Cephalotes pallidus

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

De Andrade 1999 Cephalotes OCR - Copy-476 Cephalotes-pallidus.jpg

Nothing is known about the biology of Cephalotes pallidus.

Identification

A member of the pallens clade differing from its sister species, Cephalotes pallidoides, by the following characters: in the worker, soldier and gyne, body sculpture deeper, femora less inflate, and HBaI ≤ 48, and, in the soldier and gyne only, floor of the disc with a protruding swelling and margin of the disc more densely crenulate. The soldier and the gyne of pallidus are different from all the other species of the pallens clade by the deep, broad, contiguous, irregular foveae on the head disc.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Bolivia, Brazil, Colombia, Ecuador, Guyana (type locality), Peru, Suriname.


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.

  • pallidus. Cephalotes pallidus De Andrade, in De Andrade & Baroni Urbani, 1999: 473, figs. 218-221, 390 (s.w.q.m.) GUYANA.

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

Description

Worker

Similar to the other species of the group from which it differs for one or more of the following characters. Head broader than long. Membranaceous expansions of the vertexal angles variably developed and strongly crenulate. Frontal carinae crenulate.

Mesosoma. Pronotum with a pair of developed membranaceous expansions. Mesonotum with a pair of triangular or truncate teeth. Propodeum with a pair of broad, gently convex, crenulate, membranaceous expansions, the crenulations variably impressed according to the specimen.

Anterior face of the petiole slightly concave. Petiolar sides with a pair of pointed spines more than 1.3 longer than the maximum petiolar length. Postpetiolar sides with a pair of pointed spines shorter than those of the petiole and directed forwards.

Gaster oval and with a pair of protruding membranaceous expansions reaching the stigma posteriorly and continuing as a thin margin backwards up to the posterior border.

Mid and hind femora gently angulate; mid femora with a carina; hind femora with a crest. Mid and hind basitarsi flat, with the proximal part much broader than the distal one.

Sculpture. Head dorsum minutely punctate, with dense, deep, irregular foveae diminishing in size anteriorly, sparser or rare and more superficial on the frontal carinae. Frontal carinae with strong, oblique rugosities. Ventral part of the head strongly reticulate. Mesosoma minutely punctate and with dense foveae as on the head dorsum, the foveae smaller on the mesonotum and on the propodeum. Propodeum with additional, irregular, longitudinal rugosities. Pleurae usually strongly reticulate, only with superficial, irregular, sparse foveae and few, thin rugosities in some specimens. Pedicel punctate and with small, dense, irregular foveae. Anterior third and sides of the first gastral tergite strongly reticulate and with superficial, irregular foveae; the foveae diminishing in size posteriorly and separate by thin, irregular, longitudinal rugosities only on the anterior third. First gastral sternite strongly reticulate and with irregular, thin rugosities. Remaining gastral tergites and sternites reticulate. Legs strongly reticulate and with small, irregular foveae, dense on the outer face of the tibiae.

Pilosity. Each fovea with a decumbent hair. Sides of the frontal carinae, of the vertexal angles, first gastral tergite, posterior borders of the gastral segments and legs with short, clubbed hairs, denser on the sides of the frontal carinae. Gastral sternites with two additional types of erect, pointed hairs: (1) sparse and short and, (2) rare, long and thin on the second sternite. Parts of the gaster and legs without foveae simply with appressed, thin hairs.

Colour. Brown to black with the membranaceous expansions of the body lighter.

Measurements (in mm) and indices: TL 3.97-4.49; HL 0.96-1.02; HW 1.04-1.16; EL 0.25-0.26; PW 0.90-1.00; PeW 0.63-0.72; PpW 0.52-0.61; HBaL 0.23-0.28; HBaW 0.11-0.12; CI 108.3-114.0; PI 114.0-122.1; PPeI 138.9-142.8; PPpI 161.0-173.1; HBaI 42.3-47.8.

Soldier

Head longer than broad. Sides of the disc raised and with strongly crenulate margin. Floor of the disc with a convex median tumulus pointed apically in large specimens. Vertex posteriorly variably depressed. Vertexal angles with crenulate margin.

Mesosoma. Humeral angles with a pair of obtuse, semi-membranaceous teeth. Pronotum gently converging posteriorly. Pronotal carina marked, crenulate and shortly interrupted medially, continuous and simply lower in Lhe middle in some specimens. Mesonotum with a pair of broad, round or truncate teeth. Sides of the basal face of the propodeum with one-two pairs of irregular swellings followed by a pair of stout teeth curved upwards and forwards. Declivous face of the propodeum narrowing posteriorly narrowly marginate in small specimens.

Anterior face of the petiole medially concave. Petiolar and postpetiolar sides with spines shorter and less pointed than in the worker.

Gaster oval with a pair of protruding lobes.

Mid and hind femora dorsally gently angulate and with a distal carina; the carina more impressed on the hind femora.

