Cephalotes bivestitus

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Cephalotes bivestitus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. bivestitus
Binomial name
Cephalotes bivestitus
(Santschi, 1922)

Cephalotes bivestitus P casent0217835.jpg

Cephalotes bivestitus D casent0217835.jpg

Specimen Label

Synonyms

Nothing is known about the biology of Cephalotes bivestitus.

Identification

A member of the prodigiosus clade differing from Cephalotes prodigiosus, in the soldier and gyne, by the smaller size, in the soldier only, by the floor of the disc not completely concave, and in the gyne only, by the cephalic foveae, more regular. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina (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.

  • bivestitus. Cryptocerus bivestitus Santschi, 1922d: 254 (s.w.q.) ARGENTINA. Combination in Paracryptocerus (Harnedia): Kempf, 1958a: 38; in Zacryptocerus: Brandão, 1991: 384; in Cephalotes: De Andrade & Baroni Urbani, 1999: 677. Material of the unavailable name tucumana referred here by Kempf, 1958a: 38. Senior synonym of trivialis: De Andrade & Baroni Urbani, 1999: 677.
  • trivialis. Cryptocerus (Cryptocerus) guttatus var. trivialis Santschi, 1929d: 301 (w.) ARGENTINA. Junior synonym of fiebrigi: Kempf, 1958a: 28; of bivestitus: De Andrade & Baroni Urbani, 1999: 677. [The name guttatus is a misspelling of guttifer.]

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

Description

Worker

Kempf (1958) - Total length 4.5-4.9 mm; maximum length of head 1.25-1.39 mm; of thorax 1.25-1.39 mm. Black; frontal carinae testaceous. Tips of mandibles, scapes, extensor face of tibiae, apical tarsites ferruginous or fuscous-ferruginous.

Head subopaque, rectangular, visibly longer than broad. Cephalic index (maximum width as measured in front of the eyes over maximum length as measured from the anteriormost point of frontal carinae to posteriormost point of occipital lobes) 0.82-0.86. Mandibles finely rugulose. Frontal carinae semitrasparent, without a distinctly crenulate border, straight, not conspicuously emarginate in front of, nor upturned above the eyes, very gently diverging caudad. Occipital corners obliquely truncate; occipital border shallowly emarginate. Eyes small, their greatest diameter less than one fourth of maximum head length. Upper face of head gently and evenly convex, finely reticulate-punctate, more sparsely covered with shallow, squamiferous foveolae, which occur somewhat more densely and larger towards occiput. Between the foveolae most specimens show more or less longitudinal yet rather fine rugosities. Vertex without a pair of small denticules. Lower face of head reticulate-rugose, the rugae forming elongate meshes.

Thorax subopaque. Anterior border moderately arcuate. Scapular angle subdentate, not well visible from above, lying beneath the anterior corner of the pronotal crest. This crest bears anteriorly an acute, strong tooth, followed by two or three blunt, crenate or denticulate lobes. Occasionally, the first lobe may have the form of a tooth, yet a distinctly tridentate condition of the lateral crest is rare. Promesonotal suture effaced. Sides of mesonotum angulate or even feebly dentate. Promesonotum moderatcly convex both in profile and transversely. Mesoepinotal suture absent. Anterior corner of basal face of epinotum forming a rectangular tooth, followed by another larger triangular tooth on the sides. Sides of declivity sharply marginate, the edge bearing one or several minute teeth. Basal face and declivity, as seen from the side, form an even but gentle curvature. Dorsum of thorax sculptured as head, finely reticulate-punctate, rather densely covered with squamiferous foveolae. The slightly raised intervals between the foveolae form a network of anastomosing rugosities, which are more conspicuous on thorax than on dorsum of head. Lowermost portion of declivous face finely reticulate-punctate. Laterotergite of pronotum with a few horizontal striae. Thoracic pleura finely reticulate-punctate and more coarsely rugose.

Peduncular segments subequal in width. Petiole dorsally without a transverse carina, but bearing on each side a strong pointed tooth, pointing obliquely caudad. Postpetiole with a dorsally submarginate, inclined anterior face, and with lateral spines, the tip of which is strongly recurved, acute, pointing directly caudad.

