Polyrhachis nigrita

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to: navigation, search
Polyrhachis nigrita
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Myrma
Species group: viscosa
Species: P. nigrita
Binomial name
Polyrhachis nigrita
Mayr, 1895

Polyrhachis nigrita casent0906838 p 1 high.jpg

Polyrhachis nigrita casent0906838 d 1 high.jpg

Specimen Labels

Synonyms

Bolton (1973) - Probably a ground nesting species which forages on low vegetation as the specimens from Uganda studied during the course of this survey were obtained by sweeping in a marsh. Wheeler (1922a:267) states that a single worker from Akenge, Congo (Kinshasa) was taken from the stomach of a toad.

Identification

A member of the Polyrhachis viscosa species-group. Bolton (1973) - The general body form allies this species to Polyrhachis viscosa and Polyrhachis cubaensis as was pointed out by Mayr in the original description. The species is distinguished by the marked reduction of the dorsal pair of petiolar spines and the lack of a transverse ridge separating the propodeal dorsum from the declivity.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Democratic Republic of Congo, Ghana (type locality), Uganda.

Distribution based on AntMaps

AntMapLegend.png

Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Worker

Nomenclature

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

  • nigrita. Polyrhachis nigrita Mayr, 1895: 153 (w.) GHANA. Combination in P. (Myrma): Wheeler, W.M. 1922a: 267. Senior synonym of schoutedeni: Bolton, 1973b: 328.
  • schoutedeni. Polyrhachis (Myrma) schoutedeni Santschi, 1919c: 249 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of nigrita: Bolton, 1973b: 328.

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

Description

Worker

Bolton (1973) - TL 7.0-8.9, HL 1.70-2.04, HW 1.48-1.70, CI 83-87, SL 1.89-2.22, SI 130-134, PW 1.15-1.34, MTL 1.92-2.37. (6 measured.)

Clypeus usually with the anterior margin slightly raised, may be weakly emarginate. Eyes convex; occipital margin strongly convex. Antennal scapes broadening apically, about two or three times broader at the apex than at the base but not distinctly and abruptly thickened apically as in viscosa. Alitrunk marginate throughout its length, the marginations only poorly developed. Pronotal and propodeal spines well developed, the latter without a transverse ridge running between them, the dorsum rounding evenly into the declivity. Promesonotal suture distinct, metanotal groove represented by a weakly incised line which in places fails to break the sculpturation. Petiole with the lateral pair of spines long and strong, produced outwards and upwards and curved backwards around the base of the gaster. Between these spines are a pair of short teeth, which may be reduced to blunt tubercles. Anterior face of the first gastral segment concave.

Development of erect hairs variable. In smaller specimens a few hairs are present on the anterior clypeal margin and the gastral apex only, but in larger individuals a few may also be present on the dorsum of the head and the alitrunk. Pubescence greyish white, sparse, densest on gaster and sides of alitrunk.

Clypeus with extremely fine longitudinal striae, contrasting to the rest of the head which has a fine reticulate-rugulation, the spaces enclosed by the reticulae finely punctate. A similar sculpturation is found on the dorsum of the alitrunk but laterally the rugae are effaced, leaving the surface finely reticulate-punctate. Gaster minutely and densely reticulate-punctate.

Type Material

Bolton (1973) - Holotype worker, GHANA : Chama (Brauns) (probably in Naturhistorisches Museum Wien, Vienna).

References