Cephalotes atratus

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Cephalotes atratus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. atratus
Binomial name
Cephalotes atratus
(Linnaeus, 1758)



Specimen Label


Within Cephalotes this species is the largest, one of the most abundant, and one of the most frequently encountered. The latter is due, in part, to the ability of C. atratus to thrive in urban areas. Mature colonies are comprised of several thousand individuals that can seemingly cover the trunk of the tree they inhabit when they are foraging.

This is one of the very few ants able to consume pollen, obtained by licking wind-transported pollen from leaves. The protein-rich internal part of the pollen is digested in the crop (foregut) and indigestible membranes are eliminated as 'infrabuccal pellets' through the mouth (Baroni Urbani & de Andrade 1997).

Photo Gallery

  • Cephalotes atratus dealate queen from Surinam. Copyright: Piotr Naskrecki.


A member of the atratus clade differing from its sister species Cephalotes marginatus (q. v.) by the sparser pilosity on the ventral part of the gastral sternites of the worker and of the gyne, and, in the male, for the denser foveolation of the mesosoma and by the greater CI. Both sister species (atratus and marginatus) are among the largest of the genus and differ from closely related ones by the lack of crenulation on the posterior half of the frontal carinae. (de Andrade and Baroni Urbani 1999)

Note that nematode-infected workers have a red rather than black gaster (Poinar & Yanoviak, 2008).

Keys including this Species


Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Uruguay, Venezuela.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


DaRocha et al. (2015) studied the diversity of ants found in bromeliads of a single large tree of Erythrina, a common cocoa shade tree, at an agricultural research center in Ilhéus, Brazil. Forty-seven species of ants were found in 36 of 52 the bromeliads examined. Bromeliads with suspended soil and those that were larger had higher ant diversity. Cephalotes atratus was found in 4 different bromeliads but was associated with twigs and bark cavities, rather than suspended soil or litter, of the plants.

Associations with other organisms

Worker of Cephalotes atratus infected with the nematode Myrmeconema neotropicum. The raised, red abdomen occurs when the nematode eggs are infective and ready for transport by birds. Photo courtesy of Stephen P. Yanoviak (Poinar, 2012, Fig. 12).

A known host for the fungi Ophiocordyceps cucumispora, Ophiocordyceps evansii and Ophiocordyceps niphofioides (Araujo et al., 2018; Shrestha et al., 2017) and the nematode Myrmeconema neotropicum (Poinar & Yanoviak, 2008). Note that in nematode-infected workers the gaster changes from black to red.







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

  • atratus. Formica atrata Linnaeus, 1758: 581 (w.) "AMERICA MERIDIONALI". Latreille, 1802c: 274 (q.); Spinola, 1851b: 47; Spinola, 1853: 63 (m.); Wheeler, G.C. & Wheeler, J. 1954b: 154 (l.). Combination in Cephalotes: Latreille, 1802a: 358; in Cryptocerus: Latreille, 1803: 280; in Cryptocerus (Cephalotes): Wheeler, W.M. 1916c: 12; in Cephalotes: Smith, M.R. 1949c: 19. Senior synonym of quadridens: Retzius, 1783: 76; Latreille, 1802c: 272; Kempf, 1951: 115; of dubitatus: Smith, F. 1858b: 188; of crassispina, nitidiventris, rufiventris and material of the unavailable name dehnowi referred here: Kempf, 1951: 115; of erectus: De Andrade & Baroni Urbani, 1999: 112.
  • quadridens. Formica quadridens De Geer, 1773: 609, pl. 31, figs.17-20 (w.) SURINAM. Combination in Cephalotes: Santschi, 1919f: 44. Junior synonym of atratus: Retzius, 1783: 76; Latreille, 1802c: 272. Revived from synonymy: Santschi, 1919f: 44. Subspecies of atratus: Santschi, 1920f: 148; Forel, 1922: 97. Junior synonym of atratus: Kempf, 1951: 115.
  • dubitatus. Cryptocerus dubitatus Smith, F. 1853: 216, pl. 20, fig. 1 (m.) BRAZIL. Junior synonym of atratus: Smith, F. 1858b: 188.
  • rufiventris. Cryptocerus atratus ab. rufiventris Emery, 1894e: 4 (w.) ARGENTINA. Junior synonym of atratus: Kempf, 1951: 115.
  • crassispina. Cephalotes atratus st. crassispina Santschi, 1920f: 148 (w.) BRAZIL. Junior synonym of atratus: Kempf, 1951: 115.
  • nitidiventris. Cephalotes atratus var. nitidiventris Santschi, 1920f: 148 (w.) FRENCH GUIANA. Junior synonym of atratus: Kempf, 1951: 115.
  • erectus. Cephalotes atratus subsp. erectus Kempf, 1951: 124 (w.q.) PANAMA. [First available use of Cephalotes atratus st. quadridens var. erecta Santschi, 1920f: 149; unavailable name.] Junior synonym of atratus: De Andrade & Baroni Urbani, 1999: 112.

