Cephalotes guayaki

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Cephalotes guayaki
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. guayaki
Binomial name
Cephalotes guayaki
De Andrade, 1999

Cephalotes guayaki casent0173677 profile 1.jpg

Cephalotes guayaki casent0173677 dorsal 1.jpg

Specimen labels

One collection was made in a forest. Little else is known about the biology of Cephalotes guayaki.


A member of the fiebrigi clade differing from its sister species, Cephalotes fiebrigi, in the worker, soldier and gyne by the body with sparser erect, truncate hairs. (de Andrade and Baroni Urbani 1999)

Keys including this Species


Brazil, Mato Grosso do Sul; Paraguay.

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil, Paraguay (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 New General Catalogue, a catalogue of the world's ants.

  • guayaki. Cephalotes guayaki De Andrade, in De Andrade & Baroni Urbani, 1999: 664, figs. 311, 312 (s.w.q.) PARAGUAY.

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



Differing from quadratus in the following details:

Head slightly longer than broad and less convex dorsally. Vertexal angles subtruncate. Frontal carinae concave in front of the eyes and superficially sinuous over the eyes.

Mesosoma less convex in profile. Pronotal lamellae less converging posteriorly. First pair of pronotal spines less protruding. Basal face of the propodeum with two pairs of teeth subequal in size.

Lateral expansions of the postpetiole developed anteriorly and oriented more ventrally.

Sculpture. Head, mesosoma, pedicel, outer face of the femora and tibiae with more impressed foveae. Propleurae with rare, thin, longitudinal rugosities.

Pilosity. Hairs of type (3) of quadratus (where they are restricted to the gaster) also present on the dorsum of the head, of the mesosoma, of the pedicel, and denser on the dorsum of the first gastral tergite.

Colour. Black. Legs brown. Frontal carinae light brown.

Measurements (in mm) and indices: TL 3.74-3.88; HL 0.88-0.90; HW 0.85-0.88; EL 0.25-0.26; PW 0.76; PeW 0.47-0.48; PpW 0.50-0.52; HBaL 0.32-0.33; HBaW 0.07-0.08; CI 96.6-97.8; PI 111.8-115.8; PPeI 158.3-161.7; PPpI 146.1-152.0; HBaI 21.8-24.2.


Head longer than broad, with complete disc. Floor of the disc convex only on the posterior third and gently concave anteriorly. Frontal carinae and borders of the disc crenulate and raised anteriorly. Sides of the disc strongly narrowing backwards, not hiding the eyes and connected by a convex border; posterolateral borders of the disc less marked. Vertexal angles slightly convex and with a median triangular tooth. Mandibles with a strong carina. Dorsal border of the antennal scrobes with a longitudinal, denticulate carina just in front of the eyes.

Mesosoma. Anterior pronotal border gently convex. Humeral angles with a pair of small denticles. Pronotal sides straight. Pronotal carina superficially marked. Promesonotal suture superficially impressed. Sides of the mesonotum with a broad, subround tooth. Propodeal suture impressed. Propodeum with well differentiate basal and declivous faces. Sides of the basal face with one or two small, round denticles followed by a stout tooth gently curved upwards. Declivous face converging posteriorly.

Petiole and postpetiole as in the worker but with the lateral expansions less developed.

Mid and hind femora without angles or denticles. Hind basitarsi with subparallel sides.

Gaster with narrow anterolateral lobes protruding anteriorly.

Sculpture. Head, mesosoma, pedicel, distal part of the outer face of the femora and tibiae minutely reticulate-punctate, superficially shining and foveolate, the foveae contiguous and deeper on the head dorsum and on the pronotum, slightly sparser and shallower on the ventral part of the head and on the mesonotum, oval and very superficial on the basal face of the propodeum, on the pedicel, on the outer face of the femora and on the tibiae, rare on the pleurae. Pro- and lower meso- and metapleurae with additional thin, longitudinal rugosities. Gaster and remaining parts of the legs reticulate, the reticulation more impressed on the first gastral tergite.

Pilosity. Body with three types of hairs: (1) canaliculate, originating from the foveae, subdecumbent on the head dorsum, appressed on the rest of the body, slightly shorter and thinner on the body parts without foveae; (2) subclavate and rare on the posterolateral border of the frontal carinae; (3) subtruncate and sparse on the mesosoma, on the pedicel, on the gaster and on the legs.

Colour. Black. Anterior half of the frontal carinae, pronotal sides and legs dark orange-ferruginous.

First gastral tergite with two pairs of yellow spots, the first pair close to the lobes and the second one close to the posterior border.

Measurements (in mm) and indices: TL 4.76-5.56; HL 1.24; HW 1.12-1.16; EL 0.30-0.31; PW 1.04; PeW 0.55-0.59; PpW 0.57-0.64; HBaL 0.34; HBaW 0.10; CI 90.3-93.5; PI 107.7-111.5; PPeI 176.3-189.1; PPpI 162.5-182.4; HBaI 29.4.


Differing from the soldier in the following details:

Head slightly longer than broad. Vertexal angles simply angulate medially. Humeral angles only angulate. Pronotal sides straight. Mesonotum and scutellum flat. Sides of the basal face of the propodeum with a small pair of short, round denticles and with a pair of small, stout teeth, slightly diverging. Petiolar sides with a pair of small, pointed denticles. Postpetiolar spines smaller. Gaster longer and with more protruding lobes.

Sculpture. Foveae sparser on the mesonotum and denser on the upper mesopleurae. Pleurae with rugosities present only on the lower propleurae. The rest as in the soldier.

Pilosity. Mesosoma, pedicel, gaster and legs with hairs of type (3) denser.

Colour. As in the soldier except for the frontal carinae dark orange-ferruginous.

Measurements (in mm) and indices: TL 6.12; HL 1.20; HW 1.08; EL 0.31; PW 1.02; PeW 0.52; PpW 0.57; HBaW 0.10; CI 90.0; PI 105.8; PPeI 196.1; PPpI 170.0.

Type Material

Holotype worker from San Salvador, Paraguay, Bohls leg. in Museo Civico di Storia Naturale, Genoa; paratypes 13 workers, 6 soldiers, 1 gyne, same data as the holotype in MCSN, 1 worker, same data as the holotype in Musee d'Histoire Naturelle Genève.


The Guayaki are one of the Indian tribes of Paraguay.


  • 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 664, figs. 311, 312 soldier, worker, queen described)