Cephalotes pallidicephalus

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Cephalotes pallidicephalus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. pallidicephalus
Binomial name
Cephalotes pallidicephalus
(Smith, F., 1876)

Cephalotes pallidicephalus P casent0900234.jpg

Cephalotes pallidicephalus D casent0900234.jpg

Specimen Label


Nothing is known about the biology of Cephalotes pallidicephalus.


A member of the angustus clade differing from all the other species of the genus by the first gastral sternite of the worker covered with thick, longitudinal striation. The thickness of the gastral striation is subject to some individual variation but its size in pallidicephalus regularly exceeds the condition of any other known Cephalotes species. The shape of the gastral striation may also undergo limited variation in being convergent posteriorly and less regular in some specimens. The soldier and the gyne of pallidicephalus have a similar sculpture, but thinner and restricted to the sides of the tergite. Some soldiers of Cephalotes notatus and the gynes of Cephalotes notatus and Cephalotes goeldii converge with pallidicephalus for this character. Cephalotes pallidicephalus differs from the two species of its sister clade, Cephalotes notatus and Cephalotes goeldii, in the soldier and gyne by the border of the disc less raised, and by the vertexal angles and the pronotal sides with a narrower lamellaceous border. (de Andrade and Baroni Urbani 1999)

Keys including this Species


Distribution based on Regional Taxon Lists

Neotropical Region: Brazil, Mexico (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


The biology of many Cephalotes species is not known. Ants in this genus are common in the New World tropics and subtropics and are especially abundant and diverse in the canopies of Neotropical forests. The majority of species are arboreal. Species that live in other strata inhabit smaller trees, bushes or grass stems. These noon-arboreal species, due to their accessibility, are among the better studied members of the genus. There are also species that can be found in downed wood but it is likely the wood housed the colony before it fell to the ground. Soil nests are not known for any species nor do most species appear to extensively excavate plant tissue. They nest instead in preformed cavities. Overall, ants in the genus utilize a wide range of plants. Some species are predictable in their plant use but none appear to have evolved specialized mutualisms with particular plant species.

Worker castes typically include two forms, a worker and soldier, but there are a few species that are monomorphic. The larger soldier caste typically has an enlarged head disk. In some species the head of the soldier is very different from the worker while in others these differences are less pronounced. Queens and soldiers tend to share similar head morphology. Soldiers use their heads to plug the nest entrance. This can be very effective in excluding potential intruders. Other morphological differences between the worker castes are present but these differences have not been studied as well as head moprhology.

The behavioral repertoire of Cephalotes varians has been examined in great detail (ethograms from Wilson 1976, Cole 1980 and Cole 1983). Soldiers do little else besides defend the nest. This specialized soldier behavior is presumed to be the norm for most species. An especially interesting behavior occurs when workers are dislodged from trees: they "fly" towards the tree, often grabbing the trunk well above the ground (video).

Mature nest size varies, by species, from less than a hundred to many thousands of workers. Available evidence suggests most species are monogynous. Queens may mate with multiple males.

The proventriculus of the Cephalotes is peculiar relative to other ants. The morphology of the structure suggests it serves as a powerful pump and filter. This does not appear to lead these ants to have a highly specialized diet as most species appear to be general scavengers. Foragers have been observed feeding on carrion, bird feces, extrafloral nectaries and even tending membracids. Pollen feeding has been observed in some species, and this is somewhat specialized for ants, but it is not evident that any species restricts its diet to this resource in any significant way. Evidence for pollen feeding in Cephalotes has accumulated, in part, via finding digested pollen grains seen in infrabucal pellets. It has been suggested that the morphology of the proventriculus is a specialization for processing pollen.

More research examining all aspects of the biology of Cephalotes is needed. Our present understanding of these ants is largely based on species that live in locations other than the forest canopy, which is where Cephalotes are most common and diverse.



