Polyrhachis monticola

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

Polyrhachis monticola P.jpg

Polyrhachis monticola D.jpg

Known from a single worker collected foraging on low vegetation.

Identification

Kohout (2007) - P. monticola is rather similar to Polyrhachis annulata and Polyrhachis breviata and shares with them the somewhat antero-posteriorly compressed body and the medially emarginate dorsal petiolar margin. However, monticola is easily separated by the sculpture of the mesonotal-propodeal dorsum that consists of V-shaped, posteriorly converging striae, while in annulata and breviata the striae form virtual semicircles or U-shaped patterns.

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 monticola 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.

  • monticola. Polyrhachis (Aulacomyrma) monticola Kohout, 2007a: 230, figs. 83, 86, 89 (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

Holotype: TL c. 5.19; HL 1.37; HW 1.25; CI 91; SL 1.40; SI 112; PW 1.00; MTL 1.31.

Anterior clypeal border arcuate, emarginate medially; clypeus straight in profile, basal margin weakly impressed, laterally indicated by distinct line breaking cephalic sculpture. Frontal carinae with lamellate lobes. Sides of head weakly convex in front of eyes, rounding behind into weakly convex preoccipital margin. Eyes moderately convex, only marginally exceeding lateral cephalic outline. Mesosomal dorsum immarginate for most of length, distinctly converging posteriorly. Pronotal humeri armed with broad-based, triangular, dorso-ventrally flattened teeth. Promesonotal suture relatively shallow, distinctly incised laterally; metanotal groove only weakly indicated by faint break in sculpture. Mesonotal dorsum with outermost dorsal striae forming an ill-defined lateral margin. Propodeal dorsum immarginate, terminating posteriorly in small rounded prominences formed by inwardly curved lateral striae; medially dorsum sloping into declivity in rather abrupt, uninterrupted curve. Dorsal margin of petiole with acute intercalary teeth, bordering medial emargination, margin jagged laterally, terminating in relatively long, strongly backward- curved spines with weakly upturned tips. First gastral segment concave anteriorly; concavity with blunt dorsal margin that is not elevated above dorsal surface of segment.

Mandibles finely, somewhat irregularly, longitudinally striate-rugose. Sculpture of head consisting of regularly spaced striae; V-shaped on clypeus and mostly longitudinal on sides; striae on vertex converging anteriorly between and along frontal carinae. Striae on pronotal dorsum strongly converging anteriorly; striae on mesonotal-propodeal dorsum converging posteriorly, forming V-shaped pattern; laterally striae continued obliquely onto sides. Petiole with both faces microscopically shagreened. First gastral segment distinctly, longitudinally striate laterally; dorsally striae becoming finer and less distinct, medially and anteriorly finely shagreened.

A few short, erect or curved, yellowish hairs on head, including mandibular masticatory border, anterior clypeal margin, sides of head between eyes and posterolateral corners and along leading edges of antennal scapes; hairs absent between eyes and bases of mandibles or along inferior edges of scapes. Mesosomal dorsum and first gastral segment with a few short erect hairs, variously curved. Petiole with several very short hairs fringing dorsal margin. Apex of gaster with numerous, relatively long, golden hairs. Mostly silvery, very sparse appressed pubescence on head; more abundant on pronotal humeri, propodeal dorsum, sides and upper portion of declivity, coxae, petiole and posterior margins of gastral segments; first gastral segment with distinctly golden pubescence almost obscuring sculpture.

Black; antennae, femora, bases of tibiae and basal tarsal segments very dark reddish-brown. Tip of last funicular segment, distal ends of trochanters, most of tibiae and tarsi, light to very light reddish-brown.

Type Material

HOLOTYPE: PAPUA NEW GUINEA, Morobe Prov., Sarawaget Ra., 3km E of Gain, 06º25’S, 146º46’E, 1000-1200m, rf., 26.viii.1984, R. J. Kohout acc. 84.363 (worker). Type deposition: unique holotype in Australian National Insect Collection.

Etymology

Name derived from the Latin word montis, meaning mountain.

References