Polyrhachis anderseni

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Polyrhachis anderseni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Hagiomyrma
Species group: penelope
Species: P. anderseni
Binomial name
Polyrhachis anderseni
Kohout, 2013

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Polyrhachis anderseni top.jpg

Specimen labels

Polyrhachis anderseni is one of only a few lithocolous Polyrhachis species (the others are Polyrhachis thusnelda and Polyrhachis turneri) that build their nests inside rock crevices or on the sides of rock walls (Robson & Kohout 2005).

Identification

A member of the penelope species-group in the Polyrhachis subgenus Hagiomyrma. Polyrhachis andersoni is an easily recognisable species, featuring very closely approximated, upturned, petiolar spines. It somewhat resembles Polyrhachis archeri, however, in that species the anterior clypeal margin is produced into a median denticulate flange, while it is simply medially truncate in P. anderseni. The bases of the petiolar spines in P. archeri are more distant and the propodeal spines in lateral view are directed downwards, forming a continuous line with the arching profile of the mesosomal dorsum (Fig. 6C-D). In contrast, the bases of petiolar spines in P. anderseni are closer and the propodeal spines are more horizontal.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Known only from the worker caste.

Nomenclature

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

  • anderseni. Polyrhachis (Hagiomyrma) anderseni Kohout, 2013: 528, figs. 6A-B (w.) AUSTRALIA.

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

Description

Worker

(holotype cited first): TL c. 6.80, 5.90-6.80; HL 1.62, 1.43- 1.62; HW 1.43, 1.23-1.43; CI 88, 86-92; SL 2.09, 1.87-2.12; SI 146, 138-153; PW 1.28, 1.09-1.31; MW 0.76, 0.70-0.81; PMI 168, 149-168; MTL 2.25, 2.00-2.28 (14 measured).

Anterior clypeal margin truncate medially without distinct median flange; truncate portion denticulate, laterally delimited by acute teeth. Clypeus with distinct median carina; weakly convex in profile, posteriorly rounding into moderately impressed basal margin. Frontal triangle indistinct. Frontal carinae with weakly raised margins; central area relatively wide, flat. Sides of head in front of eyes converging towards mandibular bases in straight line; behind eyes, sides widely rounding into convex occipital margin. Eyes moderately convex, in full face view not or only marginally exceeding lateral cephalic outline. Ocelli lacking. Pronotal dorsum distinctly wider than long, widest at about midlength; humeri widely rounded, with shallow depression dorsally along narrowly raised, posteriorly converging lateral margins. Mesonotal dorsum with lateral margins shallowly emarginate towards poorly indicated metanotal groove. Propodeal margins terminating posteriorly in relatively short, horizontal and subparallel, acute spines; spines about half as long as distance between tips. Anterior face of petiole rounding dorsally into upturned, subparallel, or weakly divergent, acute spines; bases of spines closely approximated, petiolar dorsum between them deeply concave, forming open ‘U’ when viewed from behind. Posterior face of petiole distinctly swollen towards base. Anterior face of first gastral segment widely rounding onto dorsum.

Mandibles finely, longitudinally striate with numerous piliferous pits. Head, mesosoma and petiole finely and uniformly reticulate-punctate. Gaster shagreened.

Mandibular masticatory and outer borders with curved golden hairs and closely appressed shorter hairs towards bases. Anterior clypeal margin medially with several, medium length setae and a few short setae fringing margin laterally. Rather sporadic, relatively short, erect hairs on dorsum of head and body, hairs on gaster distinctly longer and more abundant. Silvery, appressed pubescence in various densities over most dorsal body surfaces; pubescence silvery or pale golden and more abundant on gastral dorsum, partly hiding underlying sculpturation.

Black, with mandibular teeth, condylae and apical funicular segments medium to dark reddish-brown. Legs, including coxae, dark to very dark reddish-brown.

Type Material

Type deposition: Holotype and 2 paratypes in Australian National Insect Collection; most paratypes in Queensland Museum, 2 paratypes each in The Natural History Museum, Jonathan D. Majer Collection, Museum of Comparative Zoology, Musee d'Histoire Naturelle Genève, Tropical Ecology Research Centre and Western Australian Museum.

Etymology

Named in honor of Dr Alan N. Andersen of the CSIRO, TERC in Darwin, who has discovered many new species of Polyrhachis and other ants throughout the monsoonal and arid zones of the northern Australia.

References

  • Kohout, R.J. 2013. Revision of Polyrhachis (Hagiomyrma) Wheeler, 1911 (Insecta: Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum, Nature 56, 487-577.