Polyrhachis weissi

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Polyrhachis weissi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Myrma
Species: P. weissi
Binomial name
Polyrhachis weissi
Santschi, 1910

Polyrhachis weissi casent0403605 p 1 high.jpg

Polyrhachis weissi casent0403605 d 1 high.jpg

Specimen Labels

Synonyms

P. weissi may be regarded as the forest equivalent of revoili, which appears to be confined to savannah and veldt regions. Nests of silk and vegetable particles are constructed under leaves or between contiguous leaves which are gummed together by the silk. A small nest dissected at CRIG, New Tafo in July 1970 by P. M. Room contained seven workers, six females (all alate), five males, and 32 brood (larvae and pupae). (Bolton 1973)

Identification

Rigato (2016) - Polyrhachis weissi looks easily identifiable within the revoili-group for this unique combination of features: 1) clypeus with an uniformly rounded anterior margin; 2) head in full face view distinctly trapezoidal with a strongly transverse, weakly convex posterior border; 3) eyes moderately convex and placed close to posterior corners; 4) mesosoma fully immarginate and stout (in dorsal view pronotum and mesonotum strongly transverse, propodeal dorsum trapezoidal, much wider in front than behind and distinctly shorter than its maximum width); 5) propodeal dorsum bearing a pair of small, sharp upturned teeth at its posterior corners; 6) petiole with two pairs of spines, the mid pair slightly curved backward and distinctly longer; 7) body mostly reticulate punctate with superimposed fine longitudinal rugulae on cephalic and mesosomal dorsa (cephalic rugulae tidier); 8) standing hairs moderately long and abundant all over the body and legs, mostly yellowish in colour.

The presence and number of standing hairs on scapes could suggest the existence of two distinct species. Some nest series have 0 to few standing hairs on scapes, whereas other samples have more than 30, without any seemingly intermediate condition. Because of lack of further reliable distinctive characters, I prefer to consider these alternative conditions as a matter of intraspecific variability.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun, Central African Republic, Congo (type locality), Democratic Republic of Congo, Ghana, Guinea, South Africa, Zambia.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Alate females have been recorded from Ghana in July.

Castes

Worker

Queen

Nomenclature

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

  • weissi. Polyrhachis weissi Santschi, 1910c: 395, fig. 18 (w.) CONGO. Combination in P. (Pseudocyrtomyrma): Emery, 1925b: 207; in P. (Myrma): Wheeler, W.M. 1922a: 1004; Bolton, 1973b: 342. Subspecies of revoili: Forel, 1916: 453; Emery, 1925b: 207; Santschi, 1939c: 12. Status as species: Wheeler, W.M. 1922a: 1004; Bolton, 1973b: 342. Senior synonym of balli, conduensis, crassa and material of the unavailable name phaenogaster referred here: Bolton, 1973b: 342.
  • conduensis. Polyrhachis (Myrma) revoili var. conduensis Forel, 1915c: 351 (w.) DEMOCRATIC REPUBLIC OF CONGO. Combination in P. (Pseudocyrtomyrma): Emery, 1925b: 207. Junior synonym of weissi: Bolton, 1973b: 342.
  • crassa. Polyrhachis (Pseudocyrtomyrma) revoili subsp. crassa Emery, 1921e: 23, fig. 2 (w.q.) CAMEROUN. Junior synonym of weissi: Bolton, 1973b: 342.
  • balli. Polyrhachis (Pseudocyrtomyrma) revoili st. balli Santschi, 1939c: 10 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of weissi: Bolton, 1973b: 342.
  • natalensis. Polyrhachis natalensis Santschi, 1914e: 41 (w.) SOUTH AFRICA. Combination in P. (Myrma): Wheeler, W.M. 1922a: 999; in P. (Pseudocyrtomyrma): Emery, 1925b: 207. Status as species: Wheeler, W.M. 1922a: 999. Subspecies of revoili: Emery, 1925b: 207; Santschi, 1939c: 12. Junior synonym of revoili: Forel, 1916: 453; Arnold, 1924: 754; Bolton, 1973b: 338; of weissi: Rigato, 2016: 44.
  • donisthorpei. Polyrhachis (Myrma) revoili var. donisthorpei Forel, 1916: 453 (w.) ZAMBIA. [Also described as new by Forel, 1917: 252.] Combination in P. (Pseudocyrtomyrma): Emery, 1925b: 207. Junior synonym of revoili: Bolton, 1973b: 338; of weissi: Rigato, 2016: 44.

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 5.7-6.1, HL 1.40-1.48, HW 1.29-1.40, CI 88-95, SL 1.66-1.74, SI 124-125, PW 1.18-1.26, MTL 1.59-1.66. (15 measured.)

Anterior clypeal margin arcuate and entire. Eyes convex, the sides of the head gently convex and convergent anteriorly. Alitrunk not marginate, the dorsum convex. Promesonotal suture faint but distinct, the metanotal groove reduced to a line which only breaks the sculpturation. Pronotum very broad, more than twice the width of the propodeum measured across the teeth. Pronotum armed with a pair of short, acute spines of somewhat variable configuration; the propodeum with a pair of small, upcurved teeth. Petiole with two pairs of spines, the dorsal pair long and acute, the laterals much shorter and weakly upcurved. Anterior face of the first gastral segment shallowly concave medially.

Head and body with numerous erect hairs, white to grey in colour. Hairs very sparse or absent from the antenna! scapes. Pubescence everywhere sparse, short, greyish in colour, nowhere concealing the underlying sculpturation.

Head and entire dorsum of alitrunk finely, longitudinally striate-rugose. Gaster finely and superficially reticulate. Colour uniform black, or with the appendages somewhat lighter, either dark brown or red-brown. Antennal funiculi usually with the apical five or six segments light brown.

Queen

Bolton (1973) - As worker but with the pronotal spines reduced to mere teeth and the propodeal teeth minute or absent. The sculpturation of the mesoscutum tends to be notably finer than that of the head.

Type Material

Rigato (2016) - Holotype worker, CONGO: Brazzaville (A. Weiss) (Naturhistorisches Museum, Basel).

References