Leptogenys namoroka

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Leptogenys namoroka
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. namoroka
Binomial name
Leptogenys namoroka
Rakotonirina & Fisher, 2014

Leptogenys namoroka casent0034713 p 1 high.jpg

Leptogenys namoroka casent0034713 d 1 high.jpg

Specimen Labels

This species is known only from one specimen collected from the dry forest habitat of the PN Tsingy de Bemaraha in western Madagascar. It was found foraging 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 side of head; not extending beyond lateral cephalic border when head in full-face view; petiolar node approximately as broad as long (DNI: 115) in dorsal view; dorsum of mesosoma, petiolar node and gaster with few, short, suberect hairs and dense pubescence; dense and fine sculptures; larger species (HW: 1.38, HL: 1.58, WL: 2.47).

Leptogenys namoroka is very similar to Leptogenys tsingy in that they have small eyes, which do not break the lateral border of the head in full-face view, but L. tsingy is smaller in size (WL: 2.17–2.39), has broader petiolar node (DNI: 134–146) and is covered with abundant short suberect hairs and sparse pubescence on the dorsum of the mesosoma, petiolar node and the gaster.

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.

  • namoroka. Leptogenys namoroka Rakotonirina & Fisher, 2014: 148, figs. 16B, 18A, 164, 173 (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

(1 specimen). HW: 1.38, HL: 1.56, CI: 88, SL: 1.66, SI: 120, PW: 0.95, WL: 2.47, PNH: 0.86, PNL: 0.70, PNW: 0.81, DNI: 115, LNI: 122.

Head elongate and larger in front than behind; sides deviating outward anteriorly and rounding to medially slightly concave posterior border. Eye small; in full-face view, eye not extending beyond line of lateral cephalic border. Antennal scape relatively short, surpassing posterior margin of head by one third of its length. Clypeus broadly rounded anteriorly, bordered with white-yellowish lamella; in full-face view, median lobe of clypeus elongate, width taken from anterior level of torulus to anteromedial clypeal margin greater than maximum diameter of scape. Mandible when fully closed, basal two-thirds of blades placed tightly against anterior margin of clypeus, rest of apical portion overlapping each other and projecting further in front of clypeus. With mesosoma in dorsal view, metanotal groove impressed and transversely striate; in lateral view, propodeal lobe lacking. In dorsal view, petiolar node roughly as broad as long. FIGURE 164. Leptogenys namoroka holotype worker CASENT0072075. A: lateral view. B: head in full-face view. C: dorsal view. Mandible longitudinally striate, with sparse punctures. Dorsum of head, mesosoma and petiolar node densely and finely reticulate-rugose to densely and finely reticulate punctate. Propodeal declivity transversely rugose. Third abdominal tergite densely and finely reticulate-punctate; fourth densely and finely punctate. Pubescence abundant on entire dorsum of body, with sparse, suberect, short hairs. Color blackish dark brown, appendages dark brown at base and brown at tarsal segments and apex of gaster.

Holotype Specimen Labels

Type Material

Holotype worker: Madagascar: Mahajanga, PN Namoroka, 16.9 km 317° NW Vilanandro, -16.4067, 45.31, 100 m, tropical dry forest, sifted litter, 12–16 Nov 2002 (Fisher-Griswold, Arthropod Team) collection code BLF06582, specimen code: CASENT0034713 (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.