Cephalotes ecuadorialis

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

De Andrade 1999 Cephalotes OCR - Copy-538 Cephalotes-ecuadorialis.jpg

Nothing is known about the biology of Cephalotes ecuadorialis.

Identification

A member of the crenaticeps clade differing from its sister species, Cephalotes crenaticeps, by the presence of gastral membranaceous expansions. Both share the first gastral tergite with a pair of yellow-orange spots and the first gastral sternites laterally with longitudinal rugosities, two characters unique to ecuadorialis and crenaticeps among closely related species, but appearing homoplastically in other clades as well. C. ecuadorialis also differs from crenaticeps by the frontal carinae much more upturned over the eyes, by the broader vertexal angles, by the first gastral tergite with a narrow membranaceous expansion and with a pair of yellow-orange spots almost reaching the posterior border (shortly surpassing the stigma in crenaticeps). (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Ecuador (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.

  • ecuadorialis. Cephalotes ecuadorialis De Andrade, in De Andrade & Baroni Urbani, 1999: 534, fig. 251 (w.q.) ECUADOR.

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

Description

Worker

Head subquadrate. Frons convex. Frontal carinae crenulate, upturned above the eyes. Vertexal angles broad, truncate, bearing a membranaceous expansion with strongly crenulate margin. Vertexal margin concave. Vertex with a pair of minute denticles. Mandibles with lateral carina.

Mesosoma. Scapular angles free. Anterior pronotal border gently convex. Pronotal sides with a pair of triangular, semi-membranaceous teeth converging posteriorly in an obtuse, short tooth. Promesonotal and propodeal sutures impressed on the sides in dorsal view. Mesonotum with a minute pair of denticles. Propodeum with differentiate basal and declivous faces; sides of the basal face medially denticulate; declivous face anterolaterally marked by a pair of minute denticles, the rest converging posteriorly.

Petiole. Anterior face truncate, posterior face flat. Petiolar sides diverging up to their mid-length, where they bear a pair of small denticles strongly converging posteriorly. Postpetiole gently convex dorsally; postpetiolar spines directed slightly forwards at the base and curved backwards at the apex.

Gaster. Oval with a pair of anterolateral, narrow, membranaceous expansions not reaching the stigma posteriorly.

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

Sculpture. Head, mesosoma and pedicel reticulate and covered by foveae broader than their interspaces, slightly denser on the vertexal angles and mesosoma, smaller and superficial on the pedicel. Frontal carinae reticulate and rarely foveolate. Ventral face of the head reticulate, with faint, longitudinal rugulae and with superficial, oval foveae denser on the anterior half. Declivous face of the propodeum and propleurae longitudinally rugulose and with few, superficial foveae. Meso- and metapleurae reticulate and superficially foveolate. Gaster strongly reticulate and with superficial, minute foveae. Anterior third of the first gastral sternite and sides of the remaining two thirds covered with longitudinal, posteriorly concentric rugosities. Middle of the first gastral sternite superficially shining. Legs with the same sculpture as on the gaster but with the foveae more impressed on the extensor face of femora and tibiae. Internal face of the hind coxae with longitudinal, thin rugae.

Pilosity. Each fovea with an appressed hair. Sides of the frontal carinae and of the mesosoma, pedicel and first gastral tergite with clubbed hairs, rare on the mesosoma and pedicel. 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 sternites with rare, long, pointed hairs.

Colour. Dark brown, opaque, with lighter extensor face of the tibiae. Frontal carinae yellowish to light brown and semi-transparent. Membranaceous expansion of the vertexal border and of the gaster, apex of the pronotal teeth and of the postpetiolar spines light brown. First gastral tergite with a pair of oval, anterolateral, orange spots almost reaching the posterior border.

Measurements (in mm) and indices: TL 4.80-4.88; HL 1.16-1.18; HW 1.28-1.30; EL 0.31; PW 1.10; PeW 0.46; PpW 0.55-0.57; HBaL 0.55; HBaW 0.14; CI 110.2-110.3; PI 116.4-118.2; PPeI 239.1; PPpI 193.0-200.0; HBaI 25.4.

Queen

(tentative attribution). - Head slightly longer than broad. Disc present. Head dorsum convex posteriorly and slightly flat anteriorly. Frontal carinae strongly crenulate, expanded anteriorly, not covering the eyes, converging posteriorly and connected by a short, straight margination on the vertex. Vertexal angles obtuse and with crenulate margin. Ocelli distant from the posterior border of the disc. Mandibles laterally carinate.

Mesosoma. Anterior pronotal border convex. Humeral angles with a pair of pointed teeth. Pronotal sides straight. Pronotal carina impressed and interrupted only medially. Lower mesopleurae with a stout denticle. Mesonotum and scutellum flat. Propodeum with differentiate basal and declivous faces; sides of the basal face gently convex anteriorly, with a pair of teeth curved forwards. Declivous face with posteriorly converging sides.

Petiole with oblique anterior face and straight posteriorly; petiolar sides with a minute denticle medially. Postpetiole convex; postpetiolar sides with a pair of spines directed slightly forwards at the base and curved backwards at the apex.

Mid and hind femora not angulate. Mid and hind basitarsi flat and slightly broad at the base.

Gaster with a pair of anterolateral lobes.

Sculpture. Head dorsum superficially and minutely punctate and covered with small, superficial foveae, broader than their interspaces; frontal carinae superficially shining. Ventral part of the head minutely punctate and covered with foveae larger and less regular than those on the dorsum, denser on the sides. Pronotum, mesonotum, scutellum and upper mesopleurae strongly punctate and with variably clumped foveae. Basal face of the propodeum and pedicel strongly punctate and with dense, irregular foveae. Propleurae, lower mesopleurae and metapleurae strongly punctate and with rare, superficial foveae. Declivous face of the propodeum, legs and first tergite and sternite reticulate punctate. Anterior third of the first gastral tergite with longitudinal, irregular, thin rugosities. Remaining tergites, sternites and middle of the first gastral sternite superficially reticulate, punctate and shining.

Pilosity. Body with four type of hairs: (1) appressed, canaliculate, originating from the foveae; (2) thinner than those originating from the foveae and appressed, on the gaster and on the legs; (3) suberect, sparse and clubbed on the sides of the frontal carinae, on the vertexal angles, on the mesosoma, on the pedicel, on the gaster and on the legs; (4) long, truncate, subdecumbent on the posterior border of the tergites and of the sternites.

Colour. Dark brown with lighter legs. Frontal carinae dark ferruginous and barely semitransparent. First gastral tergite with two pairs of yellow spots, the first pair on the anterior third and surpassing the stigma posteriorly and the second pair laterally, on the posterior third.

Measurements (in mm) and indices: TL 9.00; HL 164; HW 1.64; EL 0.36; PW 1.52; PeW 0.65; PpW 0.80; HBaL 0.71; HBaW 0.22; CI 100.0; PI 107.9; PPeI 233.8; PPpI 190.0; HBaI 31.0.

Type Material

Holotype worker from Ecuador, Endese Forest Reserve, Pichincha Prov., 25.I.1994, L. E. Tennant. Paratype worker, same data as the holotype, both, holotype and paratype in Museum of Comparative Zoology.

Etymology

Ecuadorialis is a neologism indicating the provenance of the species from Ecuador.

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 534, fig. 251 worker, queen described)