Centromyrmex sellaris

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Centromyrmex sellaris
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Centromyrmex
Species: C. sellaris
Binomial name
Centromyrmex sellaris
Mayr, 1896

Centromyrmex sellaris casent0066705 profile 1.jpg

Centromyrmex sellaris casent0066705 dorsal 1.jpg

Specimen labels

Synonyms

Specimen labels show Centromyrmex sellaris has been collected from termitaries of the genus Odontotermes.

Identification

A member of the feae species group. This species and Centromyrmex angolensis are the most widely distributed and most commonly encountered species of the feae group in Africa. Superficially the two look very similar, but angolensis always has a longer, narrower head and only ever has a single stout spiniform seta at the apex of the anterior surface of the metatibia, about opposite the pectinate spur. In addition, the basal mandibular tooth in angolensis is generally absent, sometimes vestigially present, but there is never the basal tooth + diastema arrangement that is characteristic of sellaris. Care should be taken with this character because of variation in development in sellaris but it is usually a good indicator of the species. (Bolton and Fisher 2008)

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Democratic Republic of Congo, Gabon, Guinea, Ivory Coast, Kenya, Mozambique, Uganda, United Republic of Tanzania, Zambia, Zimbabwe.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

worker from Gorongosa National Park, Mozambique

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

Worker


Male

Nomenclature

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

  • sellaris. Centromyrmex sellaris Mayr, 1896: 230 (w.) CAMEROUN. Senior synonym of arnoldi, congolensis, constanciae, guineensis: Bolton & Fisher, 2008c: 22.
  • constanciae. Centromyrmex constanciae Arnold, 1915: 38, pl. 2, fig. 14 (w.q.) ZIMBABWE. Arnold, 1926: 199 (m.). Senior synonym of arnoldi: Arnold, 1926: 199 (in text). Junior synonym of sellaris: Bolton & Fisher, 2008c: 22.
  • arnoldi. Centromyrmex arnoldi Santschi, 1919b: 229, figs. a-d (w.m.) MOZAMBIQUE. Subspecies of constanciae: Santschi, 1920b: 8. Junior synonym of constanciae: Arnold, 1926: 199 (in text); of sellaris: Bolton & Fisher, 2008c: 22.
  • congolensis. Centromyrmex congolensis Weber, 1949b: 5, figs. 3, 4 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of sellaris: Bolton & Fisher, 2008c: 23.
  • guineensis. Centromyrmex arnoldi r. guineensis Bernard, 1953b: 186, fig. 1 (w.) GUINEA. Subspecies of constanciae: Bolton, 1995b: 140. Junior synonym of sellaris: Bolton & Fisher, 2008c: page.

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

Description

Worker

Bolton and Fisher (2008) - TL 4.8-6.1, HL 0.84-0.98, HW 0.90-1.13, CI 108-118, ML 0.58-0.72, MI 68-75, SL 0.64-0.76, SI 67-73, PW 0.74-0.92, WL 1.54-1.80 (15 measured).

With characters of the genus and the feae group. Head capsule in full-face view always appears obviously broader than long, CI 108 or usually more. Mandibles smooth with scattered small punctures. Masticatory margin of mandible with 7–10 small, low blunt teeth that are usually broadly low-triangular but are often reduced to mere crenulations when worn. Basal tooth at basal angle of mandible and usually obvious, only rarely reduced and insignificant. Distal of the basal tooth there is usually a diastema before the next tooth on one or both of the mandibles, but sometimes this is not apparent as a denticle may be present within the diastema on one, or less often both, of the mandibles. Dorsum and sides of head with scattered punctures on smooth cuticle, and also with weak striation within the antennal fossae and on the sides, especially anteriorly. Extent of the striate component is variable. Metatibia with only normal setae dorsally but its anterior surface, at the apex and approximately opposite the pectinate spur, with 2 (3 in a single specimen) much stouter and usually more darkly coloured spiniform setae. Petiole node in dorsal view broader than long. Pronotal dorsum, and anterior mesonotum, with widely scattered broad, shallow punctures that may be almost effaced. Pronotum dorsally also with variable weak oblique or arched faint disorganised sculpture. Colour yellow to light brown.

Queen

Bolton and Fisher (2008) - TL 6.9, HL 1.01, HW 1.12, CI 111, OI 32, ML 0.70, MI 69, SL 0.80, SI 71, PW 1.11, WL 2.00. The queen of this species should run out correctly in the key to workers but care should be taken as the queens of longiventris and ereptor remain unknown. The form of the mandible described above for the worker is reproduced in the queen caste.

Type Material

Type Specimen Labels

Bolton and Fisher (2008) - Holotype worker, CAMEROUN: no loc. 1891 (Y. Sjöstedt) (Naturhistoriska Riksmuseet) [examined] (see note 1).

Centromyrmex constanciae Syntype workers and queen, ZIMBABWE: Bembesi, 24.iii.1913 (The Natural History Museum) [worker examined].

Centromyrmex arnoldi Santschi, 1919: 229, figs. a–d. Syntype workers and males, MOZAMBIQUE: Amatongas Forest, ix.1917 (G. Arnold) (Naturhistorisches Museum, Basel) [examined].

Centromyrmex congolensis Holotype worker, DEMOCRATIC REPUBLIC OF CONGO: Niangara, 1.iii.1948 (N.A. Weber) (not in American Museum of Natural History or Museum of Comparative Zoology, presumed lost; see note 2).

Centromyrmex arnoldi r. guineensis Holotype worker, GUINEA: Mt Nimba, Nion, St.22, 700 m., 15.iv.1942 (Lamotte) (Musee National d'Histoire Naturelle) [examined].

NOTES.

1 The unique holotype of sellaris was discovered by Dr Hege Vårdal in the NHRS collection, still preserved in alcohol after 117 years. The specimen was accompanied by three labels, two of which merely stated “Camerun” and “Sjöstedt” respectively. A larger and more informative label carried the information “Riksmuseets Entomologiska Afdelning. Centromyrmex sellaris Mayr n. sp. Typ. Kamerun, 1891. Colleg. Y. Sjöstedt”. The holotype has now been mounted upon a standard card point.

2 Although the holotype of congolensis appears to have been lost, it is possible that it may still be present but unrecognised in Weber’s material, either at AMNH or MCZC. Fortunately, the original description and figures are sufficient to allow identification of the taxon. For these reasons, and because the name is a junior synonym, a neotype has not been designated.

Determination Clarifications

Bolton and Fisher (2008) - The species referred to as C. sellaris in Lévieux (1976, 1983) is correctly identified, as indicated by voucher specimens deposited in MCZC.

References