Cephalotes decolor

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

De Andrade 1999 Cephalotes OCR - Copy-516 Cephalotes-decolor had.jpg

Nothing is known about the biology of Cephalotes decolor.

Identification

A member of the pallens clade differing from Cephalotes decoloratus and Cephalotes pellans, by the following combination of characters: worker only, frontal carinae superficially and irregularly rugulose-foveolate, propodeal sides with a pair of convex, membranaceous expansions, petiole with a pair of broad, pointed spines shorter than the maximum petiolar length, gaster anteriorly protruding, anterior third and sides of the first gastral tergite covered by dense foveae; soldier and gyne, sides of the disc with dense, clubbed hairs, head dorsum without protruding tumulus; soldier only, antennal scrobes reaching at most the anterior border of the eyes, dorsum of the head with superficial, sparse, small foveae, and floor of the disc with foveae bearing appressed hairs; gyne only, head dorsum with dense, superficial foveae and CI > 96.0. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia, Venezuela (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.

  • decolor. Cephalotes decolor De Andrade, in De Andrade & Baroni Urbani, 1999: 512, figs. 241, 242 (s.w.) VENEZUELA.

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

Description

Worker

Head broader than long. Vertexal angles with a pair of narrow, round or obtuse membranaceous expansions.

Mesosoma. Anterior pronotal border convex. Anterior pronotal border with a pair of narrow, membranaceous distal expansions forming an obtuse angle with the pronotal sides. Pronotal sides with a pair of broad membranaceous expansions converging posteriorly. Promesonotal suture, in dorsal view, superficially impressed in some specimens only. Mesonotum with a pair of triangular teeth. Propodeum with weakly differentiate basal and declivous faces and completely surrounded by a pair of broad, convex, membranaceous expansions with a crenulate margin in some specimens only. Propodeal suture impressed.

Petiole. Anterior face truncate and slightly concave medially. Petiolar sides with a pair of broad, triangular, pointed spines. Postpetiolar node convex dorsally; postpetiolar sides with a pair of pointed spines directed forwards at the base.

Gaster. Oval, strongly protruding anteriorly and with a pair of membranaceous expansions surpassing the stigma posteriorly and continuing as a thin margin backwards. Hind femora gently angulate, cristate and carinate on most of their length. Mid femora gently angulate and superficially bicarinate. Mid and hind basitarsi flat, narrowing distally.

Sculpture. Head and mesosoma minutely reticulate and with superficial, dense foveae, shallower and smaller on the anterior part of the head, sparser on the frontal carinae, deeper on the vertex and on the mesosoma. Ventral part of the head reticulate in its posterior third and only superficially reticulate-foveolate in the two anterior thirds, the foveae separate by thin, irregular, longitudinal rugosities. Foveae on the mesosoma separate by irregular, longitudinal rugosities in some specimens only. Pedicel with sculpture similar to the one of the mesosoma but with shallower and smaller foveae. Pleurae reticulate and with thin, longitudinal rugosities. Gaster reticulate. First gastral tergite foveolate on the anterior third and on the sides, the foveae separate by thin, irregular, longitudinal rugosities. First gastral sternite with similar to the corresponding tergite but with less regular foveae. Center of the first gastral sternite minutely and sparsely punctate and shining. Legs reticulate with sparse, irregular, superficial foveae, smaller and dense on the outer face of the tibiae.

Pilosity. Each fovea with an appressed hair. Sides of the frontal carinae and of the vertexal angles, posterior borders of the gastral tergites, sternites and legs with rare clubbed hairs, denser on the first gastral sternite. Parts of the gaster and legs without foveae with short, appressed, thin hairs. Gastral sternites with additional rare, long, pointed hairs.

Colour. Dark brown to black with the membranaceous expansions lighter.

Measurements (in mm) and indices: TL 5.04-5.76; HL 1.14-1.32; HW 1.36-1.54; EL 0.30-0.32; PW 1.10-1.44; PeW 0.89-1.00; PpW 0.77-0.88; HBaL 0.35-0.39; HBaW 0.15-0.16; CI 116.7-119.3; PI 106.9-113.3; PPeI 134.8-144.0; PPpI 155.8-163.6; HBaI 41.0-41.6.

Soldier

Head slightly broader than long. Sides of the disc strongly raised. Floor of the disc gently convex medially. Vertexal angles completely separate from the disc, obtuse and with crenulate margin. Eyes slightly convex and hidden by the disc. Mandibles laterally carinate.

