Cephalotes cristatus

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Cephalotes cristatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. cristatus
Binomial name
Cephalotes cristatus
(Emery, 1890)

Cephalotes cristatus P casent0904908.jpg

Cephalotes cristatus D casent0904908.jpg

Specimen Label

Specimens have been collected in a variety of forest habitats. Little else is known about the biology of Cephalotes cristatus.

Identification

A member of the depressus clade characterised, in the worker, by the pronotum with a pair of short lamellae and by the vertex with denticles, in the soldier, by the pronotal lamellae truncate, in the soldier and in the gyne, by the pronotal crest strongly crenulate, and, in the gyne, by the mesopleurae densely covered with thick hairs. C. cristatus is the only species of the depressus clade reaching Mexico to the North and represented only by two Colombian records in South America. This Central American species shares by synapomorphy with Cephalotes pavonii the pronotal crest strongly raised and crenulate in the soldier and in the gyne. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Mexico, Belize, Guatemala, Honduras, Costa Rica, Colombia.

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Colombia, Costa Rica (type locality), Guatemala, Honduras, Mexico.

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.

  • cristatus. Cryptocerus cristatus Emery, 1890b: 72, pl. 9, fig. 2 (s.w.q.) COSTA RICA. [Also described as new by Emery, 1894k: 60.] De Andrade & Baroni Urbani, 1999: 335 (m.). Combination in Paracryptocerus: Kempf, 1951: 216; in Zacryptocerus: Hespenheide, 1986: 395; in Cephalotes: Baroni Urbani, 1998: 325.

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 about 5 mm. Black; the following ferruginous: frontal carinae and usually the crest on the anterolateral border of the first gastral tergite. Head slightly broader than long, the sides little diverging caudad. Frontal carinae very indistinctly crenulate, the minute projecting setulae limited to less than the anterior third. Vertex with a pair of more or less vestigial minute denticules. Occipital lobes bidentate. Thorax moderately and more or less continuously longitudinally convex. Pronotal lamellae narrower than postpetiole, longer than wide, rectangular. Behind the lamellae another short, triangular, plate-like lateral tooth, in front of the mesonotum, subequal to the lateral tooth of the mesonotum. Second epinotal spine slender, much longer than in depressus. Petiole with a long, recurved lateral spine arising from the anterior corner; the anterior border, including the spines, not continuously arcuate. Lateral spines of petiole curved forward at base, recurved and denticulate behind at apex. Gaster narrowly crested antero-Iaterad, longer than wide, its length subequal to the interocular width.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.60-6.04; HL 1.08-1.40; HW 1.46-1.88; EL 0.40-0.45; PW 1.44-1.76; PeW 0.96-1.16; PpW 0.80-0.94; HBaL 0.48-0.56; HBaW 0.15-0.20; CI 134.3-138.2; PI 101.4-109.3; PPeI 150.0-153.5; PPpI 1.80.0-187.2; HBaI 31.2-35.7.

Soldier

de Andrade and Baroni Urbani (1999) - Head subquadrate, with complete disc; head dorsum almost flat, slightly convex on the frons and weakly concave laterally. Frontal carinae with subcrenulate border, converging posteriorly. Disc, posteriorly, with a pair of developed median teeth connected each other by a median carina continuing laterally into the frontal carinae. Vertexal corners with two pairs of short, broad, obtuse teeth. Mandibles broad, their sides with an impressed, round, carinate protuberance. Eyes gently convex.

Mesosoma broad anteriorly, narrowing posteriorly. Pronotum with the anterior border convex; its sides with a developed, rectangular, humeral angles converging posteriorly. Pronotal carina well marked, raised, strongly crenulate or denticulate and interrupted medially by an impression. Promesonotal suture impressed. Mesonotum with a broad, short, obtuse tooth. Propodeal suture deeply impressed. Propodeum with poorly differentiated basal and declivous faces. Basal face broadening posteriorly and ending in a pair of broad, strongly developed, rectangular lamellae; its dorsum convex in the middle and on the same plane as the declivous face. Declivous face flat in the middle; its sides converging posteriorly.

