Leptomyrmex rufithorax

Leptomyrmex rufithorax
Leptomyrmex rufithorax
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dolichoderinae
Tribe:	Leptomyrmecini
Genus:	Leptomyrmex
Species:	L. rufithorax
Binomial name
Leptomyrmex rufithorax Forel, 1915 Specimen labels
Synonyms
Leptomyrmex erythrocephalus basirufus Wheeler, W.M., 1934

L. rufithorax has been recorded in rainforest, wet sclerophyll and dry sclerophyll. Nests occur in soil, in and under logs, and under rocks.

At a Glance

• Replete Workers

Identification

Workers of L. rufithorax are large with a broad head that is round to flat at the postocular margin, and lacking a necklike constriction. The coloration of this species is distinctive: the head, mesosoma and first gastral tergite (3rd abdominal segment) are red, the distal 2/3 of the gaster and the legs, including the coxae, are black. This species occurs in central- and south-east Queensland, where its dark coxae in combination with pale mesosoma distinguish it from sympatric congeners. L. rufithorax may resemble some dark forms of Leptomyrmex erythrocephalus (in northern New South Wales), but in these forms the gaster is uniformly black and the femora are often pale basally. In L. rufithorax workers the femora and tibiae are entirely black, with joints and tarsi showing the only hint of orange. (Lucky and Ward 2010)

Identification Keys including this Taxon

• Key to Australian Leptomyrmex Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -26.66666667° to -26.69007°.

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. ‎

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.

• rufithorax. Leptomyrmex erythrocephalus var. rufithorax Forel, 1915b: 83 (w.) AUSTRALIA. Wheeler, W.M. 1934c: 91 (m.); Lucky & Ward, 2010: 54 (ergatoid q.). Subspecies of erythrocephalus: Wheeler, W.M. 1934c: 91. Raised to species: Lucky & Ward, 2010: 53. Senior synonym of basirufus: Lucky & Ward, 2010: 53.
• basirufus. Leptomyrmex erythrocephalus subsp. basirufus Wheeler, W.M. 1934c: 90 (w.) AUSTRALIA. Junior synonym of rufithorax: Lucky & Ward, 2010: 53.

Type Material

• Leptomyrmex erythrocephalus rufithorax: Syntype, 1 worker, Blackall Range, Queensland, Australia, Mjoberg, ANIC32-001986, Australian National Insect Collection.
• Leptomyrmex erythrocephalus rufithorax: Syntype, 2 workers, Blackall Range, Queensland, Australia, Musee d'Histoire Naturelle Genève.
• Leptomyrmex erythrocephalus rufithorax: Syntype, 1 worker, Tamborine Mt. (as Mt. Tambourine), Queensland, Australia, Musee d'Histoire Naturelle Genève.
• Leptomyrmex erythrocephalus rufithorax: Syntype, 1 worker, Blackall Range, Queensland, Australia, Naturhistorisches Museum, Basel.
• Leptomyrmex erythrocephalus basirufus: Syntype, 2 workers, Buderim Mountains., Queensland, Australia, Museum of Comparative Zoology.
• Leptomyrmex erythrocephalus basirufus: Syntype, 1 worker, Bundaberg, Queensland, Australia, Museum of Comparative Zoology.

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 2.17–2.36, HW 1.34–1.56, MFC 0.28–0.37, IOD 0.81–0.92, SL 3.73–4.07, EL 0.38–0.46, WL 4.04–4.35, PW 1.12–1.34, DPW 0.41–0.51, HTL 4.67–5.13, HTWmin 0.14–0.21, HTWmax 0.26–0.30, CI 0.61–0.66, SI 2.60–2.86, OI 0.09–0.11, HTC 0.47–0.77.

Larger species (HL 2.17–2.36, HW 1.34–1.56) with broad head (CI 0.61–0.66). Head widest at eyes, sides of head convex around eyes, genae concave, posterior to eyes rounding to slightly narrowed flat postocular margin. Posterior portion of head lacking neck-like constriction. Masticatory margin of mandible with approximately 15 teeth and denticles interspersed. Anterior clypeal margin medially concave. Eyes positioned toward posterior part of head. Eyes small, round, hairless, not surpassing lateral margins of head. Antennal scapes not compressed, extending beyond the posterior margin less than 2/3 of their length.

Pronotum short. Declivity of propodeum about half the length of the dorsal face, dorsal face with transverse impression at anterior end, propodeal angle very rounded. Petiolar node triangular in profile, summit convex and rounded, with slight longitudinal impression on dorsum, anterior and posterior faces, anterior face slightly shorter than posterior face, ventral surface of petiole concave. Gaster elliptical-elongate. Legs somewhat compressed.

Body surface slightly shining, finely shagreened. Mandibles with a row of coarse punctures along margin. Pubescence fine. Greyish pilosity minimal, confined to clypeus, venter and gaster. Body and head rufotestaceous, with legs and gaster black. Head and antennae deep reddish orange, femora and tibiae dark brown, joints and tarsi yellow. Gaster black, but first segment rufotestaceous with dark outer margin.

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. Dorsal face of propodeum high, convex. Petiole broader than high, with distinct medial impression. Gaster globose, larger than in worker. Scapes, femora and tibiae broad, robust. Surface of body appearing dusty, not shining. Queen coloration as in workers.

Male

Lucky and Ward (2010) - (n = 3) HL 1.70–1.80, HW 1.26–1.33, SL 0.38–0.44, EL 0.62–0.63, HTL 4.26–4.50, CI 0.73–0.76, SI 0.29–0.33, SI2 0.66–0.76.

References

• Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67. PDF
• 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
• Oberski, J.T. 2024. Ultraconserved element (UCE) phylogenomics illuminates the evolutionary history and biogeography of Dorymyrmex pyramid ants. Systematic Entomology, 1-24 (doi:10.1111/syen.12658).

References based on Global Ant Biodiversity Informatics

• Forel A. 1915. Results of Dr. E. Mjöbergs Swedish Scientific Expeditions to Australia 1910-13. 2. Ameisen. Ark. Zool. 9(16): 1-119
• Lucky A., and P. S. Ward. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Zootaxa 2688: 1-67.
• Nakamura A., C. P. Catterall, A. P. N. House, R. L. Kitching, and C. J. Burwell. 2007. The use of ants and other soil and litter arthropods as bio-indicators of the impacts of rainforest clearing and subsequent land use. Journal of Insect Conservation 11: 177-186.
• 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.