Cephalotes pellans

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

Cephalotes pellans casent0173697 profile 1.jpg

Cephalotes pellans casent0173697 dorsal 1.jpg

Specimen labels

Specimens have been collected from the edge of campo cerrado habitat.

Identification

A member of the pallens clade differing from its sister species Cephalotes decoloratus, in the worker, by the following characters: petiole with a pair of spines 1.3 times longer than the maximum petiolar length and HBaI > 47, and, in the soldier and in the gyne, foveae on disc sparser. C. pellans is another species separated in this paper and previously confused, together with seven others, under the name Cephalotes pallens. Miniature workers, with a maximum length of 3.3 mm, are known from different localities. Similar miniature workers are unknown among other, related species, except pallens, where they appear, nonetheless, to be less frequent. There are also small soldiers and gynes with foveae on the disc denser than in the larger ones. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Bolivia, Brazil, Paraguay (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

Worker

Soldier

Nomenclature

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

  • pellans. Cephalotes pellans De Andrade, in De Andrade & Baroni Urbani, 1999: 501, figs. 235-238 (s.w.q.m.) PARAGUAY.

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

Description

Worker

Differing from Cephalotes decoloratus in the following characters. Pronotum narrower. Margin of the lateral expansions of the mesosoma minutely crenulate. Membranaceous expansions of the propodeum with or without superficial notch. Peduncular spines longer and more pointed. Gaster more elongate, its anterior expansions protruding more anteriorly, narrowing backwards, surpassing the anterior half and continuing as a thin margin until the posterior border. Mid and hind basitarsi shorter and broader.

Sculpture. Head and mesosoma with foveae denser and separate by irregular, longitudinal rugosities. Frontal carinae with less impressed foveae and with thin, longitudinal rugosities. Pleurae with thin, longitudinal rugosities, more impressed on the propleurae. Anterior third and sides of the first gastral tergite reticulate, with dense, very superficial foveae and with thin, longitudinal rugosities.

Colour. Dark brown to black with lighter membranaceous expansions.

Measurements (in mm) and indices: TL 3.28-4.86; HL 0.76-1.10; HW 0.92-1.26; EL 0.19-0.28; PW 0.76-1.08; PeW 0.60-0.92; PpW 0.52-0.68; HBaL 0.22-0.26; HBaW 0.11-0.13; CI 114.5-121.6; PI 116.7-123.1; PPeI 117.4-129.9; PPpI 141.8-158.8; HBal 50.0-52.0.

Soldier

Differing from decoloratus in the following characters. Head disc longer. Center of the disc only occasionally weakly convex. Mesosoma narrower. Mesonotal sides with or without an additional pair of minute denticles. Pedicel narrower and with shorter spines. Gaster more oval and with a pair of more protruding lobes.

Sculpture. Head dorsum minutely, superficially punctate, shining and with small, sparse foveae. Some specimens have the head dorsum covered by a very thin layer of probable camouflage material. Sculpture on the sides of the disc less dense. Ventral part of the head shining, with thin, longitudinal rugosities behind the eyes, smooth in the middle and with shallow, small foveae separated by irregular, longitudinal rugosities on the sides. Propleurae with thin, irregular, slightly transversal rugosities. First gastral tergite with more superficial and more irregular foveae separate by longitudinal, thin rugosities on the anterior third only; in some specimens the rugosities prolonging up to the posterior half.

Pilosity. As in decoloratus except some specimens with rare, short, clubbed hairs on the pronotal sides.

Colour. Dark brown to black with lighter gaster.

Measurements (in mm) and indices: TL 6.60-7.40; HL 1.80-2.16; HW 1.60-1.78; EL 0.39-0.41; PW 1.56-1.70; PeW 0.78-0.80; PpW 0.70-0.72; HBaL 0.27-0.34; HBaW 0.15-0.16; CI 82.7-87.2; PI 101.2-109.7; PPeI 195.0-215.2; PPpI 222.8-239.4; HBaI 47.0-55.6.

