Cephalotes pusillus

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Cephalotes pusillus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. pusillus
Binomial name
Cephalotes pusillus
(Klug, 1824)

Cephalotes pusillus casent0173703 profile 1.jpg

Cephalotes pusillus casent0173703 dorsal 1.jpg

Specimen labels


C. pusillus is one of the commonest and most widespread species of the genus, though its distribution is narrower than that of other common species like Cephalotes minutus and Cephalotes atratus. (de Andrade and Baroni Urbani 1999)


A member of the pusillus clade characterised in the worker and soldier by the less regular body foveae and by the narrow, semi-transparent gastral lamellae. (de Andrade and Baroni Urbani 1999)

Keys including this Species


Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Bolivia, Brazil (type locality), Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad and Tobago, 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 pusillus was found in 5 different bromeliads but was associated with twigs and bark cavities, rather than suspended soil or litter, of the plants.

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.








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

  • elongatus. Cryptocerus elongatus Klug, 1824: 214 (q.) BRAZIL. Smith, F. 1860c: 75 (w.); Smith, F. 1862d: 409 (s.). Junior synonym of pusillus: Roger, 1862c: 297; Kempf, 1951: 176.
  • pusillus. Cryptocerus pusillus Klug, 1824: 202 (w.) BRAZIL. Emery, 1890b: 75 (s.q.); Emery, 1896h: 636 (m.); Wheeler, G.C. & Wheeler, J. 1954b: 156 (l.). Combination in Cryptocerus (Paracryptocerus): Emery, 1915i: 192; in Paracryptocerus: Kempf, 1951: 176; in Zacryptocerus: Brandão, 1991: 388; in Cephalotes: Baroni Urbani, 1998: 316; De Andrade & Baroni Urbani, 1999: 172. Senior synonym of elongatus: Roger, 1862c: 297; of obtusus: Forel, 1911e: 262; of caustica: Emery, 1924d: 307; of brevispinosa and material of the unavailable name rufescens referred here: Kempf, 1951: 176.
  • caustica. Formica caustica Kollar, in Pohl & Kollar, 1832: 17, fig. 12 (w.) BRAZIL. Combination in Cryptocerus: Guérin-Méneville, 1844a: 426. Junior synonym of minutus: Emery, 1890b: 74; Forel, 1895b: 134; of pusillus: Emery, 1924d: 307; Kempf, 1951: 176.
  • obtusus. Cryptocerus obtusus Smith, F. 1858b: 191 (w.) BRAZIL. Junior synonym of pusillus: Forel, 1911e: 262.
  • brevispinosa. Cryptocerus pusillus var. brevispinosa Santschi, 1921h: 127, fig. 2 (w.) ARGENTINA. Junior synonym of pusillus: Kempf, 1951: 176.

Type Material

de Andrade and Baroni Urbani (1999):

Worker. Type locality: South America. Type material: Syntype workers presumably in the Museum fur Naturkunde der Humboldt-Universitat Berlin (Roger, 1862: 297), and in the Museo regionale di Scienze Naturali, Torino (Casolari & Casolari Moreno, 1980: 84) (not available for the present study).

Cryptocerus elongates Gyne. Type locality: South America. Type material: a gyne presumably in the Museum fur Naturkunde der Humboldt-Universitat Berlin (Roger, 1862: 297) (not available for the present study).

Formica caustica Worker. Type locality: Brazil. Type material not available for the present study. Synonymy by De Dalla Torre, 1893: 143. Note: synonym of minutus in Emery (1890) and Forel (1895).

Cryptocerus obtusus Soldier. Type locality: Santarem (Brazil). Type material: a syntype worker labelled "Santarem, 54 63, 1 74, C. obtusus (type) Sm.", other label (probably more recent): "pusillus, Rio", examined; a syntype worker labelled "Amazonas, H. W. Bates" in the Zoologische Staatssammlung, Munich (Forel, 1911b: 262), examined.

Cryptocerus pusillus var. brevispinosa Worker. Type localities: S. Ignacio, Villa Lutecia, Cerro Cora in the govern. of Misiones, Cordoba (Argentina), Paraguay, Alto da Boa Vista (Rio de Janeiro, Brazil). Type material: 3 syntype workers from Cordoba, Misiones and Paraguay in Naturhistorisches Museum, Basel (examined).

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



Kempf (1951) - Length 4.4 mm. Median head length 1.14 mm; Weber's length of thorax 1.29 mm. Black; the following ferruginous: apex of mandibles, anterior portion of frontal carinae, apex of last funicular segment, apex of femora and basitarsi, distal half of the following tarsal segments, anterolateral border of first gastral tergite, apex of lateral projections of peduncular segments.

