Leptogenys barimaso

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

Leptogenys barimaso casent0053712 p 1 high.jpg

Leptogenys barimaso casent0053712 d 1 high.jpg

Specimen Labels

A few localities in the northeast of Madagascar harbor L. barimaso. The species is known to occupy not only the natural littoral and humid forests, but also the disturbed and fragmented forest habitats in the region. Leptogenys barimaso forages on the ground and in leaf litter, but it also hunts on lower vegetation. Its nests are mainly in rotten logs and rarely in rotten branches on the forest floor.

Identification

A member of the imerinensis complex of the incisa species group. Rakotonirina and Fisher (2014) - Worker. Small peg-like setae present from near anterior border of narrowly semi-circular anteromedial clypeal lobe; mandible with inner margin evenly and slightly concave; antennal scape long (SI> 130), more than apical third surpassing posterior cephalic margin; eye breaking outline of sides of head; dorsum of head and body with standing hairs longer than maximum diameter of eye; posterior margin of petiolar node without constriction immediately above posteroventral angle.

Leptogenys barimaso is similar to Leptogenys chrislaini and Leptogenys lavavava, but in L. barimaso the inner margin of the mandible is evenly concave, the anteromedian portion of the clypeus is narrow with a rounded lobe, and abdominal tergites III and IV have long standing hairs whose length is greater than the maximum diameter of the eye. The abrupt projection of the anterior margin of the clypeus into a narrowly angulate lobe, the subquadrate head, the strongly curved basal portion of the mandible, and the shorter hairs on abdominal tergites III and IV render L. chrislaini separable from L. barimaso. In L. lavavava, the median portion of clypeus is projecting anteriorly into a toothlike spine and the basal portion of mandible is remarkably curved, extending laterally beyond the widest level of the sides of the head.

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

Worker

Nomenclature

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

  • barimaso. Leptogenys barimaso Rakotonirina & Fisher, 2014: 79, figs. 55B, 58C, 59A, 97, 113 (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

(7 specimens). HW: 1.16–1.36, HL: 1.45–1.65, CI: 80–84, SL: 1.66–2.00, SI: 133–147, PW: 0.93–1.07, WL: 2.41–2.87, PNH: 0.80–0.94, PNL: 0.82–1.00, PNW: 0.75–0.93, DNI: 88–96, LNI: 91–102.

In full-face view, head elongate and broader in front than behind; side noticeably convex and diverging anteriorly throughout length. Eye large and distinctly convex, breaking line of lateral cephalic border. Antennal scape markedly long, with more than one third its length extending beyond posterior cephalic margin. Anterior clypeal margin extending suddenly into a narrowly rounded median lobe which is bordered by a yellow-orange lamella. Mandible long and narrow, inner margin broadly concave and leaving a gap between clypeus and blades when closed; basal groove narrow. Preapical tooth or denticle may be present on each blade. In full-face view, hypostomal teeth not visible. Mesosoma in dorsal view, with impressed and transversely rugulose metanotal groove; in profile, overall shape short and high; posterolateral border of propodeum without toothlike lobe. In lateral view, petiolar node more or less elongate, dorsal outline of node convex and posterior margin inclined anteriorly; in dorsal view, node longer than broad. Constriction between abdominal segments III and IV distinct. Mandibular blade covered with interrupted short and fine striation and scattered punctures. Dorsum of head, mesosoma and petiolar node coarsely reticulate-rugose, with large punctures or foveae in between; some punctures widely spaced; declivitous surface transversely rugulose. Dorsum of head and body with long standing hairs longer than greatest diameter of eye; pubescence reduced. Color black to reddish-brown, with dark brown to lighter appendages.

Type Material

Holotype worker: Madagascar, Toamasina, Montagne d'Akirindro 7.6 km 341° NNW Ambinanitelo, -15.2883, 49.5483, 600 m, rainforest, ex rotten branch on ground, 17–21 Mar 2003 (Fisher, Griswold et al.), collection code: BLF08268, specimen code: CASENT0496058 (California Academy of Sciences). Paratypes: 5 workers with same data as holotype but specimen coded as: CASENT0496059, CASENT0496057, CASENT0247235, CASENT0247236, CASENT0247237 (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.