Leptomyrmex tibialis

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

Leptomyrmex tibialis side view

Leptomyrmex tibialis 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. tibialis has been recorded in rainforest, wet sclerophyll and dry sclerophyll. Nests occur in cavities in live or dead trees, and in soil at tree bases.

Identification

The largest of the Leptomyrmex species, L. tibialis can be identified by its large body size (HW 1.68–1.96; WL 4.51–5.13), broad head (CI 0.71–0.79), the 10+ standing hairs on the posterior face of the hind tibia, and its distinctive coloration. The majority of the body is rufotestaceous, with only the gaster, tibiae and distal portions of femora black. This species can be distinguished from its sister species by tibial coloration (pale in Leptomyrmex nigriventris; dark in L. tibialis) and by more pronounced tibial compression in L. tibialis (HTC 0.34–0.49 vs. HTC 0.52–0.66 in L. nigriventris). These two species co-occur in the region of Dorrigo, New South Wales. (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

Nomenclature

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

  • tibialis. Leptomyrmex nigriventris var. tibialis Emery, 1895g: 351 (w.) AUSTRALIA. Wheeler, W.M. 1934c: 96 (ergatoid q., m.). Subspecies of nigriventris: Wheeler, W.M. 1934c: 96. Raised to species: Lucky & Ward, 2010: 55. Senior synonym of hackeri: Lucky & Ward, 2010: 55.
  • hackeri. Leptomyrmex nigriventris subsp. hackeri Wheeler, W.M. 1934c: 99 (w.) AUSTRALIA. Junior synonym of tibialis: Lucky & Ward, 2010: 55.

Type Material

Lucky and Ward (2010) - In the original description of L. tibialis Emery (1895) stated that it was “recolté dans le nord du Queensland par M. Podenzana” but this is an evident error since this species does not occur in north Queensland. Moreover, the apparent syntype series in MSNG is from Laidley, in southern Queensland. The series comprises two workers of what is here interpreted as L. tibialis (agreeing with the original description, particularly with regard to tibial compression) and three workers of L. cnemidatus. To fix the identity of this species we have designated one of the non-cnemidatus workers as the lectotype.

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 2.31–2.63, HW 1.68–1.96, MFC 0.37–0.47, IOD 0.98–1.16, SL 3.77–4.30, EL 0.43–0.52, WL 4.51–5.13, PW 1.46–1.64, DPW 0.53–0.68, HTL 4.96–5.89, HTWmin 0.12–0.21, HTWmax 0.35–0.43, CI 0.71–0.79, SI 2.02–2.26, OI 0.09–0.11, HTC 0.34–0.49.

As in Leptomyrmex nigriventris, but generally larger (HW 1.68–1.96; WL 4.51–5.13 vs. L. nigriventris HW 1.49–1.76; WL 4.32–4.98), with head broader (CI 0.71–0.79 vs. CI 0.66–0.75). Tibiae are dark (vs. rufotestaceous) and more distinctly compressed (HTC 0.34–0.49 vs HTC 0.52–0.66).

Queen

Lucky and Ward (2010) - Head broader than in worker. Three ocelli deeply set into head in triangular formation, the anteriormost one largest, the posterior two smaller. Pronotum, mesonotum and propodeum voluminous, convex. The anterior portion of the mesonotum elevated, the posterior portion with a narrow impression before rising to the metanotal suture. Dorsal face of propodeum slightly concave. Petiole broader and higher than long, with a longitudinally grooved summit. Gaster nearly as high as long, somewhat laterally compressed, larger than in worker. Scapes, femora and tibiae broad, robust.

Surface of body subopaque, shagreened. Queen coloration similar to that of worker ; distal portions of femora deep black.

Male

Lucky and Ward (2010) - HL 1.77–1.98, HW 1.39–1.61, SL 0.72–0.78, EL 0.68–0.79, HTL 4.74–5.14, CI 0.74–0.82, SI 0.47–0.54, SI2 1.26–1.46.

Wheeler (1934) - Differing from the male of the typical Leptomyrmex nigriventris in having the head shorter, especially behind the eyes, in lacking the dark spots on the mesonotum, in having the tibiae and tips of the femora dark brown and the wings of a distinctly more yellow tinge. There is also a difference in the shape of the volsellae of the genitalia, which have the prongs of their pickaxe-shaped tips stouter and much more nearly of the same length.

References

  • 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.