Cephalotes pilosus

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Cephalotes pilosus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. pilosus
Binomial name
Cephalotes pilosus
(Emery, 1896)

Cephalotes pilosus P casent0904911.jpg

Cephalotes pilosus D casent0904911.jpg

Specimen Label

Nothing is known about the biology of Cephalotes pilosus.

Identification

A member of the fiebrigi clade differing from Cephalotes lanuginosus and Cephalotes liogaster by its denser, long, flexuous body hairs. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Brazil, Paraguay (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.

  • pilosus. Cryptocerus pilosus Emery, 1896h: 630, fig. B (s.w.) PARAGUAY. Santschi, 1921h: 127 (q.); De Andrade & Baroni Urbani, 1999: 648 (m.). Combination in Paracryptocerus (Harnedia): Kempf, 1958a: 20; in Zacryptocerus: Brandão, 1991: 387; in Cephalotes: De Andrade & Baroni Urbani, 1999: 643.

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

Description

Worker

Kempf (1958) - Total length 4.1-4.9 mm; maximum length of head 1.11-1.39 mm; of thorax 1.21-146 mm. Black; the following fuscous-ferruginous: tips of mandibles, scape, last funicular segment, femora, tibiae, the four distal tarsites; frontal carinae testaceous.

Head rather shining, subquadrate. Lateral borders scarcely sinuous, not raised above eyes, slightly diverging caudad. Dorsum of head moderately convex discally. Occipital lobes obliquely truncate, not transparent, their border irregularly crenate or notched. Occipital border broadly, but feebly, emarginate. Eyes hemispherical, bulging, their maximum diameter about one fourth of maximum head length. Frontal carinae semitransparent, in lateral view not considerably thickened just in front of the eyes.

Thorax longer than broad. Scapular angle feebly dentate, distinct from the first, acute lateral pronotal tooth, which is very conspicuous and followed posteriorly by a sharp lateral crest, on which two more, rather obtuse, teeth are apparent. Promesonotal suture obsolete. Mesonotum projecting laterad as a rectangular tooth. Mesoepinotal suture often, not always, visible, especially laterad (practically absent in the lectotype). Anterior corner of basal face of epinotum in the form of a small, more or less obtuse tooth, followed by a much larger, acute lateral tooth. Lateral border of declivous face with a rather sharp, often somewhat denticulate edge. In profile, the thorax is moderately convex, forming an even curvature, scarcely interrupted by the transition of the basal into the declivous face of epinotum. Femora fusiform, tibiae more or less cylindrical.

Petiole narrower than mesonotum, having on each side a small spine, curving obliquely caudad. Postpetiole slightly broader, the lateral spines stouter, their tips more recurved. In profile, the postpetiole is strongly convex above.

Gaster elliptical, broadly excised antero-mesially, its anterolateral lobes bluntly marginate.

Integument, with the exception of the gaster, rather shiny. Dorsum of head, thorax and pedicel reticulate-rugose and foveolate. Frontal carinae finely punctate. Mandibles finely rugose. Sides of fore coxae and laterotergite of pronotum horizontally striate. First gastral tergite finely but sharply punctate, opaque, with more or less longitudinal rugosities on the anterior half, and elongate, small sh allowly impressed squamiferous pits scattered throughout. First gastral sternite shinier, superficially reticulate-punctate.

Canaliculate, long, appressed scalelike hair on head, thorax, and pedicel; similar hair, yet simple and small on first gastral tergite. Long, flexuous, standing hair scattered over the entire body and appendages, scarce on the sides of thorax, absent latero-ventrally on peduncle.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.50-5.28; HL 1.04-1.24; HW 1.08-1.40; EL 0.29-0.32; PW 1.00-1.24 PeW 0.54-0.62; PpW 0.56-0.64; HBaL 0.44-0.48; HBaW 0.12-0.14; CI 103.8-112.9; PI 105.3-111.1 ; PPeI 178.6-211.1; PPpI 178.6-196.8; HBaI 27.3-31.8.

Soldier

Kempf (1958) - Total length 5.9-7.6 mm; maximum length of head 1.64-2.14 mm; of thorax 1.64-2.07 mm. Black; the following fuscous-ferruginous: anterolateral portions of head disc, tips of mandibles, scapes, last funicular segment, the anterior corner of pronotum; fuscous testaceous: extensor face of tibiae. Gaster with a pair of small anterolateral and another pair of slightly larger posterolateral yellowish spots, which, however, are absent in smaller specimens.

Head slightly longer than broad (largest specimen 60:58, smallest 46:44). Head disc subquadrate, with strongly rounded corners, its bottom slightly convex discally, feebly excavate anterolaterally, its lateral border scarcely upturned, but strongly crenulate. Sides of disc almost straight, the occipital border strongly and rather evenly curved. Supramandibular excision broad and bidentate. Occipital lobes feebly obliquely truncate, with a small tooth on the inner end of the truncation. Eyes rather flat.

