Polyrhachis maai

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

Polyrhachis maai P.jpg

Polyrhachis maai D.jpg

Nothing is known about the biology of Polyrhachis maai.

Identification

Kohout (2007) - P. maai is a very distinctive species that somewhat resembles Polyrhachis excellens. Both species share the similar, almost parallel-sided mesosomal dorsum with mostly longitudinal striation and a rather glossy appearance. However, besides the very prominent, anterodorsal process of first gastral segment in excellens, they differ in the sculpture of the head, that is very smooth and shiny in maai and distinctly longitudinally striate in excellens. Also the interspaces between the mesosomal striae are rather shallow in maai, while they are much deeper in excellens.

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 maai 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.

  • maai. Polyrhachis (Aulacomyrma) maai Kohout, 2007a: 227, figs. 75, 78, 81 (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. 4.84-5.34 (5.34); HL 1.28-1.37 (1.37); HW 1.12-1.26 (1.26); CI 87-92 (92); SL 1.40-1.50 (1.50); SI 119-125 (119); PW 0.90-1.00 (1.00); MTL 1.34-1.53 (2 measured).

Anterior clypeal margin arcuate, narrowly and shallowly notched medially; clypeus weakly convex in lateral view. Sides of head in front of eyes gently converging anteriorly; curving rather abruptly behind eyes into relatively short preoccipital margin. Eyes moderately convex, only marginally extending beyond cephalic outline. Frontal carinae only moderately raised; central area with short, weakly defined, median carina. Mesosomal dorsum with ill-defined margins. Pronotal dorsum with sides parallel; humeri armed with broad-based, triangular teeth with slightly raised anterior and lateral margins, with latter continued posteriorly towards well impressed promesonotal suture. Mesonotal-propodeal dorsa fused, sides weakly converging posteriorly before widening and again converging and terminating in acute teeth. Petiole with dorsal margin sharp, entire; lateral spines acute and curved backwards and slightly upwards. Anterior face of first gastral segment concave, accommodating posterior face of petiole, anterodorsal margin of concavity weakly medially produced above dorsal face of segment.

Head very smooth and shiny. Mesosomal dorsum smooth between widely spaced, longitudinal striae, that are broken at promesosotal suture and terminate at point where propodeal dorsum descends into declivity that is medially smooth, lacking any sculpture. Sides of mesosoma similarly sculptured, with striae mostly oblique. Anterior face of petiole smooth and shiny, posterior face and dorsum of first gastral segment shagreened. Sides of gaster with very fine, closely spaced, longitudinal striae.

Off-white or yellowish hairs present on mandibles, anterior portion of clypeus and leading edges of antennal scapes; a few hairs arising along frontal carinae and on vertex. In frontal view, no hairs projecting from sides of head between eyes and mandibular bases. A few short, semierect hairs, scattered over mesosomal and gastral dorsa, density and length increasing towards apex and venter of gaster. Pubescence virtually lacking, except for patches of fine, silvery short hair, at sides of propodeal declivity, anterior face of petiole, and dorsum of first gastral segment where it has distinct reddish tint.

Body, including antennal scapes and legs, virtually black, only mandibular masticatory border and apical segments of funiculi and tarsi dark to medium reddish-brown. Color of legs a shade lighter in paratype.

Type Material

HOLOTYPE: PAPUA NEW GUINEA, W. Highlands, Minj, 05º51’S, 144º40’E, 8-13.ix.1959, T.C. Maa (worker). PARATYPE: PAPUA NEW GUINEA, W. Highlands, Nondugl, 05º52’S, 144º43’E, 1600m, 9.vii.1955 (J. L. Gressitt) (worker). Type distribution: holotype in Museum of Comparative Zoology, paratype in Queensland Museum.

Etymology

Named in honor of the late T.C. (Tsing-Chao) Maa of the Tunghai University in Taiwan, who was a longtime associate of the Bernice P. Bishop Museum, Honolulu, Hawai’i. Maa was a field worker supreme who collected many of the types lodged in that museum, including a number of the new species described in this paper.

References