Queen

Differing from the soldier in the following characters. Sides of the disc with lower border. Floor of the disc flat or gently convex medially. Vertex with a small, superficial concavity. Vertexal angles less protruding than in the soldier. Humeral angles with a pair of obtuse or nearly round teeth. Pronotum, mesonotum and scutellum flat in side view. Sides of the basal face of the propodeum anteriorly gently convex and posteriorly with a pair of broad, almost round teeth separate by a deep incision. Anterior face of the petiole oblique, anterior border concave. Petiolar sides with or without a minute pair of denticles medially. Postpetiole as in the soldier but with the lateral spines shorter, truncate or pointed.

Gaster. As in the soldier but much longer. Legs as in the soldier.

Sculpture. Head dorsum superficially and minutely punctate and with variably clumped foveae missing on the anterior third of the head dorsum of some specimens. Propleurae with thin, irregular, slightly transversal rugosities. Upper and ventral part of the lower metapleurae with dense, small foveae.

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

Colour. As in the soldier.

Measurements (in mm) and indices: TL 8.52-8.68; HL 1.80-1.88; HW 1.56-1.68; EL 0.42-0.43; PW 1.44-1.58; PeW 0.58-0.62; PpW 0.70-0.73; HBaL 0.40-0.43; HBaW 0.17-0.19; CI 86.7-89.4; PI 102.6-111.1; PPeI 234.9-254.8; PPpI 200.0-217.1; HBaI 41.9-44.2.

Male

Differing from Cephalotes varians in the following characters. Frontal carinae lower. Clypeus less convex posteriorly and not incised anteriorly. Mesosoma. Pronotum in dorsal view with the sides superficially marginate. Wings more infuscate and darker.

Sculpture. Head dorsum minutely reticulate and with variably clumped foveae separate by thin, irregularly longitudinal rugosities, oriented transversally in front of the eyes and between the scapes. Ventral part of the head reticulate and with foveae separate by slightly longitudinal rugosities. Pronotum, mesonotum and scutellum with superficial, minute reticulation and with foveae as on the head dorsum, shallower, sparser and separate by thin, longitudinal rugosities on the mesonotum and on the scutellum. Basal face of the propodeum reticulate and with irregular foveae and longitudinal rugosities. Pedicel and propleurae reticulate and sometimes with few superficial foveae and short rugosities on the sides of the petiole and postpetiole and on the upper part of the propleurae. Mesopleurae reticulate and with thin, longitudinal rugosities on the posterior half, covered by superficial foveae on the center of the lower and upper mesopleurae. Metapleurae reticulate and irregularly rugose; upper part of the metapleurae with few, irregular foveae. Gaster superficially reticulate and subopaque to shining. Legs punctate, with moderately shining femora.

Pilosity. Body with long, thin, flexuous, pointed, golden hairs, dense on the head, on the mesosoma and on the pedicel, sparser on the gaster and on the femora. Gaster and legs with similar hairs but shorter, appressed on the tergites, decumbent on the sternites and on the femora. Tibiae and tarsi with short, pointed hairs.

Colour. Dark brown to black with slightly lighter coxae, proximal part of the femora, and gaster. Legs yellowish with darker tarsomeres.

Measurements (in mm) and indices: TL 4.84-4.92; HL 0.76; HW 0.92; EL 0.39-0.40; PW 0.85-0.88; PeW 0.40-0.42; PpW 0.44-0.46; HBaL 0.43-0.47; HBaW 0.09; CI 121.0; PI 104.5-108.2; PPeI 202.4-220.0; PPpI 184.8-200.0; HBaI 19.1-20.4.

Type Material

Holotype soldier from Paraguay labelled: Paraguay, Bohls, in MCSN. Paratypes: 1 worker, 2 gynes and 2 males, same data as the holotype, all Museo Civico di Storia Naturale, Genoa.

Etymology

Pellans is an anagram of pallens, the name of the species with which this one had been previously confused.

References