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

  • pallidicephalus. Cryptocerus pallidicephalus Smith, F. 1876d: 606, pl. 11, fig. 5 (q.) MEXICO. Combination in Cephalotes: De Andrade & Baroni Urbani, 1999: 708. Junior synonym of scutulatus: Kempf, 1963c: 438. Revived from synonymy and senior synonym of striativentris: De Andrade & Baroni Urbani, 1999: 708.
  • striativentris. Cryptocerus striativentris Emery, 1894c: 203, pl. 3, figs. 10-12 (s.w.) BRAZIL. [Also described as new by Emery, 1894g: 384 (footnote).] Kempf, 1958a: 83 (q.). Combination in Paracryptocerus (Harnedia): Kempf, 1958a: 80; in Zacryptocerus: Brandão, 1991: 388. Junior synonym of pallidicephalus: De Andrade & Baroni Urbani, 1999: 708.

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

de Andrade and Baroni Urbani (1999) - Cephalotes pallidicephalus has been described from Mexico without further locality. We regard the Mexican origin of this species (confirmed by the label of the holotype) as highly improbable. In fact, all the members of the angustus clade are confined to the central and southern part of South America extending up to Colombia in their northernmost range. All specimens we refer to pallidicephalus originate from south and central Brazil. Kempf (1964), after examination of the holotype gyne of pallidicephalus, concluded its synonymy with scutulatus (Smith 1867). We cannot agree with this proposal since scutulatus gynes (probably unknown to Kempf) associated with workers in MCZC and MCSN differ greatly from the pallidicephalus holotype (and other specimens as well) at least in the following characters: angulate hind femora, ocelli distant from the border of the cephalic disc, humeral angles membranaceous, and broader petiolar and postpetiolar appendages. Striativentris is a straight synonym of pallidicephalus, though it would be difficult to blame Emery for this error: the usual difficulties in recognising Smith's species from his descriptions are even worsened in this case by the geographical error.



Kempf (1958) of synonymized striativentris - Total length 3.1-4.8 mm; maximum length of head 0.89-1.35 mm; maximum length of thorax 0.89-1.35 mm. Black; the following ferruginous: tip of mandibles, funicular segments II - IV, anterolateral corners of gaster, just inside of the pale, trans lucid crest; light brown: edge of frontal carinae, tip of scape, funicular segment I, tip of femora, tibiae, tarsites; pale-testaceous: remaining portion of frontal carinae.

Head subopaque, subquadrate; slightly more elongate than in angustus, the maximum length always somewhat exceeding the interocular width. Clypeal suture vestigial. Lateral border of head somewhat diverging caudad, distinctly emarginate in front of, convex and slightly upturned above, eyes. Occipital corners obliquely truncate, the truncated edge either notched or straight, the inner angle never forming a prominent triangular tooth. Occipital border gently concave. Dorsal face of head gently convex, finely reticulate-punctate, more sparsely covered with squamiferous foveolae, which increase in number toward the occipital border. Lower face of head finely reticulate-punctate, sparsely and very superficially foveolate, the foveolae very elongate.

Thorax subopaque. Anterior border of pronotllm very gcntly convex, almost straight. Shoulders rectangular. Lateral border of pronotum quite variable, even in specimens of the followed by a sharply marginate, often irregularly crenate or denticulate crest. Especially in very small specimens, this crest presents occasionally two distinct, though apically rounded or truncate, rather foliaceous teeth, so that in this case the sides of the pronotum are really tridentate. Posterior corner of pronotum subrectangular. Promesonotal suture vestigial or absent. Mesonotum with a laterally projecting tooth on each side, which is subacute in small specimens, blunt, broadly and obliquely truncate in larger specimens. Occasionally there is a minute and sharp tooth behind the preceding tooth. Mesoepinotal suture usually absent, seldom vestigial. Lateral border of basal face of epinotum tridentate, all three teeth usually acute, the second by far the largest. Behind the third tooth, on the marginate border of the declivous face one or two very small denticles may be present. Declivous face continuous with basal face, not clearly separable from each other, forming in profile a gentle and even curvature. Dorsum of thorax finely reticulate-punctate and foveolate, in the same fashion as dorsum of head, but the foveolae are more numerous and crowded, so that on the mesoepinotum the integument becomes reticulate-rugose. Laterotergite of pronotum with longitudinal striae. Thoracic pleura principally longitudinally rugose with very densely interspersed squamiferous foveolae. Fore coxae coarsely and obliquely striate on the outer face.

