Leptogenys edsoni

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Leptogenys edsoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Leptogenys
Species group: attenuata
Species: L. edsoni
Binomial name
Leptogenys edsoni
Rakotonirina & Fisher, 2014

Leptogenys edsoni casent0147522 p 1 high.jpg

Leptogenys edsoni casent0147522 d 1 high.jpg

Specimen Labels

Leptogenys edsoni is known to nest most frequently in rotten logs and occasionally under the ground. Foraging occurs on the forest floor and in leaf litter.

Identification

A member of the attenuata species group. Rakotonirina and Fisher (2014) - Worker. Third antennal segment less than twice the length of second; eye breaking outline of side of head; mandible smooth and shining apart from scattered piligerous punctures; median lobe of clypeus mostly smooth and not markedly striate; metapleuron and each side of meso-metapleural suture finely rugose; with petiole in profile, posterodorsal angle of node not projecting posteriorly nor overhanging posterior margin.

Leptogenys edsoni can be separated from similar species in the attenuata group by its smooth anteromedian clypeal lobe and mandibles, the fine reticulate-rugae on the sides of posterior portion of mesosoma, and the straight posterolateral margin of the petiolar node.

Keys including this Species

Distribution

Madagascar endemic. This species occurs from Vohiparara near the PN Ranomafana in the northernmost range to the RS Kalambatritra in the south.

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Habitat

Distributed in the mountainous regions of the southeast of the island and rarely in lowland rainforests.

Biology

The Leptogenys genus page has more details about the general biology of ants in this genus. The following synopsis provided by Rakotonirina and Fisher (2014) offers an overview of the Malagasy Leptogenys: Recent surveys of arthropods in the Malagasy region uncovered a wealth of new species and showed that Leptogenys is one of the dominant ponerine ants widely distributed across all types of forest habitats. Workers are usually found foraging on the forest floor or in the leaf litter and only rarely on vegetation. They nest terrestrially under the soil, rocks, logs, or rootmat ground layers and in rotten logs, branches, in rotting bamboo, and rotten tree stumps. Most of the Malagasy species are endemic to Madagascar. In all Malagasy species, winged queens are absent, which limits their ability to disperse across the complex topography and various ecological barriers in the region. In the absence of alate queens, reproduction of Leptogenys in the region may be by fission, which enhances population viscosity and may result in important morphological variation across a species' geographic range. Though queens do not fly, males of Leptogenys are alate and are one of the most frequently collected ant genera in Malaise traps throughout Madagascar. Leptogenys exhibits a wide range of phenotypic diversity segregated both among spatially isolated habitats and along continuous environmental gradients.

Castes

Worker

Nomenclature

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

  • edsoni. Leptogenys edsoni Rakotonirina & Fisher, 2014: 46, figs. 1A, 20C, 28A, 63, 76 (w.q.) MADAGASCAR.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

(15 specimens). HW: 0.78–1.05, HL: 1.18–1.49, CI: 67–71, SL: 1.01–1.40, SI: 124–135, PW: 0.68–0.84, WL: 1.77–2.21, PNH: 0.53–0.68, PNL: 0.47–0.68, PNW: 0.44–0.57, DNI: 81–97, LNI: 85–116.

Head rectangular, sides almost straight and parallel to one another and meeting in rounded angle with very slightly concave posterior margin. In full-face view, eye diameter roughly one fifth the length of side of head, breaking line of side of head. Antennal scape extending beyond posterior cephalic margin by about one third of its length. Third antennal segment less than twice the length of the second. Posterior margin of propodeum at about level of propodeal spiracle with toothlike lobe. In profile, petiolar node higher than long; anterior face shorter than the posterior and rounding to dorsum, which meets the posterior face at a distinct angle, posterodorsal angle not projecting posteriorly and not overhanging posterior margin of node. Mandible smooth and shining between scattered punctures. Dorsum of head, median clypeal lobe, mesosoma, and petiolar node generally smooth and shining apart from small piligerous pits. Transverse striation or fine reticulate-rugae cover the propodeal declivity and along meso-metapleural suture; occasionally similar sculpture covers mesopleuron and lower half of propodeal lateral surface. Dorsum of body with short, yellowish-brown erect hairs and pubescence. Body color dark brown to black; tip of gaster and apical portion of appendages light brown.

Queen

(2 specimens): HW: 0.94–1.01, HL: 1.35–1.38, CI: 69–73, SL: 1.15–1.22, SI: 121–123, PW: 0.73–0.79, WL: 1.91–1.99, PNH: 0.65–0.71, PNL: 0.45–0.47, PNW: 0.59–0.64, DNI: 133–136, LNI: 146–150. Worker characters are also found in ergatoid queens, but the latter has a much shorter head, shorter but wider petiolar node, enlarged gaster and many more slender and numerous erect hairs. The mesosoma also lacks complete thoracic sclerites.

Type Material

Holotype worker: Madagascar, Toliara, RS Kalambatritra, Betanana, -23.4144, 46.459, 1360 m, montane rainforest, ex rotten log, 8 Feb 2009 (B.L. Fisher et al.) collection code: BLF21432, specimen code: CASENT0247255 (California Academy of Sciences). Paratypes: 5 workers same data as holotype but with the following specimen codes: CASENT0247209, CASENT0247252, CASENT0247253, CASENT0247254, CASENT0247256 (CASC, The Natural History Museum, Musee d'Histoire Naturelle Genève, Parc Botanique et Zoologique de Tsimbazaza).

References

  • Rakotonirina, J.C. & Fisher, B.L. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836, 1-163.