Cephalotes oculatus

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Cephalotes oculatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. oculatus
Binomial name
Cephalotes oculatus
(Spinola, 1851)

Cephalotes oculatus P casent0900232.jpg

Cephalotes oculatus D casent0900232.jpg

Specimen Label

Synonyms

Nothing is known about the biology of Cephalotes oculatus.

Identification

A member of the atratus clade characterised by the wide interocular distance and by the propodeum and mesonotum clearly marginate, as opposed to weakly or indistinctly marginate in the closest species. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Peru.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

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.

Castes

Nomenclature

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

  • oculatus. Cryptocerus oculatus Spinola, 1851b: 49 (w.) BRAZIL. [Also described as new by Spinola, 1853: 65.] De Andrade & Baroni Urbani, 1999: 141 (q.m.). Combination in Cephalotes: Emery, 1914c: 39; in Eucryptocerus: Kempf, 1951: 130; in Cephalotes: De Andrade & Baroni Urbani, 1999: 141. Senior synonym of aethiops: Smith, F. 1858b: 188.
  • aethiops. Cryptocerus aethiops Smith, F. 1853: 216, pl. 20, fig. 9 (w.) BRAZIL. Junior synonym of oculatus: Smith, F. 1858b: 188.

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

Description

Worker

Kempf (1951) - Length 7.7-8.9 mm. Distance between the most anterior projection of the frontal carinae and the apex of the internal occipital spine somewhat shorter than the interocular width. The pair of teeth on the vertex well developed. The internal occipital spines sometimes obliquely truncate or bidenticulate at apex. Upper surface of head foveolate only on posterior half, the foveolae, rather deeply impressed behind the vertical teeth. Lower surface of head with large and deeply impressed areoles. Thorax more sparsely and superficially foveolate. Scapular spines strong. Medial pronotal spines well developed. Mesonotum submarginate laterad. Basal face of epinotum rather flat, its sides marginate in front. Epinotal spines strong, usually as long as the basal face, somewhat divergent and raised upward. Basitarsus of middle and hind legs, prismatic almost as deep as broad. Petiole broader than long: its sides converging caudad. Gaster emarginate in front, the first tergite subfulgid discad, anterolaterally with projecting, large angulate lobes. Erect setae confined to femora, mandibles, lower surface of head and gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 7.76-8.68; HL 1 .88-2.04; HW 2.41-2.64; EL 0.43-0.48; PW 2.41-2.72; PeW 0.61-0.68; PpW 0.66-0.80; HBaL 0.92-1.04; HBaW 0.19-0.20; CI 128.2-135.5; PI 97.0-100.0; PPeI 400.0-406.5; PPpI 334.7-364.7; HBal 19.2-20.6.

Queen

de Andrade and Baroni Urbani (1999) - Head subquadrate, without disc. Frons convex. Frontal carinae converging anteriorly and straight up to the vertexal angles. Frontal carinae superficially crenulate and with a small tooth in the middle. Vertexal angles with two pairs of teeth, the anterior pair behind the eyes and smaller than the posterior one. Vertex marked by a pair of large, triangular teeth. Mandibles only superficially angulate.

Mesosoma. Humeral angles bearing a thick, pointed tooth. Pronotal crest well marked and interrupted in the middle by a superficial impression, slightly higher around the median interruption and superficially crenulate. Mesonotum and scutellum nearly flat in side view. Lower mesopleurae with a stout, small tooth. Basal face of the propodeum much lower than backwards. Sides of the declivous face of the propodeum converging posteriorly.

Petiole with differentiate anterior and posterior faces; anterior face truncate, posterior face sloping posteriorly. Petiole unarmed and with posteriorly converging sides. Postpetiole convex dorsally and laterally; its maximum width in the anterior half.

Gaster with a thin lateral margin not reaching the first gastral stigma.

Legs. Fore coxae round. Mid and hind femora not marked by an angle. Mid and hind basitarsi compressed laterally; their diameter constant through the whole length.

