Cephalotes simillimus

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Cephalotes simillimus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. simillimus
Binomial name
Cephalotes simillimus
(Kempf, 1951)

De Andrade 1999 Cephalotes OCR - Copy-213 Cephalotes-simillimus.jpg

Nothing is known about the biology of Cephalotes simillimus.

Identification

A member of the laminatus clade characterised in the worker by the eyes broader than 1/3 of the head length, in the worker and in the soldier by the propodeal spines expanded ventrally into a lamella. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Bolivia, Brazil, Colombia, French Guiana, Guyana (type locality), Peru, Suriname.

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.

  • simillimus. Paracryptocerus (Paracryptocerus) simillimus Kempf, 1951: 184, figs. 125, 126 (w.) GUYANA. Combination in Zacryptocerus: Brandão, 1991: 388; in Cephalotes: De Andrade & Baroni Urbani, 1999: 208.

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

Description

Worker

Length 3.9 mm. Median head length 1.00 mm; Weber's length of thorax 1.12 mm. Black; the following ferruginous: apex of mandibles, antennae, tip of femora, tibiae, tarsi, apical gastral segments, epinotal and petiolar spines. Frontal carinae yellowish-brown.

Head opaque, longer than broad, broadest behind the eyes; interocular distance distinctly shorter than maximum length of head (45 : 50). Lateral margins somewhat sinuate above the eyes, posterior margin straight mesad; the occipital angles with slightly projecting subtransversely truncate entirely infuscated lamellae, the apical border of which is nearly straight. Cheeks strongly marginate beneath, densely covered with silvery, appressed, scale-like hairs. Eyes large, their longest diameter more than 1/3 of median head length. Upper and lower surface of head finely reticulate-punctate, sparsely covered with slender, flattened, simple, appressed, silvery scale-like hairs; slightly larger, denser and somewhat canaliculate, in grooves, in front of the occipital border.

Thorax subopaque. Anterior border moderately arcuate, shoulders acutely angulate. Pronotum somewhat expanded behind laterally with small triangular teeth on each side, coalesced at their base, the posterior being smaller than the anterior tooth. Posterior corners of pronotum in the form of a subrectangular tooth, projecting. Promesonotal suture vestigial. Mesonotum comparatively broader and shorter than in minutus, each side with a small, acute tooth. Mesoepinotal suture distinct and impressed. Basal face of epinotum in the same plane as mesonotum, transverse, with two broad, flat, triangular teeth on each side, the posterior being somewhat longer. The posterior border of the second tooth forms a sharp crest which delimits the declivity laterad and behind. Dorsum of thorax flat, scarcely convex. Declivous face excavated mesad, not striated longitudinally. The entire thorax finely reticulate-punctate, dorsum with dense, elongated grooves, harboring more or less canaliculate, silvery appressed scales, denser than on head. Declivity without scales below. Laterotergites of pronotum and mesopleura indistinctly longitudinally rugose, not striated.

Petiole opaque, transverse, with distinctly set off, slender, long, lateral spine, arising from the anterior corner, pointing slightly backwards. Postpetiole as long as petiole, transverse, with shorter, broader, apically subtruncate lateral spines, curving obliquely forward. Both peduncular segments finely reticulate-punctate with scattered glistening scales.

Gaster subopaque, subcordiform, depressed, moderately convex above. First gastral tergite emarginate antero-mesally, sharply crested antero-Iaterad, not forming a distinct set off lamellate border. Tergites and sternites finely reticulate-punctate. Scale-like silvery hair appressed, simple, rather dense. Erect pile confined to 2d -4th tergites and the sternites.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.66-4.18; HL 0.91-1.00; HW 1.08-1.22; EL 0.32-0.37; PW 0.83-0.92; PeW 0.50-0.58; PpW 0.43-0.49; HBaL 0.36-0.40; HBaW 0.07-0.08; CI 116.4-125.0; PI 125.0-130.4; PPeI 156.4-169.2; PPpI 186.9-197.9; HBaI 18.9-20.5.

