Cephalotes columbicus

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Cephalotes columbicus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. columbicus
Binomial name
Cephalotes columbicus
(Forel, 1912)

Cephalotes columbicus P casent0627935.jpg

Cephalotes columbicus D casent0627935.jpg

Specimen Label

Specimens have been collected from a variety of forest and disturbed habitats, including a strange record of a column of these ants crossing a trail on a steep grassy slope. Little else is known about the biology of Cephalotes columbicus.

Identification

A member of the pusillus clade characterised in the worker and soldier by the more regular body foveae and by the broad, transparent, gastral lamellae. The worker, soldier, gyne and male of C. columbicus can be distinguished from those of Cephalotes pusillus by the shallower, more rounded foveae. In addition columbicus differs from pusillus in the worker and in the soldier by the broader lamellae of the vertex and of the gaster, in the gyne by the broader head and higher PPeI and, in the male, by higher CI and by the scutellum not strongly narrowing posteriorly. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Colombia and Venezuela

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia (type locality).

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.

  • columbicus. Cryptocerus pusillus var. columbica Forel, 1912e: 201 (s.w.) COLOMBIA. De Andrade & Baroni Urbani, 1999: 167 (q.m.). Combination in Paracryptocerus: Kempf, 1951: 183; in Zacryptocerus: Brandão, 1991: 388; in Cephalotes: De Andrade & Baroni Urbani, 1999: 163. Raised to species: De Andrade & Baroni Urbani, 1999: 163.

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 5.5 mm. Median head length 1 .3 6 mm; interocular width 1.68 mm; Weber's length of thorax 1.58 mm. Black; the following dark reddish brown: frontal carinae, apical three tarsal segments, apex of posterior epinotal spines; anterolateral lamellate border of gaster. Very similar to the typical pusillus, from which it differs by the following peculiarities:

Scales on upper surface of head minute to obsolete, especially on the anterior half. Foveolae limited to narrow band in front of the occipital border. Outer face of fore coxae distinctly striated. Foveolae on upper surface of thorax well separated by finely reticulate-punctate, flat, opaque interstices. First pronotal tooth spine-like and prominent, the second tooth rather obsolete. First epinotal tooth comparatively small, the posterior spine very long and slender; as measured from the posterior rim of the spiracle to the tip, longer than 1/3 of the maximum length of the thorax. Petiole without a lateral tooth. Scales of gaster minute, obsolete abovediscad. Integument opaque.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 5.18-5.76; HL 1.22-1.36; HW 1.68-1.88; EL 0.36-0.39; PW 1.32-1.54; PeW 0.51-0.60; PpW 0.58-0.68; HBaL 0.62-0.67; HBaW 0.13-0.16; CI 137.7-138.2; PI 122.1-127.3; PPeI 256.7-258.8; PPpI 226.5-227.6; HBal 21.0-23.9.

Solider

de Andrade and Baroni Urbani (1999) - Head broader than long and gently convex dorsally. Frontal carinae convex, converging posteriorly and terminating over the postcrior border of the eyes. Vertexal angles truncate. Vertex with a pair of median, broad denticles. Mandibles broad, with the sides neither angulate nor denticulate.

Mesosoma. Scapular angles well visible in dorsal view. Humeral angles with a triangular tooth followed by another shorter and round denticle; pronotum converging posteriorly. Pronotal carina broadly interrupted in the middle. Pro meso notal suture impressed. Sides of the mesonotum with a pair of small, pointed denticles. Propodeal suture deeply impressed. Propodeum with clearly differentiate basal and declivous faces; basal face with two pairs of lateral projections, the anterior one, minutely denticulate, pointed or obtuse, the posterior pair long, spiniform, thick and pointed.

Petiole with the anterior face truncate; its sides unarmed or with a pair of minute denticles. Postpetiole broader than the petiole and with convex dorsum; postpetiolar sides with a pair of round or subpointed teeth, originating on the anterior face and pointing outwards.

Gaster oval, with a broad lamella not surpassing the stigma posteriorly.

