Cephalotes palta

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

Cephalotes palta casent0909282 p 1 high.jpg

Cephalotes palta casent0909282 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Cephalotes palta.

Identification

A member of the angustus clade differing from its sister species, Cephalotes conspersus, in the worker by the unicolourous first gastral tergite and, in the soldier, by the denser and smaller foveae on the disc. Also in the worker by the pronotal width greater than the head length in palta vs. smaller in conspersus; by the petiolar dorsum with salient denticles in palta vs. minute in conspersus; by the postpetiole with a U-shaped carina in palta vs. simply convex in conspersus. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia (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.

  • palta. Cephalotes palta De Andrade, in De Andrade & Baroni Urbani, 1999: 693, figs. 327, 328 (w.) COLOMBIA.

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

Description

Worker

Head convex above, subquadrate. Frontal carinae diverging backwards, slightly converging in front and little upturned above eyes. Vertexal angles truncate and with two pairs of obtuse, membranaceous projections. Vertexal margin slightly concave and laterally connected with the internal pair of denticles through a thin carina. Clypeal suture impressed. Mandibles with a thin, short lateral carina.

Mesosoma convex in side view. Scapular angle visible in dorsal view. Pronotal sides with three pairs of short, membranaceous teeth, the first pair, triangular and separated from the second almost truncate one by a superficial notch on the pronotal membrane, the third pair broad, truncate and separated from the two first pairs by a deep notch. Promesonotal suture vestigial. Mesonotum with a pair of triangular teeth with pointed tip. Propodeal suture more impressed on the sides. Propodeum slightly differentiated in basal and declivous face; declivous face little concave in the middle and shorter than the basal one. Propodeal sides with four to six pairs of pointed denticles, sometimes the first, third, fifth and sixth pairs thinner and much smaller than the second and fourth pairs.

Petiole with oblique anterior face; its median dorsum with a pair of denticles on the short posterior face. Sides of the petiole with a pointed, thin spine slightly curved. Postpetiole slightly broader than petiole; middle of the postpetiolar dorsum with a V-shaped carina; postpetiolar spines directed forwards at the base and curved at the apex.

Gaster oval. Anterolateral border of the gaster with semitrasparent lamella not surpassing the level of the stigma.

Hind femora without angle or denticle in the middle.

Sculpture. Head dorsum minutely reticulate and covered by foveae as broad as their interspaces on the two anterior thirds, denser on the last third. Frontal carinae reticulate and superficially foveolate. Ventral face of the head reticulate and with slightly impressed longitudinal rugulae close to the hypostoma. Trunk, petiole, and postpetiole with the same sculpture as on the posterior third of the head dorsum, more round on the center of the trunk and less impressed on the pedicel. Middle of the declivous face of the propodeum, anterior face of the petiole, gaster and legs reticulate. Pleurae reticulate and longitudinally striate. Gaster with superficial piligerous foveae, less impressed on the sternites. Disc of the posterior half of the first gastral sternite shining.

Pilosity. Each fovea with an appressed canaliculate hair. Mandibles, border of the frontal carinae and legs with sparse, suberect, canaliculate hairs. Extensor face of the legs and gaster with appressed canaliculate hairs slightly thinner on the gaster. Apex of the tergites and sternites with two types of erect hairs: (1) short, sparse and slightly canaliculate, (2) long, rare and pointed.

Colour. Black. Frontal carinae, distal part of the scapes, basal and distal part of the funiculus, thoracic and peduncular spines, anterolateral lamellae of the gaster, apex of femora, outer face of the tibiae and tarsomeres yellowish-orange to light ferruginous.

Measurements (in mm) and indices: TL 4.46-4.62; HL 1.04; HW 1.28-1.34; EL 0.32-0.33; PW 1.12-1.18; PeW 0.59-0.61; PpW 0.63; HBaL 0.37-0.44; HBaW 0.11-0.12; CI 123.1-128.8; PI 113.5-114.3; PPeI 183.6-200.0; PPpI 177.8-187.3; HBal 27.3-29.7.

