Polyrhachis fisheri

Polyrhachis fisheri
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Camponotini
Genus:	Polyrhachis
Subgenus:	Myrma
Species group:	militaris
Species:	P. fisheri
Binomial name
	Polyrhachis fisheri; Rigato, 2016

Nothing is known about the biology of Polyrhachis fisheri.

Identification

Rigato (2016) - A large, relatively slender species in the militaris group with elongate oval head, bulging eyes, longitudinally striate sculpture on most of head and mesosoma and very long and abundant standing hairs.

Polyrhachis fisheri looks very similar to Polyrhachis latispina, with which it may be confused. The main differences between them are listed below. Polyrhachis sulcate André looks also similar, but it has a fully immarginate propodeum and a stronger rugosity covering the whole body:

Polyrhachis fisheri	Polyrhachis latispina
In full face view head distinctly elongate oval, strongly convex posteriorly; frons wider. CI 75, FI > 50.	In full face view head relatively short, broadly curved posteriorly; frons narrower. CI > 80, FI < 45.
In dorsal view pronotal spines more than twice as long as their basal width.	In dorsal view pronotal spines no more than 1.5 as long as their basal width.
Sides of mesosoma mostly distinctly longitudinally rugose throughout.	Sides of mesosoma with distinct longitudinal rugosity on pronotum, anepisternum and propodeum only; the remaining surfaces roughly irregularly rugulose and reticulate-punctate.
Propodeal dorsum and declivity separated by a sudden interruption of the strong rugosity of the dorsum, forming a weakly arched margin.	Propodeal dorsum and declivity separated by a well defined and strongly arched edge running between the base of the propodeal teeth.
Appendages both absolutely and relatively longer, SL ≈ 3.00, SI > 150, HTL >> 3.00.	Appendages both absolutely and relatively shorter, SL< 2.50, SI < 130, HTL ≈ 2.50.
Standing pilosity longer. Longest hairs on scapes and tibiae about as long as thrice and twice the scape and tibial width at midlength respectively.	Standing pilosity shorter. Longest hairs on scapes and tibiae at most slightly longer or slightly shorter than scape and tibial width at midlength respectively.

Keys including this Species

Key to Afrotropical Polyrhachis species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Gabon (type locality).

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.

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.

Biology

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

fisheri. Polyrhachis fisheri Rigato, 2016: 20, figs. 5a-c (w.) GABON.

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

Description

Worker

Holotype. HL 2.50, HW 1.87, CI 75, SL 2.98, SI 159, FW 0.98, FI 52, PW 1.53, WL 3.57, HTL 3.33.

Clypeus with a blunt longitudinal median carina, its anterior margin evenly convex and shallowly notched in the middle. Head in full face view elongate oval, strongly convex behind the eyes. Eyes placed relatively posteriorly and strongly bulging. Mesosoma moderately elongate, in profile broadly convex and interrupted by the sutures; metanotal suture more impressed than the promesonotal one. Pronotal spines long, mostly anteriorly directed. Pronotum and mesonotum almost flat transversely; propodeal dorsum weakly convex. Mesosoma distinctly marginate along its sides, the margination runs as narrow flanges along pronotum and mesonotum. In dorsal view mesonotum about 1.5 times as wide as long, propodeal dorsum slightly longer than wide. Propodeal dorsum and declivity separated by a sudden change of sculpturation. Propodeal teeth relatively long, upturned and spine-like, almost as long as the propodeal declivity. Petiole with four long spines, the dorsal pair almost parallel, upward and slightly backward directed and about 1.5 times as long as the lateral pair. First gastral tergite anteriorly flat.

Mandibles mostly finely longitudinally striolate and with sparse, small piligerous pits. Head dorsum and dorsum and sides of the mesosoma mostly distinctly longitudinally rugose. This sculpturation is regular, except anteriorly on the head, including clypeus, and below the eyes, where it is prevailingly reticulate-rugose. Propodeal declivity superficially and finely reticulate-imbricate with few weak superimposed longitudinal rugulae. Petiole rugose: the rugae encircling most of the tergite, irregular on the anterior face; space between the mid pair of spines longitudinally rugose. Ground sculpture weak on most of the body. Gaster finely reticulate-punctate, almost all of the anterior half of the dorsum of the first gastral tergite with a superimposed fine, posteriorly vanishing, longitudinal rugulation. Scapes and legs mostly roughly reticulate-punctate with distinct piligerous pits; forelegs more finely and superficially sculptured.

Standing hairs yellowish, abundant throughout and very long: the longest hairs on the appendages are about as long as thrice the scape diameter at midlength and twice the maximum tibial width. Pubescence inconspicuous on the body, minute and very sparse on the gaster.

Colour mostly black throughout, mandibular apices, except the black teeth, ferrugineous.

Type Material

Holotype. GABON: Prov. Woleu-Ntem, 31.3 km 108° ESE Minvoul, 2°04,8’N 12°24.4’E, 600 m, 12.ii.1998 (B.L. Fisher) #1693-2 (California Academy of Sciences).

References