Leptogenys toeraniva

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

Leptogenys toeraniva casent0072075 p 1 high.jpg

Leptogenys toeraniva casent0072075 d 1 high.jpg

Specimen Labels

Leptogenys toeraniva occurs in the lowland forest of RNI Betampona and Makirovana near Sambava. This species was mostly found foraging under leaf litter and rarely on the forest floor, even though many different collecting methods have been used to collect ants across Madagascar. In addition to its smaller eyes and its rarity, this result supports the idea that L. toeraniva is a hypogaeic species, living generally under the soil layers.

Identification

A member of the toeraniva species group. Rakotonirina and Fisher (2014) - Worker. Mandible capable of closing tightly against clypeus; eye small, maximum diameter less than greatest width of scape; in full-face view, head rectangular; antennal scape with erect hairs shorter than maximum width of scape; eye smaller, maximum diameter much less than the maximum width of scape. With petiole in lateral view, anterior face of node the same height as posterior face. In profile, helcium located generally 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 large indentation.

Leptogenys toeraniva is similar to Leptogenys bezanozano but easily identified by the presence of short, erect hairs on the antennal scape, transversely rugulose propodeal declivity, and the anterior and posterior margins of the petiolar node are the same height. Leptogenys bezanozano has erect hairs that are as long as or longer than the maximum width of its scape, a smooth, shiny propodeal declivity, and a shorter posterior face of the petiolar node.Workers collected from the two known localities differ in some morphological characters. Specimens from Betampona have smaller eyes whose maximum diameter is less than greatest width of scape; the mandible is smooth and shining; and the anteromedian lobe of the cypeus has a pair of anteriorly projecting peg-like setae. In contrast, worker specimens from Makirovana forest have larger eyes, the maximum diameter slightly greater than maximum diameter of scape; mandible smooth and shining on basal half and finely striate on distal half; and the anteromedian lobe of the clypeus with three anteriorly projecting peg-like setae.

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

Male

Nomenclature

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

  • toeraniva. Leptogenys toeraniva Rakotonirina & Fisher, 2014: 136, figs. 3C, 3D, 4C, 4D, 5B, 153, 158 (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: 0.85–1.01, HL: 1.21–1.45, CI: 69–73, SL: 1.16–1.49, SI: 132–147, PW: 0.74–0.87, WL: 1.90–2.24, PNH: 0.70–0.83, PNL: 0.70–0.83, PNW: 0.64–0.71, DNI: 83–93, LNI: 94–104. FIGURE 153. Leptogenys toeraniva holotype worker CASENT0072075.

Head oblong, lateral margin approximately straight from anterior portion of head to posterior third and rounding gradually to posterior border. Eye small, greatest diameter less than maximum width of scape. Clypeus projecting anteriorly into prominent triangular lobe; semi-translucent lamella on lateral and anteromedian lobes separated by impression or notch. Mandible with convex inner margin; blades widest at apical third and closing tightly against clypeus when at rest. In full-face view, antennal scape long, surpassing posterior cephalic border by one-third of apical portion. In dorsal view, metanotal groove distinct and cross-ribbed. Petiolar node noticeably longer than broad in dorsal view. In profile, node longer than high, with anterior and posterior faces at the same height and meeting the dorsal face in rounded angle; subpetiolar process double, consisting of anterior triangular tooth and posterior rounded lobe separated by indentation. In side view, helcium located approximately near mid-height of anterior margin of third abdominal segment; prora voluminous and anteroventral angle of third abdominal sternite rounded; prora and anteroventral section separated by strong indentation. Dorsum of head, promesonotum, petiolar node and gastral tergites generally smooth and shining, with scattered small punctures from which hairs arise. Sculptures of head in front of eye rugulose, which become punctate at level of eyes and sparsely punctate in posterior cephalic portion. Propodeal dorsum with faintly fine rugulae between punctures; propodeal declivity transversely striate. Scape with erect hairs shorter than greatest width of scape. Color dark brown, with lighter appendages and tip of gaster.

Holotype Specimen Labels

Type Material

Holotype worker: Province Toamasina, RNI Betampona, Camp Vohitsivalana, 37.1 km 338° Toamasina, -17.924, 49.1997, 390 m, rainforest, sifted litter, 28 Nov 2005 (B.L. Fisher et al.), collection code: BLF13125, specimen code: CASENT0072075 (California Academy of Sciences). Paratype worker: from same locality as holotype, but -17.8867, 49.2025, 520 m, rainforest, ground forager, 2 Dec 2005 (B.L. Fisher et al.), collection code: BLF13322, specimen code: CASENT0067668 (CASC).

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.