Gaster subopaque, oval. Strongly emarginate antero-mesally, the anterolateral lobes almost semicircular, solid, without a distinctly marginate border. First tergite extremely finely reticulate-punctate. A few longitudinal but short rugosities extending from the postpetiolar insertion caudad. Squamiferous foveolae very shallow and sparse.

Dorsum of head, thorax, and peduncular segments bearing in the foveolae appressed, silvery, canaliculate, scalelike hair. Similar hair bit simple, on the first gastral tergite. Standing hair, as usual, confined to the posterior and ventral face of gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.38-5.24; HL 1.02-1.26; HW 1.10-1.36; EL 0.30-0.33; PW 0.96-1.12; PeW 0.49-0.59; PpW 0.50-0.60; HBaL 0.39-0.45; HBaW 0.09-0.10; CI 103.6-107.9; PI 114.6-121.4; PPeI 178.2-195.9; PPpI 175.0-192.0; HBaI 22.5-25.6.

Soldier

Kempf (1958) - Total length 7.3-8.0 mm; maximum length of head 2.10-2.25 mm; of thorax 1.89-2.03 mm. Black; the following ferruginous: head disc, (excepting the black clypeal and frontal region), sides of head, legs (usually more or less infuscated); yellowish-brown: triangular area on each shoulder, lateral borders of mesonotum, extensor face of tibiae. The four spots of the first gastral tergite pale-testaceous.

Head somewhat shining; longer than broad, surmounted by an elongate, completely marginate disc, which is much broader in front than behind, its sides converging caudad, with a feeble constriction near the level of the eyes, its posterior border evenly rounded. The anterior four fifths of the cephalic disc form a circular, pronouncedly excavate area, with strongly raised, scarcely crenulate lateral borders. The center of the excavation, coinciding with the vestigially limited clypeal and frontal area, slightly raised and convex. The posterior fifth of the head disc, which is sickle-shaped, is flat, with narrowly crested lateral and posterior border. Mandibles strongly reticulate-rugose. Eyes feebly convex, scarcely visible from above, being partly covered by the head disc. In side view, the dorsal face of the head disc invisible, being concealed by the sides of the disc. Lower border of cheeks carinate. Occipital lobes bluntly angulate, with rounded, carinate borders. Floor of head disc and sides of head coarsely reticulate-rugose, with deeply impressed, circular, large foveae, the bottom of which is shining. About 18 foveae may be counted along a line drawn transversely across the head disc, at the level of the eyes. Lower face of head more shining, with coarser rugosities and more spaced foveolae.

Thorax slightly shining, compact. Anterior corner of pronotum dentate, its sides subparallel until reaching the weakly crested, mesally interrupted transverse carina. From this point the sides gently converge caudad toward the mesonotum. Promesonotal suture distinct. Mesonotum having on each side a projecting, bluntly rounded, posteriorly marginate, lobe. Mesoepinotal suture scarcely impressed mesially. Basal face of epinotum about three times as broad, as long along the midbody line, having a short, bluntly rounded tooth on each side, and another more pronounced tooth on each posterior corner. Declivous face less than twice as long as basal face, feebly marginate at the sides. Sculpture of thoracic dorsum as on head disc, yet the rugosities are broader, the foveolae smaller, less deeply impressed and often somewhat elongate, especially on mesoepisternum. Laterotergites of pronotum with oblique striation. Remaining parts of the sides of the thorax reticulate-rugose, with horizontally elongate, shallow foveolae. Declivous face reticulate-punctate.

Peduncular segments slightly shining, with the dorso-lateral sculpture as on dorsum of thorax. Petiole as broad as postpetiole, its anterior face, which is nearly vertically truncate, finely reticulate-punctate, its sides with a strong, short spine, pointing obliquely caudad. Postpetiole with strong lateral processes, which are strongly recurved and resemble the beak of an eagle. Anterior face of postpetiole somewhat inclined, meeting the dorsal face at angle, which separates both faces by a weakly marginate transverse carina.

Gaster subopaque, elliptical, elongate, with subparallel sides, strongly emarginate anteromesally, the projecting anterolateral lobes with immarginate border. First gastral tergite reticulate-punctate, with sparse, shallowly impressed sljuamiferous punctures. A few more or less longitudinal and widely spaced rugosities on the anterior portion of the first tergite.

