Leptogenys ambo

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

Leptogenys ambo casent0175328 p 1 high.jpg

Leptogenys ambo casent0175328 d 1 high.jpg

Specimen Labels

Leptogenys ambo is known only from the montane rainforests in the north of Madagascar. It has been collected from a pitfall trap in Anjanaharibe-Sud, and foraging on the forest floor in Marojejy. One single worker was found nesting in a rotten log in the RS Manongarivo.

Identification

A member of the saussurei species group. Rakotonirina and Fisher (2014) - Worker. Mandible short and robust, capable of closing tightly against clypeus; anterior clypeal margin medially projecting into triangular lobe; clypeus with sharp edge or lamella. Eye large, maximum diameter larger than maximum width of antennal scape. Dorsum of head and mesosoma distinctly sculptured; with mesosoma in dorsal view, metanotal groove indistinct; petiolar node in dorsal view, with straight posterior margin.

This species can be distinguished from the rest of the saussurei group by the indiscernible metanotal groove and the absence of a median excision on the posterior margin of the petiolar node as seen dorsally.

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

Worker

Nomenclature

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

  • ambo. Leptogenys ambo Rakotonirina & Fisher, 2014: 118, figs. 37A, 137, 144 (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

(3 specimens). HW: 1.01–1.21, HL: 1.55–1.75, CI: 65–70, SL: 1.38–1.64, SI: 129–140, PW: 0.92–1.08, WL: 2.30–2.65, PNH: 0.83–1.04, PNL: 0.82–0.98, PNW: 0.70–0.86, DNI: 86–98, LNI: 101–116.

Head distinctly elongate, sides almost straight and diverging slightly anteriorly along length; posterior margin roughly straight. Eye placed anteriorly, the center closer to base of mandible than to midlength of lateral outline of head. Clypeus with median lobe terminating into double small teeth anteriorly; lateral border fringed with semi-translucent lamella. Lamellate membrane of mandibular inner margin rounding into basal preapical tooth, followed by median blunt angle, then sharp apical tooth. In dorsal view, metanotal groove absent; with mesosoma in profile, mesopleural sulcus indistinct, suture between metapleural and propodeum lacking. In dorsal view posterior margin of petiole straight, not medially excised. In profile, anterolateral portion of head from level of eye finely rugose, usually superimposed with large punctures. With head in dorsal view, dorsum densely punctate or reticulate-rugose, with large punctures between them; punctures sparser towards posterior cephalic margin. Mandible with longitudinal striolae and scattered punctures. In dorsal view, pronotum punctate; rest of dorsum of mesosoma sparsely punctulate. In profile, mesopleuron and lower half of lateral surface of propodeum generally smooth, with scattered punctures; upper half of lateral surface of propodeum finely rugulose apart from punctures. Petiolar node dorsally with scattered punctures; in profile, lower half of lateral surface generally smooth, and upper surface finely rugulose with superimposed punctures. Gaster smooth between scattered, small punctures.

Type Material

Holotype worker: Province Antsiranana, RS Manongarivo, 14.5 km 220° SW Antanambao, -13.9983, 48.4167, 1175 m, montane rainforest, ex rotten log, 19–25 Oct 1998 (B.L. Fisher) collection code: BLF01951, specimen code: CASENT0175361 (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.