Ancyridris polyrhachioides

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Ancyridris polyrhachioides
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Ancyridris
Species: A. polyrhachioides
Binomial name
Ancyridris polyrhachioides
Wheeler, W.M., 1935

Ancyridris polyrhachioides casent0102469 profile 1.jpg

Ancyridris polyrhachioides casent0102469 dorsal 1.jpg

Specimen Label

The type specimens were collected from the stomach of a flycatcher. Additional specimens have been collected from forest habitat; some taken at honey baits and others foraging on vegetation.

Identification

Apart from the curious and unmyrmicine spines on its epinotum and petiole, this ant bears a general resemblance to Aphaenogaster or certain worker forms of Pheidole, but there are several structural characters, like the median tooth of the clypeus, the peculiar, laterally directed tooth on the mesosterna, and the large size of the coxae and first gastric segment, which suggest that we are dealing with a representative of some aberrant and archaic group, another of the living fossils which are continually turning up in the Papuan and Australian Regions. (Wheeler 1936)

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 Ancyridris polyrhachioides for further details

Biology

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.

  • polyrhachioides. Ancyridris polyrhachioides Wheeler, W.M. 1935a: 2, fig. 1 (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

Length nearly 6 mm.

Head slightly longer than broad, slightly narrower in front than behind, evenly convex above, with convex posterior border, rounded sides and posterior corners, the latter marginate inferiorly. Antennal foveae large, confluent with the clypeal foveae. Eyes elongate-elliptical, somewhat pointed anterio-inferiorly, moderately convex, situated about twice their length from the anterior corners of the clypeus. Mandibles convex, with straight external borders, their masticatory borders with three stout apical, and six or seven smaller and blunter basal, teeth. Antennae slender; scapes nearly straight, distinctly thickened toward their tips, which extend about one fifth their length beyond the posterior border of the head; first and second funicular joints nearly twice as long as broad, 3d-6th proportionally shorter, 7th-9th, again, longer and broader, the enlarged terminal joint as long as the preceding two together. Thorax fully three times as long as broad, broadest through the pronotum, which, however, is narrower than the head, with convex, swollen sides, its dorsal portion rising rather steeply from the stout neck and forming an evenly but not strongly convex, trapezoidal plate, slightly broader than long and slightly broader in front than behind, with straight, anteriorly submarginate sides, its anterior or humeral angles produced as thick, blunt projections, its posterior corners subrectangular, small but distinctly projecting beyond the lateral border of the mesonotum. Mesonotum in profile rounded and sloping, continuing the even convexity of the pronotum, from above broader than long. Epinotum longer than broad, broader behind than in front, its base straight and horizontal, rising slightly and abruptly at its anterior end above the mesoepinotal impression, decidedly longer than the sloping concave declivity. The large epinotal spines are stout at the base, directed outward, upward and backward, with their flattened apical thirds turned downward. laterally and forward. Petiole about three times as long as broad, broader behind at the node than in front, the sides nearly straight, except for the projecting spiracles on the peduncle, in profile with the dorsal surface of the latter nearly straight, gradually sloping upward to the node, which is half as high as the length of the petiole, abruptly descending behind to a short posterior peduncle. The spines into which the node is produced are as long as its height, rapidly tapering, acute, directed outward and backward and curved almost imperceptibly downward. Postpetiole slightly broader than the petiole, about one and one-third times as broad as long, its nodal portion square from above, in profile subconical, lower than the petiolar node, its anterior slope straight, longer than the more abrupt and distinctly concave posterior slope. Gaster scarcely larger than the head, the first segment, which is evenly convex, in dorsal view almost concealing the small posterior segments, its anterior border semicircular, not concave at the insertion of the postpetiole.

Smooth and shining; mandibles, clypeus, except its posterior median portion, lobes of frontal carinae and anterior third of head more subopaque and finely granular, the mandibles also coarsely and sparsely punctate; front on each side with about ten rounded, costa-like longitudinal rugae, which are longest just above the eyes; cheeks and gula on each side with similar but less pronounced rugae. Legs, prosterna and anterior portion of neck less shining than the thorax, densely granular; coxae, petiole and postpetiole more superficially granular or shagreened. Gaster highly polished, with very minute and very sparse, piligerous punctures.

Hairs yellowish, almost lacking on the body, short on the mandibles, longer on the terminal gastric segments, first gastric segment with very short, sparse, appressed hairs or pubescence. Similar but longer appressed hairs occur on the femora, but their tips and the tibiae, especially on their flexor surfaces, bear long, sparse, rather delicate suberect hairs, which become coarser, shorter, stiffer and more oblique on the tarsi. Scapes and funiculi with sparse rather oblique, stiff hairs which are shorter than those on the tibiae. Each of the humeral protuberances of the pronotum bears a singular, very long, delicate, lash-like hair, and there is a similar hair on each side of the median line near the posterior end of the pronotum.

Black; mandibles, insertions of scapes, three terminal funicular joints, neck, prosterna, tarsi and tips of epinotal and petiolar spines red; scapes, bases of mandibles, femora and tibiae darker, brownish red; dental borders of mandibles dark brown; mouth parts yellowish.

Type Material

Described from two somewhat damaged specimens belonging to the Museum of Comparative Zoology. They were found by Mr. James Greenway in the stomach of a flycatcher (Poecilodryas cyanea subcyanea De Vis) taken during 1932 by Mr. H. Stevens on Mt. Misim in the Morobe District of New Guinea (Papua).

References

  • Wheeler, W. M. 1935a. Two new genera of myrmicine ants from Papua and the Philippines. Proc. N. Engl. Zool. Club 15: 1-9 (page 2, fig. 1 worker described)