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Polyrhachis nigrita
| Polyrhachis nigrita | |
|---|---|
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| 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
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| Synonyms | |
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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
- Key to Afrotropical Polyrhachis species
- Key to Afrotropical Polyrhachis species (Bolton 1973, OUTDATED)
Distribution
Latitudinal Distribution Pattern
Latitudinal Range: 2.91667° to -0.166666667°.
| North Temperate |
North Subtropical |
Tropical | South Subtropical |
South Temperate |
- Source: AntMaps
Distribution based on Regional Taxon Lists
Afrotropical Region: Democratic Republic of Congo, Ghana (type locality), Uganda.
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Countries Occupied
| Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species. |
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Estimated Abundance
| Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species. |
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Biology
Castes
Worker
       
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Nomenclature
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- 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
- Bolton, B. 1973b. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History) Entomology. 28:283-369. (page 328, Senior synonym of schoutedeni)
- Mayr, G. 1895. Afrikanische Formiciden. Ann. K-K. Naturhist. Mus. Wien 10: 124-154 (page 153, worker described)
- Wheeler, W. M. 1922b. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. II. The ants collected by the American Museum Congo Expedition. Bull. Am. Mus. Nat. Hist. 45: 39-269 (page 267, Combination in P. (Myrma))
References based on Global Ant Biodiversity Informatics
- Bolton B. 1973. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History). Entomology 28: 283-369.
- Mikissa J. B., J. H. C. Delabie, J. L. Mercier, and D. Fresnau. 2008. Preliminary Assessment on the Interactions of Wasmannia auropunctata in Native Ant Communities (Hymenoptera: Formicidae) of a Mosaic Gallery Forest/Savannah in Lope National Park, Gabon. Sociobiology 51(1): 207-218.