Leptogenys tsingy

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

Leptogenys tsingy casent0000793 p 1 high.jpg

Leptogenys tsingy casent0000793 d 1 high.jpg

Specimen Labels

The species nests in rotten logs and dead branches above the ground, and forages in leaf litter.

Identification

A member of the ridens complex of the truncatirostris species group. Rakotonirina and Fisher (2014) - Worker. Clypeus with median carina, distance between anterior level of torulus and anteromedial clypeal margin greater than maximum width of scape; antennal scape relatively short; eye small, maximum diameter roughly one-fifth the length of sides of head, not extending beyond lateral cephalic border when head in full-face view; node broader than long (DNI: 134–146); dorsum of mesosoma, petiolar node and gaster with few short suberect hairs and dense pubescence; dense and fine sculpture; smaller species (HW: 1.20–1.34, HL: 1.42–1.56, WL: 2.17–2.39).

Leptogenys tsingy is very similar to Leptogenys namoroka, but the former has the petiolar node broader than long in dorsal view (DNI: 134–146), body sculpture much coarser, and more suberect hairs and sparse pubescence, whereas the latter has a much longer petiolar node (DNI: 115), finer body sculpture, fewer short, suberect hairs and abundant pubescence. Both species belong to the ridens species complex, together with Leptogenys ridens and Leptogenys fotsivava. As a consequence, L. tsingy can be confused with L. ridens and L. fotsivava, but L. ridens is characterized by a longer antennal scape and larger eyes and L. fotsivava has much larger eyes that break the outline of the sides of the head.

Keys including this Species

Distribution

The distribution of L. tsingy is limited to the dry forest habitats on Tsingy in the PN Tsingy de Bemaraha and PN Namoroka between 100 m and 150 m.

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.

  • tsingy. Leptogenys tsingy Rakotonirina & Fisher, 2014: 154, figs. 17B, 18A, 167, 175 (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

(6 specimens). HW: 1.20–1.34, HL: 1.42–1.50, CI: 85–89, SL: 1.33–1.53, SI: 111–115, PW: 0.88–0.96, WL: 2.17–2.39, PNH: 0.82–0.90, PNL: 0.55–0.64, PNW: 0.78–0.86, DNI: 134–146, LNI: 134–150.

In full-face view, head roughly subquadrate, but slightly wider in front of level of eyes; sides meeting more or less concave posterior margin in a convex line. In full-face view, maximum eye diameter about one-fifth the length of lateral cephalic margin; eye location not interrupting lateral border of head in full-face view. Antennal scape relatively short, only one-fourth of distal portion reaching posterior cephalic border. In full-face view, anteromedial clypeal margin bordered by whitish lamella; length of median lobe of clypeus measured from anterior level of antennal insertion to anteromedial clypeal margin roughly greater than maximum width of scape. With head in full-face view and mandible fully closed, basal two-thirds of blades tightly closed against anterior margin of clypeus while distal thirds cross each other and apparently project downward in front of anteromedial clypeal margin. With mesosoma in dorsal view, metanotal groove distinct, marked by few transverse striae. In lateral view, posterolateral margin of propodeum without visible lobe. Petiolar node wider than long in dorsal view, with posterior margin straight and lateral margin broadly rounding to convex anterior margin. Mandible longitudinally striate, superimposed with scattered small punctures. Propodeal declivity with transverse rugulae. Body generally covered by coarse rugae with higher ridge, dorsum of head, mesosoma and petiolar node reticulate-rugulose interspersed by scattered foveoles or large punctures. Third and fourth abdominal tergites reticulate-rugulose but with denser and more elongate punctures. Dorsum of body covered by short and numerous standing hairs and sparse pubescence. Integument black to dark brown and appendages generally brown, tip of gaster and apical portion of appendages lighter in color.

Type Material

Holotype worker: Madagascar, Mahajanga, PN Tsingy de Bemaraha, 10.6 km ESE 123° Antsalova, -18.7094, 447182, 150 m, tropical dry forest on Tsingy, ex rotten log, 16–20 Nov 2001 (Fisher-Griswold Arthropod Team) collection code: BLF06538, specimen code: CASENT0493181 (California Academy of Sciences). Paratypes: 3 workers with the same data as holotype but specimen coded as CASENT0196369, CASENT0493182, CASENT0247215 (CASC, The Natural History Museum).

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.