Leptomyrmex varians

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

Leptomyrmex varians side view

Leptomyrmex varians top view

Specimen labels

Synonyms
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. varians has been recorded in dry sclerophyll and Eucalyptus, Casuarina, Melaleuca and Callitris open forests. Nests occur as large or small craters in soil, in the open, or at the base of live trees.

Identification

L. varians is a distinctly slender and elongate species that occurs in southeastern to central Queensland, from approximately Brisbane to Mackay, in a broad arc that sweeps inland. This species tolerates drier habitat than most other species in the genus. Coloration is usually pale orange with contrasting black legs, including coxae but excluding tarsi, and dark brown antennal scapes and tips. This species may be confused with two other pale-bodied congeners with which it is sympatric in southeast Queensland, Leptomyrmex cnemidatus and Leptomyrmex rufipes. Distinguishing L. varians from these species are the entirely dark coxae, femora and tibiae; in Leptomyrmex cnemidatus the coxae and proximal portion of femora are pale and in L. rufipes the tibiae are pale. Furthermore, the narrowed, but not constricted or projecting posterior margin of the head in L. varians is unlike that in L. cnemidatus (broadly rounded) or L. rufipes (constricted and projecting).

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

Colour variation in L. varians.

Nomenclature

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

  • varians. Leptomyrmex varians Emery, 1895g: 352, fig. 3 (w.) AUSTRALIA. Senior synonym of angusticeps, decipiens: Lucky & Ward, 2010: 58. See also: Wheeler, W.M. 1934c: 101.
  • decipiens. Leptomyrmex erythrocephalus var. decipiens Wheeler, W.M. 1915d: 268 (w.) AUSTRALIA. Wheeler, W.M. 1934c: 90 (m.). Subspecies of erythrocephalus: Wheeler, W.M. 1934c: 90. Junior synonym of varianss: Lucky & Ward, 2010: 58.
  • angusticeps. Leptomyrmex varians st. angusticeps Santschi, 1929f: 93, fig. 3 (m.) AUSTRALIA. Junior synonym of varians: Lucky & Ward, 2010: 58.

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) - HL 1.92–2.18, HW 1.04–1.19, MFC 0.22–0.28, IOD 0.61–0.70, SL 3.89–4.28, EL 0.36–0.43, WL 3.78–4.29, PW 1.01–1.18, DPW 0.37–0.52, HTL 4.77–5.53, HTWmin 0.13–0.16, HTWmax 0.20–0.31, CI 0.53–0.59, SI 3.31–3.82, OI 0.10–0.15, HTC 0.44–0.64.

Medium sized species (HL 1.92–2.18; HW 1.04–1.19) with a distinctly narrow head (CI 0.53–0.59) excluding mandibles, nearly twice as long as broad. Head widest at eyes, sides of head nearly straight and parallel, posterior to eyes narrowing with straight sides toward posterior margin, forming a slightly constricted ‘neck’. Masticatory margin of mandible with approximately 25 small teeth mostly of uniform size, with larger teeth confined to anterior half. Anterior clypeal margin weakly convex. Eyes positioned approximately at midline of head, small, convex, hairless, surpassing margins of head. Antennal scapes very slender and terete, extending beyond posterior margin by nearly 2/3 of their length.

Pronotum slightly more than 1.5 times as long as broad. Declivity of propodeum very convex, about half the length of the dorsal face, which is flat to weakly concave in profile. Petiolar node triangular in profile with faint longitudinal impression on dorsal face of petiole. Posterior face of petiole longer than anterior face, angle rounded, ventral surface concave. Gaster narrow, elliptical. Legs very slender, tibiae mildly compressed.

Surface subopaque, very finely shagreened. Mandibles with a row of coarse punctures along apical border. Pubescence whitish, extremely short and fine hairs on mandibles and clypeus feebly developed. Long, coarse black hairs on venter sparse. Generally, head, thorax and antennae rufotestaceous, with antennal scapes and tips of mandibles dark brown, and with legs, including coxae, black. Tarsi yellow. Gaster, pronotum and sometimes a spot on the mesonotum black. Some series, however, are brownish-black, with a slight bluish sheen, and only the antennae, tarsi and anterior third of head are lighter (e.g. specimens from Isla Gorge NP, 50km N Taroom and White Mountains NP).

Male

Lucky and Ward (2010) – measurements (n = 4) HL 1.53–1.58, HW 1.12–1.16, SL 0.34–0.37, EL 0.55–0.61, HTL 4.22–4.71, CI 0.72–0.75, SI 0.30–0.32, SI2 1.01–1.11.

References

  • Emery, C. 1895h. Descriptions de quelques fourmis nouvelles d'Australie. Ann. Soc. Entomol. Belg. 39: 345-358 (page 352, fig. 3 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, W. M. 1934c. A second revision of the ants of the genus Leptomyrmex Mayr. Bull. Mus. Comp. Zool. 77: 69-118 (page 101, see also)