Sculpture. Head dorsum minutely punctate and with deep, large, irregular, contiguous foveae; some specimens with the foveae less regular and separate by oblique rugosities. Internal border of the disc strongly punctate occasionally superimposed to irregular, short rugosities. Floor and sides of the disc often completely covered by a thick layer of probable camouflage material; when uncovered the internal surface of the disc shining. Sides of the disc densely and irregularly foveolate-rugulose, more superficially on the anterior half. Ventral part of the head shining, punctate and with irregular longitudinal rugosities. Mesosoma punctate and with dense, irregular foveae. Pedicel with sculpture similar to the one on the mesosoma but the foveae shallower and smaller. Pleurae reticulate and with superimposed irregular foveae on the dorsal half of the propleurae and upper border of the metapleurae; rugosities between the foveae in large specimens only. Gaster and legs with sculpture similar to the worker.

Pilosity. Foveae on the head dorsum with a suberect, slightly clubbed hair; those on the mesosoma, pedicel, gaster and legs with an appressed or decumbent hair. Borders of the disc and foveae on the sides of the head with erect, long, clavate hairs. Vertexal angles, pronotum, pedicel, gastral tergites and legs with rare, clubbed hairs. First gastral sternite with pointed hairs similar to those of the worker. Body parts without foveae with sparse, appresscd, thin, short hairs.

Colour. Brown to black.

Measurements (in mm) and indices: TL 5.08-6.87; HL 1.40-1.88; HW 1.30-1.64; EL 0.30-0.31; PW 1.24-1.56; PeW 0.63-0.69; PpW 0.55-0.67; HBaL 0.26-0.32; HBaW 0.12-0.14; CI 87.2-92.8; PI 104.8-109.4; PPeI 196.8-226.1; PPpI 225.4-232.8; HBaI 43.7-48.1.

Queen

Differing from the soldier in the following characters. Sides of the disc with lower border. Median depression on the vertex deeper.

Mesosoma. Humeral angles obtuse. Pronotal carina less evident and lower. 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 and separate by a deep incision.

Anterior face of the petiole oblique and gently concave medially. Petiolar sides with a pair of small denticles. Postpetiole convex; its sides with a pair of broad, short spines pointed posteriorly.

Gastral anterior lobes more developed.

Legs as in the soldier.

Sculpture. As in the soldier but the transversal rugosities on the floor of the disc are unknown. Foveae on the propodeum smaller. Upper and center of the lower mesopleurae with dense, small foveae, more regular on the upper mesopleurae.

Pilosity. As in the soldier except for the clubbed hairs on the pedicel, on the gaster, on the legs and on the mesosoma, slightly denser.

Colour. As in the soldier.

Measurements (in mm) and indices: TL 7.32-7.72; HL 1.52; HW 1.40-1.42; EL 0.36; PW 1.32-1.42; PeW 0.54-0.60; PpW 0.66-0.72; HBaL 0.38-0.40; HBaW 0.15-0.18; CI 92.1-93.4; PI 100.0-106.1; PPeI 237.5-244.4; PPpI 183.7-215.1; HBaI 39.5-45.0.

Male

Similar to the other species of the group from which it differs for one or more of the following characters. Frontal carinae strongly raised and convex. Clypeus gently convex posteriorly and not incised anteriorly. Pronotum in dorsal view with traces of scapular angles.

Sculpture. Head dorsum minutely reticulate, irregularly foveolate-rugose, the rugae oriented transversally in front of the eyes and between the scapes. Ventral part of the head reticulate; its posterior sides rugulose-foveolate, the rugae oblique and the foveae small; ventral part of the head medially with longitudinal rugosities. Pronotum minutely reticulate and with foveae separate by few, thin rugosities on the sides. Mesonotum slightly shining and with minute, superficial reticulation and with superficial, sparse foveae, the reticulation more impressed and the foveae smaller on the posterior part, both structures superimposed by thin, longitudinal rugosities. Scutellum with sculpture similar to the one on the posterior part of the mesonotum but with denser rugosities. Basal face of the propodeum reticulate and longitudinally rugulose. Propleurae reticulate. Mesopleurae superficially reticulate and with thin, longitudinal rugosities on the posterior half, covered by superficial foveae on the center of the lower and of the upper mesopleurae. Metapleurae reticulate and irregularly rugose; the rugosities oriented longitudinally on the lower part. Pedicel superficially reticulate and with thin rugosities on the sides. Gaster superficial!y reticulate and shining.

Pilosity as in the other species of the group.

Colour. Black. Coxae, proximal part of the femora, pedicel and gaster brown. Legs dark yellow with darker tarsomcres.

Measurements (in mm) and indices: TL 5.04; HL 0.74; HW 0.88; EL 0.35; PW 0.88; PeW 0.35; PpW 0.37; HBaL 0.46; HBaW 0.07; CI 118.9; PI 100.0; PPeI 251.4; PPpI 237.8; HBaI 15.2.

Type Material

Holotype soldier from Guyana labelled: Kartabo, B. G. Jul. Aug. 1920, W. M. Wheeler Museum of Comparative Zoology. Paratypes: 27 workers and 15 soldiers, same data as the holotype MCZC, Museu de Zoologia da Universidade de Sao Paulo.

Etymology

In Latin pallidus has the same meaning as pallens, the name of one of the species with which the present had been previously confused.

Determination Clarifications

We listed under this species part of the pallens specimens identified by Kempf (1958 a) after a re-study of the material examined by him. The statement of misidentification of the pallens referred by Wheeler & Holldobler (1985) is equally based on examination of their material.

References