Foveolae of the head disc and sides of head, with a central, scalelike, curved, thick hair, the tip of which projects beyond the rim of the pit, as in fiebrigi. Rim of head disc with projecting clavate setae. Scalelike hair of thorax and gaster appressed, smaller, silvery, smallest on gaster. Standing hair, as usual, only on the tip and venter of gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 7.48-7.72; HL 1.80; HW 1.80-1.82; EL 0.35-0.36; PW 1.72; PeW 0.78-0.81; PpW 0.80-0.81; HBaL 0.48-0.50; HBaW 0.13-0.1 ; CI 100.0-101.1; PI 104.6-105.8; PPeI 212.3-220.5; PPpI 212.3-215.0; HBaI 27.1-30.0.

Queen

Kempf (1958) - Total length 8.2-8. 8 mm; maximum length of head 1.85-2.03 mm; of thorax 2.36-2.50 mm. Diagnostic features as in soldier. The lightly colored parts (head disc, sides of head, shoulders, extensor face of tibiae) are orange instead of ferruginous, but the center of head disc is much more extensively infuscated. Portions overlying the antennal scrobe transparent in part. Head disc with an anterior circular excavation, which is much shallower than in soldier, with the lateral borders less strongly raised, but more conspicuously crenulated. The posterior fifth of head disc transversely convex, in lateral view distinctly sloping downward toward occiput, forming a very obtuse, yet visible angle with the anterior portion. Occipital border nearly straight and sharply marginate. Ocelli minute, the antero-median ocellus being located in the excavate portion of head disc, the two postero-lateral ocelli in the posterior portion, facing obliquely caudad and laterad. Thorax less elongate than in fiebrigi, the sides of the pronotum slightly diverging caudad. Scutum broader than long. Mesopleural tooth obtuse, yet distinguishable. Peduncular segments similar to those of fiebrigi. Gaster more deeply emarginate antero-mesally, the anterolateral lobes rounded. Sides of gaster subparallel. Wings subhyaline, only slightly infuscated, the venation as in fiebrigi. Fore wings, when folded over the back, distinctly project beyond the posterior tip of the gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 8.36-8.80; HL 1.64-1.68; HW 1.56-1.64; EL 0.36; PW 1.52-1.56; PeW 0.64-0.66; PpW 0.72-0.79; HBaL 0.55-0.56; HBaW 0.12; CI 95.1-97.6; PI 102.6-105.1; PPeI 236.4-237.5; PPpI 197.5-211.1; HBal 21.4-21.8.

Type Material

de Andrade and Baroni Urbani (1999):

Worker and gyne. Type locality: Hualffn (Catamarca, Argentina). Type material 5 workers, 3 soldiers, 4 gynes (all paratypes) labelled “Catamarca, Hualffn (Weiser), Cryptocerus bivestitus, Santo type”, in Naturhistorisches Museum Basel; 1 worker with additional label “Co- (topo) type, bivestitus paratypus, Kempf det.”, in Museu de Zoologia da Universidade de Sao Paulo, examined.

Cryptocerus peltatus Ellenriederi. Worker. Synonymy with bivestitus proposed by Kempf (1958 a: 50) and confirmed by our examination of part of the relevant material.

Cryptocerus guttatus (sic) var. trivialis. Worker. Type locality: Chafinian (Catamarca, Argentina). Type material: Holotype (unique) in Naturhistorisches Museum Basel, examined.

References

  • Brandão, C. R. F. 1991. Adendos ao catálogo abreviado das formigas da região Neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412 (page 384, Combination in Zacryptocerus)
  • de Andrade, M. L. 1999b. [Untitled. Series of 33 new species, attributed to de Andrade only.] In: De Andrade, M. L., Baroni Urbani, C. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttg. Beitr. Naturk. Ser. B (Geol. Paläonto (page 677, Combination in Cephalotes, Senior synonym of trivialis)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 38, Combination in Paracryptocerus (Harnedia), Material of the unavailable name tucumana referred here)
  • Santschi, F. 1922e. Description de nouvelles fourmis de l'Argentine et pays limitrophes. An. Soc. Cient. Argent. 94: 241-262 (page 254, soldier, worker, queen described)