Leptomyrmex darlingtoni

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Leptomyrmex darlingtoni
Leptomyrmex darlingtoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Leptomyrmex
Species: L. darlingtoni
Binomial name
Leptomyrmex darlingtoni
Wheeler, W.M., 1934

Leptomyrmex darlingtoni side view

Leptomyrmex darlingtoni 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.

Leptomyrmex darlingtoni has been recorded from rainforest, savannah, Araucaria forest and Eucalyptus woodland, in ground nests

Identification

Leptomyrmex darlingtoni is distinctive for its small size and restricted geographic range. This species can be distinguished from its only sympatric congener, Leptomyrmex rufipes, by its smaller size, HW 0.94–1.03 mm; WL 3.11–3.30 mm (L. rufipes HW 1.08–1.39 mm; WL 3.61–4.52mm), and the rounded postocular portion of the head, which lacks the neck-like constriction of L. rufipes. (Lucky and Ward 2010)

Identification Keys including this Taxon

Distribution

it is found only on Cape York Peninsula, as far south as the vicinity of Cooktown.

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 of this species have not been collected.

Worker

Nomenclature

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

  • darlingtoni. Leptomyrmex darlingtoni Wheeler, W.M. 1934c: 104, fig. 13 (w.m.) AUSTRALIA. Senior synonym of fascigaster, jucundus: Lucky & Ward, 2010: 29.
  • fascigaster. Leptomyrmex darlingtoni subsp. fascigaster Wheeler, W.M. 1934c: 107 (w.) AUSTRALIA. Junior synonym of darlingtoni: Lucky & Ward, 2010: 29.
  • jucundus. Leptomyrmex darlingtoni subsp. jucundus Wheeler, W.M. 1934c: 107 (w.) AUSTRALIA. Junior synonym of darlingtoni: Lucky & Ward, 2010: 29.

Type Material

Described from numerous workers and two males taken by Dr. P. J. Darlington from a single colony at Lankelly Creek, in the McIlthwaite Range, Cape York Peninsula, Queensland. There are several fine repletes among the workers.

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 = 7) HL 1.60–1.72, HW 0.94–1.03, MFC 0.18–0.21, IOD 0.56–0.62, SL 3.36–3.73, EL 0.35–0.38, WL 3.11–3.30, PW 0.85–0.92, DPW 0.31–0.34, HTL 2.87–4.19, HTWmin 0.11–0.14, HTWmax 0.21–0.24, CI 0.56–0.62, SI 3.51–3.77, OI 0.09–0.11, HTC 0.50–0.61.

Small species (HW 0.94–1.03 mm; WL 3.11–3.30 mm) with head, excluding mandibles, less than twice as long as broad (CI 0.56–0.62) and widest at eye level. Sides of head straight, genae parallel and slightly con¬cave. Behind the eyes, sides gently rounding to a flat postocular margin. Masticatory margin of mandible with approximately 15 small, irregular teeth and denticles. Anterior clypeal margin weakly concave medially. Eyes positioned posterior to midline of head, relatively large and convex, hairless, not surpassing lateral margins of head. Antennae extremely long and slender (SI 3.51–3.77), somewhat compressed, scapes surpassing poste¬rior margin of head by 3/5 their length.

Pronotum slender, distinctly elongate. Propodeum short, not much longer than broad, propodeal angle very rounded, dorsal face weakly convex, declivitous face short. Gently sloping petiolar node a triangular wedge with broad base, anterior and posterior faces meeting at sharp angle, in profile anterior face 2/3 length of posterior face, ventral surface of petiole weakly convex. Gaster elongate-elliptical. Legs very long and slender tibiae compressed but not dramatically so (HTC 0.50–0.61).

Surface very finely shagreened and somewhat shining throughout. Pubescence white, moderately dense over whole surface. Pilosity sparse, confined to clypeus, mandibles, apical portions of the tibiae, gastral ven¬trites and 4th (apical) tergite. Pilosity lacking on the 6th abdominal tergite. Head and antennae rufotestaceous, but color pattern on remainder of body variable, ranging from dark with rufotestaceous legs to rufotestaceous body with black gaster and legs dark reddish brown with testaceous joints. An entirely pale yellow form is also known. Femora and tibiae. Intermediate forms may be mottled with dark spots on a pale thorax, with gaster either entirely black or with first tergite pale.

Male

Lucky and Ward (2010) – measurements (n = 2) HL 1.40–1.44, HW 0.93–1.02, SL 0.37–0.38, EL 0.53–0.58, HTL 3.12–3.22, CI 0.66–0.70, SI 0.36–0.40, SI2 1.20–1.37.

Wheeler (1934) - Head narrow, without the mandibles nearly twice as long as the ocular diameter. Eyes very large and prominent, placed at the middle of the sides; postocular region subtrapezoidal, its posterior border straight, as broad as the length of the adjacent sides; cheeks plus the outer corners of the clypeus nearly as long as the eyes, feebly concave and somewhat converging anteriorly. Ocelli large and prominent. Mandibles slender with acute tips, their masticatory border without denticles, much longer than the internal border and forming with it a distinct but rounded angle. Clypeus nearly as long as broad, with straight anterior border. Antennae as long as the body; scapes somewhat less than three times as long as broad; first funicular joint slightly longer than broad, the second only a little longer; joints 3-5 much longer, the third bent near its apex, the fourth and fifth more uniformly bowed. Thorax rather short compared with that of other species, mesepisterna very prominent; mesonotum longer than broad, narrowed anteriorly, epinotum less than twice as long as broad, its base in profile rather straight, sloping, twice as long as the more sloping declivity and passing into it without a perceptible angle. Petiole somewhat longer than broad, its node much lower than in the worker, in profile straight and horizontal in' the middle, convex in front and sloping behind. Gaster clavate, its first segment narrowed anteriorly, the genitalia large and extruded, of a very different structure from those of the other species; squamulae separated at the base; stipites narrowed at the base, with broad, bilobed tips; volsellae large, flattened, bearing at their tips a curved three-pronged crosspiece, the longest slender and acute prong directed posteriorly; sagittae forming a large keel-shaped structure, with its ventral border regularly serrate. Legs very long and slender, hind femora constricted and flexed in the middle; all the tibiae bisinuately bent. Wings short and narrow, measuring only 6 mm.; pterostigmal appendage vestigial, reduced to a mere nodule; basal half of cubitus absent.

Sculpture, pilosity and pubescence as in the worker, but the coxae and legs without hairs; squamulae very smooth and shining; hairs on the borders of the stipites long and delicate but not dense.

References

  • Lucky, A. 2011. Molecular phylogeny and biogeography of the spider ants, genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution 59: 281-292.
  • Lucky, A. & Ward, P.S. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr. Zootaxa 2688: 1-67.
  • Wheeler, W. M. 1934c. A second revision of the ants of the genus Leptomyrmex Mayr. Bull. Mus. Comp. Zool. 77: 69-118 (page 104, fig. 13 worker, male described)