Head subopaque, about as long as broad; interocular distance subequal to maximum length of head (57:58). Sides of head subparallel, posterior margin between the internal corners of the short, obliquely truncate, infuscated occipital lamellae evenly curved and emarginate. Apical border of occipital lamellae straight. Cheeks strongly marginate beneath, densely covered with flat, silvery hairs, which lie in grooves on the posterior portion of the vertex. Eyes small, their maximum diameter less than 1 /3 of the median head length.

Thorax opaque. Anterior border arcuate, shoulders angulate. Pronotum somewhat expanded laterally behind into a narrow, denticulate crest, with two short teeth on each side, the posterior tooth distinctly shorter than the anterior; posterior corner of pronotum rectangular and projecting. Promesonotal suture distinct. Mesonotum on each side with a very small, subrectangular tooth. Mesoepinotal suture vestigial, obsolete mesad. Basal face of epinotum in the same plane as mesonotum, transverse, very short, with a short lateral tooth, longer than the second pronotal tooth, and a very long, subcylindrical posterior spine arising from the posterior corner, diverging about 45° degrees from the longitudinal axis. Dorsum of thorax moderately both longitudinally and transversely convex. Declivous face not excavate mesad, nor crested laterad. The entire thorax finely reticulate-punctate, with rather dense, sharply impressed, more or less elongate foveolae, each containing an appressed silvery, elongate glistening scale. Declivous face without nacrosculpture and without scales. Laterotergite of pronotum and mesopleura more or less regularly rugose and sparsely scaled.

Petiole opaque, transverse, with a very small somewhat recurved lateral denticule. Postpetiole opaque, as broad as petiole, with a broad, apically truncate, posteriorly subdentate-projection on each side, curving slightly forward. Both peduncular segments finely reticulatepunctate with sparse, glistening appressed hairs.

Gaster opaque, elliptical, emarginate anteriorly mesad. First gastral tergite with a very narrow, not distinctly set off nor crested antero-Iateral border. Tergites and sternites finely and rather sharply reticulate-punctate. Scales of gaster sparser, more slender than on head and thorax, not lying in distinctly excavated foveolae. Erect pile confined to mandibles and to the 2-4th tergites and the sternites of the gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.84-5.52; HL 0.98-1.32; HW 1.24-1.76; EL 0.30-0.36; PW 0.92-1.38; PeW 0.37-0.57; PpW 0.44-0.66; HBaL 0.46-0.58; HBaW 0.10-0.15; CI 121.6-133.3; PI 127.5-134.8; PPeI 200.0-259.4; PPpI 204.2-209.1; HBaI 20.4-25.9.


Kempf (1951) - Length 7.5 mm. Median head length 1 .95 mm; Weber's length of thorax 2.12 mm. Black; the following ferruginous: the four apical tarsal segments of the fore legs and the two apical segments of the mid and hind legs. Tips of last funicular segments orange-brown.

Head subopaque, somewhat shorter than wide. Frontal carinae strongly converging anteriorly, prolonged behind above the eyes in the form of a raised carinule, fading out before reaching the occipital corner. Upper surface of head distinctly convex, vertex with a pair of faint, not tuberculate median swellings on the posterior border. Occiput truncate, immarginate above; occipital angles form a scarcely projecting blunt, strong tubercle. Cheeks not marginate beneath in front; a vestigial margination beneath the eye is present. Eyes very little convex. Upper and lower surface of head finely and shallowly reticulate, the upper surface with rather dense, small foveolae in which a minute, not shiny, scale is visible. foveolae slightly more crowded, longer on occiput. Still larger and more deeply impressed on occiput and lower surface of head, containing a short decumbent, somewhat glistening seta.

Thorax subopaque. Anterior border arcuate, shoulder subangulate. Sides of pronotum diverging until reaching the lateral end of the transverse crest, having before the crest a stout, apically rounded tooth, projecting obliquely forwars and laterad. Transverse pronotal crest broadly interrupted mesad, and obsolescent towards the sides. Lateral border of pronotum angulate at the crest, and converging posteriorly behind the crest. Promesonotum, in profile, greatly convex. Promesonotal suture more or less distinct laterad, vestigial mesad. Sides of mesonotum subparallel with a small posterior, acute, lateral tooth. Mesoepinotal suture impressed and distinct. Basal face of epinotum transversely convex, with a small, blunt tooth antero- Iaterad, and a much longer and stronger, blunt spine on the posterior corner, slightly more divergent than in worker. Entire thorax finely and sharply reticulate-punctate. Dorsum of thorax and laterotergite of pronotum covered with rather dense, elongate deeply impressed setiferous foveolae. declivous face and posterior portion of the sides of the thorax with more or less vestigial, irregular, fine rugosities.