Petiole almost flat and sloping anteriorly; its anterior border anteriorly concave. Petiolar sides converging posteriorly, with a well developed spine directed backwards in their first half. Postpetiole, in lateral view, slightly convex, the middle of its dorsum gently concave; postpetiolar spines thick, arising from the anterior face of the postpetiole and curved backwards.

Gaster oval and with a broad anterolateral lobe. Anterolateral border of the first gastral sternite with a thin margin not reaching the stigma.

Hind femora medially angulate. Hind basitarsi flat and with broad base.

Sculpture. Head disc superficially reticulate and covered by small foveae almost as broad as their interspaces and diminishing in size anteriorly. Vertex, ventral face of the head and pronotum with foveae denser, deeper and larger than those on the posterior part of the head disc; the foveae are sparser in the middle of the ventral part of the head and on the propleurae. Mesonotum with the same type of sculpture as on the pronotum, but the foveae smaller and denser. Basal face of the propodeum, lower meso- and metapleurae and petiolar and postpetiolar dorsum deeply reticulate and with dense, oval foveae; the same type of sculpture but more superficial on the distal part of the extensor face of the femora and of the tibiae. Declivous face of the propodeum, upper metapleurae, legs and gaster simply reticulate. Sparse to rare foveae on the upper mesopleurae. Anterior fourth of the first gastral tergite with dense piligerous punctures, this same type of sculpture but sparser on the remaining tergite and on the anterior and posterior faces of the legs.

Pilosity. Each fovea with an appressed canaliculate hair. Legs with rare, thin, appressed hairs. Crenulations of the frontal and pronotal carinae with an erect, slightly canaliculate hair, the same type of hairs, but rarer on the sides of the thorax and of the pedicel, sparse and longer on the legs and on the gaster. Apex of the gastral sternites with sparse, long, slightly pointed hairs.

Colour. Opaque black. Frontal carinae dark ferruginous, tip of the last funicular joint and tarsomeres lighter. Head superficially shining.

Measurements (in mm) and indices: TL 7.20-7.64; HL 1.72-1.88; HW 2.24-2.40; EL 0.48-0.53; PW 2.28-2.40; PeW 1.24-1.32; PpW 1.12; HBaL 0.60-0.62; HBaW 0.22-0.24; CI 127.6-130.2; PI 98.2-100.0; PPeI 172.7-193.5; PPpI 203.6-214.3; HBaI 35.5-40.0.

Queen

Kempf (1951) - Length 10 mm. Black. Head as in soldier, frontal carinae s lightly less expanded, more distinctly crenulate. Vertex with a median bidentate transverse crest, the lateral carina more or less vestigial. Sides of pronotum with an acute scapular spine, pointing obliquely forward. Dorsum of pronotum with a serrated transverse crest, the median portion touching the anterior margin of the pronotum. Basal face of epinotum with a small lateral and a somewhat longer posterior tooth. Lower mesopleura with a strong tooth. Petiole less than twice as long as broad, the sides forming an obtuse stout tooth or angle, when seen from above. Postpetiole with a short conical, stout spine on each side, curving forward and recurving apically. Gaster elongate, slightly emarginate anteromesad, distinctly marginate, not crested antero-laterad. Wings infumated, veins dark brunneous. Fore wing with a transverse cubital vein. Marginal cell closed and appendiculate.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 10.40-10.56; HL 2.00-2.12; HW 2.30-2.36; EL 0.56; PW 2.28-2.36; PeW 0.92-1.04; PpW 1.24-1.28; HBaL 0.76; HBaW 0.28; CI 111.3-115.0; PI 100.0-100.9; PPeI 226.9-247.8; PPpI 183.9-184.4; HBaI 36.8.