Legs. Fore coxae protruding anteriorly. Mid and hind femora dorsally neither angulate nor denticulate. Mid and hind basitarsi not flat and without broad base.

Sculpture. Head deeply and irregularly foveolate; the foveae denser and deeper on the vertexal angles and absent on the frontal carinae. A microscopic reticulation fills the interfoveal spaces and the frontal carinae. Ventral face of the head, propleurae and pronotum similarly sculptured but the foveae are denser, larger and deeper. Mesonotum sculptured as the vertexal angles. Basal face of the propodeum with dense, almost contiguous, round and oval foveae superimposed by reticulation. Declivous face of the propodeum simply reticulate and with longitudinal rugosities on the sides. Meso- and metapleurae reticulate and with sparse, superficial, oval foveae. Pedicel reticulate and with dense, superficial, irregular foveae. Gaster and legs reticulate. Outer face of the fore coxae with superficial longitudinal rugosities on the posterior half. Anterior fourth of the first gastral tergite with superficial, oval foveae. Centre of the posterior half of the first gastral sternite shining. Outer face of tibiae irregularly foveolate.

Pilosity. Each fovea bears a minute appressed hair. Other body surface without foveae with appressed, sparse, thin, short hairs. Posterior border of the gastral segments and legs with sparse clavate hairs. Gastral sternites with suberect, long, pointed hairs.

Colour. Black. Frontal carinae and gastral lamellae ferrugineous, tarsomeres darker.

Measurements (in mm) and indices: TL 6.88-7.28; HL 1.72-1.80; HW 2.32-2.40; EL 0.44-0.45; PW 2.08-2.10; PeW 0.68-0.66; PpW 0.73-0.76; HBaL 0.68-0.72; HBaW 0.18-0.19; CI 133.3-134.9; PI 111.5-114.3; PPeI 305.9-318.2; PPpI 276.3-284.9; HBal 26.4-26.5.

Queen

de Andrade and Baroni Urbani (1999) - Head strongly convex dorsally. Frontal carinae convex anteriorly; their sides converging in front of and ending before the posterior border of the eyes. Vertexal angles nearly round. Vertex with a pair of low median swellings. Mandibles as in the soldier.

Mesosoma. Humeral angles with a pointed anterior tooth. Pronotal carina narrow, superficially interrupt in the middle, poorly marked on the sides. Mesonotum and scutellum flat. Lower mesopleura with a broad, round denticle. Basal face of propodeum with a pair of thick teeth with round or pointed apex and slightly diverging; declivous face, posteriorly, with converging sides.

Petiole with the anterior face oblique, posterior face short and declivous posteriorly; petiolar sides convex, unarmed or armed with a pair of minute denticles. Postpetiole broadly convex; anterior sides of the postpetiole with a broad, obtuse expansions or unarmed.

Gaster protruding anteriorly and with a margination not surpassing the stigma posteriorly.

Legs. Fore coxae with an anterior lobe. Mid and hind femora not angulate. Mid and hind basitarsi not flat and not broad at the base.

Sculpture. Head covered with small foveae sometimes as broad as their interspaces, denser on the vertexal angles and minutely reticulate. Frontal carinae minutely reticulate and without foveae. Ventral part of the head superficially shining and with dense, deep foveae. Pronotum and propleurae reticulate and with dense, deep foveae. Upper and anterior half of the lower mesopleurae, dorsal third of the metapleurae, basal face of the propodeum, posterior face of the petiole and postpetiole reticulate and with dense, small, slightly irregular foveae. Mesonotum superficially shining and with variably clumped foveae separated by longitudinal, irregular rugosities. Scutellum with sculpture similar to the one of the mesonotum but denser. Anterior face of the petiole, posterior half of the lower mesopleurae, remaining metapleurae, gastral tergites and legs reticulate. Anterior fourth of the first gastral tergite with small foveae more superficial posteriorly. Outer face of the tibiae with minute, irregular foveae. Gastral sternites superficially reticulate on the sides and shining in the middle.

