Cephalotes christopherseni

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Cephalotes christopherseni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. christopherseni
Binomial name
Cephalotes christopherseni
(Forel, 1912)

Cephalotes christopherseni P casent0217836.jpg

Cephalotes christopherseni D casent0217836.jpg

Specimen Label

Specimens have been collected from second growth and riparian forest. Little else is known about the biology of Cephalotes christopherseni.

Identification

de Andrade and Baroni Urbani (1999) - A member of the laminatus clade differing from other species of the clade by the autapomorphic loss of the gastral spots of the gyne, substituted by a dark reddish macula. Among the closest related species, christopherseni workers can be separated from those of Cephalotes spinosus by the shorter vertexal lamellae, and, in the worker and in the soldier, by the shorter gastral lamellae, by the presence of mesonotal spines and by the absence of golden hairs on the mesosoma. From Cephalotes minutus and Cephalotes simillimus this species differs for having a bispinose (not lamellate) pronotum.

The workers of christopherseni differ from those of Cephalotes inaequalis, Cephalotes laminatus and Cephalotes spinosus (the three species resulting as in group in our cladistics analysis) by the shorter vertexal and gastral lamellae, from laminatus and spinosus by the shorter pronotal spines, and from spinosus by the presence of mesonotal spines and by the absence of golden hairs on the mesosoma. The soldier of christopherseni differs from the soldiers of these species by the head less shining, by the superficial carina connecting the spines on the vertex, by the gastral lamellae shorter and by the basal face of the propodeum strongly punctate and with dense, oval foveae. The gyne of christopherseni differs from all the others of the laminatus clade for having a unique gastral macula substituting the yellow spots of the other species.

Some Venezuelan workers differ from the typical christopherseni in having a nearly unarmed petiole or very reduced petiolar spines, shorter propodeal spines, and a broader head.

Keys including this Species

Distribution

Panama, Colombia: Bolivar, Caldas, Casanare, Choco, and N. Santander, Venezuela, and Guyana.

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia (type locality), Panama, 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.

  • christopherseni. Cryptocerus laminatus r. christopherseni Forel, 1912e: 204 (s.w.) COLOMBIA. Wheeler, G.C. & Wheeler, J. 1986f: 494 (l.); De Andrade & Baroni Urbani, 1999: 211 (q.m.). Combination in Cryptocerus (Paracryptocerus): Emery, 1924d: 307; in Paracryptocerus: Kempf, 1951: 166; in Zacryptocerus: Brandão, 1991: 385; in Cephalotes: De Andrade & Baroni Urbani, 1999: 211. Raised to species: Kempf, 1972a: 176.

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 5.4 mm. Median head length 1.36 mm. Weber's length of thorax 1 .57 mm. Black; the following light ferruginous: frontal carinae, occipital lamellae, tip of last funicular segment, lamellate border of first gastral tergite. The following slightly darker: 1st funicular segment, apices of thoracic spines, peduncular teeth, apices of tarsal segments.

Head subopaque; slightly broader than long, broadest behind the eyes, narrowed in front, interocular distance slightly longer than maximum length of head (71:69). Posterior margin straight, the occipital angles with projecting obliquely truncate lamellae, the apical border of which is scarcely sinuate. Cheeks strongly marginate beneath, densely scaled. Eyes small, their maximum diameter distinctly less than one third of the median head length. Integument very finely reticulate-punctate, sparsely covered with silvery, slender, simple, appressed scalelike hairs, longer than in inaequalis, larger, canaliculate, situated in grooves in front of the occipital border.

Thorax opaque. Anterior border moderately arcuate, shoulders sharply angulate. Pronotum somewhat expanded laterally behind the shoulders, with two short, unequal and slightly upturned spines on each side, the posterior spine being shorter than the anterior. Posterior corner of pronotum projecting, as a more or less rectangular tooth. Promesonotal suture vestigial. Mesonotum with a small and acute lateral tooth. Mesoepinotal suture more or less distinct. Basal face of epinotum in the same plane as mesonotum, transverse, with a short and straight anterolateral spine, as long as the second pronotal spine and a much longer, slender spine projecting laterad and somewhat caudad from the posterior corner. Microsculpture as on head, but the very sparse, mostly canaliculate, decumbent, silvery, long scales lie in elongate grooves. Declivous face of epinotum not excavated mesally nor crested laterad. Laterotergite of pronotum and mesopleura longitudinally striated.

