Cephalotes bohlsi

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Cephalotes bohlsi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. bohlsi
Binomial name
Cephalotes bohlsi
(Emery, 1896)

Cephalotes bohlsi P casent0904904.jpg

Cephalotes bohlsi D casent0904904.jpg

Specimen Label

Synonyms

Nothing is known about the biology of Cephalotes bohlsi.

Identification

de Andrade and Baroni Urbani (1999) - A member of the fiebrigi clade differing from its closest species, Cephalotes jheringi, in the worker and in the soldier by the sculpture less impressed and by the foveae sparser. Cephalotes bohlsi appears to be a rare species. The workers are quite similar to those of jheringi but the soldiers allow an easy separation of the two species. Besides of the character already mentioned in the diagnosis, another character useful to separate workers and soldiers of both species is the shape of the expansions of the peduncular segments, much larger and broader in bohlsi than in jheringi. The soldiers of bohlsi and jheringi are easily distinguishable for the foveae of the body much smaller, sparser and more superficial in bohlsi than in jheringi.

The head of the soldier of bohlsi resembles somewhat Cephalotes bruchi in sculpture and shape of the disc, but in bohlsi the posterior border of the sides of the disc is more marked than in bruchi.

Keys including this Species

Distribution

Argentina, Mato Grosso, Brazil and Paraguay.

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps

AntMapLegend.png

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.

  • bohlsi. Cryptocerus bohlsi Emery, 1896h: 631, fig. C (s.w.) PARAGUAY. Combination in Paracryptocerus (Harnedia): Kempf, 1958a: 101; in Zacryptocerus: Brandão, 1991: 385; in Cephalotes: De Andrade & Baroni Urbani, 1999: 623. Senior synonym of medusa: Kempf, 1958a: 101.
  • medusa. Cryptocerus (Paracryptocerus) bohlsi var. medusa Santschi, 1919f: 45 (s.) BRAZIL. Junior synonym of bohlsi: Kempf, 1958a: 101.

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

Description

Worker

de Andrade and Baroni Urbani (1999) - Head subquadrate. Vertexal angles round, with a narrow, semitransparent lamellaceous border, continuos or with a small, obtuse tooth. Vertexal margin concave. Frontal carinae weakly upturned over the eyes. Mandibles laterally carinate.

Mesosoma gently convex in side view. Scapular angles visible in dorsal view. Pronotal sides with a narrow lamella with three pairs of teeth, the first pair more pointed. Sides of mesonotum with a pair of small teeth. Promesonotal suture superficially impressed. Propodeal suture impressed laterally and interrupted medially. Propodeum with differentiate basal and declivous faces and with the sides narrowing backwards; sides of the basal face of the propodeum with two pairs of teeth, the first pair sometimes simply angulate and the second one larger; sides of the declivous face of the propodeum posteriorly with a narrow, semitransparent lamella unarmed or with one or two pairs of denticles.

Petiole anteriorly truncate; its anterior border superficially concave medially. Petiolar spines arising from the anterior face of the petiole, pointed and curved backwards. Postpetiole as broad as or slightly broader than the petiole, with broad lateral expansions, strongly developed anteriorly, curved and pointed backwards.

Gaster suboval, with a pair of broad anterolateral lobes with a marked margin not surpassing the stigma posteriorly.

Mid and hind femora not angulate; mid and hind basitarsi flat and with subparallel sides.

Sculpture. Head dorsum and mesosoma minutely reticulate, the reticulation more impressed on the mesosoma, and with small, superficial foveae, deeper, denser and larger on the posterior fourth of the head and on the anterior part of the pronotum, shallower on the frontal carinae. Ventral face of the head minutely reticulate and with dense, suboval foveae and irregular, longitudinal rugosities less impressed in the middle. Pleurae reticulate, with few, thin, longitudinal rugosities on the propleurae and with oval foveae on the lower meso- and metapleurae. Pedicel with the same sculpture as the mesosoma but more irregular.

First gastral tergite minutely reticulate, with small, very superficial foveae and with few, thin, longitudinal rugosities close to the postpetiolar articulation. First gastral sternite with reticulation larger than the one on the corresponding tergite, less impressed in the middle of its posterior half.

Legs reticulate and with superimposed small, oval foveae on the outer face of the femora and tibiae.

Pilosity. Body with three types of hairs: (1) appressed and generally originating from each fovea, of size proportional to the one of the fovea from which they originate, i. e. larger on the posterior fourth of the head dorsum and on the anterior part of the pronotum; much shorter and thinner on the body parts without foveae; (2) slightly clubbed, rare, on the sides of the frontal carinae and on the legs; slightly longer on the posterior borders of the gastral segments; (3) long and pointed on the posterior border of the gastral sternites.

