Leptomyrmex varians

Leptomyrmex varians
Leptomyrmex varians
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Leptomyrmecini
Genus:	Leptomyrmex
Species:	L. varians
Binomial name
Leptomyrmex varians Emery, 1895 Specimen labels
Synonyms
Leptomyrmex erythrocephalus decipiens Wheeler, W.M., 1915 Leptomyrmex varians angusticeps Santschi, 1929

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.

At a Glance

• Replete Workers

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

• Key to Australian Leptomyrmex Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -13.73333° to -30.7°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Leptomyrmex 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.

Images from AntWeb

Worker. Specimen code casent0011997. Photographer Andrea Lucky, uploaded by California Academy of Sciences.	Owned by PSWC, Philip S. Ward Collection.

Colour variation in L. varians.

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Phylogeny

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.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• 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

• Leptomyrmex varians: Syntype, 1 worker, Rockhampton, Queensland, Australia, Museo Civico di Storia Naturale, Genoa.
• Leptomyrmex varians: Syntype, 3 workers (reported as males), Byfield (as Beyfield), Queensland, Australia, Naturhistorisches Museum, Basel.
• Leptomyrmex erythrocephalus decipiens: Syntype, 6 workers, Gin-Gin, Queensland, Australia, Museum of Comparative Zoology.
• Leptomyrmex erythrocephalus decipiens: Syntype, 3 workers, Gin-Gin, Queensland, Australia, National Museum of Natural History.

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. Bulletin of the Museum of Comparative Zoology 77: 69-118 (page 101, see also)

References based on Global Ant Biodiversity Informatics

• Baroni Urbani C. 1977. Katalog der Typen von Formicidae (Hymenoptera) der Sammlung des Naturhistorischen Museums Basel (2. Teil). Mitt. Entomol. Ges. Basel (n.s.) 27: 61-102.
• Lucky A., and P. S. Ward. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Zootaxa 2688: 1-67.
• Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.
• Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.
• Wheeler W. M. 1934. A second revision of the ants of the genus Leptomyrmex Mayr. Bulletin of the Museum of Comparative Zoology 77: 69-118.