Centromyrmex gigas

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Centromyrmex gigas
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Centromyrmex
Species: C. gigas
Binomial name
Centromyrmex gigas
Forel, 1911

Centromyrmex gigas casent0179476 profile 1.jpg

Centromyrmex gigas casent0179476 dorsal 1.jpg

Specimen labels

According to Luederwaldt (1926: 238), who discovered two colonies of the present species in termite nests of Syntermes dirus Burmeister (probably not dirus but wheeleri, cf. Araujo, 1958: 211-2), single colonies seem to consist of very few individuals and alate sexual offspring is found in the nest in October. One nest contained only three individuals (incipient colony?). H. S. Lopes, as reported by Borgmeier (1937: 223), found the same species at Manguinhos, Rio de Janeiro City, likewise in a nest of Syntermes sp. (Kempf 1967)

Identification

A member of the brachycola species group.

Keys including this Species

Distribution

Kempf reports this species from southeastern Brazil and adjacent areas of Argentina.

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Brazil (type locality), French Guiana.

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

All of the species in the genus appear to be termitophagous and all are superbly adapted to this specialised predatory life style. Observations of some species have found them to be rather helpless when placed in an exposed, open situation. Weber described what happened when he found a worker “just beneath the soil surface under a thin cover of dead leaves”. The ant was “completely helpless when exposed to the daylight and writhed about when placed on the ground or in my palm. It made no attempt to run away, curling and uncurling without stinging, though it had a long, stout sting”. In other words, it seemed unable to walk when removed from its specialised habitat and placed on a surface where it could not use its specialised legs. If not discovered within a termite nest, individuals are occasionally found in the top soil or the root-mat below the leaf litter layer, where their short, powerful, spiny legs facilitate their movement. (Weber 1949, Bolton and Fisher 2008).

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • gigas. Centromyrmex gigas Forel, 1911c: 287 (w.) BRAZIL. Borgmeier, 1937b: 223 (q.). See also: Kempf, 1967b: 407.

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

Description

Worker

Kempf (1967) - Total length about 12 mm. Head length 1.76-1.92 mm; head width 1.94-2.23 mm; thorax length 2.93-3.20 mm; hind tibia length 1.20-1.33 mm; hind metatarsus length 0.85-0.96 mm. Rather reddish brown than amber-colored, generally darker than Centromyrmex brachycola. Mandibles distinctly dentate at basal half, chewing border forming an obtuse angle with basal border. Head distinctly broader than long, sides more rounded, converging cephalad. Occiput gently concave. Clypeus without a median tumulus on disc. At posterior end of frontal sulcus often a rudimentary ocellus. Mesoepinotal suture either absent or indicated by a faint transverse notch. Mesopleura often divided by a transverse suture into anepisternum and catepisternum. Epinotum not so strongly constricted nor depressed as in brachycola; basal face often with a faint, saddle-shaped impression in the middle; declivous face less oblique than in brachycola. Metasternal angle more extensively striolate. Mesial spur of middle tibiae long and projecting beyond apex of tibia. Extensor face of hind tibiae with spine-like setae on apical half. Petiole as shown in Figs. 9 and 10; note the long subpetiolar process. Sternum I of gaster with a marginate tuberosity beneath petiolar insertion.

Queen

Kempf (1967) - Head length 1.86-2.00 mm; head width 2.13-2.29 mm; maximum diameter of eyes 0.53-0.67 mm; thorax length 3.47-4.00 mm. Similar to the worker with the usual differences of the caste. Wings as in brachycola, hind wing with 8 hamuli.

Type Material

Kempf (1967) - Syntypes in the collections of the Departamento de Zoologia da Secretaria de Agricultura de Sao Paulo (DZSP), of Forel and in my own (WWK).

References