Cephalotes membranaceus

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Cephalotes membranaceus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. membranaceus
Binomial name
Cephalotes membranaceus
(Klug, 1824)

Cephalotes membranaceus P casent0900239.jpg

Cephalotes membranaceus D casent0900239.jpg

Specimen Label

Synonyms

Nothing is known about the biology of Cephalotes membranaceus.

Identification

A member of the clypeatus clade characterised in the worker and in the soldier by the body light ferruginous-brown with the head, mesosoma, pedicel and gaster surrounded by a semitransparent lamellaceous border, and, in the soldier and in the gyne, by the head with an incomplete disc. The soldier and the gyne of this species have traces of a cephalic disc, missing in the other related species. The closest relative of membranaceus is Cephalotes clypeatus and both species, clypeatus and membranaceus, share the propodeal spines of the soldier strongly curved up- and forwards. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (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.

  • membranaceus. Cryptocerus membranaceus Klug, 1824: 208 (w.) BRAZIL. Kempf, 1973c: 453 (s.q.). Combination in Cephalotes: Emery, 1914c: 39; in Zacryptocerus: Emery, 1915i: 192; in Cephalotes: Baroni Urbani, 1998: 326; De Andrade & Baroni Urbani, 1999: 294. Senior synonym of fervidus: Kempf, 1958a: 135. See also: Kempf, 1951: 141.
  • fervidus. Cryptocerus fervidus Smith, F. 1876d: 605, pl. 11, fig. 1 (q.) BRAZIL. Junior synonym of membranaceus: Kempf, 1958a: 135.

Description

Worker

Kempf (1951) - Length 5.6 mm. Median head length 1.46 mm. Weber's length of thorax 1.58 mm. Ochraceous, darker than the preceding species [clypeatus], subopaque, strongly shagreened.

Head transverse. Frontal carinae not hyaline, semiopaque, due to strong sculpture; rounded anteriorly, sinuate laterally and strongly upturned, vertical and lobate above the eyes. Occipital angle dentate with a broad, blunt, stout tooth projecting from beneath. Eye stalk not completely united with frontal carinae, the apical end free.

Thorax similar to that of clypeatus, except the sculpture. Scapular spines more recurved. No trace of transverse pronotal crest. Mesonotal tooth slender, cylindrical, and pigmented. Mesoepinotal suture more or less distinct. Epinotal spine developed, projecting belong the enveloping border. Legs lacking foveolae. Femora angulate above, greatly inflated, upper face marginate distad, beginning from the angle. Basitarsus not quite as broad as in clypeatus.

Petiole transverse, slightly narrower than in clypeatus, lateral spines slender, blunt at apex, very little upturned. Ventral face with a small midventral hyaline tooth. Postpetiole slightly longer than petiole, the lateral teeth about half as long as the total width of the body.

Gaster circular, broadly surrounded by a horizontal, coarsely sculptured, laminate border which is notched mesially behind.

Foveolae indistinct to obsolete; pilosity consisting of long, silvery, appressed, and scalelike hair.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.56-7.36; HL 1.52-1.74; HW 2.44-2.70; EL 0.28-0.32; PW 2.52-2.88; PeW 0.95-1.08; PpW 0.89-1.04; HBaL 0.66-0.80; HBaW 0.23-0.25; CI 155.2-161.2; PI 93.7-100.0; PPeI 265.3-275.0; PPpI 276.9-286.9; HBaI 31.2-34.8.