Thorax usually as broad as long. Pronotum laterally bidentate, with a distinct, crenulate, transverse crest, which is broadly interrupted mesally. Mesonotum with a bluntly rounded and submarginate lateral lobe. Mesoepinotal suture impressed. Basal face of epinotum with an obtusely angulate lobe on each side and on each posterior corner there is a strong, usually blunt, tooth, pointing upward and laterad. Lowcr half of slightly excavate declivity with a sharp lateral crest. Mesopleura with a blunt vestigial tooth near its antero-ventral corner. Legs as in worker, femora more incrassated, less distinctly fusiform.

Pedicel as in worker. Lateral spines of petiole and postpetiole stouter and more recurved. Gaster as in worker.

Integument less shining than in worker. Head disc, occiput and mandibles sharply reticulate-rugose with crowded, deeply impressed pits within the meshes of the anastomosing rugosities. Sculpture more superficial over the antennal scrobe. Sides of head and lower face coarsely foveolate with the intervals finely reticulate-punctate. Thorax and pedicel sculptured as head disc, the foveolae less crowded. On the laterotergite of pronotum there prevail longitudinal and somewhat curved rugosities. Gaster opaque, sculpture as in worker. Pilosity, in general as in worker. Each foveola of head disc bears a rather thin squamiform hair, which is more or less decumbent, and does not project beyond the rim of the pit. Scalelike hair of thorax and femora more conspicuous. Long, thin, flexuous standing hair around the rim of head disc, present also on the sides of head, occipital lobes, dorsum of thorax, peduncle and gaster, as well as on legs.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 6.76-7.64; HL 1.72-1.96; HW 1.80-2.08; EL 0.33-0.39; PW 1.80-2.00; PeW 0.80-0.84; PpW 0.85-0.88; HBaL 0.44-0.52; HBaW 0.16-0.17; CI 104.2-106.1; PI 100.0-104.3; PPeI 219.0-265.0; PPpI 209.1-230.8; HBaI 31.9-36.4.

Queen

de Andrade and Baroni Urbani (1999) - Head broader than long, with a complete disc. Floor of the disc convex posteriorly, flat or gently concave anteriorly. Frontal carinae and borders of the disc strongly crenulate and weakly raised anteriorly. Sides of the disc subparallel, not hiding the eyes in dorsal view and connected by a convex border less marked in correspondence with the angles. Vertexal angles convex and with crenulate border. Mandibles with a strong carina. Dorsal border of the antennal scrobcs with a longitudinal, denticulate carina just in front of the eyes, the carina sometimes crenulate after the denticle.

Mesosoma. Amerior pronotal border gently convex. Humeral angles with a pair of small denticles. Pronotal sides weakly convex. Pronotal carina superficially marked. Mesonotum and scutellum flat. Propodeum with well differentiate basal and declivous faces. Sides of the basal face with a small pair of short, obtuse denticles and with a pair of large, stout teeth slightly diverging and directed backwards. Declivous face concave in the middle; its sides converging posteriorly and carinate.

Petiole with the anterior face oblique and gently concave medially; its sides with a pair of small denticles curved backwards. Postpetiole convex and with a "U" shaped carina. Postpetiolar sides with a pair of little developed, round expansions arising from the anterior border and pointed backwards.

Gaster with a pair of anterolateral lobes not strongly protruding anteriorly.

Mid and hind femora without angles or denticles. Hind basitarsi with subparallel sides.

Wings as in the male.

Sculpture. Head, mesosoma and pedicel minutely reticulate-punctate and with contiguous foveae, the foveae larger on the head, more regular on the pronotum, on the mesonotum and on the scutellum, more impressed on the head dorsum and on the propodeum. Foveae of the ventral part of the head and on the pleurae superimposed to irregular, longitudinal rugosities, except those on the upper mesopleurae. Gaster and legs reticulate, the reticulation less impressed on the posterior half of the first gastral sternite, shining. Anterior fourth of the first gastric tergite, outer face of the femora and tibiae with superficial, small, oval foveae. Anterior third of the first gastral tergite and sides of the anterior half of corresponding sternite with few, longitudinal rugosities.

Pilosity. Body with three types of hairs: (1) originating from part of the foveae, canaliculate, suberect, on the head dorsum, appressed on the other body parts; similar but shorter and thinner on the parts without foveae; (2) pointed, long and flexuous originating from foveae of the head, of the mesosoma, of the pedicel and of the gaster, and present also on the parts of the gaster and of the legs without foveae, but slightly shorter, on the first gastral tergite.

Colour. Black. Frontal carinae and pronotal sides yellow-brown. First gastral tergite with a small pair of dark yellow spots behind the lobes.

