Leptomyrmex unicolor

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Leptomyrmex unicolor
Leptomyrmex unicolor
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. unicolor
Binomial name
Leptomyrmex unicolor
Emery, 1895

Leptomyrmex unicolor side view

Leptomyrmex unicolor top view

Specimen labels

Evolutionary Relationships
Leptomyrmex
Neotropical

Leptomyrmex neotropicus (fossil only)



Leptomyrmex relictus



Australasian
Micro-Leptomyrmex

Leptomyrmex burwelli



Leptomyrmex dolichoscapus



Macro-Leptomyrmex


Leptomyrmex mjobergi




Leptomyrmex varians




Leptomyrmex unicolor





Leptomyrmex flavitarsus



Leptomyrmex puberulus





Leptomyrmex darlingtoni




Leptomyrmex fragilis



Leptomyrmex niger











Leptomyrmex erythrocephalus




Leptomyrmex wiburdi




Leptomyrmex cnemidatus




Leptomyrmex nigriventris



Leptomyrmex tibialis









Leptomyrmex geniculatus




Leptomyrmex nigriceps



Leptomyrmex pallens






Leptomyrmex rufithorax




Leptomyrmex rufipes




Leptomyrmex rothneyi



Leptomyrmex ruficeps










Based on Barden et al., 2017. Note only selected Leptomyrmex species are included.

L. unicolor has been recorded in rainforest and wet sclerophyll. Nests occur in soil, in or under logs, and in leaf litter at base of live trees.

Identification

This species is restricted to the Australian Wet Tropics, where it can be easily distinguished from its sympatric congeners (Leptomyrmex rufipes, Leptomyrmex ruficeps and Leptomyrmex mjobergi) by its large body and broad head, which are covered with dense pubescence. The eyes are distinctly hairy, and the coloration is uniformly black, with contrasting white tarsi. (Lucky and Ward 2010)

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

Queens have yet to be collected.

Worker

Nomenclature

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

  • unicolor. Leptomyrmex unicolor Emery, 1895g: 352, figs. 3, 4 (w.) AUSTRALIA. Wheeler, G.C. & Wheeler, J. 1951: 180 (l.); ; Lucky & Ward, 2010: 58 (m.). See also: Wheeler, W.M. 1915d: 261; Wheeler, W.M. 1934c: 108.

Type Material

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

Description

Worker

Lucky and Ward (2010) - measurements (n = 10) HL 1.79–1.99, HW 1.37–1.51, MFC 0.25–0.31, IOD 0.67–0.77, SL 3.54–3.91, EL 0.39–0.44, WL 3.27–3.73, PW 1.05–1.21, DPW 0.34–0.40, HTL 3.99–4.84, HTWmin 0.12–0.17, HTWmax 0.23–0.27, CI 0.72–0.80, SI 2.58–2.74, OI 0.08–0.10, HTC 0.45–0.70.

Large species (HL 1.79–1.99; HW 1.37–1.51) with broad head (, CI 0.72–0.80), excluding mandibles head width 3/4 of length. Head widest at eye level, sides of head broadly convex with concave genae. Postocular margin broadly rounded. Masticatory margin of mandible with approximately 7 large teeth interspersed with 10 denticles. Anterior clypeal margin concave. Eyes positioned posterior to midline of head, small, not surpassing margin of head. Pilosity on eyes distinct. Antennal scapes somewhat flattened, extending beyond posterior margin nearly 3/5 of their length.

Pronotum rather short, less than 1.5 times as long as broad. Dorsal face and declivity of propodeum subequal in length, dorsal face convex in profile, angle broadly rounded. Petiole narrow, with low rounded node, posterior and anterior slopes subequal, ventral surface of petiole feebly convex. Gaster slender, more than three times as long as broad. Legs slender, tibiae very slightly flattened.

Surface subopaque, finely and densely shagreened. Mandibles smooth and shining along apical borders and at tips, with a few coarse punctures. Pilosity mostly on clypeus, mandibles and venter, prominent black hairs on coxae, abundant minute oblique black hairs on scapes and legs. Eyes distinctly hairy. Body, femora and tibiae black, with bluish-green reflections. Mandibles and labium brownish yellow, antennal scapes black, with apical 1/4th brown. Metatarsi white, remaining tarsal joints, tibial spurs and funiculi yellowed.

Male

Lucky and Ward (2010) - HL 1.67–1.68, HW 1.03–1.09, SL 0.41–0.43, EL 0.69–0.71, HTL 3.98–4.07, CI 0.62–0.65, SI 0.39–0.40, SI2 1.07–1.08.

References

  • Emery, C. 1895h. Descriptions de quelques fourmis nouvelles d'Australie. Ann. Soc. Entomol. Belg. 39: 345-358 (page 352, figs. 3, 4 worker described)
  • Lucky, A. 2011. Molecular phylogeny and biogeography of the spider ants, genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 59: 281-292. doi:10.1016/j.ympev.2011.03.004
  • Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67. PDF
  • Wheeler, G. C.; Wheeler, J. 1951. The ant larvae of the subfamily Dolichoderinae. Proc. Entomol. Soc. Wash. 53: 169-210 (page 180, larva described)
  • Wheeler, W. M. 1915e. The Australian honey-ants of the genus Leptomyrmex Mayr. Proc. Am. Acad. Arts Sci. 51: 255-286 (page 261, see also)
  • Wheeler, W. M. 1934c. A second revision of the ants of the genus Leptomyrmex Mayr. Bull. Mus. Comp. Zool. 77: 69-118 (page 108, see also)