Polyrhachis mamba

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

Polyrhachis mamba casent0009244 p 1 high.jpg

Polyrhachis mamba casent0009244 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Polyrhachis mamba.

Identification

Kohout (2007) - P. mamba is similar to Polyrhachis kokoda, with distinguishing characters given in the remarks section of the latter species. Among these, the most important are the flat eyes in mamba that do not reach the lateral cephalic outline in full face view. Also, the striae on the vertex in mamba are tranversely bowed, while they are longitudinal in kokoda. One dealate queen was collected foraging with workers on the trunks and branches of freshly felled trees on the edge of a recent rainforest clearing. The second queen was collected with a kokoda worker at Oivi Ridge nr Kokoda.

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 mamba 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.

  • mamba. Polyrhachis (Aulacomyrma) mamba Kohout, 2007a: 229, figs. 82, 85, 88 (w.q.) 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. 6.00, 5.04-5.54; HL 1.47, 1.31-1.40; HW 1.28, 1.12-1.18; CI 87, 84-85; SL 1.47, 1.37-1.40; SI 115, 119-122; PW 1.06, 0.90-0.94; MTL 1.50, 1.34-1.40 (4 measured).

Anterior clypeal margin arcuate, entire to narrowly truncate or very shallowly emarginate medially. Longitudinal median carina weakly raised, terminating posteriorly in a shallow basal margin. Frontal carinae strongly sinuate with rather short, laminate, anteriorly sharply truncate lobes. Side of the head in front of eyes very weakly convex, rounded behind into preoccipital margin. Eyes flat, situated well forward on sides of head, virtually identical to those in Polyrhachis impressa and Polyrhachis roomi, not breaking lateral cephalic outline in full face view. Mesosoma immarginate laterally and posteriorly. Pronotal humeri armed with rather broad-based, laterally and anteriorly directed, more-or-less blunt spines. Promesonotal suture shallow; metanotal groove lacking. Petiole in profile with dorsum rounded, lateral teeth minute, upturned. Anterior face of first gastral segment convex.

Mandibles finely and densely, longitudinally striate. Dorsum of head with mostly regular striae, similar to those in P. roomi in orientation; longitudinal and anteriorly converging on clypeus; obliquely curving from sides of head towards basal clypeal margin; transverse and anteriorly bowed on vertex, outermost striae converging forwards between frontal carinae. Mesosoma with striation resembling that of P. kokoda, notably on mesonotum and propodeum. Pronotal striation in mamba somewhat different, due to shape of dorsum between pronotal spines; curved inwards in kokoda, straight in mamba. Anterior and posterior faces of petiole with tranverse, slightly dorsally bowed striae, that are connected along sides. First gastral segment with sides finely longitudinally striate; dorsally striae becoming less distinct, dorsum finely shagreened.

Short to medium length, erect, curved or sinuate, off-white to silvery hairs present on dorsum of head, mesosoma, petiole and first gastral segment; somewhat longer, yellowish to golden and more erect hairs on legs and gaster. Appressed, mostly greyish pubescence in various densities on most of body, notably on pronotal dorsum, including spines, meso- and metapleuron, lateral borders of propodeal declivity and coxae; somewhat longer on dorsum of gaster and almost obscuring underlying sculpture.

Black; mandibular masticatory border, antennal scapes, joints of femora and tibiae, basal tarsal segments and apical segments of gaster dark reddish-brown. Funiculi, except base of first segment, and most of legs light to very light reddish-yellow.

Similar to worker with usual differences indicating caste. Sculpture of head and body similar to worker, direction of striae following structural characteristics of fully developed mesosoma. Colour as in worker except funiculi distinctly darker and femora and tibiae with more extensive dark patches around joints.

Queen

TL c. 6.35; HL 1.53; HW 1.37; CI 89; SL 1.56; SI 114; PW 1.34; MTL 1.59 (1 measured).

Type Material

HOLOTYPE: PAPUA NEW GUINEA, Northern Prov., Owen Stanley Ra., Mamba Plantation, c. 7km WNW of Kokoda, 08º51’S, 147º41’E, 500m, 31.viii-1.ix.1984, R. J. Kohout acc. 403) (worker). PARATYPES: data as for holotype (60 workers, 1 dealate queen). Type distribution: holotype, most paratype workers and paratype queen in Australian National Insect Collection; 2 paratype workers in each The Natural History Museum, California Academy of Sciences, Museum of Comparative Zoology, Los Angeles County Museum of Natural History and Queensland Museum.

Etymology

Species named after the type locality, Mamba Plantation nr Kokoda, Papua New Guinea.

References