Type Material

de Andrade and Baroni Urbani (1999): Formica quadridens. Type locality: Surinam.

Cryptocerus dubitatus. Male. Type locality: Brazil. Type material presumably lost (neither in the BMNH nor in Oxford University Museum of Natural History).

Cryptocerus atratus ab. Rufiventris. Worker. Type locality: Tucuman (Argentina). Type material not available for the present dtudy.

Cephalotes atratus var. nitidiventris. Worker. Type locality: Cayenne and Lumier River (French Guyana). Type Material: 2 syntype workers labeled “America, Cayena 1905, E. Grouvelle” (sic) in Naturhistorisches Museum, Basel, examined.

Cephalotes atratus stirps crassispina. Worker. Type localities: Mato Grosso (Brazil), Formosa (Misiones, Argentina), and Santa Trinidad (Paraguay). Type material 3 workers from Urucuru, Mato Grosso (Silvestri), 3 workers from Formosa (Argentina, Joergensen), 1 worker from Paraguay without further data, all in NHMB, examined. Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



Kempf (1951) - Monomorphic. Length 8-14 mm. Black; the following fuscous ferruginous: two semitranslucid spots on each frontal carinae, tips of tarsi.

Head subopaque; finely reticulate-punctate. Mandibles densely and finely rugose and punctured. Frontal carinae slightly diverging caudad, scarcely upturned laterad, vestigially crenulate anteriorly with only a few projecting setae, remaining part not crenulate and without setae. Occiput continuous with upper surface of head, inclined ventrad; its angles with a pair of spines. Vertex without spines nor swellings. Lower occipital border straight, carinulate. Upper surface of head and cheeks covered with sparse oval foveolae, containing a short, scalelike, silvery, decumbent hair. Lower surface of head more coarsely reticulate-rugose and foveolate. Apical segment of maxillary palpi somewhat longer than the preceding.

Thorax subopaque. Shoulders obtusely dentate. Scapular spines strong, obliquely inclined backward, and laterad, subacuminate, the apical half more or less recurved, with a small tooth projecting from the anterior face at the bent. Median pronotal spines usually minute, vestigial or absent. Promesonotum moderately longitudinally convex, immarginate laterad. Promesonotal suture distinct. Mesonotum flat, with a minute tubercle laterally toward the posterior angle. Mesoepinotal suture distinct and impressed. The basal face of the epinotum slightly inclined forward, immarginate laterad, slightly constricted in front of the oblique, more or less divergent, straight to slightly curved epinotal spines. Entire thorax finely reticulate-punctate, with sparse setigerous foveolae, crowded and more deeply impressed on pronotum, very sparse on the pleura, leaving free spaces, which arc mostly longitudinally rugose. Mesopleura with a small tooth above the anterior corner of the mid coxae. Declivous face mostly without coarse sculpture. Outer surface of fore coxae transversely striated. Legs without foveolae, but with appressed setae. Oblique setae on apical end of femora, tibiae and on tarsi. Petiole shorter than broad, subcuboidal, denesely foveolate above and on the sides, with a small sidewards projecting tubercle or tooth on each anterior corner. Ventral face strongly keeled, ending anteriorly in an obtuse tooth. Postpetiole more than 1.5 times as broad as long. Sides with a conspicuous, anteriorly angulate, posteriorly rounded swelling, the sides converging caudad. Upper face flat, with a pair of small tubercles on the anterior border. Ventral face with a large, truncate, rounded or bifid lobe, projecting ventrad and somewhat cehalad. Sculpture as on petiole.