Colour. Black. Frontal carinae, mesosomal and peduncular spines yellowish to light brown. Outer face of the mid and/or fore tibiae brown.

Measurements (in mm) and indices: TL 4.54-4.96; HL 1.06-1.16; HW 1.18-1.32; EL 0.28-0.34; PW 1.02-1.20; PeW 0.54-0.57; PpW 0.55-0.56; HBaL 0.37-0.43; HBaW 0.13-0.14; CI 111.3-113.8; PI 110.0-115.7; PPeI 178.9-222.2; PPpI 185.4-214.3; HBaI 30.2-37.8.

Soldier

de Andrade and Baroni Urbani (1999) - Head almost as broad as long, with complete disc. Floor of the disc gently convex posteriorly and oblique anteriorly. Borders of the disc not raised. Sides of the disc narrowing backwards, not hiding the eyes and connected by a truncate or subconvex border thicker than the one on the sides. Frontal carinae weakly crenulate. Vertexal angles broad and obtuse. Mandibles with a strong carina. Dorsal border of the antennal scrobes with a longitudinal, denticulate carina just in front of the eyes.

Mesosoma. Anterior pronotal border gently convex. Humeral angles with a pair of small teeth. Pronotal sides straight. Pronotal crest marked, thickening from the sides towards the center where it is interrupted by a sulcus. Promesonotal suture impressed. Sides of the mesonotum with a broad, round tooth. Propodeal suture deeply impressed. Propodeum with well differentiate basal and declivous faces. Sides of the basal face with a small protuberance followed by a pair of short, broad, triangular teeth and by a pair of large, stout teeth curved upwards. Declivous face concave in the middle; its sides converging, carinate laterally and with or without a minute pair of denticles posteriorly.

Petiole with the anterior face truncate and superficially concave medially; its sides with a pair of short, pointed spines curved backwards. Postpetiole convex. Postpetiolar sides with a pair of thick, round expansions arising from the anterior border and directed anterolaterally.

Gaster oval and with a pair of protruding, anterolateral lobes.

Mid and hind femora without angle or denticle. Hind basitarsi slightly more compressed apically than distally and with subparallel sides.

Sculpture. Head dorsum moderately shining, punctate and with superficial, variably clumped, small foveae shallower on the frontal carinae, the punctuation more impressed on the posterior half. Ventral part of the head shining, sparsely punctate-foveolate. Mesosoma reticulate-punctate and with dense, small foveae, larger on the pronotum, sparser on the basal face of the propodeum and absent on the declivous one. Pleurae reticulate, with sparse, suboval foveae, denser on the lower mesopleurae. First gastral tergite reticulate and with superficial, oval foveae slightly more impressed on the anterior third. Remaining tergites and sternites reticulate, the reticulation more superficial on the posterior half of the first gastral sternite and on the remaining sternites. Legs simply reticulate. Outer face of the femora and of the tibiae with superficial, oval foveae.

Pilosity. As in the worker.

Colour. Sides and ventral part of the head, mesosoma, pedicel and gaster black; legs lighter with the outer face of the tibiae brown. Frontal carinae and border of the disc dark orange to light brown. Remaining head dorsum dark brown.

Measurements (in mm) and indices: TL 7.56; HL 1.84; HW 1.80; EL 0.36; PW 1.68; PeW 0.73; PpW 0.75; HBaL 0.46; HBaW 0.16; CI 97.8; PI 107.1; PPeI 230.1; PPpI 224.0; HBaI 34.8.

Holotype Specimen Labels

Type Material

de Andrade and Baroni Urbani (1999):

Worker and Soldier. Type locality: San Salvador (Paraguay). Type material 1 worker and 2 soldiers in Museo Civico di Storia Naturale, Genoa, 1 worker 1 soldier in Musee d'Histoire Naturelle Genève all syntypes and labelled only Paraguay, examined.

Cryptocerus bohlsi var. medusa. Soldier. Type locality: Mato Grosso (Brazil). Type material possibly lost: the specimen labelled as “Type” in Naturhistorisches Museum Basel is from Argentina (Gran Chaco) and not from Brazil.

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 623, Combination in Cephalotes)
  • Emery, C. 1896h. Formiciden, gesammelt in Paraguay von Dr. J. Bohls. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 9: 625-638 (page 631, fig. C soldier, worker described)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 101, Combination in Paracryptocerus (Harnedia), Senior synonym of medusa)