Peduncular segments subopaque, the dorsolateral sculpture as on head and thorax. Petiole subequal in width to the postpetiole, its anterior face obliquely truncate, finely reticulate-punctate, usually not sharply marginate nor denticulate at its point of contact with the dorsal face, but sometimes as in angustus. Lateral spines of both segments depressed, platelike, foliaceous, semitransparent, more recurved than in angustus. Dorsal face of postpetiole more gently convex than in angustus.

Gaster subopaque, elliptical, strongly emarginate antero-mesially, the anterolateral border with a transparent thin crest, which extends backwards beyond the conspicuous stigma of the first gastral tergite, which is very sharply reticulate-punctate, and covered with superficially impressed elongated squamiferous foveolae. First sternite, as a rule, very coarsely and regularly longitudinally striate.

Pilosity essentially the same as in Cephalotes angustus.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.80-5.16; HL 0.98-1.30; HW 1.04-1.44; EL 0.28-0.34; PW 0.92-1.26; PeW 0.50-0.66; PpW 0.54-0.71; HBaL 0.35-0.43; HBaW 0.07-0.11; CI 106.0-110. 8; PI 112.8-117.4; PPeI 173.3-190.9; PPpI 164.9-177.5; HBaI 20.5-25.6.


Kempf (1958) of synonymized striativentris - Total length 4.7-6.3 mm; maximum length of head 1.46-2.00 mm; maximum length of thorax 1.32-1.64 mm: Black; the following yellowish-brown: lateral portions of transverse carina, edge of lateral lobes of mesonotum, teeth of basal face of epinotum, apical half of extensor face of femora; ferruginous: mandibles, edges of yellowish-brown markings on thorax and gaster, tarsites; testaceous: tibiae, the four spots on the first gastral tergite, which in full grown workers are fused in a horseshoe-like fashion, as shown by the figure. All sharply marginate edges inside the light areas are conspicuously darker.

Head subopaque, surmounted by an oval, somewhat excavated, disc. Borders of disc scarcely crenulate, conspicuously raised and upturned laterally, concealing the floor of the disc, when seen in profile. Occipital border of disc not raised, round, not truncate. Clypeal suture, at most vestigial, usually absent. Floor of disc, except for the raised lateral borders, rather flat, with a very gentle anteromedian convexity, flanked by very shallow concavities above the antennal scrobe, where the integument is somewhat transparent. Occipital lobes sharply marginate, the lateral border gently convex, the posterior angle obtuse. Floor of disc and sides of head finely reticulate-punctate, coarsely reticulate-rugose and foveolate, the squamiferous foveolae much broader than the raised intervals. Lower face of head rather shiny, almost smooth postero-laterally, with very superficial microsculpture and sparse foveolae.

Thorax subopaque dorsally, opaque laterally. Pronotum nearly as broad as head, its anterior corner with a triangular tooth, its sides slightly excised behind the tooth, then convex at the level of the transverse carina, then strongly converging mesad toward the mesonotum. Transverse pronotal carina, as seen from the front, very deeply excised in the middle, concave laterally, when seen from above; very prominent and sharply edged, excepting the mesial notch. Promesonotal suture vestigial. Mesonotum with a broad, obliquely truncate and marginate projecting lobe on each side. Mesoepinotal suture deeply impressed laterally, usually well marked but superficial mesially. Basal face of epinotum very short and broad, its lateral border with a triangular tooth and its posterior corner with a very stout, apically rounded tooth which points upward and laterad. Dorsum of thorax finely reticulate-punctate, sparsely foveolate on pronotum, more densely foveolate on mesoepinotum, the foveolae much smaller than those on cephalic disc. Laterotergite of pronotum sparsely foveolate and somewhat rugose. Pleura mainly foveolate. Fore coxae slightly rugose on the outer face.

