Polyrhachis lumi

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Polyrhachis lumi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Aulacomyrma
Species: P. lumi
Binomial name
Polyrhachis lumi
Kohout, 2007

Polyrhachis lumi casent0009231 p 1 high.jpg

Polyrhachis lumi casent0009231 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Polyrhachis lumi.

Identification

P. lumi is close to Polyrhachis exarata, but has the head, in full face view, distinctly larger and the eyes only reaching and not exceeding the lateral cephalic outline; the mesosoma in lateral view strongly arched, terminating in rather distinct, posteriorly and dorsally directed, blunt teeth and the legs dark brown. In contrast, the eyes in exarata clearly break the lateral cephalic outline, the mesosomal dorsum is almost flat with the propodeum terminating in narrowly rounded processes that are weakly widened laterally before rounding inwards and forming a transverse posterior margin and the legs are mostly yellow.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea (type locality).

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Polyrhachis lumi for further details

Biology

The subgenus this species is a member of, Aulacomyrma, is poorly colected. Kohout (2007) summarized what is known about their biology in a revision of the species in the subgenus. This offers an explanation as to why most Aulacomyrma are known from few collections and specimens. There are only two records of nests being found. A small colony of Polyrhachis dohrni was collected by Kohout from a dry hollow twig on a living tree at the edge of lowland rainforest. The internal walls of the twig cavity were lined with a little silk. Ward collected a nest of Polyrhachis wardi from a dry twig of a rainforest tree. The colonies of both species were rather small, with only a few workers (5 and 11 respectively, including 2 and 3 alate queens and a single male). If such a nesting pattern is the norm for other species of the subgenus, that might explain the general scarcity of Aulacomyrma material even in the best collections. Many Aulacomyrma species are described and only known from a holotype.

Castes

Nomenclature

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

  • lumi. Polyrhachis (Aulacomyrma) lumi Kohout, 2007a: 201, figs. 11, 14, 17 (w.) NEW GUINEA.

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

Description

Worker

TL c. 5.69-5.90 (5.69); HL 1.50-1.53 (1.53); HW 1.31-1.37(1.37); CI 89, 87-89 (89); SL 1.53-1.56 (1.56); SI 114-117 (114); PW 1.15-1.18 (1.18); MTL 1.43-1,47 (1.47) (3 measured).

Clypeus arcuate, anterior margin medially truncate; median carina blunt, but distinct; in profile clypeus straight with base rather flat. Frontal triangle well defined. Frontal carinae sinuate with raised laminate lobes; central area relatively wide with weak, blunt, longitudinal carina. Sides of head in front of eyes weakly converging towards mandibular bases. Eyes moderately convex, in full face view just reaching lateral cephalic outline. Mesosoma with lateral margins converging posteriorly. Pronotal humeri armed with broad-based, acute teeth, their anterior and lateral margins sharp and distinctly raised. Mesonotum and propodeum with hairline break in dorsal sculpture and emarginations of lateral margins indicating position of metanotal groove. Propodeal dorsum with lateral margins emarginate, terminating posteriorly in blunt, tooth-like prominences that are distinctly raised, posterior margins continued for some distance, forming short, transverse, medially unconnected ridges. Dorsal margin of petiole sharp, with some irregularities along outline, lateral petiolar spines acute, posteriorly curved. Anterior face of first gastral segment medially concave with anterodorsal margin of concavity blunt. Sculpture of body consisting of more-or-less regular striae of various intensities, striae rather flat and anteriorly converging on clypeus and vertex, where they are strongly impressed, meeting along midline; striae mostly longitudinal on sides of head. Mesosomal dorsum with striae regularly spaced, those along pronotal margin somewhat converging anteriorly towards pronotal collar; striae converging posteriorly on propodeum and oblique on sides of mesosoma. Both faces of petiole finely shagreened. Sides of first gastral segment with regular longitudinal striae, less distinct on dorsum. Erect to semi-erect, medium length hairs on mandibular masticatory border, median portion of anterior clypeal margin, along frontal carinae, antennal scapes and vertex. In full face view, hairs completely absent from sides of head between eyes and mandibular bases. Dorsum of mesosoma and gaster with numerous erect hairs that are directed posteriorly on gastral dorsum and distinctly longer towards apex of gaster. Petiole with a few, short, erect hairs along dorsal margin. Mostly silvery, appressed pubescence scattered in various densities over body; most dense on pronotal humeri and propodeal dorsum, almost obscuring underlying sculpture. Pubescence off-white or yellowish on gaster, densest along gastral margins and curving towards midline.

Black; distal funicular segments and legs medium to dark reddish-brown.

Type Material

HOLOTYPE: PAPUA NEW GUINEA: West Sepik Prov., Torricelli Mts, Lumi, 03º28’S, 142º02’E, 400-550m, 4-13.viii.1984, R. J. Kohout acc. 84.273) (worker). PARATYPES: data as for holotype (2 workers). Type distribution: holotype in Australian National Insect Collection, 1 paratype each in Queensland Museum and Museum of Comparative Zoology.

Etymology

Named after the type locality, Lumi village in the Torricelli Mountains, Papua New Guinea.

References