Cephalotes lanuginosus

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Cephalotes lanuginosus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. lanuginosus
Binomial name
Cephalotes lanuginosus
(Santschi, 1919)

Cephalotes lanuginosus casent0173685 profile 1.jpg

Cephalotes lanuginosus casent0173685 dorsal 1.jpg

Specimen labels

Synonyms

Specimens have been collected in bosque bajo in Paraguay.

Identification

A member of the fiebrigi clade differing from its sister species, Cephalotes liogaster, in the worker, soldier and gyne by the larger and more protruding eyes, and by the subopaque gaster. These two species are very similar and both show great morphological and sculptural variation. All three female castes have (1) the ventral process of the petiole with a small, round denticle in lanuginosus vs. broad and truncate in liogaster; and (2) the mesonotal expansions extremely small (sometimes absent in the workers) in lanuginosus vs. well developed in liogaster. In addition to that, large soldiers and large gynes of lanuginosus have a well developed pronotal crest, much higher than the one of liogaster soldiers and gynes independently of their size. (de Andrade and Baroni Urbani 1999)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina (type locality), 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.

  • lanuginosus. Cryptocerus (Paracryptocerus) lanuginosus Santschi, 1919f: 46 (w.) ARGENTINA. De Andrade & Baroni Urbani, 1999: 654 (s.q.m.). Combination in Cephalotes: De Andrade & Baroni Urbani, 1999: 652. Junior synonym of liogaster: Kempf, 1958a: 25. Revived from synonymy and senior synonym of lobigaster: De Andrade & Baroni Urbani, 1999: 652.
  • lobigaster. Cryptocerus (Paracryptocerus) lobigaster Santschi, 1919f: 47, fig. 4 (w.) ARGENTINA. Junior synonym of liogaster: Kempf, 1958a: 25; of lanuginosus: De Andrade & Baroni Urbani, 1999: 652.

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 slightly broader than long. Vertexal angles subround, with slightly crenulate border and with a median pair of denticles. Vertexal margin concave. Frontal carinae slightly upturned over the eyes. Compound eyes large and strongly protruding. Mandibles superficially carinate laterally.

Mesosoma gently convex in side view. Scapular angles reduced but visible in dorsal view. Pronotum with a lateral lamella bearing three pairs of teeth of variable size, the first pair large and pointed, the second and third ones small, more pointed in small workers and simply angulate in large workers. Sides of mesonotum unarmed, rarely with a minute denticle. Promesonotal suture poorly impressed. Propodeal suture superficially impressed. Propodeum with differentiate basal and declivous faces; sides of the basal face with a denticle followed by a tooth, sometimes the denticles simply angulate or absent; sides of the declivous face of the propodeum unarmed, or with two pairs of small denticles.

Petiole with truncate and deeply concave anterior face, and bearing or not a pair of lateral denticles. Petiolar spines arising from the anterior face of the petiole, pointed and curved backwards. Postpetiole as broad as the petiole; its lateral expansions broad, developed anteriorly, curved and pointed backwards.

Gaster suboval, with a pair of broad, anterolateral lobes.

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

Sculpture. Body slightly shining, minutely reticulate-punctate, the reticulation very superficial or absent on the frontal carinae, on the anterior fourth of the first gastral tergite, on the sides of the corresponding sternite, and on the legs. Remaining part of the first gastral sternite shining. Head, mesosoma, pedicel foveolate, the foveae larger, sparser and more regular on the frons, very irregular on the ventral part of the head and on the pedicel. Frontal carinae, ventral part of the head, pleurae and anterior half of the first gastral tergite with additional, thin rugosities, more longitudinally parallel on the frontal carinae, on the sides of the head, on the propleurae and on the anterior half of the first gastral tergite, less regular on the meso- and metapleurae and concentric behind the mouth and in front of the postoccipital bridge. Distal part of the outer face of the femora, and tibiae with superficial, irregular foveae.

Pilosity. Body with four types of hairs: (1) appressed and originating from part of the foveae, of size proportional to the one of the fovea from which they originate; similar hairs of variable size on the body parts without foveae; (2) pointed, long, flexuous, originating either from the undifferentiated integument or from the remaining foveae not bearing type (1) hairs; (3) short and truncate on the two last funicular joints and on the tarsomeres; (4) longer than type (3) and pointed, on the remaining funicular joints and on the mandibles.

Colour. Black. Frontal carinae yellow-orange and semitransparent. Tarsomeres light brown.

Measurements (in mm) and indices: TL 4.32-5.00; HL 1.02-1.16; HW 1.08-1.28; EL 0.30-0.32; PW 0.93-1.16; PeW 0.50-0.64; PpW 0.51-0.65; HBaL 0.41-0.51; HBaW 0.10-0.13; CI 105.9-112.3; PI 110.3-116.1; PPeI 180.0-200.0; PPpI 178.5-186.2; HBaI 22.94-25.5.

Soldier

de Andrade and Baroni Urbani (1999) - Head as broad as long, with complete disc. Floor of the disc convex posteriorly and concave anteriorly. Frontal carinae and borders of the disc strongly crenulate and raised only anteriorly. Sides of the disc subparallel, converging backwards, not hiding the eyes and connected by the convex posterior border of the disc. Vertexal angles broad, convex, converging towards the vertex and with strongly crenulate border. 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 pointed teeth. Pronotal sides gently convex with or without a crenulate border on the anterior half only. Pronotal carina generally well marked (less so among small specimens), strongly crenulate and medially interrupted by a sulcus. Promesonotal suture deep and less impressed medially. Sides of the mesonotum with a small, broad, round expansion. Propodeal suture impressed. Propodeum with well differentiate basal and declivous faces. Sides of the basal face with a small pair of short, broad, subround or truncate teeth and with a pair of large, stout teeth curved upwards. Declivous face medially concave, its sides converging posteriorly.

