Cephalotes palustris

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

De Andrade 1999 Cephalotes OCR - Copy-327 Cephalotes-palustris.jpg

Nothing is known about the biology of Cephalotes palustris.

Identification

A member of the depressus clade characterised in the worker by the vertexal angles with a pair truncate lamellae and by the mesopleurae not densely covered with thick hairs, and, in the soldier, by the pronotal lamellae truncate and by the pronotal crest not crenulate.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil, Guyana (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.

  • palustris. Cephalotes palustris De Andrade, in De Andrade & Baroni Urbani, 1999: 322, fig. 139 (s.w.) GUYANA.

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

Kempf (1951), without having seen Peruvian specimens, considered part of the material on which we based the description of this species to be pavonii, a species described from Peru the types of which have been presumably lost. The availability of Peruvian material for the present study allows the separation of part of the examples from the lower basin of the Rio Amazonas from what we believe to be true pavonii for the characters we list in the diagnosis. (de Andrade and Baroni Urbani 1999)

Description

Worker

Kempf (1951), for Paracryptocerus subpavonii (misidentification), as given in de Andrade and Baroni Urbani (1999) - Length 5.4 mm. Median head length 1.36 mm; Weber's length of thorax 1.58 mm. Black; the following ferruginous and subtransparent: Frontal carinae, occipital lobes, lateral projections of thorax and peduncle. Ferruginous and opaque: first funicular segment, tibiae and tarsi, except the basitarsus: Fuscous rufous: tip of mandibles, and femora. Tip of last funicular segment orange-brown.

Head broader than long: The frontal carinae distinctly crenulate and beset with projecting setulae along the anterior half. Upper surface of head rather flat anteriorly and laterad, conspicuously convex discad and caudad. Sides of head upturned above the eyes. Occipital corners with a bidenticulate lobe.

Pronotum with a broadly expanded lateral lamella, about as long as broad, broader than the length of the postpetiole, and a broad, plate-like, more or less rounded lobe, separated from the anterior lamella by a deep notch. Anterior border of the lamella convex, lateral border crenulate, posterior border concave. Mesonotum with a conspicuous spine on each side. Sides of epinotum with a large, plate-like anterior spine, and a shorter, rather slender and acute triangular tooth, arising well in front of the posterior corner of the declivous face.

Petiole broader than postpetiole, the spines plate-like, truncate at apex; the anterior border, including the spines, evenly rounded. Postpetiole with acute, apically recurved lateral spines.

Gaster emarginate antero-mesad, crested antero-laterad. About as long as broad. Sculpture and pilosity similar to that of the other species of the group.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.96-5.72; HL 1.20-1.36; HW 1.64-1.84; EL 0.40-0.42; PW 1.76-1.92; PeW 1.12-1.28; PpW 0.96-1.08; HBaL 0.50-0.53; HBaW 0.15-0.18; CI 132.3-140.0; PI 93.2-97.9; PPeI 150.0-157.1 ; PPpI 172.0-183.3; HBaI 32.1-35.5.

Soldier

Kempf (1951), for Paracryptocerus subpavonii (misidentification), as given in de Andrade and Baroni Urbani (1999) - Length 7.7 mm. Median head length 2.00 mm; Weber's length of thorax 2.17 mm. Black; the following fuscous ferruginous: anterior portion of frontal carinae, tibiae and basitarsi. Tarsi lighter.

Extremely similar to Cephalotes cordatus, from which it differs by the following characters: Pronotum without macrosculpture, smooth and fulgid. Basal face of epinotum with a broad triangular tooth on the side, the posterior border of which forms the outer border of a subequal posterior tooth; which is not upturned, nor sends out a median carinule. Declivous face finely but sharply reticulate, scales and foveolae confined to narrow band near the upper border. Anterior border of petiole not evenly curved, the slender lateral spines, pointing obliquely backward, are more or less distinctly set off from the body of the segment.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.68-7.60; HL 1.72-1.96; HW 2.16-2.36; EL 0.45-0.48; PW 2.24-2.52; PeW 1.22-1.28; PpW 1.04-1.16; HBaL 0.50-0.60; HBaW 0.20-0.24; CI 120.4-125.6; PI 93.6-98.3; PPeI 180.6-209.0; PPpI 207.4-223.1; HBaI 40.0-41.1.

Type Material

Holotype worker from Kartabo, Guyana, July-August 1920, W. M. Wheeler (Museum of Comparative Zoology); paratypes 8 workers and 1 soldier, same data as the holotype (MCZ and Museu de Zoologia da Universidade de Sao Paulo).

Etymology

From the Latin palustris ( = swampy) referred to the area where this species has been collected.

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 322, fig. 139 soldier, worker described)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244.