Pilosity. Each fovea bears a minute appressed hair. Other surfaces without foveae with short, appressed, sparse, thin hairs. Mesosoma, pedicel and gaster with slightly clavate, subdecumbent hairs, denser on the sternites. Gastral sternites with additional sparse, suberect, long, pointed hairs.

Colour. Black. Frontal carinae dark ferrugineous.

Measurements (in mm) and indices: TL 11.04-11.93; HL 1.92-2.06; HW 2.32-2.54; EL 0.48-0.52; PW 2.16-2.52; PeW 0.83-0.96; PpW 1.04-1.20; HBaL 0.78-0.79; HBaW 0.20-0.22; CI 117.6-123.3; PI 100.0-107.4; PPeI 260.2-262.5; PPpI 200.0-210.0; HBaI 25.3-28.2.

Male

de Andrade and Baroni Urbani (1999) - Head (eyes included) more than 1/3 broader than long; sides of the head convex and converging posteriorly. Vertex dorsally protruding, bearing salient ocelli. Compound eyes broadly convex, in the middle of the sides of the head. Frontal carinae diverging backwards, not reaching the median ocellus posteriorly. Frons flat. Clypeus convex.

Mandibles not carinate. Scapes thick, twice as long as the first funicular joint; remaining funicular joints filiform and thickening from the base to the apex.

Mesosoma. Pronotum in dorsal view with the sides diverging backwards, without carinae. Mesonotal scutum convex in side view; median Mayrian furrow little impressed. Scutellum convex, its sides gently converging posteriorly. Propodeum with differentiate basal and declivous faces; basal face gently convex; declivous face shorter than the basal one and almost straight. Propodeal sides divides from the dorsal face by a longitudinal carina.

Petiole with concave anterior face, superior face, flat and convex posteriorly; petiolar sides unarmed or with a pair of small denticles medially. Postpetiole convex dorsally; its sides with a pointed denticle.

Gaster as broad as the mesosoma.

Wings. As in the gyne.

Sculpture. Head dorsum irregularly rugulose and punctate; both structures are superimposed to irregular foveae on the vertexal angles and on the ventral face of the head. Ventral part of the head around the eyes with transversal rugosities. Mesosoma and peduncular segments reticulate and with very superficial, irregular foveae and thin longitudinal rugosities, the foveae absent on the declivous face of the propodeum and on the metapleurae; the reticulation stronger on the pedicel. First gastral tergite strongly reticulate and slightly granulose laterally in some specimens; this same type of sculpture but more superficial on the remaining tergites and on the sternites. Legs superficially reticulate and slightly shining. Outer face of the fore femora with faint, longitudinal rugulations.

Pilosity. Body with dark yellow, long, flexuous, thin, pointed hairs, dense on the head, on the mesosoma, on the pedicel and on the gaster, sparser on the legs. Legs with additional similar hairs but appressed, thinner and shorter.

Colour. Black. Coxae, two proximal thirds of the femora, and tarsi brown. Distal third of the femora and of the tibiae yellow.

Measurements (in mm) and indices: Measurements (in mm) and indices: TL 8.28-8.40; HL 1.08; HW 1.44; EL 0.49-0.52; PW 1.48-1.56; PeW 0.86-0.87; PpW 1.00-1.04; HBaL 0.88; HBaW 0.14-0.15; CI 133.3; PI 93.6-97.3; PPeI 172.1-179.3; PPpI 148.0-150.0; HBaI 15.9-17.0.

Type Material

de Andrade and Baroni Urbani (1999) - Worker, soldier. Type locality: Magdalena (Santa Marta, Colombia). Type material: 19 workers, 12 soldiers labelled "Santa Marta, Colombie", Forel, in Musee d'Histoire Naturelle Genève, 1 worker in Naturhistorisches Museum Basel, examined.

References

  • 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)
  • 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 167, queen, male described, page 163, Combination in Cephalotes and raised to species)
  • Forel, A. 1912f. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mém. Soc. Entomol. Belg. 19: 179-209 (page 201, soldier, worker described)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 183, Combination in Paracryptocerus)