Cephalotes incertus

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Cephalotes incertus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. incertus
Binomial name
Cephalotes incertus
(Emery, 1906)

Cephalotes incertus casent0173681 profile 1.jpg

Cephalotes incertus casent0173681 dorsal 1.jpg

Specimen labels

Nothing is known about the biology of Cephalotes incertus.

Identification

A member of the pinelii clade differing from its sister species, Cephalotes caribicus, by the lobate gaster of the worker. This is the species with the lightest body colour within the clade, a condition rendering the characteristic maculation of the gaster less visible than in other, related species. One of the Argentinean workers from Ceibalito has the medial part of the gaster entirely black. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Brazil, Argentina, Paraguay.

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina (type locality), Brazil, Paraguay.

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.

  • incertus. Cryptocerus incertus Emery, 1906c: 171, fig. 31 (w.) ARGENTINA. Kempf, 1952: 16 (q.); Kempf, 1974a: 71 (s.). Combination in Cryptocerus (Cyathocephalus): Santschi, 1921h: 125; in Paracryptocerus (Harnedia): Kempf, 1952: 15; in Zacryptocerus: Kempf, 1974a: 71; in Cephalotes: De Andrade & Baroni Urbani, 1999: 420.

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

Description

Worker

Kempf (1952) - Length 4.0 mm. Median head length 0.90 mm. Weber's length of thorax 1.10 mm. Ferruginous; the head slightly darker. Membranaceous borders of thorax and the frontal carinae pale yellow-ferruginous.

Head subquadrate, longer than wide (45:39), as long as thorax. Sides of head straight, not upturned above eyes. Occipital corners rounded, not membranaceous. Occipital border scarcely emarginate. Greatest diameter of eyes less than one fourth of maximum head length.

Thorax longer than wide across the pronotum. Membranaceous border of pronotum and epinotum much narrower than in the other species of the group. Anterior angle of pronotum obtuse, the sides converging caudad. Mesonotum with a broad, blunt, more or less rounded, marginate lobe on each side. Mesoepinotal suture obsolete mesally. Epinotum as broad as mesonotum, narrower than pronotum. Declivous face differentiated from basal face. Hind femora not longitudinally marginate nor crested above the apical half.

Peduncular segments massive. Petiole excavate antero-mesally, with narrowly crested lateral lobe. Postpetiole with an elliptical, membranaceous lobe on each side, the lobes constricted at their base.

Gaster longer than broad, ovate, broadest behind the half of its length. Anterolateral lobes angulate and narrowly crested.

Subopaque, finely shagreened. Dorsum of head, thorax and peduncular segments foveolate, each foveola containing an elongate, oval, canaliculate, golden, appressed scale. No erect setae on the first gastral tergite.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.44-4.38; HL 0.80-0.96; HW 0.80-1.04; EL 0.20-0.24; PW 0.70-0.90; PeW 0.37-0.50; PpW 0.40-0.55; HBaL 0.23-0.26; HBaW 0.07-0.10; CI 100.0-108.3; PI 114.3-115.5; PPeI 180.0-189.2; PPpI 163.6-175.0; HBaI 30.4-38.5.

Soldier

Kempf (1974) - Total length 4.5 mm; head length 1.24 mm; head width 1.27 mm; Weber's length of thorax 1.35 mm; width of pronotum 1.27, of mesonotum 0.84, of propodeum 0.73 mm; length and width of petiole 0.26 and 0.49 mm; length and width of postpetiole 0.25 and 0.53 mm; maximum width of gaster 1.11 mm. Ferruginous; mandibles fuscous brown; subtranslucid portion of head disc above antennal scrobe, membranaceous margins of pronotum and propodeum, and lateral appendages of petiole and postpetiole yellowish brown.

Head quadrate, scarcely broader than long. Cephalic disc deeply emarginate above mandibles, anterolaterally evenly rounded, postero-laterally obliquely truncate, posteriorly vestigially between a pair of faint and blunt teeth; rim of disc scarcely crenulate, never glassy nor translucid, obliquely upturned on sides; disc proper gently transversely convex in the middle behind clypeus, moderately concave postero-laterally at level of eyes; clypeal and frontal sutures more or less distinct. Occipital lobes rectangular with sharply carinate margins and a faint carina extending from the occipital corner upward to disc, but fading out before reaching the rim of the latter, separating the lateral faces from the occipital face of head below disc. Inferior border of cheeks continued backwards below eyes and distinctly marginate.

Thorax longer than maximum width of pronotum. Anterior border of the latter straight in the middle, gently deflected caudad on lateral sixth on both sides; lateral corner rectangular, scarcely excavate, narrowly membranaceous; transverse pronotal carina blunt and low, narrowly interrupted in the middle. Promesonotal suture distinct. Mesonotum less than twice as broad as long, the prominent lateral lobes bluntly rounded at apex to obtusely angulate. Metanotal suture indistinct. Propodeum with narrow, membranaceous lateral borders, the border slightly constricted just behind the anterior corner, setting off a shorter membranaceous lobe; at the junction of the basal with the declivous face the border contains a low, solid denticle pointing upward; declivous face shallowly excavate above petiolar insertion. Base of fore coxae anteriorly not drawn out into a pointed cone. Hind femora bluntly angulate above, but without a longitudinal crest on apical half. First tarsomere of hind legs compressed and broadened, shorter than the remaining four tarsomeres combined.

Pedicellar segments rather stout and solid. Petiole as long as postpetiole, antero-mesially excised, laterally with a short, posteriorly strongly deflected apically bluntly pointed membranaceous lobe (as in worker). Postpetiole slightly broader than petiole, with an elliptical membranaceous lobe on each side, the lobes constricted at their base. Gaster much longer than broad, the anterolateral lobes drawn out and mesially angulate to subdentate, not membranaceous.