Peduncular segments as in worker, but the petiole is distinctly narrower, bearing on each side a short tooth, which points obliquely caudad. Postpetiole, as seen in profile, conspicuously convex above, its lateral spines solid, not platelike.

Gaster subopaque, the thin anterolateral crest and the lateral margination of the first gastral tergite as in angustus, the sides of gaster, however, less convex. First gastral sternites longitudinally striato-rugose, striae not as coarse as in worker.

Pilosity as in angustus, except for the hair arising from the pits of the cephalic disc, which is minute, scarcely visible, not glittering, nor strictly decumbent.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 5.32-6.50; HL 1.52-1.80; HW 1.52-1.76; EL 0.36-0.41; PW 1.44-1.68; PeW 0.56-0.65; PpW 0.65-0.72; HBaL 0.39-0.42; HBaW 0.10-0.11; CI 97.8-100.0; PI 104.8-106.4; PPeI 240.0-278.6; PPpI 221.5-233.3; HBaI 25.6-26.2.


de Andrade and Baroni Urbani (1999) - Head disc present. Head dorsum slightly concave on its anterior half and flat posteriorly. Frontal carinae expanded anteriorly, converging posteriorly and connected with the convex posterior border of the disc. Vertexal angles convex and with strongly marginate border. Eyes weakly convex and visible in full face view. Ocelli far from the posterior border of the head disc. Dorsal border of the antennal scrobes with a thick carina ending in a small, obtuse denticle just before the eyes. Anterior clypeal border concave. Mandibles with a lateral carina and partially hidden by the frontal cannae.

Mesosoma. Humeral angles obtuse and marginate. Pronotal sides straight. Pronotal carina marked, shortly interrupted in the middle. Promesonotal suture impressed. Lower mesopleurae with a denticle. Mesonotum and scutellum almost flat. Propodeum differentiated in basal and declivous face; basal face short, little convex dorsally and with a superficial furrow in the middle; its sides with two pairs of short, triangular teeth, the anterior pair on the beginning of the basal face, separate from the second pair by the converging sides; declivous face concave in the middle.

Petiole with distinctly differentiated anterior and posterior faces; anterior face oblique; posterior face flat; sides of the petiole with a pair of small denticles pointed backwards. Postpetiole broadly convex; postpetiolar spines arising from the anterior border of the petiole and recurved.

Gaster with an anterolateral lamella, not reaching the stigma.

Legs. Fore coxae with a round denticle anteriorly. Mid and hind femora without angles or denticles. Mid and hind basitarsi with subparallel sides and slightly narrow at base.

Sculpture. Head dorsum with deep, anastomosing foveae. Sides of the head with the same type of sculpture as the head dorsum but smaller and shallower. Ventral part of the head superficially and minutely punctate, slightly shining and with rare, superficial foveae. Mesosoma and pedicel superficially reticulate-punctate and covered by smaller foveae than those on the head dorsum, broader than their inters paces, denser on the mesopleurae, on the scutellum, on the basal face of the propodeum, on the sides and on the posterior face of the petiole and on the postpetiole. Propleurae and metapleurae reticulate-punctate and rarely foveolate. Dedivous face of the propodeum, anterior face of the petiole, legs and gaster reticulate-punctate. Very superficial, sparse, small, piligerous foveae on the anterior third of the gaster; similar foveae on the outer face of the tibiae. Sides of the first gastral sternite with longitudinal rugae.

Pilosity. Most of the foveae with a slightly canaliculate hair, suberect on the head dorsum and appressed on the other foveae. Borders of the disc and few foveae on the mesosoma and on the pedicel with an erect, subclavate hair; similar subclavate hairs on the gaster and on the legs, denser on the posterior borders of the tergites and sternites. Gaster and legs with a additional type of hair: (1) short, appressed and thin.