Gaster elliptical, subopaque to subfulgid, finely reticulate-punctate, covered with larger, elongate, shallow grooves, containing a decumbent hair. Posterior half of first sternites and the exposed portion of the tergites and sternites 2-4 with sparse, suberect, pale-brownish hairs.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 7.64-15.10; HL 1.60-3.30; HW 2.08-4.50; EL 0.48-0.80; PW 1.88-4.80; PeW 0.50-1.00; PpW 0.59-1.08; HBaL 1.32-2.30; HBaW 0.34-0.51; CI 130.0-136.4; PI 93.7-112.9; PPel 349.3-480.0; PPpl 317.9-444.4; HBal 22.2-25.7.


Kempf (1951) - Length up to 23 mm. Somewhat similar to the worker. Black, subopaque. Head somewhat broader than long. Mandibles strongly rugose. Clypeus much broader than long, subtriangular. Frontal carinae distinctly converging anteriorly, not parallel not upturned laterally, slightly crenulate on anterior third, with a few projecting setae. Vertex with a pair of obtuse swellings, just in front of the subtruncate occiput. Occipital angles bituberculate. Cheeks immarginate below. culpture as in worker. Thorax subopaque. Pronotum immarginate cephalad and laterad. Shoulders low, bluntly angulate. Scapular spines short, stout, acute. Transverse crest of pronotum vestigial, not carinate, two median pronotal spines short, obtuse. Mesopleura with a small tooth above the mid coxa. Epinotum narrow, immarginate, laterad, spines short, icrassate at base, apices slightly diverging, their interapical distance less than 1/2 of the maximum width of thorax. Declivous face twice as long as basal face of epinotum. Sculpture as on head. Basitarsus of mid and hind leg flattened and broadened, not as thin as in worker. Petiole short, about twice as broad as long, the upper face presenting a transverse keel. Postpetiole longitudinally, greatly convex, with a large, blunt, rounded swelling laterad, about twice as broad as long. Ventral lobe less conspicuous than in worker. Both peduncular segments coarsely and rather densely foveolate. Gaster as in worker, more elongate, sides subparallel, the microsculpture less prominent; first tergite rather fulgid discad, sparsely foveolate, the foveolae smaller than on thorax and on head. Wings infumated. Fore wing with fuscous stigma and a dark streak along the subcostal vein. Marginal cell closed and appendiculate. Submarginal cell shorter than in Zacryptocerus clypeatus. Transverse cubital vein absent, the cubital vein touching the marginal cell. Second abscissa of subcostal vein shorter than the section of basal vein that encloses the submarginal cell. Occasionally stubs projecting from the cubital vein into the ubmarginal cell and the apical field.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 15.06-19.50; HL 2.76-3.65; HW 3.32-4.50; EL 0.64-0.80; PW 2.60-4.50; PeW 0.96-1.40; PpW 1.16-1.60; HBaL 1.76-2.00; HBaW 0.486-0.60; CI 120.0-126.5; PI 93.3-127.7; PPeI 270.8-321.4; PPpI 224.1-281.2; HBaI 27.3-30.0.


Kempf (1951) - Length 13.2 mm. Median head length 1.53 mm. Weber's length of thorax 4.05 mm. Black: the following brunneous: antennae, coxae, trochanters, base of femora. Orange-brown: gaster, femora, tibiae, tarsi.

