Leptogenys rabesoni

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

Leptogenys rabesoni casent0195430 p 1 high.jpg

Leptogenys rabesoni casent0195430 d 1 high.jpg

Specimen Labels

This species is only recorded once from the dry forest habitats of Tsiombikibo near Mitsinjo in western Madagascar where the worker specimens were found foraging on the ground.

Identification

A member of the fiandry species group. Rakotonirina and Fisher (2014) - Worker. Eye maximum width roughly equal to widest portion of antennal scape; dorsum of body mostly punctate; mandibular blades striate; masticatory margin with two teeth, one apical and a second preapical; mesopleuron and lower half of lateral surface of propodeum densely and finely reticulate-rugulose; node approximately as high as long in profile; posterior margin of propodeum with distinct toothlike lobe; dorsum of body with short subdecumbent or apressed hairs.

This species is easily distinguishable from other species within the same species group by its longitudinally striate mandible. The mandible of other species is smooth and shiny.

Keys including this Species

Distribution

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

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

Nomenclature

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

  • rabesoni. Leptogenys rabesoni Rakotonirina & Fisher, 2014: 72, figs. 8A, 88, 93 (w.) MADAGASCAR.

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

Description

Worker

(4 specimens). HW: 0.77–0.81, HL: 1.07–1.10, CI: 70–73, SL: 0.83–0.90, SI: 108–115, PW: 0.54–0.67, WL: 1.60–1.70, PNH: 0.50–0.53, PNL: 0.45–0.49, PNW: 0.45–0.47, DNI: 96–100, LNI: 106–112.

Head weakly broader in front and slightly narrower in the back; sides almost straight. Maximum width of eye roughly equal to largest width of scape. Anterior clypeal margin projecting into triangular lobe covered with narrowly rounded semi-translucent lamella. Mandible with three teeth, one apical plus two preapical, middle tooth very small and resembles denticle or blunt angle. Antennal scape barely surpassing posterior cephalic margin. Propodeum without distinct lobe. In lateral view, petiolar node approximately as high as long; anterior and posterior faces meeting dorsum in a distinct angle. Subpetiolar process consisting of anterior tooth or lobe and small posterior triangular tooth. In profile, anteroventral angle of third abdominal segment protruding anteriorly as sharp ventrally directed lobe. Mandible longitudinally striate, interspersed with sparse punctures. Dorsum of head covered with dense and fine small punctures. Pronotum and petiolar node with punctures but not as dense and as strong as those on head; propodeum and third and fourth abdominal segments generally smooth dorsally. With mesosoma in profile, mostly lower half of mesopleuron and propodeum finely reticulate rugulose or finely striate. Erect hairs absent from antennal scape except for the basal portion; long erect hairs may be present on anterior border of pronotum. Hairs on dorsum of the remainder of pronotum and mesonotum to gaster short and subdecumbent or appressed.

Holotype Specimen Labels

Type Material

Holotype worker: Madagascar, Mahajanga, Mitsinjo, Tsiombikibo Forest m., -16.0833, 45.8667, dry forest, on ground, 18 Apr 1993 (P. Rabeson) MCZ code: MCZ0.1117W, AntWeb specimen code: CASENT0195430 (Museum of Comparative Zoology). Paratypes: 3 workers with same data as holotype but with MCZ codes: MCZ0.1117W, MCZ0.1118W and following AntWeb specimen codes: CASENT0195431, CASENT0195432, CASENT0195429 (MCZC, California Academy of Sciences).

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.