Petiole opaque, transverse, with distinctly set off, slender, long, subacute lateral spines, arising from the anterior corner. Postpetiole slightly longer than petiole, transverse, with shorter, broader, apically rounded, lateral spine, curving slightly forward. Both segments sculptured as thorax, the scales somewhat shorter and simple, not lying in distinct grooves.

Gaster subfulgid, elongate cordiform, very convex above. First gastral tergite with rather narrow, distinctly set off anterolateral lamellate border. Tergites and sternites finely and rather sharply reticulate-punctate. Scales of gaster sparser, simple, short, not lying in foveolae. Erect pilosity confined to 2nd to 4th tergites and sternites.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.48-5.56; HL 1.10-1.32; HW 1.48-1.84; EL 0.34-0.40; PW 1.20-1.52; PeW 0.56-0.60; PpW 0.52-0.60; HBaL 0.52-0.60; HBaW 0.11-0.14; CI 134.5-139.4; PI 121.0-133.3; PPeI 200.0-271.4; PPpI 213.3-253.3; HBaI 21.1-23.3.

Soldier

Kempf (1951) - Length 7.0 mm. Median head length 1.83 mm; Weber's length of thorax 2.00. Black; the following ferruginous: frontal carinae in part (partly translucid), tip of last antennal segment, outer face of tibiae, tip of femora, three apical segments of tarsi. Fuscous: remaining part of appendages. Lamellate border of first gastral tergite semitranslucid.

Head subopaque; shorter than wide in front of the eyes (86:93). Frontal carinae greatly rounded anteriorly, prolonged and slightly upturned above the eyes in the form of a raised carinule, fading out before reaching the subangulate and projecting occipital corner. Upper surface of head very little convex. Eyes scarcely convex. Vertex with a pair of dentiform projections, occipital border between these teeth distinctly and sharply marginate. Occiput truncate mesad. Cheeks immarginate beneath. A distinct carinule below the eyes, extending to the occipital corners. Integument finely and shallowly reticulate-punctate. Upper surface of head with sparse, small foveolae, containing no distinctly visible hair. Foveolae somewhat more crowded on occiput. Sparser but larger on lower surface of head, containing a distinctly visible decumbent seta.

Thorax subopaque above. Anterior border arcuate, shoulders subangulate, not visible from above. Pronotum expanded laterally with two small, rather blunt teeth on each side; between the posterior pair of teeth a transverse crest, broadly interrupted mesad, vestigial laterad, the inner end raised, almost tooth-like. Sides of pronotum converging mesad behind the crest, the posterior corners subrectangular and projecting. Promesonotal suture vestigial. Mesonotum with a small, more or less rectangular lateral tooth. Mesoepinotal suture impressed. Epinotum opaque, transverse; the basal face with a short, triangular tooth anterolaterally and a much larger, stout, strongly diverging tooth at the posterior corner, having a ventral lobe near its tip. Microsculpture as on head. Dorsum of thorax and laterotergite of pronotum covered with rather dense, deeply impressed setiferous foveolae, much larger than on upper surface of head, rounded on mesonotum, elongate on epinotum. Declivous face and posterior portion of the sides of the thorax without conspicuous macrosculpture; declivous face not crested on the sides.

Petiole opaque, transverse, anterior corners rounded; with a rather short, acute, scarcely recurved tooth on each side. Postpetiole with a plate-like lateral tooth, curving slightly foreward. Both segments finely reticulate-punctate, opaque, covered with vestigial foveolae and rugosities.

Gaster subopaque, subcordiform, about as long as wide. First gastral tergite with a narrow, semitranslucid lamellate anterolateral border; finely reticulate.