Head, without mandibles much broader than long (103 : 63). Mandibles finely rugulose and punctate; chewing border with distinct apical and preapical tooth. Clypeus transverse, anterior face truncate, subperpendicular to upper surface of head, posterior half at right angles to it; horizontal. Anterior border straight, posterior border marked by a deep transverse depression in front of the antennal sockets. Entire clypeus finely shagreened. Frontal carinae scarcely expanded, divergent caudad, fading out before the posterior border of eye. Antennal scrobes indistinct. Ocelli on vertex, conspicuous, subequal to diameter of second funicular segment. First funicular segment shorter than broad. Second funicular segment longer than the following, except of the apical segment.

Thorax subopaque, almost twice as long as maximum width (83 : 47). Pronotum immarginate laterad, with a minute tooth on the anterior angle, and a longer blunt tooth somewhat behind; rugose-reticulate and foveolate. Scutum convex with deeply impressed Y-shaped Mayrian furrows, antero-mesal part deeply and densely foveolate, postero-lateral portion more sparsely and shallowly foveolate. Scutellum similarly sculptured with anterolateral lobes almost constricted off by a deep transverse furrow immediately behind the anterior border. Basal face of epinotum shorter than declivous face, transversely convex, immarginate laterally, posterior corners with a sharp carinule, reticulate-rugose and foveolate. Declivous face finely reticulate, subfulgid, with a few faint, distinct rugulae. Sides of mesothorax finely shagreened anteriorly, sparsely, shallowly foveolate and rugose posteriorly. Basitarsi elongate, compressed.

Petiole subopaque, slightly broader than long, anterior face truncate, excavate, the sides somewhat converging behind, finely shagreened above, finely longitudinally rugose laterad, and reticulate-rugose antero-laterad. Postpetiole broader than long, sides greatly convex, subtuberculate, sculptured as petiole.

Gaster subopaque, short, fusiform, finely shagreened. Subgenital plate transverse, apical border rounded.

Wings leathery, infumated. Veins brunneous. Fore wings with fuscous stigma, and fuscous streak along the subcostal vein. Marginal cell closed and appendiculate. Discoidal cell extremely small. Transverse cubital vein present, cubital vein not touching the marginal cell.

Pilosity gold-brown. Antennae with dense fine pubescence. Long dense hair on head and thorax; sparse, appressed on first gastral tergite, erect on apical border of the gastral tergites and sternites.

Certain features are highly variable, even among males of the same nest. Among those are the occipital spines, which may form mere perpendicular carinule on each side, or even be quite obsolete. The same is true for the carinules on the posterior corner of the epinotum, which may be occasionally tooth-like. The sculpture in some instances is coarser than in the specimen described above. The following variability occurs in the fore wing: discoidal cell always small, sometimes minute, open or even completely absent. Stubs projecting into submarginal cell from various places of the recurrent and the cubital veins.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 9.78-13.21; HL 1.28-1.68; HW 1.68-2.16; EL 0.53-0.70; PW 1.60-2.24; PeW 0.72-0.92; PpW 0.88-0.96; HBaL 1.32-1.84; HBaW 0.18-0.26; CI 128.3-131.9; PI 96.4-105.0; PPeI 227.3-272.2; PPpI 208.3-233.3; HBaI 13.3-15.1.


