Cephalotes auriger

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

De Andrade 1999 Cephalotes OCR Cephalotes-auriger.jpg

Nothing is known about the biology of Cephalotes auriger.

Identification

de Andrade and Baroni Urbani (1999) - A member of the texanus clade characterised, in the worker, by the thinner and less regular striation on the mesosoma, by the first gastral tergite bearing appressed, dense, broad, golden hairs, and by the presence of a bold area on the posterior border of the first gastral tergite.

Cephalotes auriger is the sister species of Cephalotes chacmul. Both species are very similar and - within the texanus clade - they share synapomorphically the anterior border of the pronotum separate from the first pair of pronotal teeth and the posterior face of the femora with superficial, longitudinal rugosities. The worker of C. auriger can be distinguished from that of Cephalotes chacmul, other than by the marked golden pilosity of the gaster, by the rugosities on the dorsum of the mesosoma less impressed, by the first gastral sternite with less longitudinal rugosities, and by the first gastral segment longer.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Mexico (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.

  • auriger. Cephalotes auriger De Andrade, in De Andrade & Baroni Urbani, 1999: 615, fig. 288 (w.) MEXICO.

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

Description

Worker

Head subquadrate. Frons convex. Frontal carinae superficially crenulate, upturned above the eyes. Vertexal angles round and with crenulate margin. Vertexal margin gently concave medially. Mandibles with superficial lateral carina.

Mesosoma. Scapular angles visible i n dorsal view. Anterior pronotal border straight. Pronotal sides with a narrow lamella with three teeth, the first and the second pair pointed, the third obtuse. Promesonotal and propodeal sutures, in dorsal view, impressed on the sides. Mesonotum with a small pair of lateral teeth. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of teeth followed by a pair of denticles, the second pair of teeth larger than the first one; declivous face of the propodeum converging posteriorly.

Petiole. Anterior face truncate, bearing a small pair of denticles dorsally, posterior face sloping posteriorly. Petiolar sides diverging into a pair of long, pointed spines directed backwards, converging posteriorly after the spines. Postpetiolar node gently pointed in the middle dorsally; postpetiolar spines long, pointed, directed slightly forwards at the base and strongly curved backwards at the apex, the sides converging posteriorly after the spines.

Gaster. Oval with a pair of anterolateral, narrow, membranaceous expansions not reaching the stigma posteriorly.

Hind femora angulate. Hind basitarsi long and not broadening at the base.

Sculpture. Head minutely punctate and with foveae broader than their interspaces, diminishing in size anteriorly, denser on the vertexal angles. Frontal carinae with superficial, sparse foveae, sparser anteriorly. Ventral face of the head reticulate, longitudinally rugose, the rugae more irregular on the anterior half where they are superimposed to superficial, oval foveae. Mesosoma minutely reticulate, with superficial, slightly irregular, thin longitudinal, rugosities and foveae, the rugosities more impressed and regular on the propodeum. Pleurae reticulate, with longitudinal, thin, rugosities on the propleurae and dense, superficial, oval foveae on the meso- and metapleurae. Pedicel reticulate and with dense, oval foveae. First gastral tergite minutely reticulate; its anterior third with thin, longitudinal rugae. First gastral sternite minutely punctate and with thin, longitudinal rugosities on the anterior third and on the sides. Middle of the first gastral sternite shining. Legs with the same sculpture as the first gastral tergite but with the foveae more impressed on the distal part of the outer face of femora and tibiae. Posterior face of the femora with longitudinal, thin rugae.

Pilosity. Each fovea with an appressed hair; similar hairs but not originating from the foveae on the whole sides and on the center of the posterior half of the first gastral tergite; remaining parts of the first gastral tergite with thinner and shorter hairs. Sides of the frontal carinae, mesosoma, pedicel and first gastral tergite with slightly clubbed hairs. First gastral sternite and border of the remaining sternites with thin, subdecumbent, sparse, pointed hairs, longer on the border of the first sternite. First sternite also with appressed hairs thicker and shorter than the pointed hairs.

Colour. Black with lighter femora. Mesosomal and pedicellar spines, tibiae and tarsomeres yellowish to light brown, tarsi darker. Frontal carinae yellowish and semi-transparent. First gastral tergite with a pair of oval, anterolateral, orange spots partially hidden by the golden hairs and not surpassing the stigma posteriorly. Gaster, dorsally, and extensor face of the legs covered by thick, golden hairs.

Measurements (in mm) and indices: TL 3.59-4.02; HL 0.86-0.96; HW 0.92-1.04; EL 0.25; PW 0.78-0.89; PeW 0.49; PpW 0.56-0.59; HBaL 0.31-0.33; HBaW 0.07; CI 107.0-108.3; PI 116.8-118.0; PPeI 159.2-181.6; PPpI 139.3-150.8; HBaI 21.2-22.6.

Type Material

Holotype worker from Mexico, Quintana Roo, S. Miguel, Cozumel Island, VII.1959, N. L. H. KRAUSS; paratype worker same data as the holotype, both in National Museum of Natural History.

Etymology

From the Latin auriger = bearing gold (Cicero), referred to the coloration of the gaster.

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 615, fig. 288 worker described)