Cephalotes frigidus

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Cephalotes frigidus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. frigidus
Binomial name
Cephalotes frigidus
(Kempf, 1960)

Nothing is known about the biology of Cephalotes frigidus.

Identification

A member of the angustus clade differing from Cephalotes adolphi and Cephalotes dentidorsum, in the worker, by the second pair of pronotal teeth lamellaceous and flat instead of solid and turned upwards. C. frigidus and its closest relatives adolphi and dentidorsum are well differentiated from the other members of the angustus clade by the long, thin spines of the petiole and of the postpetiole.

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.

  • frigidus. Paracryptocerus (Harnedia) frigidus Kempf, 1960f: 440, fig. 19 (w.) BRAZIL. De Andrade & Baroni Urbani, 1999: 731 (s.q.). Combination in Zacryptocerus: Brandão, 1991: 386; in Cephalotes: De Andrade & Baroni Urbani, 1999: 729.

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 3.9 mm; maximum length of head 1.14 mm; maximum width of head in front of the eyes 1.08; maximum diameter of eyes 0.29 mm; Weber's length of thorax 1.10 mm; maximum width of gaster 1.16 mm. Black, mandibles, antennae, legs except fore coxae, tips of occipital lobes, thoracic and pedicellar spines brown or ferruginous; frontal carinae and anterolateral foliaceous border of gaster testaceous.

Head subopaque, subquadrate. Mandibles finely and densely reticulate-punctate, opaque. Clypeal suture vestigial. Frontal carinae flat, depressed, semitranslucid, superficially reticulate-punctate above without conspicuous foveolae; borders anteriorly vestigially crenulate; lateral borders rather straight, evenly converging cephalad. Sides of head slightly but distinctly emarginate in front of eyes, convex and somewhat upturned above eyes. Occipital lobes with obliquely truncate and feebly crenate crest. Eyes very prominent, remarkably convex. Dise of cephalic dorsum moderately convex in both directions, front, vertex and occiput densely and finely reticulate-punctate, with sparser, larger, sharply impressed oval foveolae. Cheeks more heavily shagreened, with irregular rugulae and indistinct foveolae, lower border marginate. Gular surface reticulate-punctate with fine and sparse longitudinal rugulae.

Thorax subopaque, reticulate-punctate. Scapular corner free, angulate and subdentate. Lateral margin of pronotum tridentate, the first tooth acute, the following two teeth obtuse to blunt at apex. Promesonotal suture obsolete. Mesonotum at each side with a blunt to slightly bifid projecting tooth. Mesoepinotal suture practically absent, indicated laterally by a faint depression. Lateral margin of epinotum with 3 to 4 teeth, the anterior pair acute, the second the largest, the following 1-2 teeth minute, none at the bottom of the declivous face. Basal face of epinotum grading into declivous face. Dorsum of thorax reticulate-rugose and densely foveolate. Laterotergite of pronotum with a few horizontal costae. Remainder of sides of thorax longitudinally rugose and foveolate. Fore coxae laterally transversely costate. All legs subopaque and finely reticulate-punctate. Femora spindle-shaped. Tibiae not prismatic.

Petiolar and postpetiolar nodes with a prominent, drawn out spiniform appendage at each side. Postpetiole slightly broader than petiole. Body of petiole with an anterior subvertical truncate face, separated laterally from dorsal face by a faint and short transverse carinule. Postpetiolar dorsum in profile feebly convex. Both pedicellar segments subopaque, reticulate-punctate, and indistinctly reticulate-rugose.

Gaster broad oval, reticulate-punctate, subopaque, with super-imposed fine longitudinal but frequently anastomosing rugulae. Anterolateral foliaceous border subhyaline, relatively narrow, terminating posteriorly at the level of the first gastral spiracle.

Erect hairs scarce. Short, apically blunt setae anterolaterally on rim of frontal carinae, and on sides of head behind the eyes and in front of occipital corner. Longer and more pointed hairs on apex of gaster, including the anterior margin of the first tergite. Squamiform, canaliculate, silvery appressed hairs rather abundant in all foveolae on dorsum of body, more sparsely on frontal carinae, gular face, legs and posterior half of gaster, where they are narrower, simple and usually not canaliculate.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.84-4.14; HL 0.98-1.04; HW 1.04-1.16; EL 0.27-0.29; PW 0.92-1.00; PeW 0.59-0.63; PpW 0.64-0.68; HBaL 0.32-0.34; HBaW 0.09; CI 106.1-111.5; PI 113.0-116.0; PPeI 155.9-158.7; PPpI 143.7-147.0; HBaI 26.5-28.1.

Soldier

de Andrade and Baroni Urbani (1999) - Head subquadrate, almost as broad as long, with a complete disc. Floor of the disc oblique on the anterior third and flat posteriorly. Border of the disc moderately raised and lamellaceous. Vertexal angles obtuse and bearing a broad lamella continuing up to the eyes. Mandibles with a strong carina. Dorsal border of the antennal scrobes with a short denticulate carina just in front of the eyes. Eyes convex and largely hidden by the disc.

Mesosoma. Scapular angles visible and short. Anterior pronotal border subtruncate. Pronotal sides with a pair of broad expansions, anteriorly obtuse, medially truncate, posteriorly strongly converging. Border of the anterior half of the pronotal expansions lamellaceous. Pronotal carina lamellaceous, strongly developed, thickening medially from the sides; medially the lamella is interrupted by a superficial sulcus. Promesonotal suture impressed. Mesonotum with a broad, round tooth with lamellaceous border. Propodeal suture deeply impressed. Propodeum with well differentiate basal and declivous faces. Sides of the basal face diverging posteriorly, with a pair of small, triangular teeth followed by another pair of large teeth curved upwards and forwards at the apex. Declivous face concave in the middle; its sides converging posteriorly.