Soldier

Length 5.9 mm. Median head length 1.65 mm; Weber's length of thorax 1 .73 mm. Black; the following ferruginous: outer border of frontal carinae, antennae, tibiae, tarsi, tips of femora, apical border of gastral tergites and sternites.

Head subfulgid, scarcely longer than wide. Frontal carinae arcuate, diverging caudad to above the posterior end of the antennal scrobe, where they form a distinct yet very obtuse angle, prolonged above the eyes, but more or less obsolete, never forming a raised crest. Occiput distinctly truncate, the upper border not sharply marginate above. Occipital corners rounded. Occipital border blunt, slightly convex. Upper surface of head moderately convex above, slightly impressed mesad, cheeks immarginate below. Upper surface of head very finely punctate, with sparse, small foveolae, in which no distinct hair is visible. Foveolae slightly larger on occiput, still larger containing a visible, decumbent seta, on lower surface of head.

Thorax subfulgid above. Anterior border arcuate, shoulders rounded, sides of pronotum diverging posteriorly with a short, stout and acute, lateral tooth, pointing obliquely forward, then parallel and straight until reaching the lateral corner of the bluntly rounded more or less vestigial and mesally interrupted transverse pronotal keel, then converging towards the mesonotum. Posterior corners rounded. Promesonotum in profile greatly convex. Promesonotal suture vestigial. Mesonotum with a stout and bluntly rounded lateral tooth. Mesoepinotal suture impressed and distinct. Epinotum subopaque. Basal face of epinotum transverse, the posterior border concave and submarginate. Sides with an anterolateral broad, short, triangular tooth and a somewhat longer and more acute, posterior spine which is greatly diverging, having beneath a crest which delimits the entire side of the declivous face, and with a small tooth projecting from the crest beneath the posterior epinotal spine. Declivous face without macrosculpture. Microsculpture of promesonotum as on head, epinotum and sides of thorax finely reticulate-punctate. Upper surface of thorax with sparse, deeply impressed foveolae, rounded on promesonotum, elongate and not as deep on epinotum. Sides of thorax without macrosculpture; declivous face with transversely arcuate, more or less vestigial rugosities.

Petiole opaque, transverse, with a short, stout, subacute and recurved lateral tooth. Posterior half shallowly transversely concave. Postpetiole slightly longer than petiole, as wide as petiole, with very broad, plate-like, apically truncate, lateral projections.

Gaster subopaque, elongate; anterior border deeply emarginate; anterolaterally strongly marginate, without forming a disLinct lamellate border. Sides of gaster moderately convex. Tergites and sternites finely reticulate-punctate, without foveolae.

All foveolae, except the ones on the upper surface of head and promesonotum have a distinct, decumbent, flattened seta, which is shiny and scale-like on the epinotum. Sides sparsely scaled. Gaster with small, decumbent, shiny scales. Erect pile confined to the tergites 2 - 4, the sternites and the posterior half of the first tergite of the gaster.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.98-6.48; HL 1.40-1.68; HW 1.52-1.76; EL 0.40-0.45; PW 1.24-1.54; PeW 0.63-0.77; PpW 0.62-0.72; HBaL 0.42-0.44; HBaW 0.11-0.12; CI 104.8-108.6; PI 114.3-122.6; PPeI 189.2-205.8; PPpI 194.4-213.9; HBaI 25.6-28.6.

Type Material

de Andrade and Baroni Urbani (1999) - Worker, soldier. Type locality: Kartabo (Guyana). Type material: holotype worker in Museum of Comparative Zoology, 13 syntype workers, 6 syntype soldiers labelled: "Kartabo. B. G., Jul. Aug. 1 920, W. M. Wheeler Collection", MCZC and Museu de Zoologia da Universidade de Sao Paulo, 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 388, 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 208, Combination in Cephalotes)
  • Kempf, W. W. 1951. A taxonomic study on the ant tribe Cephalotini (Hymenoptera: Formicidae). Rev. Entomol. (Rio J.) 22: 1-244 (page 184, figs. 125, 126 worker described)