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

Gaster oval and with a pair of anterolateral lobes.

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

Sculpture. Head, mesosoma and pedicel, outer face of the femora and of the tibiae superficially shining, minutely reticulate-punctate and foveolate; the foveae more regular on the head dorsum, sparser on the frontal carinae, smaller on the pedicel. Pleurae with rugosities superimposed to the reticulation, the rugosities longitudinal on the propleurae, irregular on the meso- and lower metapleurae and oblique on the upper metapleurae. Gaster reticulate, the reticulation less impressed on the posterior half of the first gastral sternite. Anterior fourth of the first gastral tergite with additional, small, superficial foveae and with few longitudinal rugosities. Distal part of the outer face of the femora, and tibiae with superficial, irregular, small foveae.

Pilosity. As in the worker.

Colour. Black. Head dorsum and pronotal sides orange to light brown. First gastral tergite with two pairs of orange spots, the first pair behind the lobes and the second one close to the posterior border. Few specimens with the whole pronotum, part of the mesonotum, the propodeal sides, and the outer ace of the tibiae orange. Some specimens without gastral spots.

Measurements (in mm) and indices: TL 6.56-8.02; HL 1.72-1.96; HW 1.68-1.96; EL 0.36-0.40; PW 1.60-1.92; PeW 0.70-0.84; PpW 0.73-0.84; HBaL 0.45-0.51; HBaW 0.14-0.16; CI 97.7-102.3; PI 102.1-105.0; PPeI 225.3-240.0; PPpI 219.2-228.6; HBaI 31.1-31.4.

Queen

de Andrade and Baroni Urbani (1999) - Head of variable width, slightly narrower or broader than long, with a complete disc. Floor of the disc convex posteriorly and gently concave anteriorly. Frontal carinae and borders of the disc strongly crenulate and raised anteriorly only. Sides of the disc converging backwards, not hiding the protruding eyes and connected by a convex or truncate border; small gynes have the posterior sides of the disc with less marked border. Vertexal angles convex, with a median pair of denticles and with crenulate border. Mandibles with a strong carina. Dorsal border of the antennal scrobes with a longitudinal carina bearing a tooth in front of the eyes; the tooth may be preceded by a crenulation among small specimens.

Mesosoma. Anterior pronotal border gently convex. Humeral angles with a pair of small denticles. Pronotal sides straight and sometimes weakly marginate. Pronotal carina well marked and strongly crenulate in large specimens; small specimens have the pronotal carina less marked on the sides. 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 teeth pointing laterally. Declivous face medially concave; its sides converging posteriorly and superficially carinate laterally.

Petiole with the anterior face oblique and deeply concave medially; its sides with a pair of small, pointed denticles curved backwards. Postpetiole convex. Postpetiolar sides with a pair of variably developed round expansions arising from the anterior border and directed backwards.

Gaster with a pair of protruding anterolateral lobes.

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

Sculpture. As in the soldier except for the foveae, less impressed on the mesonotum and on the scutellum.

Pilosity. As in the worker and soldier.

Colour. As in the soldier.

Measurements (in mm) and indices: TL 8.78-9.32; HL 1.72-1.74; HW 1.68-1.78; EL 0.40; PW 1.60-1.76; PeW 0.64-0.73; PpW 0.74-0.87; HBaL 0.57-0.60; HBaW 0.16; CI 97.7-102.3; PI 101.1-105.0; PPeI 241.1-250.0; PPpI 202.3-216.2; HBaI 26.7-28.1.

Male

de Andrade and Baroni Urbani (1999) - Very similar to the male of Cephalotes pilosus but differing from it in the details listed below: Eyes larger. Scutellum broader and less convex dorsally. Anterior face of the petiole less concave. Petiole and postpetiole broader.

Sculpture. First gastral tergite more shining. Body rugosities more regular, parallel; thicker on the propodeum and on the pedicel.

Pilosity. Flexuous hairs less dense.

Colour. Black. Distal third of the femora, tibiae and tarsi dark yellow.

Measurements (in mm) and indices: TL 5.88-6.56; HL 0.90-0.92; HW 1.16; EL 0.48; PW 1.04-1.10; PeW 0.60; PpW 0.63; HBaL 0.52-0.55; HBaW 0.12-0.13; CI 126.1-128.9; PI 105.4-111.5; PPeI 173.3-183.3; PPpI 165.1-174.6; HBaI 23.1-23.6.

Type Material

de Andrade and Baroni Urbani (1999):

Worker. Type locality: Alta Gracia (Cordoba, Argentina). Type material: 2 syntype workers labelled “Cryptocerus lanuginosus, type, Sant., Cordoba, Alta Gracia, Bruch leg.", in Naturhistorisches Museum Basel, examined. Synonymy with liogaster by Kempf, 1958 a: 25.

Cryptocerus lobigaster. Worker. Type locality: Cabana (Cordoba, Brazil). Type material: holotype worker (unique) labeled “Cryptocerus lobigaster, type, Sant., Argentine, Cabana, (Scott leg)”, in NHMB, 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 654, soldier, queen, male described; page 652, Combination in Cephalotes, Revived from synonymy and senior synonym of lobigaster)
  • Kempf, W. W. 1958a. New studies of the ant tribe Cephalotini (Hym. Formicidae). Stud. Entomol. (n.s.) 1: 1-168 (page 25, Junior synonym of liogaster)
  • Santschi, F. 1919f. Nouveaux formicides de la République Argentine. An. Soc. Cient. Argent. 87: 37-57 (page 46, worker described)