Polyrhachis parva

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

Polyrhachis parva casent0217436 p 1 high.jpg

Polyrhachis parva casent0217436 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Polyrhachis parva.

Identification

Kohout (2007) - Superficially similar to Polyrhachis exarata, with the differences listed under the remarks section of that species.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

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

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Polyrhachis parva 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

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.

  • parva. Polyrhachis (Aulacomyrma) parva Kohout, 2007a: 204, figs. 20, 23, 26 (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. 4.18-4.69 (4.59); HL 1.09-1.25 (1.18); HW 0.92-1.12 (1.04); CI 84-90 (88); SL 1.12-1.28 (1.28); SI 114-125 (123); PW 0.87-1.03 (0.94); MTL 1.18, 1.06-1.22 (1.18) (6 measured).

Anterior clypeal margin with shallow notch medially; clypeus in profile straight anteriorly, with a weakly impressed basal margin. Frontal carinae sinuate, with laminate lobes. Sides of head in front of eyes gently converging towards bases of mandibles. Eyes convex, distinctly breaking lateral cephalic outline. Mesosomal dorsum marginate along entire length, margins distinctly converging posteriorly. Pronotal humeri armed with broad-based, forward projecting, triangular teeth. Promesonotal suture distinct; metanotal groove lacking. Propodeal dorsum terminating posteriorly in minute blunt angles, their posterior margins continuous and meeting medially, forming transverse, somewhat medially weakened ridge separating propodeal dorsum from declivity. Dorsal margin of petiole acute, entire, terminating laterally in acute, outwards and backwards curved spines. First gastral segment concave anteriorly; anterodorsal margin of concavity acute, produced dorso-medially and weakly raised above dorsal face of segment.

Mandibles finely longitudinally striate, becoming finely rugose-punctate towards masticatory borders. Head, including clypeus, regularly, longitudinally striate. Mesosomal dorsum longitudinally striate, interspaces wider than those on head; striae mostly oblique on lateral mesosoma. Petiole with anterior and posterior faces shagreened, wrinkled on sides. First gastral segment finely, longitudinally, striate-rugose laterally, shagreened dorsally.

Entire body with relatively short, erect or curved, silvery hairs. Appressed, mostly silvery pubescence abundant everywhere, notably on dorsum of mesosoma, where it fills interspaces between striae; dense on dorsum of gaster, partly obscuring underlying sculpture.

Black. Antennal scapes, joints of femora, tibiae and basal tarsal segments very dark brown, almost black. Mandibular masticatory border reddish brown. Funiculi reddish-brown at bases, each subsequent segment progressively lighter.

Type Material

HOLOTYPE: PAPUA NEW GUINEA, Central Prov., nr Eilogo, 21.xii.1980, J. W. Ismai (worker). PARATYPES: data as for holotype (4 workers). Type distribution: holotype in The Natural History Museum; 1 paratype each in, Australian National Insect Collection, California Academy of Sciences, Museum of Comparative Zoology and Queensland Museum.

Etymology

Derived from the Latin word parvus, meaning little, in reference to its small size.

References