Colour. Ventral part of the head, clypeus, mesosoma, pedicel, coxae and femora black, gaster lighter. Center of the head disc, humeral angles, tibiofemoral articulations, tarsomeres light brown. Head disc up to the sides and tibiae dark yellow. Gaster with two pairs of broad yellow spots, the anterior pair surpassing the stigma posteriorly and interconnected in the middle, the second pair beginning from the posterior half of the first gastral tergite and almost reaching its posterior border.

Measurements (in mm) and indices: TL 7.40-8.44; HL 1.64-1.80; HW 1.56-1.68; EL 0.38-0.42; PW 1.52-1.60; PeW 0.56-0.64; PpW 0.74-0.80; HBaL 0.48-0.53; HBaW 0.13-0.14; CI 93.3-95.3; PI 102.5-105.0; PPeI 250.0-271.4; PPpI 200.0-213.3; HBaI 25.5-27.1.


de Andrade and Baroni Urbani (1999) - Differing from the male of angustus in the following details:

Vertexal angles with a pair of small median denticles. Frontal carinae more marked. Mandibles shorter. Anterior pronotal border straight. Humeral angles well visible, obtuse or weakly pointed. Pronotal sides marginate and parallel. Anterior face of the petiole more concave medially.

Sculpture. Body less shining, more opaque and covered with deeper reticulation. Head, mesosoma and sides of the pedicel with deeper, irregular foveae separate by irregular, short rugosities on the head, on the pronotum and on the basal face of the propodeum. Pleurae with denser longitudinal rugosities, well impressed on the propleurae, irregular on the metapleurae.

Colour. Head, mesosoma and pedicel black. Coxae and gaster brown, two proximal thirds of the femora lighter. Remaining parts of the legs yellowish.

Measurements (in mm) and indices: TL 5.05-5.44; HL 0.77-0.80; HW 0.94-1.00; EL 0.39-0.40; PW 1.04-1.12; PeW 0.40-0.42; PpW 0.40-0.43; HBaL 0.55-0.58; HBaW 0.06-0.07; CI 122.1-125.0; PI 89.3-90.4; PPeI 260.0-266.7, PPpI 260.0-260.5; HBaI 10.9-12.1.

Type Material

Holotype Specimen Labels

de Andrade and Baroni Urbani (1999) –

Gyne. Type locality: Mexico (probably erroneous). Type material: holotype gyne labelled “Cryptocerus pallidicephalus, (type) Smith, Mexico” in The Natural History Museum (Kempf, 1964 a: 438), examined.

Cryptocerus striativentris. Worker, soldier. Type locality: Santa Catarina. Type material: 1 worker labelled “Santa Catarina, Mayr”, Museo Civico di Storia Naturale, Genoa; 2 workers, 1 soldier labelled “Itajahy, Bresil, F. Muller”, Museo Civico di Storia Naturale, Genoa; also probably belonging to the type series: 9 workers, 4 soldiers (some pins with cotype label) in Musee d'Histoire Naturelle Genève; 1 worker, in Naturhistorisches Museum, Basel; 1 soldier, in Museum of Comparative Zoology; all examined.


  • 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 708, Combination in Cephalotes, Revived from synonymy and senior synonym of striativentris)
  • Kempf, W. W. 1963c. Nota sinonímica acêrca de formigas da tribo Cephalotini (Hymenoptera, Formicidae). Rev. Bras. Biol. 23: 435-438 (page 438, Junior synonym of scutulatus)
  • Smith, F. 1876d. Descriptions of new species of Cryptoceridae, belonging to the genera Cryptocerus, Meranoplus, and Cataulacus. Trans. Entomol. Soc. Lond. 1876: 603-612 (page 606, pl. 11, fig. 5 queen described)

References based on Global Ant Biodiversity Informatics

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  • Forel A. 1912. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mémoires de la Société Entomologique de Belgique. 19: 179-209.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Ulyssea M.A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603-–611.
  • 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).
  • de Andrade, M.L. & C. Baroni Urbani. 1999. Diversity and Adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Serie B 271. 893 pages, Stuttgart