Cephalotes crenaticeps

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Cephalotes crenaticeps
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. crenaticeps
Binomial name
Cephalotes crenaticeps
(Mayr, 1866)

Cephalotes crenaticeps casent0178646 profile 1.jpg

Cephalotes crenaticeps casent0178646 dorsal 1.jpg

Specimen labels

Nothing is known about the biology of Cephalotes crenaticeps.

Identification

A member of the crenaticeps clade differing from its sister species, Cephalotes ecuadorialis, by the absence of gastral expansions. The workers of crenaticeps differ from those of ecuadorialis (its sister species) by the yellow spot on the first gastral tergite not reaching the posterior border, by the narrower membranaceous expansions of the vertexal angles, by the frontal carinae weakly upturned over the eyes and by the absence of membranaceous expansions of the first gastral tergite. The gyne from Ar. Rancho Grande (MCZC) has the foveae on the head disc slightly smaller than those of the other gynes examined during the present study. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Venezuela and Colombia.

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia (type locality), 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

Nomenclature

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

  • crenaticeps. Cryptocerus crenaticeps Mayr, 1866a: 515, pl., fig. 15 (q.) COLOMBIA. De Andrade & Baroni Urbani, 1999: 528 (s.w.). Combination in Paracryptocerus (Harnedia): Kempf, 1958a: 138; in Zacryptocerus: Brandão, 1991: 385; in Cephalotes: De Andrade & Baroni Urbani, 1999: 528.

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

Description

Worker

de Andrade and Baroni Urbani (1999) - Head subquadrate. Frons convex. Frontal carinae crenulate, little upturned above the eyes. Vertexal angles truncate, bearing a narrow, membranaceous expansion with strongly crenulate margin. Vertexal margin concave. Vertex with a pair of minute denticles better marked in larger specimens. Mandibles with a lateral carina.

Mesosoma. Scapular angles free. Anterior pronotal border gently convex. Pronotal sides with a pair of triangular, pointed, semi-membranaceous teeth and converging posteriorly in an obtuse, short tooth. Promesonotal suture in dorsal view better impressed on the sides. Propodeal suture impressed. Mesonotum with or without a minute pair of denticles. Propodeum with a small swelling or denticle between the basal and declivous faces; sides of the basal face straight; sides of the declivous face converging posteriorly.

Petiole with truncate anterior face, gently sloping anteriorly and with a small pair of minute denticles dorsally; posterior face flat. Petiolar sides diverging into a small denticle medially and strongly converging posteriorly. Postpetiolar node gently concave dorsally; postpetiolar spines directed slightly forwards at the base and curved backwards at the apex.

Gaster. Suboval without protruding lobes or membranaceous expansions.

Hind femora without angles or denticles. Hind basitarsi long, flat and slightly broader at the base.

Sculpture. Head dorsum, mesosoma and pedicel reticulate and covered by oval foveae broader then their interspaces, the foveae slightly denser on the vertexal angles and mesosoma, smaller and superficial on the pedicel, and larger and less regular on the ventral part of the head. Frontal carinae reticulate and with sparse and superficial foveae. Declivous face of the propodeum and propleurae longitudinally rugulose and with rare, superficial foveae on the proplcurae only. Meso- and metapleurae reticulate and superficially foveolate. Gaster strongly reticulate and with superficial, minute foveae. Anterior third of the first gastral sternites and sides of the remaining two thirds covered with thin, longitudinal, posteriorly concentric rugosities. Legs with the same sculpture as the gaster but with the foveae more impressed on the extensor face of femora and tibiae.

Pilosity. As in ecuadorialis.

Colour. Dark brown. Frontal carinae yellowish to light brown and semi-transparent. Membranaceous expansion of the vertexal angles, tip of the pronotal teeth and of the postpetiolar spines light brown. First gastral tergite with a pair of oval, anterolateral, orange spots shortly surpassing the stigma posteriorly. Proximal half of the femora light brown, distal half of the femora and remaining legs yellowish to ferruginous.

Measurements (in mm) and indices: TL 4.00-4.40; HL 100-1.06; HW 1.12-1.20; EL 0.26-0.28; PW 0.95-1.08; PeW 0.47-0.48; PpW 0.54-0.56; HBaL 0.41-0.44; HBaW 0.10-0.11; CI 112.0-113.7; PI 111.1-117.9; PPeI 202.2-225.0; PPpI 175.9-192.8; HBaI 24.4-25.0.

Soldier

de Andrade and Baroni Urbani (1999) - Head disc subquadrate, with strongly crenulate border and much more raised on the sides than posteriorly; sides of the disc broad anteriorly, not covering completely the eyes and strongly converging after the eyes to a short, straight carina on the vertex. Floor of the disc with a small medial tumulus. Vertexal angles obtuse to pointed, completely separate from the disc and with strongly crenulate border. Mandibles laterally carinate and laterally hidden by the frontal carinae.

Mesosoma. Anterior pronotal border straight. Scapular angles free. Humeral angles diverging to a broad, triangular, pointed spine where they continue into the pronotal crest. Posterior half of the pronotal sides strongly converging. Pronotal carina high, superficially crenulate and diminishing in height only in the middle where it is notched. Pronotal suture variably impressed. Promesonotal suture deeply impressed. Mesonotal sides with a small pair of broad, round or apically pointed teeth. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of teeth, the first pair in the middle, the second pair between the two faces and curved upwards. Declivous face of the propodeum narrowing posteriorly.

