Cephalotes depressus

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

Cephalotes depressus casent0173671 profile 1.jpg

Cephalotes depressus casent0173671 dorsal 1.jpg

Specimen labels

Synonyms

Specimens have been collected in pasture and scrub vegetation. Little else is known about the biology of Cephalotes depressus.

Identification

A member of the depressus clade differing from its sister species Cephalotes eduarduli, in the worker, soldier and gyne by the absence of erect, truncate hairs on the mesosoma, on the pedicel and on the first gastral tergite, in the soldier and in the gyne by the head dorsum opaque. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Venezuela, Guyana, Ecuador, Brazil, Bolivia, Argentina, and Paraguay.

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Bolivia, Brazil (type locality), Ecuador, Guyana, Paraguay, Venezuela.

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

Worker

Soldier

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • depressus. Cryptocerus depressus Klug, 1824: 204 (w.) BRAZIL. Emery, 1906c: 170 (s.q.m.); Forel, 1906d: 235 (q.m.); De Andrade & Baroni Urbani, 1999: 355 (m.). Combination in Paracryptocerus: Kempf, 1951: 218; in Zacryptocerus: Brandão, 1991: 385; in Cephalotes: Baroni Urbani, 1998: 326; De Andrade & Baroni Urbani, 1999: 352. Junior synonym of pavonii: Roger, 1861b: 173; Forel, 1895b: 134. Revived from synonymy: Forel, 1912e: 200. Senior synonym of sorocabensis: Kempf, 1951: 218.
  • sorocabensis. Cryptocerus depressus var. sorocabensis Forel, 1912e: 200 (s.) BRAZIL. Junior synonym of depressus: Kempf, 1951: 218.

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

Description

Worker

Kempf (1951) - Length 4.5-6 mm. Black; the following ferruginous to testaceous: frontal carinae, occipital lobes, tips of lateral spines on thorax and peduncle, and anterolateral border of gaster. Reddish-brown to fuscous-brown: Mandibles, antennae, tibiae, and tarsi.

Head subquadrate, slightly broader than long. Frontal carinae distinctly crenulate and beset with small projecting setulae on the anterior half; very little diverging caudad. Occipital lobes bidenticulate, the inner tooth subacute, the outer tooth blunt. Pronotal lamellae short, not longer than broad, the second tooth of the pronotum, behind the lamella small, smaller than the lateral mesonotal tooth. First lateral epinotal spine not recurved, the second spine very short, in the form of a triangular tooth, removed from the posterior corner of the declivous face. Petiole with a lateral slender spine, arising from the side, its base removed backward from the often subangulate anterior corner of the segment. Postpetiole with an anterior lateral stout spine, recurved at apex. Gaster subcordiform, longer than wide, longer than the interocular width. The anterolateral border of the first tergite distinctly but narrowly crested.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.20-5.80; HL 0.92-1.32; HW 1.16-1.72; EL 0.32-0.44; PW 1.00-1.68; PeW 0.64-0.98; PpW 0.55-0.76; HBaL 0.32-0.48; HBaW 0.10-0.19; CI 126.1-130.3; PI 103.1-116.0; PPeI 156.2-171.4; PPpI 181.8-221.0; HBal 31.2-39.6.

Soldier

Kempf (1951) - 7 mm. Black; the following lighter, more or less ferrugenous: anterior portion of frontal carinae, tips of femora, tibiae and tarsi, tips of lateral pronotal and epinotal lobes, peduncular spines.

Head subquadrate, the upper surface of head rather convex. Frontal carinae sharply crenulated, with small setulae projecting from the notches. Vertex with a vestigial transverse median carinule, the small teeth more or less vestigial; occiput subtruncate. Upper surface of head finely punctate and subfulgid. Shoulders distinct, pronotum greatly expanded laterad, the posterior portion, of the sides strongly converging and somewhat emarginate. Transverse pronotal crest vestigial mesad. Mesonotum with a rounded lateral lobe. Basal face of epinotum very short mesad, with a postero-lateral bituberculate on each side, the base of which forms a faint carinule separating the declivous face from the basal face, fading out towards the middle. Petiole and postpetiole as in worker, the petiole still narrower, the lateral spines shorter. The postpetiole with stouter, more recurved lateral spines.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.44-7.08; HL 1 .60-1 .76; HW 2.00-2.22; EL 0.44; PW 1.96-2.12; PeW 0.96-1.08; PpW 0.84-0.94; HBaL 0.52-0.56; HBaW 0.20; CI 124.4-126.1; PI 102.0-104.7; PPeI 196.30-204.1; PPpI 225.5-238.1; HBaI 35.7-38.5.

