Leptogenys grandidieri

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Leptogenys grandidieri
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Leptogenys
Species group: attenuata
Species: L. grandidieri
Binomial name
Leptogenys grandidieri
Forel, 1910

Leptogenys grandidieri casent0101589 profile 1.jpg

Leptogenys grandidieri casent0101589 dorsal 1.jpg

Specimen labels

Individual workers of this species have been found foraging on the forest floor and through leaf litter. Nests were discovered under the ground and in rotten logs.

Identification

A member of the attenuata species group. Rakotonirina and Fisher (2014) - Worker. Third antennal segment of normal length, less than twice of the length of the second; eye breaking outline of sides of head; basal half of mandible finely longitudinally striate, apical portion faintly striate or smooth between sparse punctures; metapleuron finely rugulose; posterior portion and anterodorsal level of mesopleuron finely rugulose or with superficial rugulae; posterodorsal angle of node projecting posteriorly and overhanging its posterior margin.

Leptogenys grandidieri is easily recognized by the combination of the following characters: the striation on mandible, the presence of sculpture on the sides of the mesosoma, and the backward projection of the posterodorsal angle of petiolar node over its posterior margin. This species is very similar to Leptogenys edsoni but in the later the dorsal and posterior faces of petiole meet at a right-angle. Leptogenys manongarivo is similar with respect to the posterior projection of the posterodorsal corner of petiolar node, but L. manongarivo lacks sculpture on the sides of the mesosoma.

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

Habitat

The high and mid-elevational montane rainforest in the PN Andohahela in the south-east of Madagascar is the only site where L. grandidieri is known. The species is absent from the dry forest habitats adjacent to these mesic forests in the park.

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

Male

Nomenclature

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

  • grandidieri. Leptogenys (Lobopelta) grandidieri Forel, 1910a: 17 (w.) MADAGASCAR. See also: Bolton, 1975a: 296.

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

Description

Worker

Rakotonirina and Fisher (2014) - (9 specimens). HW: 0.83–0.89, HL: 1.24–1.34, CI: 65–68, SL: 1.16–1.25, SI: 138–144, PW: 0.70–0.75, WL: 1.92–2.07, PNH: 0.56–0.60, PNL: 0.53–0.57, PNW: 0.43–0.49, DNI: 79–89, LNI: 101–111.

Head subrectangular, lateral margin meets in rounded angle the slightly medially concave posterior border. In cephalic full-face view, eye breaking outline of side of head; maximum diameter between one-fourth and one-fifth the length of lateral cephalic border. One-fourth the length of antennal scape extending beyond posterior margin of head. Third antennal segment normal, less than twice the length of the second. Basal margin of mandible broadly rounded, rarely with blunt angle or very small preapical tooth. Propodeal lobe toothlike. With petiolar node in profile, posterodorsal angle projecting posteriorly and overhanging posterior margin; anterior margin shorter than posterior margin, node higher than long and inclined anterad. Mandible finely longitudinally striate from base to midlength; distally, sculpture becomes faintly striate or smooth between sparse punctures. Median lobe of clypeus smooth, besides sparse, small punctures. Dorsum of head, mesosoma and petiolar node generally smooth and shining. Sides of mesosoma, at least on suture between mesopleuron and metapleuron, transversely striate or finely reticulate-rugose; most often this sculpture can be found on mesopleuron and metapleuron. Propodeal declivity transversely striate or rugulose. Standing hairs present on dorsum of head, mesosoma, petiolar node and gaster. Body color dark brown to reddish brown with lighter appendages.

Holotype Specimen Labels

Queen

Rakotonirina and Fisher (2014) - (2 specimens): HW: 0.92–0.94, HL: 1.33–1.34, CI: 69–70, SL: 1.17–1.18, SI: 126–127, PW: 0.77, WL: 1.95–1.96, PNH: 0.71–0.72, PNL: 0.47–0.48, PNW: 0.64–0.65, DNI: 135–137, LNI: 147–153. Characters as in worker but head broader, without ocelli and with shorter scape. Mesosoma with incomplete thoracic sclerites. In dorsal view, petiolar node much broader than long. Gastral segments enlarged.

Type Material

Rakotonirina and Fisher (2014) - Holotype worker, Madagascar, Fort-Dauphin (Sikora), AntWeb CASENT0101589 (Musee d'Histoire Naturelle Genève) [examined].

References

  • Bolton, B. 1975a. A revision of the ant genus Leptogenys Roger (Hymenoptera: Formicidae) in the Ethiopian region with a review of the Malagasy species. Bull. Br. Mus. (Nat. Hist.) Entomol. 31: 235-305 (page 296, see also)
  • Forel, A. 1910a. Glanures myrmécologiques. Ann. Soc. Entomol. Belg. 54: 6-32 (page 17, worker described)
  • Rakotonirina, J.C. & Fisher, B.L. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836, 1-163.