Leptogenys chrislaini

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

Leptogenys chrislaini casent0107500 p 1 high.jpg

Leptogenys chrislaini casent0107500 d 1 high.jpg

Specimen Labels

This species is known only from the littoral forest of Ambondrobe near Vohemar and the humid forest of Makirovana near Sambava in northeastern Madagascar. It forages in leaf litter and nests in rotten logs.

Identification

A member of the imerinensis complex of the incisa species group. Rakotonirina and Fisher (2014) - Worker. Median portion of clypeus abruptly projecting anteriorly into short, narrowly angulate lobe; small peg-like setae projecting anteriorly from near anterior margin of lobe; basal portion of mandible distinctly arched in full face view, but not extending laterally beyond cephalic outline; antennal scape relatively short; in full-face view, eye breaking lateral cephalic margin; head subquadrate; in lateral view, posterior border of petiolar node without constriction near its posteroventral angle.

Leptogenys chrislaini closely resembles Leptogenys barimaso but L. chrislaini can be separated by the abrupt projection of the anterior margin of the clypeus into a narrowly angulate lobe, the subquadrate head, and the strongly curved basal portion of the mandible. It can be confused with Leptogenys lavavava but the latter has an elongate head, spiniform anteromedial clypeal lobe, and broadly curved mandibular blades which extend laterally beyond the lateral cephalic margin. Populations of L. chrislaini from the two known localities show differences in some morphological characters. Worker specimens from Makirovana Forest are slightly larger and have longer antennal scapes than those from Ambondrobe.

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.

  • chrislaini. Leptogenys chrislaini Rakotonirina & Fisher, 2014: 81, figs. 48C, 58B, 59B, 98, 114 (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: 1.51–1.73, HL: 1.80–2.01, CI: 83–88, SL: 1.64–2.11, SI: 104–133, PW: 1.07–1.23, WL: 2.76–3.14, PNH: 0.88–0.99, PNL: 0.84–1.00, PNW: 0.84–0.93, DNI: 88–108, LNI: 92–111.

Head subquadrate, sides almost straight and weakly rounding to a slightly concave posterior margin. Eye large and slightly protruding, maximum diameter greater than widest part of scape. Antennal scape relatively short, usually less than a fourth of its apical portion attaining posterior cephalic margin. Clypeus anteriorly projecting into narrowly triangular median lobe, borderedby bluntly triangular subopaque lamella. Mandible elongate, strongly curved near base, but not extending laterally beyond lateral cephalic border; feebly concave to almost straight towards the apex; basal groove narrow; preapical tooth or denticle may be present near sharp apical tooth. In full-face view, hypostomal teeth short and bluntly triangular. With mesosoma in dorsal view, metanotal groove impressed and transversely striate; in lateral view, propodeum relatively high and short; posterior margin of propodeum with blunt angles at level of propodeal spiracle. Petiolar node roughly as high as broad in profile, with anteriorly sloped posterior margin; constriction absent near posteroventral angle of node; in dorsal view, petiolar node as long as broad or slightly longer than broad. Constriction between third and fourth abdominal segments feebly visible. Mandible basally striate; median portion smooth with faint striation and scattered piligerous pits; about apical third portion densely and finely striate. Head dorsum reticulate-rugose to densely and finely reticulate-rugose, interspersed with punctures which become larger and more widely spaced near posterior margin. Mesosoma and petiolar node densely and finely reticulate-rugose, with scattered punctures; pronotal punctures much smaller than those on rest of mesosoma; propodeal declivity with transverse rugulae. Gastral tergites one and two finely microreticulate and with shallow, elongate large punctures. Entire body covered with slender erect hairs and very abundant pubescence. Antennal scape with suberect hairs shorter than maximum diameter of scape. Black species, with reddish-brown appendages having lighter apices.

Type Material

Holotype worker: Madagascar, Antsiranana: Ambondrobe, 41.1 km 175° Vohemar, -13.7153, 50.1017, 10 m, littoral rainforest, ex rotten log, 30 Nov 2004 (B.L. Fisher), collection code: BLF11141, specimen code: CASENT0107500 (California Academy of Sciences). Paratypes: 5 workers with same data as holotype but specimen coded as: CASENT0247262, CASENT0247263, CASENT0247264, CASENT0247265, CASENT0247266 (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.