| Leptomyrmex geniculatus|
|Based on Barden et al., 2017. Note only selected Leptomyrmex species are included.|
Collected in rainforest and dry forest but its nesting habits are unknown.
The distinctive color pattern that distinguishes Leptomyrmex geniculatus from its two New Caledonian congeners is the combination of dark gaster and dark distal portions of the femora on an otherwise orange body. In some specimens the pronotum may also be dark. Aside from these color differences, this species greatly resembles Leptomyrmex pallens and Leptomyrmex nigriceps. There are scattered records of this species throughout the island, where it has been found in sympatry with L. pallens. This species appears to be less commonly encountered than L. pallens. (Lucky and Ward 2010)
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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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.
Queen and male unknown.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- geniculatus. Leptomyrmex pallens var. geniculata Emery, 1914f: 418 (w.) NEW CALEDONIA. Subspecies of pallens: Wheeler, W.M. 1934c: 109. Raised to species: Lucky & Ward, 2010: 36.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Lucky and Ward (2010) – measurements (n = 7) HL 1.80–1.95, HW 0.99–1.10, MFC 0.22–0.26, IOD 0.55–0.61, SL 3.36–3.81, EL 0.33–0.38, WL 3.21–3.52, PW 0.86–0.94, DPW 0.40–0.43, HTL 3.80–4.17, HTWmin 0.10–0.15, HTWmax 0.17–0.19, CI 0.54–0.57, SI 3.39–3.63, OI 0.09–0.11, HTC 0.61–0.85.
L. geniculatus is a small species (HW 0.99–1.10 mm; WL 3.21–3.52 mm) with elongate head nearly twice as long as broad, excluding mandibles (CI 0.54–0.57). Sides of head parallel, slightly convex, posterior to eyes head narrowing gently to flat postocular margin. Approximately 15 teeth and denticles interspersed on masticatory margin of mandible. Anterior clypeal margin flat to weakly concave. Eyes positioned approxi¬mately at midline of head, relatively large, convex, hairless, not reaching the lateral margins of head. Antennae extremely slender, but not compressed. Scapes extending past the posterior margin by 2/3 their length.
Pronotum elongate. Propodeum short, dorsal face about 1.5 times as long as the convex declivitous face, angle rounded. Dorsal face of propodeum convex, with a transverse impression at the anterior end. Petiolar node small, triangular in profile with a rounded dorsum. Anterior, dorsal and posterior face of petiole with longitu¬dinal impression posterior face longer than anterior, ventral surface flat. Gaster broadly elliptical. Legs very slender, not compressed (HTC 0.61–0.85).
Surface finely and densely shagreened, slightly shining. Mandibles with a single row of coarse punctures along margin. Pubescence white, extremely fine standing hairs scarce, confined to clypeus, venter and gaster. Body mostly pale rufotestaceous, with first two segments of gaster and distal 1/2 to 1/3 of femora black. Head and sometimes pronotum slightly darker than body.
Lucky and Ward (2010) – Syntypes, 2 workers, New Caledonia: Coula-Boréaré (Sarasin & Roux) Museo Civico di Storia Naturale, Genoa; syntypes, 2 workers, New Caledonia: Tchalabel (Sarasin & Roux) MSNG; also 1 syntype worker, New Caledonia: "New Caledonia" Museum of Comparative Zoology. One worker from Coula-Boréaré here designated lectotype (CASENT0127391).
- Emery, C. 1914f. Les fourmis de la Nouvelle-Calédonie et des îles Loyalty. Nova Caled. A Zool. 1: 393-437
- 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 (Hymenoptera: Formicidae). Zootaxa 2688:1-67.