Petiole and legs as in the worker.

Gaster oval, little protruding anterolaterally and with a faint margin not surpassing the stigma posteriorly.

Sculpture. Head dorsum superficially reticulate and covered with round foveae broader than their interspaces. Ventral face of the head reticulate and with broad, dense, deep, oval foveae forming few, irregular rugosities. Mesosoma and pedicel reticulate and covered by oval foveae, larger on the pronotum, denser and smaller on the mesonotum and propodeum, superficial on the pedicel. Declivous face of the propodeum reticulate only. Pleurae reticulate and with oval foveae, sparser on the propleurae. Propleurae with few, irregular rugae. Gaster reticulate and with minute, superficial foveae. Legs with the same sculpture as on the gaster but with the foveae better impressed on the extensor face of the femora and tibiae. Anterior third of the first gastral sternite and sides of the two posterior thirds with thin, irregular rugosities. Middle of the first sternite shining.

Pilosity. Each fovea with an appressed, broad hair. Sides of the frontal carinae, of the vertexal angles, of the mesosoma, of the pedicel and first gastral tergite with clubbed hairs. Similar hairs or slightly longer on the border of the remaining gastral segments and on the legs. First gastral sternite and border of the remaining ones with sparse, long, pointed hairs.

Colour. Dark brown. Frontal carinae, border of the vertexal angles, of the pronotal and postpetiolar spines reddish. First gastral tergite anterolaterally with a pair of oval, orange spots shortly surpassing the stigma posteriorly. Proxima half of the femora light brown, distal half and remaining legs yellowish to ferruginous.

Measurements (in mm) and indices: TL 6.04; HL 152-1.56; HW 1.68-1.72; EL 0.30; PW 1.74-1.80; PeW 0.62; PpW 0.69-0.72; HBaL 0.48-0.50; HBaW 0.14; CI 107.7-113.1; PI 93.3-98.8; PPeI 280.6-290.3; PPpI 250.0-252.2; HBaI 28.0-29.2.

Queen

de Andrade and Baroni Urbani (1999) - Head disc present. Head dorsum flat with gently concave frontal carinae. Frontal carinae strongly crenulate, expanded anteriorly, not covering the eyes, strongly converging posteriorly and connected by a short, straight carina on the vertex. Vertexal angles obtuse and with crenulate margin. Ocelli close to the posterior border of the head disc. Mandibles with a lateral carina and partially hidden by the frontal carinae.

Mesosoma. Anterior pronotal border straight. Scapular angles short but visible. Humeral angles with a triangular spine converging posteriorly and connected to the pronotal crest which is developed. Pronotal sides posterior to the angles straight. Promesonotal suture impressed. Lower mesopleurae with a denticle. Mesonotum and scutellum flat. Propodeum with differentiate basal and declivous faces; sides of the basal face with two pairs of teeth, the first pair obtuse, the second pair thin, smaller than the first and curved forwards. Declivous face with the sides converging posteriorly.

Pedicel as in the soldier but with the spines less developed.

Legs and gaster as in the soldier, but the gaster longer.

Sculpture. Head dorsum superficially reticulate and covered with round foveae, broader than their interspaces. Mesosoma reticulate and with oval foveae, denser and smaller on the scutellum and on the propodeum, sparser on the mesonotum. Ventral face of the head reticulate and with broad, dense, deep, oval foveae forming few, irregular rugosities. Declivous face of the propodeum reticulate only. Pleurae reticulate and with foveae, dense on the mesopleurae, sparser on the propleurae and rare on the metapleurae. Metapleurae with few, thin, longitudinal rugosities. Gaster reticulate and with minute, superficial foveae. Legs with the same sculpture as on the gaster but with the foveae deeper on the extensor face of the femora and tibiae. First gastral sternite shining in the middle.

Pilosity. As in the soldier but with the clubbed hairs sparse on the whole body.

Colour. As in the soldier.

Measurements (in mm) and indices: TL 8.04-8.32; HL 160-1.68; HW 1.64-1.72; EL 0.33-0.37; PW 1.60-1.70; PeW 0.58-0.64; PpW 0.75-0.80; HBaL 0.56-0.64; HBaW 0.15-0.17; CI 102.4-102.5; PI 97.6-105.0; PPeI 258.1-293.1; PPpI 210.5-224.0; HBaI 26.6-28.6.

Type Material

Gyne. Type locality: Colombia. Type material: holotype gyne labelled "Columb., Typ., Collect. G. Mayr, crenaticeps G. Mayr, Type" in Naturhistorisches Museum Wien, Vienna, examined. (de Andrade and Baroni Urbani 1999)

References

  • 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 528, soldier, worker described,page 528, Combination in Cephalotes)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 138, Combination in Paracryptocerus (Harnedia))
  • Mayr, G. 1866a. Myrmecologische Beiträge. Sitzungsber. Kais. Akad. Wiss. Wien Math.-Naturwiss. Cl. Abt. I 53: 484-517 (page 515, pl., fig. 15 queen described)