Mesosoma. Humeral angles with a pair of obtuse teeth. Pronotal sides gently convex and slightly converging posteriorly. Pronotal crest marked and interrupted only medially. Pronotal suture in dorsal view superficially impressed medially and more impressed laterally. Promesonotal suture impressed. Mesonotal sides with a pair of broad, truncate teeth. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of broad, round teeth or swellings followed by a pair of stout teeth curved up and forwards.

Petiole. Anterior face truncate and slightly concave medially. Petiolar sides with a pair of broad, triangular spines. Postpetiole much more convex dorsally than in the worker; its sides with a pair of round spines directed forwards at the base.

Gaster. Oval with a pair of protruding anterior lobes.

Mid and hind femora dorsally weakly angulate and bicarinate distally.

Sculpture. Head dorsum superficially and minutely punctate and with small, sparse foveae denser on the vertex and on the vertexal angles, larger in small specimens. Floor of the disc completely shining, sometimes covered by a very thin layer of probable camouflage material. Sides of the head disc punctate, posteriorly, densely and irregularly foveolate, the foveae separate by irregular rugosities, transversal in front of the eyes, anteriorly with sparse, superficial foveae, the rugosities and the punctuations more impressed near the antennal scrobes. Ventral part of the head posteriorly shining, with superficial punctuations and sparse foveae, the punctuations more impressed and the foveae larger and denser anteriorly. Mesosoma punctate and densely foveolate. Pedicel with sculpture similar to the one of the mesosoma but the foveae shallower and smaller. Pleurae reticulate, punctate, with rugosities thin, transversal on the propleurae and longitudinal on the ventral part of the meso- and on the posterior border of the metapleurae; propleurae with additional sparse foveae. Gaster and legs sculptured as in the worker except for the sides of the first gastral tergite and sternite with less foveae.

Pilosity. As in the worker except for the much longer and denser clubbed hairs on the external border of the disc, on the sides of the head and of the vertexal angles. Cephalic disc ventrally with few clubbed hairs on the anterior border and with one layer of long, appressed hairs internally.

Colour. Dark brown to black with darker head.

Measurements (in mm) and indices: TL 6.78-8.96; HL 2.08-2.28; HW 2.00-2.32; EL 0.34-0.40; PW 1.64-2.20; PeW 0.88-1.16; PpW 0.78-1.04; HBaL 0.34-0.40; HBaW 0.16-0.19; CI 101.7-104.9; PI 104.9-105.4; PPeI 186.4-189.6; PPpI 210.2-211.5; HBaI 47.0-47.5.

Queen

Differing from the soldier in the following: sides of the disc with less raised border. Floor of the disc flat or gently convex medially. Vertex with a small, median, superficial concavity.

Mesosoma. Humeral angles obtuse. Pronotum, mesonotum and scutellum flat in side view. Sides of the basal face of the propodeum anteriorly convex and posteriorly with a pair of teeth slightly diverging externally.

Petiole. Anterior face oblique and separated from the posterior one by a superficial, incomplete carina. Petiolar sides with a pair of minute denticles medially. Postpetiole as in the soldier but with the lateral spines shorter and truncate.

Gaster. Similar to the one of the soldier but much longer.

Sculpture. Head dorsum superficially and minutely punctate and with dense foveae. Upper and ventral part of the lower metapleurae with dense, small foveae.

Pilosity. As in the soldier except for sides of the mesosoma with rare, long, clubbed hairs as on the sides of the head.

Colour. As in the soldier with lighter gaster and legs.

Measurements (in mm) and indices: TL 9.80-10.0; HL 2.04-2.08; HW 1.98-2.00; EL 0.43-0.45; PW 1.80-1.84; PeW 0.80-0.85; PpW 0.96-0.98; HBaL 0.51-0.52; HBaW 0.20-0.21; CI 96.1-97.0; PI 107.6-111.1; PPeI 216.5-225.0; PPpI 187.5-187.7; HBaI 39.2-40.4.

Type Material

Holotype soldier from Venezuela labelled: Pq. Nac. Mochima, Sucre, 50 m, 02.X.1986, E. Cancello & C. R. F. Brandao. Paratypes 16 workers and 3 soldiers, same data as the holotype, all Museu de Zoologia da Universidade de Sao Paulo.

Etymology

In Latin decolor is a synonym of pallens, the name of the species with which the present had been previously confused.

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 512, figs. 241, 242 soldier, worker described)