Male

de Andrade and Baroni Urbani (1999) - tentative attribution; We are rather confident on the attribution to this species of the previously undescribed male in the USNM unaccompanied by workers. Its label is very similar (though not identical) to the label of cristatus workers in Museu de Zoologia da Universidade de Sao Paulo and this is the sole known Mesoamerican species of the clade.

Head (eyes included, mandibles excluded) about 1/3 broader than long. Vertexal margin straight, carinate and ending in two broad, obtuse angles. Vertexal angles diverging towards the posterior border of the eyes. Ocelli protuberant from the weakly convex vertex. Eyes broadly convex. Frontal carinae diverging backwards and not reaching the posterior border of the eyes. Frons flat. Clypeus weakly convex and declivous anteriorly; its anterior border straight. Mandibles slender and laterally carinate. Scapes twice as long as the first funicular joint; remaining funicular joints thickening from the base to the apex.

Mesosoma. Pronotum broadening backwards in dorsal view. Scapular angles distinct from the pronotal sides. Humeral angles with a pair of denticles. Pronotal sides superficially carinate. Mesonotum convex; median Mayrian carina and parapsidal furrows impressed; scutellum convex. Propodeum with slightly differentiate basal and declivous faces; basal and declivous faces converging posteriorly; basal face posteriorly declivous and unarmed.

Petiole narrower than the postpetiole and with a deeply concave anterior border; petiolar dorsum declivous anteriorly; anterior third of the petiolar sides diverging, remaining two posterior thirds strongly converging backwards. Postpetiole weakly convex dorsally; postpetiolar sides with a pair of triangular teeth, and converging posteriorly.

Gaster almost as broad as the mesosoma.

Wings. As in the gyne.

Sculpture. Body deeply reticulate-punctate. Head with irregular, sparse and variably marked rugosities, thicker on the posterior third and on the ventral part of the head, more regular on the periocular area, very thin on the frons; frons with additional minute foveae. Pronotum, mesonotum and scutellum with irregular foveae, absent on the centre of the pronotum. Basal face of the propodeum with longitudinal rugosities reaching the anterior half of the declivous face. Pleurae with rugosities, longitudinal on the lower pro- and metapleurae, irregular on the mesopleurae and upper metapleurae, absent on the upper propleurae. Mesopleurae with additional, irregular foveae. Pedicel, gaster and legs superficially reticulate-punctate, the punctures more impressed on the tibiae.

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

Colour. Dark brown to black. Scapes, gaster and legs light brown.

Measurements (in mm) and indices: TL 5.42; HL 0.92; HW 1.28; EL 0.44; PW 1.12; PeW 0.51; PpW 0.63; HBaL 0.73; HBaW 0.14; CI 139.1; PI 114.3; PPeI 219.3; PPpI 203.2; HBaI 19.2.

Syntype Specimen Labels

Type Material

de Andrade and Baroni Urbani (1999) - Worker, soldier and gyne. Type locality: Alajuela and Jimenez, Costa Rica. Type material: 2 workers, 1 gyne labeled "Alajuela, Alfaro" Museo Civico di Storia Naturale, Genoa, 3 workers and 1 gyne labelled "Costa Rica, Jimenez, Alfaro" MCSN, 2 workers, 2 soldiers, 2 gynes labelled "Costa Rica, Alfaro" MCSN, Musee d'Histoire Naturelle Genève, 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 325, Combination in Cephalotes)
  • 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 335, male described)
  • Emery, C. 1890b. Voyage de M. E. Simon au Venezuela (Décembre 1887 - Avril 1888). Formicides. Ann. Soc. Entomol. Fr. (6)(10): 55-76 (page 72, pl. 9, fig. 2 soldier, worker, queen described)
  • Hespenheide, H.A. 1986. Mimicry of ants of the genus Zacryptocerus. J. N. Y. Entomol. Soc. 94: 394-408 (page 395, Combination in Zacryptocerus)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 216, Combination in Paracryptocerus)