Measurements (in mm) and indices: TL 8.26-8.34; HL 1.52-1.56; HW 1.62-1.64; EL 0.33-0.35; PW 1.60-1.52; HBaL 0.50-0.54; HBaW 0.16; PeW 0.65-0.66; PpW 0.74-0.77; CI 105.1-106.6; PI 102.5-106.6; PPeI 233.8-242.4; PPpI 205.4-207.8; HBaI 29.6-32.0.

Male

de Andrade and Baroni Urbani (1999) - Head (eyes included, mandibles excluded) about 1/3 broader than long; vertexal margin straight, faintly carinate and continuing with a round angle into the sides. Vertex convex. Ocelli protuberant. Eyes broadly convex and placed in the middle of the sides of the head. Frontal carinae diverging backwards and not reaching the posterior border of the eyes. Frons flat and separate from the clypeus by a furrow. Clypeus convex. Mandibles short, superficially carinate laterally and with a single distinct apical tooth. Scapes thick, twice as long as the first funicular joint.

Mesosoma. Pronotum in dorsal view with nearly parallel sides; mesonotum convex; median Mayrian carina and parapsidal furrows weakly impressed; scutellum convex, its sides converging posteriorly; propodeum with well differentiate basal and declivous faces; basal face gently convex and sloping posteriorly, its sides converging posteriorly towards the declivous face, the latter with lateral and median carinae.

Petiole as broad as or slightly narrower than the postpetiole and with an anteriorly deeply concave node; petiolar sides slightly convex. Postpetiole gently convex dorsally; postpetiole, in dorsal view, in form of an inverted trapeze.

Gaster almost as broad as the mesosoma.

Wings. Fore wings with R+Sc superficially connected to a marked pterostigma. cu-a superficially connected with A. 2r marked, Rsf5 connected to R1. Distal parts of A, CuAl and Mf4 less pigmented. Hind wings with R, M+CuA, M and 1A marked; distal part of M and CuA vestigial.

Sculpture. Head dorsum reticulate, with irregular, small foveae superimposed by few rugosities. Eyes surrounded by transversal rugosities. Ventral face of the head with the same sculpture as on the head dorsum but with denser foveae and longitudinal rugosities. Pronotum reticulate, with more irregular foveae and rugosities. Mesonotum and scutellum superficially reticulate, with superimposed small, sparse and shallow foveae and with few longitudinal rugosities more impressed on the scutellum. Propodeum with broad, irregular, deep reticulation. Propleurae reticulate and with irregular, thin, rugulae. Mesopleurae with the same sculpture as on the mesonotum, but the rugosities on its posterior part only. Lower metapleurae superficially reticulate and longitudinally rugulose; upper metapleurae reticulate and irregularly rugulose. Peduncular segments superficially reticulate and longitudinally rugulose. First gastral tergite deeply reticulate and with sparse piligerous foveae; its anterior half with longitudinal rugosities. Remaining tergites with the posterior border broadly reticulate and with piligerous foveae. First gastral sternite with the same type of sculpture as on the first tergite but less impressed. Extensor face of the legs reticulate; anterior and posterior faces of the legs superficially reticulate to shining.

Pilosity. Body with dense, long, suberect, flexuous hairs; these same hairs but decumbent, sparser and shorter on the tarsi. Funiculi densely covered by thin, short, decumbent hairs; similar hairs on the internal face of the tibiae and on the tarsi.

Colour. Black. Apex of femora, tibiae and tarsi yellowish-brown.

Measurements (in mm) and indices: TL 5.80-6.20; HL 0.8-0.88; HW 1.04-1.12; EL 0.40-0.44; PW 1.04-1.16; PeW 0.52-0.54; PpW 0.52-0.58; HBaL 0.48-0.54; HBaW 0.11-0.12; CI 123.8-127.3; PI 96.5-103.7; PPeI 192.6-223.1; PPpI 179.3-207.7; HBaI 22.2-22.9.

Type Material

Syntype Specimen Labels

de Andrade and Baroni Urbani (1999) - Worker and soldier. Type locality: San Salvador (Paraguay). Type material: lectotype worker (designated by Kempf, 1958 a: 20) labelled: first label (handwriting of Emery) “Cryptocerus pilosus Em, n. sp.”, second label “Paracryptocerus (H.) pilosus (Emery), Lectotype”, third label (typewritten) “Paracryptocerus pilosus record in type book under 60990”, in the National Museum of Natural History; 2 soldiers, 2 small soldiers and 5 workers (all paratypes) labelled “Paraguay, Bohls” in Museo Civico di Storia Naturale, Genoa, and 2 workers and 1 soldier (all paratypes) labelled “Cryptocerus pilosus Em., Paraguay”, in Musee d'Histoire Naturelle Genève, all 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 387, 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 648, male described, page 643, 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 630, fig. B soldier, worker described)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 20, Combination in Paracryptocerus (Harnedia))
  • Santschi, F. 1921h. Quelques nouveaux Cryptocerus de l'Argentine et pays voisins. An. Soc. Cient. Argent. 92: 124-128 (page 127, queen described)