Leptogenys fasika

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

Leptogenys fasika casent0141839 p 1 high.jpg

Leptogenys fasika casent0141839 d 1 high.jpg

Specimen Labels

Leptogenys fasika is restricted to the northern tip of Madagascar along the sandy habitats of Ampombofofo, Analabe, Orangea, and Sakalava beach, where worker specimens have been found foraging on the ground and on the lower portions of shrub vegetation. In these sandy localities, the species generally nests under the ground and very rarely in rotten logs or under stones. The most recent collecting event for this species was in Orangea in May 2010. In this sandy soil forest, this species nested in the ground and was observed foraging on the surface during the day for beetles, flies, and crickets. As solitary foragers returned with large prey, at half a meter from the nest entrance recruitment would begin to help the foragers carry their prey into the nest. (Rakotonirina and Fisher 2014)

Identification

A member of the attenuata species group. Rakotonirina and Fisher (2014) - Worker. Third antennal segment of normal length, less than twice the length of the second; eye breaking outline of side of head; mandible smooth and shining apart from scattered piligerous punctures; metapleuron generally smooth. With petiole in profile, posterodorsal angle of node not projecting posteriorly nor overhanging the posterior margin; node as long as high (LNI: 100–106), anterior face of node visibly separated from sharp anteriorpetiolar ridge. In dorsal view, petiole robust (DNI: 83–89), width decreasing gradually from anterad, anterior portion of node not clearly compressed laterally; hairs whitish yellow.

Workers of L. fasika might be confounded with those of Leptogenys variabilis, but the former is larger (HW: 1.20–1.31, PW: 0.98–1.11), the antennal scape relatively longer and the petiolar node as long as high in profile; the node in dorsal view is more robust, without distinct lateral compression on the anterior portion; and the color of hairs on dorsum of body is whitish yellow. By contrast, L. variabilis workers are smaller (HW: 0.75–1.08, PW: 0.60–0.91) and have a shorter antennal scape; a much longer petiolar node in lateral view (LNI: 91–105) that is narrower with clearly laterally pinched anterior portion in dorsal view; hairs on body dorsum yellowish-brown.

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

Habitat

Sandy beach.

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.

  • fasika. Leptogenys fasika Rakotonirina & Fisher, 2014: 48, figs. 28B, 30C, 31A, 64, 77 (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

(9 specimens). HW: 1.20–1.31, HL: 1.64–1.76, CI: 73–75, SL: 1.63–1.81, SI: 135–145, PW: 0.98–1.11, WL: 2.62–2.86, PNH: 0.80–0.95, PNL: 0.78–0.89, PNW: 0.70–0.77, DNI: 83–89, LNI: 100–106.

Head elongate, weakly broadened anteriorly, sides slightly diverging to front, meeting generally the straight posterior margin in convex line. In cephalic full-face view, eye with maximum diameter one-fourth the length of lateral margin of head, breaking outline of side of head. Antennal scape long, surpassing posterior cephalic margin by one third its length. Third antennal segment less than twice the length of second. Propodeal lobe lacking. In dorsal view, petiolar node massive, width decreasing gradually from back to front, anterior portion without clear lateral compression. In profile, node approximately as long as high; distance between anterior face of node and anterior sharp ridge for junction to propodeum distinct. Mandible smooth apart from scattered piligerous punctures; clypeus finely rugose or with scattered piligerous punctures. Dorsum of head and body generally smooth and shining; side of mesosoma and propodeal declivitous surface smooth and shiny. Body covered with dense whitish yellow standing hairs and pubescence. Integument black, with bluish reflection or opalescence; tip of gaster and distal part of appendages light brown to yellow.

Type Material

Holotype worker: Madagascar, Antsiranana, Forêt d’Orangea, 3.6 km 128° SE Remena, -12.25889, 49.37467, 90 m, littoral rainforest, ground nest, 22–28 Feb. 2001 (Fisher, Griswold et al.) collection code: BLF03224, specimen code: CASENT0416215 (California Academy of Sciences). Paratypes: 6 workers, with same data as holotype but specimen coded: CASENT0247203, CASENT0247242, CASENT0416216, CASENT0416217, CASENT0416218, CASENT0416220 (CASC, The Natural History Museum, Musee d'Histoire Naturelle Genève, Parc Botanique et Zoologique de Tsimbazaza).

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.