Polyrhachis volkarti

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Polyrhachis volkarti
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Myrma
Species group: revoili
Species: P. volkarti
Binomial name
Polyrhachis volkarti
Forel, 1916

Polyrhachis volkarti casent0250031 p 1 high.jpg

Polyrhachis volkarti casent0250031 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Polyrhachis volkarti.

Identification

Rigato (2016) - A medium sized revoili-group species with lobed clypeus, immarginate mesosoma (at most the pronotum bears a trace of lateral margination), and propodeal dorsum wider than long.

The P. volkarti gyne looks very similar to the Polyrhachis kohli gyne, except for the significant differences concerning pilosity and propodeum summarized under kohli. The workers I assigned to volkarti have pilosity and propodeal proportions highly comparable to those of the holotype gyne; yet further discoveries could demonstrate such workers to belong to a still undescribed species.

Bolton (1973) - P. volkarti is distinguished by its narrow build, truncate clypeal lobe, lack of a metanotal groove and presence of a pair of propodeal ridges.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps

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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.

  • volkarti. Polyrhachis (Myrma) revoili r. volkarti Forel, 1916: 453 (q.) DEMOCRATIC REPUBLIC OF CONGO. Combination in P. (Pseudocyrtomyrma): Emery, 1925b: 207. Raised to species: Bolton, 1973b: 341.

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 5.9, HL 1.37, HW 1.00, CI 73, SL 1.81, SI 181, PW 0.89, MTL 1.70.

Median portion of clypeus projecting anteriorly as a truncated, rectangular lobe. Head long and relatively narrow; the eyes strongly convex, almost hemispherical. Sides of head in front of the eyes weakly convex, somewhat convergent anteriorly. Alitrunk convex transversely, long and narrow, not at all marginate. Pronotum armed with a pair of short, triangular spines; the propodeum with a pair of short transverse ridges separating the dorsum from the declivity. The ridges do not meet medially and a small but distinct gap is present. Promesonotal suture represented by a faint line which just breaks the sculpturation; metanotal groove absent. Petiole armed dorsally with a pair of spines and laterally with a pair of teeth. Anterior face of the first gastral segment concave medially.

Entirety of head, body and appendages covered with abundant long, fine, erect hairs, some of which are curved or gently sinuate. Pubescence dense and greyish in colour.

Clypeus and gaster finely and densely reticulate; head and dorsum of alitrunk finely and densely longitudinally rugose, the rugae overlying a superficial reticulate-puncturation. Sides of the alitrunk with a fine rugoreticulum.

Rigato (2016) - workers from the Republic of the Congo (n=5) HL 1.36–1.45, HW 1.11–1.16, CI 80–83, SL 1.74–1.85, SI 151–162, FW 0.40–0.41, FI 35–37, PW 1.00–1.06, WL 1.87–1.99, HTL 1.70–1.81. They look conspecific with the holotype gyne in all main features, even if sometimes an ill-defined trace of pronotal margination appears anteriorly behind the pronotal teeth.

Queen

Bolton (1973) - As worker but with the pronotal spines and propodeal ridges very much reduced, the latter to a pair of short, rounded prominences, best seen in posterior view. Sculpturation of the alitrunk finer, the longitudinal rugae of the alitrunk suppressed in favour of the reticulate-puncturation.

Rigato (2016) - Holotype. HL 1.50, HW 1.15, CI 77, SL 1.95, SI 170, FW 0.41, FI 36, MnL 1.78, ScW 1.45, WL 2.52, HTL 1.97.

Clypeus bearing a slightly protruding rectangular lobe at its anterior margin. Head in full face view oval, wider behind than in front, posterior margin evenly convex without distinct posterior corners; sides in front of the eyes straight. Eyes relatively large and convex. Ocelli small. Pronotal and propodeal sides immarginate. Pronotal teeth small and robust. Propodeal dorsum distinctly wider than long, arched both longitudinally and transversely. Propodeal ridges small and far apart, between them the propodeal dorsum smoothly merges into the declivity. Petiole with a mid pair of diverging and slightly backward bent spines, whose reciprocal distance is about twice the length of each spine, and a pair of much shorter lateral teeth raising near the bases of the spines. First gastral tergite anteriorly weakly concave.

Mandibles mostly smooth and shining, weakly shagreened at their insertion. Body and appendages finely reticulate-punctate; sculpturation stronger on the opaque head and mesosoma. Cephalic dorsum, except clypeus, with a superimposed longitudinal fine rugulation.

The whole body and appendages with fairly abundant standing hairs; longest hairs occur on scutellum and cephalic dorsum. Hairs on tibiae short, at most as long as maximum tibial width; hairs on scapes at most 1.5 as long as the maximum scape diameter. Pubescence whitish, moderately long and abundant throughout the body, but never hiding the sculpturation; on the gaster the distance between two adjacent elements is about equal to their length.

Colour mostly black, tibiae dark brown, tarsi apically partially ferrugineous. Funiculi mostly ferrugineous, except the 4 basalmost joints, which are basally darkened. Mandibles apically ferrugineous.

Type Material

Rigato (2016) - Holotype gyne, DEMOCRATIC REPUBLIC of the CONGO (H. Kohl). (Musee d'Histoire Naturelle Genève) [examined].

References