Anterior face of the petiole separate from the posterior one by a thin, transversal carina; anterior face truncate and superficially concave medially; posterior face sloping backwards. Sides of the petiole with a pair of thin, pointed, medial teeth directed backwards. Postpetiolar node acuminate. Postpetiolar sides with a pair of thick, round expansions arising from the anterior border, directed anterolaterally and pointed backwards.

Gaster oval and with a pair of broad, anterolateral lobes.

Mid and hind femora without angles or denticles. Hind basitarsi slightly more compressed apically than distally and with a broader base.

Sculpture. Head dorsum superficially punctate and covered by contiguous, deep, irregular foveae, smaller on the anterior third. Ventral part of the head punctate-foveolate, the foveae deeper, denser and larger on the postero-lateral parts. Mesosoma with the same type of sculpture as the posterior part of the head dorsum, but with more regular, shallower, and smaller foveae on the basal face of the propodeum. Pleurae, pedicel, outer face of the femora and of the tibiae reticulate and with small, very superficial, oval foveae, absent on the metapleurae, larger on the pro- and mesopleurae. Gaster and remaining parts of the legs reticulate.

Pilosity. Each fovea of the head dorsum with a canaliculate-subclavate hair, suberect on the two posterior thirds and decumbent on the anterior third; other body foveae with appressed, canaliculate hairs of size proportional to the one of the fovea from which they originate. Other parts of the legs and of the gaster with the same appressed hairs as the mesosoma, but thinner, denser on the first gastral sternite. Sides of the head disc, pedicel, legs and posterior border of the tergites and sternites with suberect, rare, clubbed hairs.

Colour. Ventral part of the head, center of the mesosoma, two ventral thirds of the pleurae, pedicel, gastral sternites, coxae, two proximal thirds of the femora, and tarsi brown-black; sides and dorsum of the head, sides of the mesonotum, last dorsal third of the pleurae, peduncular spines and remaining parts of the legs yellow-orange. First gastral tergite yellow and with the following parts dark brown: latero-ventral and posterior borders and a central, dorsal inverted triangle.

Measurements (in mm) and indices: TL 6.52; HL 1.80; HW 1.84; EL 0.35; PW 1.76; PeW 0.82; PpW 0.86; HBaL 0.43; HBaW 0.13; CI 102.2; PI 104.5; PPeI 214.6; PPpI 204.6; HBaI 30.2.

Queen

de Andrade and Baroni Urbani (1999) - Differing from the soldier in the following details:

Anterior third of the head less oblique than in the soldier. Sides of the disc with superficially crenulate border. Eyes largely visible in dorsal view. Humeral angles with a pair of short, triangular, lamellaceous expansions. Pronotal sides straight. Pronotal carina less high. Mesonotum and scutellum slightly convex in side view. Basal face of the propodeum with two pairs of teeth, the first pair small and triangular, the second one larger, subpointed and directed backwards. Petiole subquadrate, without transversal carina; anterior face of the petiole sloping and the posterior one short and declivous. Petiolar sides with a pair of minute, pointed denticles. Postpetiole less acuminate, more convex and with a short U -shaped carina; lateral expansions of the petiole smaller.

Gaster oval. Anterolateral gastral lobes protruding and with a very thin margin not reaching the stigma posteriorly.

Sculpture. Similar to the one of the soldier except: anterior half of the ventral part of the head with, sparse, irregular, longitudinal rugosities; foveae more superficial and more regular on the mesosoma; pleurae with longitudinal rugosities, thicker on the propleurae, transversal on the upper metapleurae, absent on the upper mesopleurae; upper mesoplcurae densely covered by small foveae; coxae with rugosities, transversal on the fore coxae and longitudinal on the mid and hind coxae; anterior third of the first gastral tergite with superficial, very thin, longitudinal, slightly irregular rugosities; sides of the first gastral sternite with irregular, very thin and superficial rugosities.

Pilosity. As in the soldier but with the following differences: clubbed hairs denser and also present on the mesosoma and on the gaster. First gastral sternite with sparser thin, hairs.

Colour. Ventral part of the head, mesosoma, pedicel, gaster and coxae black; sides of the head, of the floor of the disc and of the pronotum yellow-orange; center of the disc and clypeus light brown. Two proximal thirds of the femora and tarsi brown. Remaining parts of the legs yellow. Sides of the first gastral tergite with two pairs of broad, yellow spots, the first pair in the anterior third and the second one in the posterior third.

Measurements (in mm) and indices: TL 7.56; HL 1.62; HW 1.60; EL 0.34; PW 1.56; PeW 0.66; PpW 0.79; HBaL 0.49; HBaW 0.15; CI 98.8; PI 102.6; PPeI 236.4; PPpI 197.5; HBaI 30.6.

Type Material

de Andrade and Baroni Urbani (1999) - Worker. Type locality: Cabo Frio (Rio de Janeiro, Brazil). Type material: 1 worker (holotype), in Instituto Biologico, Sao Paulo, not available for the present study.

References

  • Brandão, C. R. F. 1991. Adendos ao catálogo abreviado das formigas da região Neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412 (page 386, Combination in Zacryptocerus)
  • 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 731, soldier, worker described, page 729, Combination in Cephalotes)