All foveolae, except on upper surface of head, contain a decumbent seta, which is flattened, shiny, and scal e-like on thorax and peduncle. Erect pilosity on the terminal tergites of the gaster and the sternites. First gastral tergite beset with minute appressed setulae. Scales canaliculate on dorsum of thorax.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.08-7.84; HL 1.56-2.12; HW 2.12-2.60; EL 0.43-0.45; PW 1.96-2.24; PeW 0.75-0.84; PpW 0.70-0.90; HBaL 0.64-0.72; HBaW 0.14-0.18; CI 122.6-135.9; PI 108.2-116.1; PPeI 261.3-266.7; PPpI 248.9-280.0; HBal 21.8-25.0.

Queen

de Andrade and Baroni Urbani (1999) - Head dorsally convex. Frontal carinae converging anteriorly, their sides gently convex and ending behind the eyes. Vertexal angles obtuse. Vertex with a pair of median, stout denticles higher than the vertexal angles. Anterior clypeal border slightly concave medially and with a pair of small lateral denticles. Mandibles broad, without a lateral tumulus or denticle. Cheeks without carina.

Mesosoma. Humeral angles with a pointed anterior tooth. Pronotal carina narrow and superficially interrupted in the middle, in some specimens absent laterally. Mesonotum and scutellum flat. Lower mesopleura with a large, stout tooth. Sides of the basal face of propodeum gently convex and bearing, laterally, a pair of curved, stout, round teeth; sides of the declivous face converging posteriorly.

Petiole with the anterior face oblique and slightly concave medially; posterior face of the petiole declivous dorsally; petiolar sides gently convex, with or without a small posterior denticle. Postpetiole broadly convex, with a depression on the middle of the dorsum; anterior sides of the postpetiole with a stout, obtuse or round tooth.

Gaster with a broad, marginate, anterior lobe.

Legs. Fore coxae round anteriorly. Mid and hind femora not angulate. Hind basitarsi nearly flat and slightly broadened at their base.

Sculpture. Head dorsum minutely reticulate-punctate and with small, superficial foveae smaller than their interspaces, the foveae more superficial and sparser on the frontal carinae. Ventral face of the head, anterior part of the pronotum and propleurae reticulate and with dense, deep, foveae larger than their interspaces. Posterior part of the pronotum, basal face of the propodeum, anterior third of the declivous face of the propodeum, upper meso- and metapleurae, anterior half of the lower mesopleurae, sides of the petiolar dorsum and postpetiole reticulate and with dense, deep foveae smaller than on the ventral face of the head. Anterior half of the mesonotum and scutellum superficially reticulate, almost shining, with sparse foveae; posterior half of the mesonotum with dense foveae superimposed by irregular, nearly longitudinal rugulae. Middle of the petiolar dorsum, posterior half of the lower mesopleurae, lower metapleurae, two posterior thirds of the declivous face of the propodeum, gaster and legs reticulate. Gaster with sparse, superficial foveae, in some specimens the foveae denser and more impressed on the anterior third of the first gastral tergite. Extensor face of the tibiae with irregular foveae.

Pilosity. Each fovea bears a thin, appressed hair; pronotal sides and legs with rare, long, slightly clavate, suberect hairs; hairs similar to those on the pronotal sides but shorter and sparser on the first gastral tergite, denser and of the same length on the remaining gastral tergites and on the sternites. Legs and gastral segments with sparse, thin hairs similar to those arising from the foveae.

Colour. Black. Gaster, tibiae and tarsomeres dark red to brown. Frontal carinae light brown and semitransparent. Gaster with a reddish macula anteriorly.

Measurements (in mm) and indices: TL 9.82-10.90; HL 1.76-2.16; HW 2.24-2.52; EL 0.48-0.50; PW 2.08-2.48; PeW 0.79-1.00; PpW 0.81-1.20; HBaL 0.75-0.76; HBaW 0.20-0.21; CI 116.7-127.3; PI 101.6-107.7; PPeI 240.0-263.3; PPpI 200.0-256.8; HBal 26.3-28.0.

