Polyrhachis sculpta

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Polyrhachis sculpta
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Campomyrma
Species: P. sculpta
Binomial name
Polyrhachis sculpta
Emery, 1887

Polyrhachis sculpta casent0905815 p 1 high.jpg

Polyrhachis sculpta casent0905815 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Polyrhachis sculpta.

Identification

Kohout (2007) - P. sculpta is characterized by the posteriorly less distinct lateral margins of the mesosoma, leaving the propodeum only weakly margined laterally and completely immarginate posteriorly. The sculpture of the vertex is transversely bowed in contrast to the longitudinal striation of the rest of the head. With its rather untidy silvery pubescence sculpta superficially resembles Polyrhachis variegata, but they differ in many aspects, especially the eyes, that are convex in sculpta, and distinctly flat in variegata. The propodeal declivity is virtually vertical in sculpta, while it is distinctly oblique in variegata. The anterodorsal margin of first gastral segment is elevated above the dorsal surface of the segment in sculpta, while it is only weakly concave in variegata, with the dorso-medial margin blunt.

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 sculpta 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.

  • sculpta. Polyrhachis sculpta Emery, 1887a: 226 (w.) NEW GUINEA. Combination in P. (Campomyrma): Emery, 1925b: 180; in P. (Aulacomyrma): Kohout, 2007a: 207.

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

Description

Worker

Kohout (2007) - Dimensions of holotype: TL c. 5.24; HL 1.40; HW 1.18; CI 84; SL 1.47; SI 124; PW 1.09; MTL 1.34.

Clypeus arcuate, medially shallowly emarginate with distinct longitudinal median carina; in profile clypeus virtually straight with basal margin weakly impressed medially. Frontal triangle indistinct. Frontal carinae strongly sinuate with raised laminate lobes. Eyes relatively large, convex, in full face view clearly breaking lateral cephalic outline. Sides of head only weakly converging anteriorly, convex and converging behind eyes. Pronotal and mesonotal dorsa marginate, lateral margins of propodeal dorsum ill-defined. Pronotal humeri armed with triangular teeth, lateral margins shallowly emarginate at bases. Promesonotal suture distinct; metanotal groove lacking, position indicated by interruption of lateral mesosomal margin. Propodeal dorsum descending into virtually vertical declivity in rather abrupt, medially unbroken curve; lateral propodeal margins terminating in small, blunt, tubercles. Petiole with sharp dorsal margin, shallowly emarginated medially; lateral teeth short, very weakly curved backwards. First gastral segment concave anteriorly, anterodorsal margin of concavity elevated above dorsal surface of segment.

Mandibles finely, longitudinally striate. Sides and front of head regularly, longitudinally striate, striae on clypeus converging anteriorly and meeting along midline; striae on vertex distinctly transversely bowed, almost semicircular. Mesosoma with striae converging anteriorly on pronotal dorsum, somewhat V-shaped on mesonotal and propodeal dorsa and oblique on sides. Petiole and dorsum of gastral segments shagreened.

Silvery or off-white hairs present on all body surfaces and appendages. Numerous, semi-erect to erect, very short to medium length hairs on front and sides of head in front of eyes; hairs very short and strongly anteriorly inclined on vertex. Antennal scapes with numerous hairs along leading edges and at distal ends. Hairs on pronotal dorsum very uneven in length and direction, ranging from short to medium, erect to semi-erect or undulated; hairs mostly posteriorly directed on mesonotal and propodeal dorsa. Petiole with a few hairs along dorsal margin. Gaster with mostly short, posteriorly directed hairs on dorsum of first gastral segment, increasing in length and density towards gastral apex where they are relatively long and more golden. Silvery appressed pubescence scattered over body; most dense on dorsum and sides of propodeum, where it almost completely hides underlying sculpture, and along posterior margins of gastral segments.

Black, with antennal scapes, basal segments of funiculi and femora very dark reddish brown. Apical segments of funiculi, tibiae and tarsi light to very light yellowish brown.

Type Material

Kohout (2007) - Holotype worker. Type locality: NEW GUINEA, Sorong (L. M. D’Albertis), Museo Civico di Storia Naturale, Genoa (examined).

References