Leptomyrmex ramorniensis

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Leptomyrmex ramorniensis
Leptomyrmex ramorniensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. ramorniensis
Binomial name
Leptomyrmex ramorniensis
Smith, D.J. & Shattuck, 2009

Leptomyrmex ramorniensis side view

Leptomyrmex ramorniensis top view

Specimen labels

Leptomyrmex ramorniensis is known only from Ramornie State Forest, near Grafton, north¬eastern New South Wales. Given the extensive trapping program undertaken in this region by NEFBS (Grey & Cassis, 1994) and the wide distribution found for the closely related Leptomyrmex aitchisoni, it seems likely that this single forest represents the total range of the species. (Smith and Shattuck 2009)

Identification

Head relatively short (CI greater than 80); antennae relatively short (SI less than 150) and extending beyond the vertex of the head by less than half their length; palps short, not reaching the posterior of the head; hind tibial spurs with barbules longer than the width of the shaft. This species is morphologically distinct from all other micro-Leptomyrmex species and is in some ways the least typical Leptomyrmex species so far known. It differs in having a shorter and wider head and relatively short antennae, palps and legs. (Smith and Shattuck 2009)

Identification Keys including this Taxon

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

These conspicuous ants are most often encountered individually or as small groups of 2 or 3 foragers on the surface of the ground any time of the day or night. Because of their long legs and thin bodies, they superficially resemble spiders. This is especially true when they are disturbed, as they extend their legs, raise their gasters, and run quickly to escape danger. This has led to their being given the common name "spider ants."

Nests are found in soil or in dead wood, either standing or on the ground, and are often at the base of trees. Colony sizes average a few hundred workers and a single queen. In all but a handful of species, the queen is wingless and worker-like, differing from workers only in being slightly larger and with an enlarged mesosoma. In a few species the queens are fully winged, as they are in most other ants.

When a large source of food is found, workers of Leptomyrmex will return to their nest and recruit additional workers to help utilise the newly found resource. They also use workers as "living storage vessels". These special workers, called repletes, accept liquids from returning foragers who transfer their liquid foods to these selected workers. These special workers continue to accept liquids until their gasters become greatly enlarged and extended. When enlarged, repletes cannot escape the nest and remain inside suspended from the ceiling. They can retain these fluids for extended periods and dispense it on demand when food is in short supply.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • ramorniensis. Leptomyrmex ramorniensis Smith, D.J. & Shattuck, 2009: 66, figs. 16-18, 19, 21, 24 (w.) AUSTRALIA.

Type Material

  • Holotype, worker, Ramornie State Forest, Track off T-Ridge Rd, New South Wales, Australia, Australian Museum.
  • Paratype, 3 workers, Ramornie State Forest, Track off T-Ridge Rd, New South Wales, Australia, Australian Museum.

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

Description

Worker

With head in full face view vertex of head flat, corners rounding evenly into sides of head. Sides of head weakly curved, head widest posterior to the eyes, head relatively short and wide in comparison with other species. Eyes relatively small and placed posterior to a line drawn across the mid-length of the head. Antennal scapes relatively short surpassing the vertex by about half its length. Palps relatively short, extending about ¾ the length of the underside of the head, palp formula 6, 4. Anterolateral hypostoma reduced to a thin sclerite, medial hypostoma weakly notched. Mesonotum without a raised anterior region. Dorsum of propodeum short, less than 1/3 the length of the propodeal declivity. Legs short in comparison with the other species of micro-Leptomyrmex. Hind tibial spur with well developed barbules (barbules longer than the width of the shaft), basal section smooth. Petiolar scale present, ridged and with a distinct angle dorsally, in profile acutely angular, weakly inclined anteriorly, anterior and posterior faces of the scale approximately equal in length. Head, mandibles and mesosoma uniformly brown, legs and antennae lighter, gaster darker. Erect setae found only on the clypeus and gaster. Dense white adpressed pilosity of equal length on all surfaces.

Measurements. Worker (n = 12) - CI 81–91; EL 0.16–0.19; HL 0.77–0.90 HW 0.66–0.78; MTL 0.62–0.72; SI 127–143; SL 0.87–1.05; WL 1.11–1.37.

References