  • Araújo, J.P.M., Evans, H.C., Kepler, R., Hughes, D.P. 2018. Zombie-ant fungi across continents: 15 new species and new combinations within Ophiocordyceps. I. Myrmecophilous hirsutelloid species. Studies in Mycology 90: 119–160 (DOI 10.1016/j.simyco.2017.12.002).
  • Baroni Urbani C., de Andrade M.L. 1997. Pollen Eating, Storing, and Spitting by Ants. Naturwissenschaften 84: 256–258.
  • DaRocha, W. D., S. P. Ribeiro, F. S. Neves, G. W. Fernandes, M. Leponce, and J. H. C. Delabie. 2015. How does bromeliad distribution structure the arboreal ant assemblage (Hymenoptera: Formicidae) on a single tree in a Brazilian Atlantic forest agroecosystem? Myrmecological News. 21:83-92.
  • de Andrade, M. L.; Baroni Urbani, C. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Series B (Geolgie and Palaontologie). 271:1-889. (page 112, Senior synonym of erectus)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 115, Senior synonym of quadridens, Senior synonym of crassispina, nitidiventris, rufiventris, and material of the unavailable name dehnowi referred here)
  • Latreille, P. A. 1802a. Histoire naturelle des fourmis, et recueil de mémoires et d'observations sur les abeilles, les araignées, les faucheurs, et autres insectes. Paris: Impr. Crapelet (chez T. Barrois), xvi + 445 pp. (page 348, Combination in Cephalotes)
  • Latreille, P. A. 1802b. Histoire naturelle générale et particulière des Crustacés et des insectes. Tome 3. Familles naturelles des genres. Paris: F. Dufart, xii + 467 pp. (page 274, queen described, page 272, Senior synonym of quadridens)
  • Latreille, P. A. 1803. Histoire naturelle générale et particulière des Crustacés et des insectes. Tome 5. Paris: F. Dufart, 406 pp. (page 280, Combination in Cryptocerus)
  • Linnaeus, C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Holmiae [= Stockholm]: L. Salvii, 824 pp. (page 581, worker described)
  • Poinar, G., Yanoviak, S.P. 2008. Myrmeconema neotropicum n. g., n. sp., a new tetradonematid nematode parasitising South American populations of Cephalotes atratus (Hymenoptera: Formicidae), with the discovery of an apparent parasite–induced host morph. Systematic Parasitology 69 (2): 145–153 (doi:10.1007/s11230-007-9125-3).
  • Retzius, A. J. 1783. Caroli de Geer. Genera et species insectorum e generosissimi auctoris scriptis extraxit, digessit, Latine quoad partem reddidit, et terminologiam insectorum Linneanam addidit. Lipsiae [= Leipzig]: Cruse, 220 pp. (page 76, Senior synonym of quadridens)
  • Sanjuan, T. I., A. E. Franco-Molano, R. M. Kepler, J. W. Spatafora, J. Tabima, A. M. Vasco-Palacios, and S. Restrepo. 2015. Five new species of entomopathogenic fungi from the Amazon and evolution of neotropical Ophiocordyceps. Fungal Biology. 119:901-916. doi:10.1016/j.funbio.2015.06.010
  • Shrestha B, Tanaka E, Hyun MW, Han JG, Kim CS, Jo JW, Han SK, Oh J, Sung JM, Sung GH. 2017. Mycosphere Essay 19. Cordyceps species parasitizing hymenopteran and hemipteran insects. Mycosphere 8(9): 1424–1442 (DOI 10.5943/mycosphere/8/9/8).
  • Smith, F. 1858a. Catalogue of hymenopterous insects in the collection of the British Museum. Part VI. Formicidae. London: British Museum, 216 pp. (page 188, Senior synonym of dubitatus)
  • Smith, M. R. 1949c. On the status of Cryptocerus Latreille and Cephalotes Latreille (Hymenoptera: Formicidae). Psyche (Camb.) 56: 18-21 (page 19, Combination in Cephalotes)
  • Spinola, M. 1851b. Compte rendu des Hyménoptères inédits provenants du voyage entomologique de M. Ghiliani dans le Para en 1846. Extrait des Mémoires de l'Académie des Sciences de Turin (2) 13: 3-78 (page 47, male? described)
  • Spinola, M. 1853. Compte rendu des Hyménoptères inédits provenants du voyage entomologique de M. Ghiliani dans le Para en 1846. Mem. R. Accad. Sci. Torino (2) 13: 19-94 (page 63, male described)
  • Wheeler, G. C.; Wheeler, J. 1954b. The ant larvae of the myrmicine tribes Cataulacini and Cephalotini. J. Wash. Acad. Sci. 44: 149-157 (page 154, larva described)
  • Wheeler, W. M. 1916c. Ants collected in British Guiana by the expedition of the American Museum of Natural History during 1911. Bull. Am. Mus. Nat. Hist. 35: 1-14 (page 12, Combination in Cryptocerus (Cephalotes))