Male

de Andrade and Baroni Urbani (1999) - Head (eyes included) more than 1/3 broader than long; sides of the head strongly convex and converging towards the occiput. Vertex dorsally gently protruding. Compound eyes broadly convex. Frontal carinae short and not reaching the median ocellus posteriorly. Frons flat. Clypeus convex posteriorly and truncate anteriorly. Mandibles short; external face without carina. Scapes thick, twice as long as the first funicular joint; remaining funicular joints thickening from the base to the apex.

Mesosoma. Pronotum in dorsal view with the sides diverging backwards, without carinae. Mesonotal scutum convex in side view; median Mayrian furrow little impressed. Basal and declivous faces of the propodeum differentiate; basal face gently convex and sloping backwards; declivous face posteriorly marked by a longitudinal, convergent carina.

Petiole with truncate anterior face; posterior face sloping posteriorly. Petiole laterally unarmed. Postpetiole, laterally, with a pair of small, median denticles.

Wings as in the gyne.

Gaster as broad as the mesosoma.

Sculpture. Head dorsum reticulate and irregularly rugulose, the rugae more transversal around the eyes; this sculpture superimposed to foveae, larger, slightly, irregular on the posterior third of the head, smaller, shallower and regular on the frons. Ventral part of the head reticulate and strongly rugulose. Pronotum, mesonotum, scutellum, pro- and mesopleurae minutely and superficially reticulate and covered with shallow foveae, the reticulation more impressed on the pronotum and on the propleurae. Basal face of the propodeum punctate and with irregular rugosities; deelivous face of the propodeum superficially reticulate and with thin, longitudinal rugosities in the middle. Pedicel superficially reticulate and laterally covered by thin, longitudinal rugosities. First gastral tergite and sternite reticulate; the reticulation more superficial on the remaining tergites and sternites. Legs superficially and minutely reticulate and slightly shining.

Pilosity. Body with light ferruginous, flexuous, thin, pointed hairs dense on the head, on the mesosoma, on the pedicel and on the ventral face of the femora, sparser on the gaster. Gaster and legs with additional, similar hairs but shorter, appressed on the tergites, on the sternites and, on the femora, on the superior, on the external, and on the internal sides. Tibiae and tarsi with short, pointed hairs.

Colour. Black with lighter gaster. Femora, tibiae and tarsi yellow.

Measurements (in mm) and indices: TL 8.28; HL 1.12; HW 1.56; EL 0.49; PW 1.48; PeW 0.92; PpW 0.96; HBaL 0.92; HBaW 0.15; CI 139.3; PI 105.5; PPeI 160.9; PPpI 154.2; HBaI 16.3.

Type Material

de Andrade and Baroni Urbani (1999) - Worker and soldier. Type locality: Several localities in Colombia, Panama without further locality. Type material: lectotype and one paralectotype workers labelled: "Santa Marta, Colombie" selected by Kempf (1951) in Musee d'Histoire Naturelle Genève, examined, 7 workers same label as the lectotype, 7 syntype workers labelled "Dibulla, Colombie", two syntype workers and 1 soldier labelled "Panama, Christophersen", all in MHNG, examined; one worker labelled "Dibulla, Colombie" in Naturhistorisches Museum Basel examined.

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 211, queen, male described, combination in Cephalotes)
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 307, Combination in Cryptocerus (Paracryptocerus))
  • Forel, A. 1912f. Formicides néotropiques. Part II. 3me sous-famille Myrmicinae Lep. (Attini, Dacetii, Cryptocerini). Mém. Soc. Entomol. Belg. 19: 179-209 (page 204, soldier, worker described)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 166, Combination in Paracryptocerus)
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 176, Raised to species)
  • Wheeler, G. C.; Wheeler, J. 1986f. Supplementary studies on ant larvae: Myrmicinae (Hymenoptera: Formicidae). J. N. Y. Entomol. Soc. 94: 489-499 (page 494, larva described)