Queen

Kempf (1951) - Length 10 mm. In general similar to that of cristatus. Frontal carinae regularly and very sharply crenulate. Vertex without a distinct median bicarinate crest. Occipital angle simple, not bidenticulate. Transverse pronotal crest not serrated, with a more or less continuous edge. Scapular spine short, directed sideward, not foreward. Lower mesopleura without a conspicuously projecting tooth, usually more or less obsolete. Epinotal teeth shorter. Petiole about as long as wide, sides sub-parallel, constricted behind, the sides forming a small, rectangular denticle in front of the constriction. Postpetiole somewhat broader than long, much narrower than in cristatus. Wings infuscated, the veins dark brunneous. Fore wing with a closed and appendiculate marginal cell, the transverse cubital vein present.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 9.52-10.16 HL 1.80-1.84; HW 2.04-2.08; EL 0.48; PW 1.92-2.08; PeW 0.80-0.92; PpW 1.00-1.06; HBaL 0.68-0.70; HBaW 0.24-0.25; CI 113.0-113.3; PI 100.0-106.2 PPeI 226.1-240.0; PPpI 1.92.0-196.2; HBaI 35.3-35.7.

Male

de Andrade and Baroni Urbani (1999) - Head (eyes included, mandibles excluded) 1/3 broader than long; vertexal angles obtuse and carinate. Ocelli protuberant on the convex vertex. Eyes broadly convex and placed in the middle of the sides of the head. Frontal carinae raised, diverging backwards and not reaching the posterior border of the eyes. Frons flat. Clypeus convex dorsally. Mandibles slender, laterally carinate and with three distinct apical teeth. Scapes thick, twice longer than the first funicular joint; remaining funicular joints thickening from the base to the apex.

Mesosoma. Pronotum in dorsal view broadening backwards; its sides with a superficial lateral carina in some specimens only. Mesonotum convex; median Mayrian carina and parapsidal furrows weakly impressed. Scutellum convex, its sides converging posteriorly. Propodeum with slightly differentiate basal and declivous faces; basal face convex, its sides converging posteriorly.

Petiole narrower than postpetiole with a deeply concave anterior border. Sides of the petiolar node convex and posteriorly converging. Postpetiole convex in dorsal view; its sides anteriorly with an obtuse, short denticle or gently convex.

Gaster as broad as or broader than the mesosoma.

Wings. Fore wings with R+Sc superficially connected with a marked pterostigma. 2r marked, Rsf5 connected with R1. Distal parts of A, Cu-A1 and Mf4 vestigial. Hind wings with R, M+ CuA, M and 1A marked; CuA, M and distal part of 1A vestigial.

Sculpture. Body covered by deep reticulation less impressed on the gaster and on the legs. Head dorsum with small, superficial foveae, denser on the posterior fourth and on the frons. Periocular area with transversal rugosities. Ventral part of the head and mesosoma with large, deep, irregular foveae. Pleurae with longitudinal, thin rugosities; mesopleurae with very superficial, small foveae. Pedicel with few rugosities.

Pilosity. Head and mesosoma covered by long, dense, sub erect, hairs, sparser and subdecumbent on pedicel, on the gaster and on the legs. Funiculi densely covered by thin, short, decumbent hairs, similar but thinner, sparser and slightly longer hairs on the legs and on the gaster.

Colour. Head, mesosoma and pedicel black; proximal half of the legs and gaster light brown to black. Distal half of the legs and wing veins yellowish brown. Wings slightly infuscated and transparent.

Measurements (in mm) and indices: TL 5.40-6.38; HL 0.80-0.90; HW 1.12-1.24; EL 0.39-0.46; PW 0.96-1.12; PeW 0.48-0.64; PpW 0.56-0.70; HBaL 0.50-0.60; HBaW 0.11-0.13; CI 135.6-140.0; PI 108.9-116.7 PPeI 192.3-200.0; PPpI 166.7-171.4; HBaI 20.3-23.5.

Type Material

de Andrade and Baroni Urbani (1999):

Worker. Type locality: Guanabara, Rio de Janeiro. Type material: not available for the present study.

Cryptocerus depressus var. sorocabensis. Soldier. Type locality: Sorocaba (Sao Paulo). Type material 7 workers and 2 small soldiers labelled: "Sorocaba, Provo St. Paolo, Goldi, C. depressus v. sorocabensis For., type", 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)
  • Brandão, C. R. F. 1991. Adendos ao catálogo abreviado das formigas da região Neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412 (page 385, 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 355, male described, page 352, Combination in Cephalotes)
  • Emery, C. 1906c [1905]. Studi sulle formiche della fauna neotropica. XXVI. Bull. Soc. Entomol. Ital. 37: 107-194 (page 170, soldier, queen, male described)
  • Forel, A. 1895b. A fauna das formigas do Brazil. Bol. Mus. Para. Hist. Nat. Ethnogr. 1: 89-139 (page 134, Junior synonym of pavonii)
  • Forel, A. 1906d. Fourmis néotropiques nouvelles ou peu connues. Ann. Soc. Entomol. Belg. 50: 225-249 (page 235, queen, male described)
  • Forel, A. 1912f. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mém. Soc. Entomol. Belg. 19: 179-209 (page 200, Revived from synonymy)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 218, Combination in Paracryptocerus, page 218, Senior synonym of sorocabensis)
  • Klug, F. 1824. Entomologische Monographien. Berlin: Reimer, 242 pp. (page 204, worker described)
  • Roger, J. 1861b. Myrmicologische Nachlese. Berl. Entomol. Z. 5: 163-174 (page 173, Junior synonym of pavonii)