A. Wheeler, G.C. & Wheeler, J. 1956: 386 (l.); Petralia & Vinson, 1980: 381 (l.). Combination in Leptalea: Smith, M.R. 1951a: 788; in Pseudomyrmex: Wheeler, G.C. & Wheeler, J. 1956: 386. Subspecies of flavidulus: Enzmann, E.V. 1944: 66. Revived status as species: Smith, M.R. 1947f: 544; Creighton, 1950a: 80. See also: Blum & Callahan, 1963: 69; Ward, 1985b: 235.

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



Ward (1985) - Measurements (n = 70): HL 0.78-1.06, HW 0.68-0.89, MFC 0.011-0.024, CI 0.77-0.91, OI 0.54-0.62, REL 0.45-0.54, REL2 0.53-0.65, OOI 0.78-2.08, VI 0.67-0.84, FCI 0.015-0.033, SI 0.41-0.49, SI2 0.68-0.85, FI 0.37-0.45, PDI 1.10-1.52, MPI 0.022-0.054, NI 0.54-0.67, PLI 0.47-0.62, PWI 0.38-0.52, PPWI 0.85-1.18.

Diagnosis. - Medium-sized species (for the pallidus group), with moderately broad head (HW 0.68-0.89, CI 0.77-0.91); anterior clypeal margin medially flat, laterally angulate: distance between frontal carinae less than basal width of scape; eyes moderately long. EL greater than scape length: occipital margin convex, flat or weakly concave, in full-face, dorsal view; lateral margins of pronotum rounded; metanotal groove present but shallow; basal face of propodeum longer than declivitous face, and more or less differentiated from it; petiole slender, with a distinct anterior peduncle and anteroventral tooth. Head subopaque to weakly shining; frons densely punctulate on a coriarious background; punctures less dense on the vertex which remains (at least weakly) coriarious; dorsum of mesosoma and petiole sublucid, coriarious-punctulate, becoming coriarious-imbricate laterally; postpetiole and gaster weakly shining, covered with numerous, very fine piligerous punctures. Erect pilosity sparse, lacking on mesonotum, propodeum, and mid and hind femora; one to several erect setae on dorsum of head, pronotum, petiole, postpetiole, and abdominal tergite IV. Fine, appressed pubescence present on most parts of body, forming a moderately dense mat on abdominal tergite IV, which partially obscures the sheen of the integument. Body orange-brown, with paler mandibles and appendages: a pair of anterolateral fuscous patches sometimes present on abdominal tergite IV.

Type Material

Ward (1985) - One syntype queen (dealate), one syntype worker, "U.S.” (The Natural History Museum) (Examined). Syntype worker here designated as LECTOTYPE.


  • Blum, M. S.; Callahan, P. S. 1963. The venom and poison glands of Pseudomyrmex pallidus (F. Smith). Psyche (Camb.) 70: 69-74 PDF (page 69, see also)
  • Creighton, W. S. 1950a. The ants of North America. Bull. Mus. Comp. Zool. 104: 1-585 (page 80, Revived status as species)
  • Enzmann, E. V. 1944. Systematic notes on the genus Pseudomyrma. Psyche (Camb.) 51: 59-103 (page 66, Variety of flavidulus)
  • Koch, E. B. A., W. Dattilo, F. Camarota, and H. L. Vasconcelos. 2018. From species to individuals: does the variation in ant-plant networks scale result in structural and functional changes? Population Ecology. 60:309-318. doi:10.1007/s10144-018-0634-5
  • MacKay, W.P. & MacKay, E.E. 2002. The Ants of New Mexico: 400 pp. Edwin Mellen Press, Lewiston, N.Y.
  • Petralia, R. S.; Vinson, S. B. 1980 [1979]. Comparative anatomy of the ventral region of ant larvae, and its relation to feeding behavior. Psyche (Camb.) 86: 375-394 (page 381, larva described)
  • Smith, F. 1855c. Descriptions of some species of Brazilian ants belonging to the genera Pseudomyrma, Eciton and Myrmica (with observations on their economy by Mr. H. W. Bates). Trans. Entomol. Soc. Lond. (2) 3: 156-169 (page 160, worker described)
  • Smith, M. R. 1947f. A generic and subgeneric synopsis of the United States ants, based on the workers. Am. Midl. Nat. 37: 521-647 (page 544, Revived status as species)
  • Smith, M. R. 1951c. Family Formicidae. Pp. 778-875 in: Muesebeck, C. F., Krombein, K. V., Townes, H. K. (eds.) Hymenoptera of America north of Mexico. Synoptic catalogue. U. S. Dep. Agric. Agric. Monogr. 2:1-1420. (page 788, Combination in Leptalea)
  • Ward, P. S. 1985b. The Nearctic species of the genus Pseudomyrmex (Hymenoptera: Formicidae). Quaest. Entomol. 21: 209-246 (page 235, see also)
  • Wheeler, G. C.; Wheeler, J. 1956. The ant larvae of the subfamily Pseudomyrmecinae (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 49: 374-398 (page 386, larva described)
  • Wheeler, G. C.; Wheeler, J. 1956. The ant larvae of the subfamily Pseudomyrmecinae (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 49: 374-398 (page 386, Combination in Pseudomyrmex)