Leptogenys avo

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

Leptogenys avo casent0034742 p 1 high.jpg

Leptogenys avo casent0034742 d 1 high.jpg

Specimen Labels

The two worker specimens of L. avo were from high altitude localities in eastern Madagascar. They were found foraging in the leaf litter of montane rainforest.

Identification

A member of the toeraniva species group. Rakotonirina and Fisher (2014) - Worker. Mandible capable of closing tightly against clypeus; eye not flattened, slightly protruding from head capsule; antennal scape with erect hairs shorter than maximum width of scape; eye larger, maximum diameter greater than the maximum width of scape. Propodeal declivity transversely striate; in profile, anterodorsal and posterodorsal margin of petiolar node at the same height and helcium located approximately near mid-height of anterior margin of third abdominal segment. Prora voluminous and anteroventral section of third abdominal sternite rounded; prora and anteroventral angle separated by strong indentation.

This species is known from two specimens, one from each of two sites. The specimen from PN Masoala has eye diameter roughly as large as the greatest width of the scape; petiolar node in profile approximately as high as long; propodeum shorter, the dorsum of which meets the declivity in a distinct angle; and no sculpture apart from piligerous punctures on the third abdominal tergite. By contrast, the holotype specimen from Anjanaharibe Makira is characterized by a larger eye whose diameter is distinctly greater than the maximum width of the scape; petiolar node in profile elongate, with convex dorsal margin; propodeal dorsum elongate, meeting the declivity in an almost rounded angle; and strong sculpture on the body with punctures present between fine rugulation on the third abdominal tergite.

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.

  • avo. Leptogenys avo Rakotonirina & Fisher, 2014: 133, figs. 5A, 151, 156 (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

(2 specimens). HW: 1.01, HL: 1.42–1.45, CI: 69–71, SL: 1.44–1.49, SI: 143–147, PW: 0.84–0.87, WL: 2.21–2.24, PNH: 0.79–0.83, PNL: 0.76–0.83, PNW: 0.69–0.71, DNI: 83–93, LNI: 100–104.

Width of head slightly increasing from back to front; lateral border almost straight and meets the posterior margin in a rounded angle. Maximum eye diameter distinctly greater than widest part of scape. Mandible elongate with convex inner margin, closing tightly against clypeus. Antennal scape surpassing posterior margin of head by one third of its length. Metanotal groove impressed, with transverse striation. In dorsal view, petiolar node distinctly longer than broad. With petiole in profile, node roughly as high as broad, junction of anterior and posterior faces to dorsal margin in convex line; subpetiolar process consisting of ventrally directed lobe anteriorly followed by an indentation and small tooth posteriorly. Constriction between third and fourth abdominal segments lacking. Helcium roughly situated near mid-height of third abdominal segment; prora voluminous and anteroventral angle of third abdominal sternite rounded. Dorsum of head coarsely rugose and interspersed with large punctures from anterior portion of head to posterior third, behind which the sculptures become scattered punctures. Pronotum transversely rugulose, with sparse punctures. Dorsum of mesonotum, propodeum and petiolar node reticulate-rugulose. Sides of mesosoma coarsely rugose, with fine reticulation superimposed with large punctures. In lateral view, anterior half of third abdominal tergite finely rugulose, the interspaces of which are punctate.

Type Material

Holotype worker: Province Toamasina, Montagne d’Anjanaharibe, 19.5 km 27° NNE Ambinanitelo, -15.1783, 49.635, 1100 m, montane rainforest, sifted litter, 12–16 Mar 2003 (Fisher, Griswold et al.), collection code: BLF08150, specimen code: CASENT0034742 (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.