Integument opaque to subopaque throughout, finely reticulate-punctate. Cephalic disc slightly shining due to superficial microsculpture, with sparse, shallow, oval, squamiferous foveolae; the minimum diameter of the latter subequal to distance between the foveolae. Sides and occiput similarly sculptured, microsculpture stronger, foveolae more crowded; the same holds true for the thoracic dorsum and the dorsum of the postpetiole; gular face of head, sides of thorax (except catepisternum of mesonotum), legs, postpetiole and gaster without distinct foveolae. All foveolae contain golden, canaliculate, appressed scales, which are also present on gular face of head, on sides of mesonotum and on legs, less conspicuous and smaller on gaster. No short, blunt hairs projecting laterally from beneath the rim of the cephalic disc.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.84-5.44; HL 1.04-1.16; HW 1.24-1.32; EL 0.24-0.26; PW 1.24-1.32; PeW 0.49-0.53; PpW 0.53-0.57; HBaL 0.31-0.33; HBaW 0.11-0.12; CI 113.8-119.2; PI 100.0; PPeI 249.0-253.1; PPpI 213.6-234.0; HBaI 35.5-36.4.

Queen

Kempf (1952) - Length 6.1 mm. Median head length 1.20 mm. Weber's length of thorax 1.68 mm. Subopaque. Ferruginous. Disc of head with reddish tinge, frontal carinae, membranaceous border of pronotum and epinotum, lateral projections of petiole lighter, with yellowish or lurid hues. Mandibles, funicular segments and tarsi erruginous.

Head subquadrate, the maximum length slightly exceeding the interocular width. Mandibles finely punctured, except the chewing border, which is smooth and shiny, with four distinct teeth toward apex. Supramandibular excision about twice as broad as deep. Clypeus vestigial, elongate. Frontal carinae prolonged caudad above eyes in the form of a very slightly raised carina, which bends obliquely mesad behind the eyes in order to join with the transverse crest of the vertex. Head disc somewhat convex. Ocelli small, amber in color. The median ocellus somewhat larger than the lateral ones. Occipital corners flattened, rounded and crested. A crest, rising shortly behind the posterior condyle of the mandible runs backwards beneath the eye to the occipital corner. Funicular segments 2-8 much broader than long. Penultimate funicular segment conspicuously longer than the preceding segment. Integument finely reticulate-punctate with sparse, large and somewhat elongate squamiferous foveolae, shallow and very sparse on anterior half of cephalic disc, larger, more deeply impressed and crowded, toward the occiput. Cheeks very densely foveolate rugose with crowded scales. All scales are decumbent and silvery.

Thorax longer than broad across the pronotum. The latter sharply marginate anteriorly and laterally; the anterior border transverse and almost straight, the lateral borders subparallel and crested, the shoulders rounded. Transverse pronotal carina absent. Scutum broader than long and flat. Thorax distinctly constricted in front of the epinotum. Basal face of epinotum transversely convex, half as broad as maximum length of thorax; its lateral borders being crested and its posterior corners having a blunt short tooth. Declivous face at right angle to basal face, with a lateral crest arising from beneath the posterior teeth of the basal face. Dorsum of thorax and mesopleura finely reticulate-punctate with sparse, squamiferous foveolae, less conspicuous than those on the cephalic disc. Laterotergites of pronotum and sides of epinotum shagreened, without scales. Declivous face finely punctate and perpendicularly striolated. Femora fusiform, without a distinct angle near the middle of the upper face.

Petiole broader than long; each side with a projecting lobe, which is continuous anteriorly with the anterior border of the petiole, but distinctly set off posteriorly. Anterior face of petiole perpendicularly excavated; dorsum transversely convex. Postpetiole wider than petiole, wider than long. Lateral lobes as in worker, but not quite membranaceous. Dorsum and sides of perpendicular segments sculptured as thorax, with appressed scales.

Gaster elongate, nearly twice as long as broad, with subparallel sides. Anterolateral lobes angulate mesially, not distinctly crested. Finely shagreened, without conspicuous foveolae, but with sparse, short, minute, appressed, silvery scales. Sternites and terminal tergites of gaster with sparse, short and erect setae.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 5.28; HL 1.08; HW 1.22; EL 0.24; PW 1.08; PeW 0.51; PpW 0.58; HBaL 0.32; HBaW 0.12; CI 113.0; PI 113.0; PPeI 211.8; PPpI 186.2; HBaI 37.5.

Type Material

de Andrade and Baroni Urbani (1999) - Worker. Type locality: Corrientes (Argentina). Type material: holotype worker labelled "Corrientes, 15.VI.900" Museo Civico di Storia Naturale, Genoa, examined.

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 420, Combination in Cephalotes)
  • Emery, C. 1906c [1905]. Studi sulle formiche della fauna neotropica. XXVI. Bull. Soc. Entomol. Ital. 37: 107-194 (page 171, fig. 31 worker described)
  • Kempf, W. W. 1952. A synopsis of the pinelii-complex in the genus Paracryptocerus (Hym. Formicidae). Stud. Entomol. 1: 1-30 (page 16, queen described, page 15, Combination in Paracryptocerus (Harnedia))
  • Kempf, W. W. 1974a. Taxonomic and faunistic notes on some Neotropical Cephalotini ants (Hymenoptera, Formicidae). Rev. Bras. Entomol. 18: 67-76 (page 71, soldier described, page 71, Combination in Zacryptocerus)
  • Santschi, F. 1921h. Quelques nouveaux Cryptocerus de l'Argentine et pays voisins. An. Soc. Cient. Argent. 92: 124-128 (page 125, Combination in Cryptocerus (Cyathocephalus))