Soldier

Kempf (1973) - Total length 8.0 mm; head length 2.56 mm; maximum head width 2.97 mm; maximum diameter of eyes 0.34 mm; Weber's length of thorax 2.59 mm; maximum width of pronotum 3.03 mm; gaster length 3.08 mm; gaster width 2.84 mm. Differs from the respective worker in the ensuing characters: Cephalic disc with sides subparallele, scarcely converging in front except for the anterior curvature; integument only superficially punctulate, quite shining, and densely foveolate bearing a simple appressed hair; vertex with a mesially strongly bidentate, transverse carina that attains the lateral margin at both sides; occiput vertically truncate behind this carina; eye stalk not detached from the head proper, yet between the upper orbit of eye and the rim of cephalic disc is a deeply excavated groove; thorax similarly sculptured as head on dorsum and sides of pronotum, the latter with a strongly elevated, foliaceous trans verse carina on dorsum which is semicircularly excised in the middle; in side-view, the anterior portion of the pronotum in front of the carina forms a right angle with the posterior portion behind the carina and the mesonotum; membranaceous borders of pronotum and propodeum narrower and the enelosed spines stronger, those of the propodeum shorter and morc upturned; gaster relatively more elongate and membranaceous border laterally somewhat narrower.

Intermediates have the transverse pronotal carinae more or less developed and the thoracic dorsum foveolate, but the cephalic sculpture is unvariably as in the worker, and they also lack the bidentate carina on vertex.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 8.44-9.08; HL 2.08-2.16; HW 2.88-3.00; EL 0.32-0.34; PW 3.00-3.04; PeW 1.16-1.20; PpW 1.08-1.12; HBaL 0.80-0.82; HBaW 0.27-0.28; CI 138.5-138.9; PI 94.7-100.0; PPeI 253.3-258.6; PPpI 271 .4-277.8; HBaI 32.9-35.0.

Queen

Kempf (1973) - With the same features as the soldier, but the head is rather subquadrate than transverse; transverse carinae of vertex and pronotum much lower, the former bidentatc in the middle; thorax and gaster lacking the encircling, semitransparent, laminate borders, except for the anterolateral corners of tergum I of gaster. Differs from the female of clypeatus as follows: integument subopaque, finely and densely punctulate throughout; foveolae on cephalic disc and thoracic dorsum denser, crowded; vertex of head with a transverse carina besides the pair of teeth; transverse carina of pronotum more elevated and foliaceous; propodeal spines longer and subacute; first tarsomere of hind leg long, not longer than, as tarsomeres 2 - 5 combined; lateral spines of postpetiole longer, about one half as long as length of postpetiole; tergum I of gaster anterolaterally narrowly crested but lacking the white spots encircled with black on each corner.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 11.76-12.40; HL 2.16-2.28; HW 2.44-2.68; EL 0.40-0.44; PW 2.60-2.68; PeW 0.82-0.92; PpW 1.24-1.32; HBaL 0.88-0.94; HBaW 0.28-0.29; CI 110.9-117.5; PI 91.0-101.5; PPeI 286.9-317.1; PPpI 200.0-209.7; HBaI 30.8-32.9.

Type Material

Holotype Specimen Labels

de Andrade and Baroni Urbani (1999):

Worker. Type locality: Brazil. Type material: not available for the present study.

Cryptocerus fervidus. Gyne. Type locality: Rio de Janeiro. Type material: Holotype Gyne in The Natural History Museum (Kempf, 1964 a: 438), examined.

References

  • Baroni Urbani, C. 1998b. The number of castes in ants, where major is smaller than minor and queens wear the shield of the soldiers. Insectes Soc. 45: 315-333 (page 326, Combination in Cephalotes)
  • 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 294, Combination in Cephalotes)
  • Emery, C. 1914b. Cephalotes et Cryptocerus. Le type du genre Crematogaster. Ann. Soc. Entomol. Belg. 58: 37-39 (page 39, Combination in Cephalotes)
  • Emery, C. 1915g. Noms de sous-genres et de genres proposés pour la sous-famille des Myrmicinae. Modifications à la classification de ce groupe (Hymenoptera Formicidae). Bull. Soc. Entomol. Fr. 1915: 189-192 (page 192, Combination in Zacryptocerus)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 141, see also)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 135, Senior synonym of fervidus)
  • Kempf, W. W. 1973c. A new Zacryptocerus from Brazil, with remarks on the generic classification of the tribe Cephalotini (Hymenoptera: Formicidae). Stud. Entomol. 16: 449-462 (page 453, soldier, queen described)
  • Klug, F. 1824. Entomologische Monographien. Berlin: Reimer, 242 pp. (page 208, worker described)