Soldier

Head with a complete disc, concave anteriorly and flat posteriorly. Sides of the head disc gently converging before the beginning of the eyes and connected with the posterior border of the disc. Borders of the head disc strongly marginate and weakly raised posteriorly. Vertexal angles much lower than the disc, convex, with a median denticle and marginate up to the anterior part eyes. Clypeal border concave and medially delimited by two denticles. Mandibles with a strong carina. Dorsal border of the antennal scrobes with a carina ending in an obtuse denticle just before the eyes. Eyes flat and partially hidden by the head disc.

Mesosoma broad and almost flat in side view. Humeral angles obtuse. Anterior half of the pronotum sloping anteriorly; its anterior border convex mesially. Pronotal sides marginate and slightly converging posteriorly. Pronotal carina thickening from the sides to the center where it is interrupted by a superficial sulcus. Promesonotal suture more impressed on the sides. Mesonotum with a pair of broad, round expansion. Propodeal suture deeply impressed. Propodeum well differentiated in basal and declivous faces. Basal face medially as high as the mesonotum, laterally lower. Sides of the basal face of the propodeum with two pairs of teeth, the first pair short, broad and with almost round tip, the second one large, broad, thick, curved upwards and forwards at the apex and with obtuse tip. Declivous face concave in the middle; its sides converging posteriorly.

Petiole differentiated in anterior and posterior faces; anterior face oblique, almost truncate, separated from the short, declivous posterior face by an incomplete transversal carina. Sides of the petiole with a pair of short, thick teeth slightly curved backwards. Postpetiole convex and with a U-shaped carina in the middle of the dorsum. Postpetiolar sides with a pair of thick teeth arising from the anterior border and directed anterolaterally. Tip of the postpetiolar spines almost round.

Gaster oval, with a broad, protruding, anterolateral lobe. Anterolateral border of the first gastral tergite with a thin margin not reaching the stigma.

Hind femora without angle or denticle in the middle. Hind basitarsi slightly more compressed apically than distally, and without broad base.

Sculpture. Head dorsum minutely reticulate and covered by small foveae slightly broader than their interspaces, shallower and smaller on the frontal carinae. Sides of the head superficially reticulate and with foveae half of the size of those on the disc, deeper on the posterior half. Ventral part of the head reticulate-foveolate anteriorly, this sculpture becomes less impressed and shining posteriorly. Mesosoma reticulate, with foveae almost as broad as those on the side of the head, the foveae are slightly larger and sparse on the pronotum, smaller, on the mesonotum and on the basal face of the propodeum. Declivous face of the propodeum reticulate and with faint, transversal rugosities on the middle. Pleurae reticulate; propleurae with nearly longitudinal striae, this same sculpture but less regular and faint on the lower metapleurae. Sparse foveae on the meso and metapleurae. Posterior face of the petiole, postpetiole with oval and superficial foveae. Anterior face of the petiole, gaster and legs reticulate. Extensor face of the legs and anterior fourth of the first gastral tergite with superficial, oval foveae. Disc of the posterior half of the first gastral sternite shining.

Pilosity. Each fovea with an appressed canaliculate hair. Legs and gaster with the same appressed hairs as on each fovea, thinner on the gaster. Mandibles, anterior border of the head disc, mesosoma, pedicel, legs and gaster with rare, suberect, subclavate hairs. Apex of the tergites and sternites with two types of erect hairs: (1) short, sparse and slightly canaliculate, (2) long, rare and pointed.

Colour. Ventral part of the head including the ventral third of its sides, clypeus, thorax, pedicel, coxae, femora and gaster black. Head dorsum, including the two dorsal thirds of the sides of the head, mandibles, sides of the pronotum, of the propodeum and of the pedicellar spines, apex of femora, outer face of tibiae and tarsomeres yellowish-orange, with darker antennae and basitarsi. Gaster with two pairs of yellow spots, the first pair anterolaterally, the second one placed on the postero-lateral half of the gaster.

Measurements (in mm) and indices: TL 6.40; HL 1.76; HW 1.76; EL 0.36; PW 1.64; PeW 0.61; PpW 0.67; HEaL 0.43; HBaW 0.14; CI 100.0; PI 117.3; PPeI 268.8; PPpI 244.8; HBaI 32.6.

Type Material

Holotype worker from Colombia, Santa Marta, FOREL, in Musee d'Histoire Naturelle Genève; paratype, one worker, same data and collection as the holotype in MHNG.

Etymology

This species is named after the Palta, one of the ancient peoples of Colombia.

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 693, figs. 327, 328 worker described)