Petiole opaque, transverse, its sides subparallel, with a minute denticule. Postpetiole opaque, slightly broader than petiole, with a tapering, plate-like lateral projection, the apex of which is rounded in front, sub dentate behind, curving slightly forward. Both segments finely reticulate-punctate, covered with vestigial foveolae and rugosities.

Gaster subopaque, elliptical, finely reticulate-punctate, not foveolate, deeply emarginate in front mesad. First gastral tergite anterolaterally sharply marginate, not forming a lamellate border.

All foveolae bear a decumbent seta, which is slightly flattened and glistening on thorax and peduncle. Erect setae on the terminal tergitcs and on the sternites of the gaster. First gastral tergite covered with minute, decumbent setae laterad, almost scaleless discad.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.44-7.76; HL 1.60-1.90; HW 2.24-2.36; EL 0.45-0.48; PW 1.80-2.04; PeW 0.62-0.78; PpW 0.71-0.89; HBaL 0.64-0.66; HBaW 0.18-0.19; CI 124.2-130.0; PI 115.5-115.7; PPeI 261.5-290.3; PPpI 229.2-253.5; HBaI 28.1-28.8.


Kempf (1951) - Length 10.5 mm. Median head length 2.13 mm; interocular width 2.27 mm; Weber's length of thorax 3 . 1 7 mm. Black; tip of last funicular segment fuscous ferruginous. In general resembling minutus, from which it differs by the appreciably larger size, the black coloration of the appendages, the lack of the yellow maculae on the first gastral tergite. The head is shorter than wide, the upper face subopaque, greatly convex, with a distinct carinule laterad, below the eyes. Occiput subtruncate, immargin ate above. Pronotum with a distinct transverse crest. Sides of petiole without a spine, or tooth; subparallel. Sides of thorax more extensively foveolate.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 9.77-11.16; HL 1.76-1.96; HW 2.10-2.36; EL 0.45-049; PW 1.96-2.26; PeW 0.87-0.91; PpW 0.99-1.12; HBaL 0.72-0.75; HBaW 0.19; CI 119.3-127.3; PI 103.7-107.1; PPeI 222.7-248.3; PPpI 198.0-201.8; HBaI 25.3-26.4.


  • n = 22, 2n = 44, karyotype = 28M+16A (Brazil) (Cristiano et al., 2017).


  • Baroni Urbani, C. 1998b. The number of castes in ants, where major is smaller than minor and queens wear the shield of the soldiers. Insectes Soc. 45: 315-333 (page 316, Combination in Cephalotes)
  • Brandão, C. R. F. 1991. Adendos ao catálogo abreviado das formigas da região Neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412 (page 388, Combination in Zacryptocerus)
  • 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 172, Combination in Cephalotes)
  • Emery, C. 1890b. Voyage de M. E. Simon au Venezuela (Décembre 1887 - Avril 1888). Formicides. Ann. Soc. Entomol. Fr. (6)(10): 55-76 (page 75, soldier, queen described)
  • Emery, C. 1896h. Formiciden, gesammelt in Paraguay von Dr. J. Bohls. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 9: 625-638 (page 636, male described)
  • Emery, C. 1915g. Noms de sous-genres et de genres proposés pour la sous-famille des Myrmicinae. Modifications à la classification de ce groupe (Hymenoptera Formicidae). Bull. Soc. Entomol. Fr. 1915: 189-192 (page 192, Combination in Cryptocerus (Paracryptocerus))
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 307, Senior synonym of caustica)
  • Forel, A. 1911g. Die Ameisen des K. Zoologischen Museums in München. Sitzungsber. Math.-Phys. Kl. K. Bayer. Akad. Wiss. Münch. 11: 249-303 (page 262, Senior synonym of obtusus)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 176, Senior synonym of brevispinosa, and material of the unavailable name rufescens referred here.)
  • Klug, F. 1824. Entomologische Monographien. Berlin: Reimer, 242 pp. (page 202, worker described)
  • 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
  • Roger, J. 1862c. Synonymische Bemerkungen. 1. Ueber Formiciden. Berl. Entomol. Z. 6: 283-297 (page 297, Senior synonym of elongatus)
  • Wheeler, G. C.; Wheeler, J. 1954b. The ant larvae of the myrmicine tribes Cataulacini and Cephalotini. J. Wash. Acad. Sci. 44: 149-157 (page 156, larva described)