Sculpture. Head minutely reticulate and with superficial and variably clumped foveae, larger on the vertex. Ventral part of the head and propleurae with the same type of sculpture as on the vertex but with larger and deeper foveae. Pronotal dorsum, mesonotum, basal face of the propodeum and upper mesopleurae minutely reticulate and with foveae as broad as on the vertex, more superficial on the mesonotum. First gastral tergite with sparse, oval, superficial foveae and impressed by two sets of very thin, superficial, concentric rugulosities originating respectively at about one third and two thirds of the length of the sclerite. Lower mesopleurae, metapleurae, declivous face of the propodeum, first gastral sternite and legs reticulate; remaining tergites and sternites reticulate and irregularly rugulose. Lower mesopleurae with rare, superficial foveae. Anterior and posterior faces of the tibiae with faint, thin, longitudinal rugosities.

Pilosity. Each fovea bearing a thin, appressed hair; border of the frontal carinae and remaining body surfaces with additional, sparse, long, slightly clavate, erect and suberect hairs, longer and denser on the legs and on the apex of the gaster.

Colour. Black. Antennae and tarsomeres brown. First gastral tergite superficially shining.

Measurements (in mm) and indices: TL 13.94; HL 2.56; HW 3.00; EL 0.60; PW 3.12; PeW 1.00; PpW 1.16; HBaL 1.32; HBaW 0.27; CI 117.2; PI 96.1; PPeI 312.0; PPpI 269.0; HBaI 20.4.

Male

de Andrade and Baroni Urbani (1999) - Head (eyes included) about 1/3 broader than long. Vertexal angles medially with a curved carina continuing frontally up to the internal border of the eyes. Vertexal margin prolonged backwards into a neck. Vertex and compound eyes as in opacus. Frontal carinae high, broad, with irregular border and posteriorly obtuse and continuing backwards as a thin, irregular frontal margin, not reaching the impair ocellus. The rest as in opacus.

Mesosoma. Pronotum and mesonotum similar to opacus but much broader. Basal face of the propodeum gently convex, medially impressed, and sloping backwards less abruptly than in opacus; sides of the basal face gently converging backwards, with a carinate, almost round tooth on the posterior half. Declivous face marked, laterally, by a pair of longitudinal, convergent carinae.

Petiole and postpetiole cylindrical, shorter and more convex dorsally than in opacus; anterior border of the petiolar face truncate, weakly concave in the middle and not carinate dorsally. Postpetiole laterally tuberculate.

Gaster with its maximum width at the posterior border of the first segment, three times broader than its articulation with the postpetiole.

Sculpture. As in opacus but with the following differences: foveae more regular and deeper on the head, pronotum, mesonotum and scutellum; basal face of the propodeum with deeper, denser, irregular foveae; declivous face of the propodeum with thick, sparse, longitudinal rugosities; centre of the mesopleurae with superficial foveae; pedicel with sparse superficial depressions superimposed by irregular, longitudinal rugosities; legs less shining than in opacus.

Pilosity. As in opacus.

Colour. Head, mesosoma and pedicel opaque black. First gastral tergite and coxae brown, remaining tergites and sternites lighter. Legs dark ferrugineous with darker femora.

Measurements (in mm) and indices: TL 8.60-8.84; HL 1.28-1.32; HW 1.56-1.64; EL 0.56-0.59; PW 1.48-1.56; PeW 0.60-0.66; PpW 0.68-0.72; HBaL 1.24; HBaW 0.16; CI 121.9-124.2; PI 105.1-105.4; PPeI 236.4-246.7; PPpI 216.7-217.6; HBaI 12.9.

Holotype Specimen Labels

Type Material

de Andrade and Baroni Urbani (1999):

Worker. Type locality: Belem (Para, Brazil). Type material: presumably lost, not in the Spinola collection (Casolari & Casolari Moreno, 1980).

Cryptocerus aethiops Worker. Type locality: Brazil. Type material: a worker (holotype), without locality label in the The Natural History Museum, examined.

References

  • 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 141, queen, male described, Combination in Cephalotes)
  • Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 39, Combination in Cephalotes)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 130, Combination in Eucryptocerus)
  • 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 aethiops)
  • 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 49, worker described)