Leptogenys sahamalaza

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

Leptogenys sahamalaza casent0416181 p 1 high.jpg

Leptogenys sahamalaza casent0416181 d 1 high.jpg

Specimen Labels

A rare Leptogenys known only from one worker specimen found foraging on the ground of the dry forest habitat in the PN Sahamalaza in northwestern Madagascar.

Identification

A member of the voeltzkowi complex of the incisa species group. Rakotonirina and Fisher (2014) - Worker. Anterior clypeal margin projecting medially into a narrow, rounded lobe; small peg-like setae present near apical portion of the lobe; antennal scape short; less than apical fourth reaching posterior margin of head; eye extending beyond the lateral cephalic margin when head viewed in full face; mandible with curved angle near the base; posterior face of petiolar node with a large groove at its posteroventral section, near the junction to gaster; antennal scape and tibia with subdecumbent short hairs; third abdominal tergite finely reticulate-rugulose.

Leptogenys sahamalaza is versy similar to Leptogenys vitsy and Leptogenys voeltzkowi in that they have peg-like setae on the anterior margin of the clypeus, the lamella is restricted to the small and rounded median lobe of the clypeus, the antennal scape lacks erect hairs, and that the posterior margin of the node is constricted at the posteroventral angle near the junction to gaster. However, L. voeltzkowi is larger in size, their eyes do not break the outline of side of the head. In L. vitsy, the mandibles are almost straight near the base, the antennal scape and the tibia are covered with erect to suberect short hairs and the third abdominal tergite is densely punctate.

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.

  • sahamalaza. Leptogenys sahamalaza Rakotonirina & Fisher, 2014: 97, figs. 57B, 107, 123 (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: 1.32, HL: 1.46, CI: 90, SL: 1.54, SI: 117, PW: 0.96, WL: 2.44, PNH: 0.85, PNL: 0.72, PNW: 0.81, DNI: 112, LNI: 118.

Head more or less subquadrate, sides slightly convex and diverging anteriorly. Eye medium and weakly convex, maximum diameter just exceeding widest part of antennal scape, and splitting line of lateral cephalic border when head in full-face view. Antennal scape relatively short, with less than one third its length reaching posterior cephalic margin. In full-face view, anterior clypeal margin projecting into narrowly rounded lobe, which is bordered by subopaque, yellowish membrane. Mandible elongate and narrow, noticeably curved near base; rest relatively straight and slightly curving when close to apical tooth, leaving a gap with clypeus when closed; basal groove impressed and preapical tooth lacking. With mesosoma in dorsal view, metanotal groove distinct and transversely striate; in profile, propodeum short and high. Petiolar node generally as broad as high in profile; anterior margin rounding to the dorsum, which meets the posterior margin at a distinct angle; distinct constriction present on posterior border of node at posteroventral angle. Abdominal segments III and IV with visible constriction between them. Mandible striate and interspersed with widely spaced punctures. Dorsum of head and pronotum densely and finely reticulate-rugulose; remainder of mesosoma and petiolar node with dense and fine reticulate-rugulae, superimposed by sparse, larger punctures. Third abdominal tergite densely and finely reticulate-rugulose with widely spaced, long punctures; the fourth covered with shallow, elongate punctures. Dorsum of body covered by standing hairs and pubescence; hairs on antennal scape and tibiae short and subdecumbent. Color of integument black, with apical portion of appendages and tip of gaster brown.

Holotype Specimen Labels

Type Material

Holotype worker: Madagascar, Antsiranana, Forêt d'Anabohazo, 21.6 km 247° WSW Maromandia, -14.3089, 47.9143, 120 m, tropical dry forest, pitfall trap, 11–16 Mar 2001 (Fisher, Griswold et al.), collection code: BLF03335, specimen code: CASENT0416181 (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.