Leptogenys acutirostris

Leptogenys acutirostris
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Ponerinae
Tribe:	Ponerini
Genus:	Leptogenys
Species group:	saussurei
Species:	L. acutirostris
Binomial name
	Leptogenys acutirostris; Santschi, 1912 Specimen labels

Leptogenys acutirostris has been found foraging on the forest floor and in leaf litter. Generally nests in rotten logs.

Identification

A member of the saussurei species group. Rakotonirina and Fisher (2014) - Worker. Mandible elongate and robust, capable of closing tightly against clypeus; anterior clypeal margin medially projecting into triangular lobe; clypeus with sharp edge laterally and bordered with lamella anteriorly. Eye large, diameter markedly greater than maximum width of antennal scape. Dorsum of head and mesosoma distinctly sculptured; with mesosoma in dorsal view, metanotal groove distinctly visible. In dorsal view, posterior margin of petiolar node straight not medially emarginate; in profile posterolateral margin without small tooth, but blunt angle.

Leptogenys acutirostris is very similar to Leptogenys saussurei and Leptogenys lohahela due to the presence of a metanotal groove, but the excised posterior margin of the petiolar node of L. saussurei renders it distinguishable from L. acutirostris. Leptogeenys acutirostris can be separated from Leptogenys lohahela by its larger size and the presence of a blunt angle on the posterolateral margin of the node. In L. lohahela, body size is smaller and a sharp denticle is present on the posterolateral margin of the petiolar node.

Keys including this Species

Key to Malagasy Leptogenys

Distribution

Endemic to Madagascar, Leptogenys acutirostris is found in the lowland rainforest in the northeast of the island. Its range is between the PN Marojejy in the north and RS Ambatovaky in the South.

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of MalLeptogenys 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


.	Owned by Museum of Comparative Zoology.

Images from AntWeb


Holotype of Leptogenys acutirostris. Worker. Specimen code casent0101130. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by NHMB, Basel, Switzerland.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

acutirostris. Leptogenys saussurei st. acutirostris Santschi, 1912b: 150 (w.) MADAGASCAR. Raised to species: Bolton, 1975a: 297.

Description

Worker

Rakotonirina and Fisher (2014) - (9 specimens). HW: 1.75–1.92, HL: 2.31–2.85, CI: 67–78, SL: 2.24–2.42, SI: 122–130, PW: 1.50–1.62, WL: 3.68–3.98, PNH: 1.29–1.44, PNL: 1.21–1.34, PNW: 1.07–1.23, DNI: 85–93, LNI: 104–111.

Head rectangular, lateral border slightly convex at level of eyes. Clypeus with large triangular median lobe, bordered with semi-translucent lamella, not bidentate anteriorly; lateral edge continuous and sharp. Translucent lamella on mandibular inner margin forming two close preapical teeth or blunt angles before reaching more distant, sharp apical tooth. In profile, mesopleural sulcus indistinct. With mesosoma in dorsal view, metanotal groove distinctly visible. In dorsal view, petiolar node elongate, posterior margin straight, not medially excised; in profile posterior margin without small teeth at mid-height, but with blunt angle. Head dorsum in front of level of anterior margin of eye longitudinally rugose, but densely punctate between level of anterior and posterior of ocular margin; posteriorly punctures become larger and scattered, spaces between them smooth. Mandible with fine longitudinal striation near base and sparsely punctuate towards apex. Mesosoma and petiolar node with interspersed punctures, the space between them are smooth and shining; sides may be faintly striate or reticulate-rugose. Upper level of propodeal declivity generally smooth and with transeverse striation or rugulation at level of propodeal lobe. Gaster generally smooth. Color with bluish reflection.

Type Material

Rakotonirina and Fisher (2014) - Holotype worker, Madagascar (Le Moult) (Naturhistorisches Museum, Basel) AntWeb specimen code: CASENT0101130 [examined].

References

Bolton, B. 1975a. A revision of the ant genus Leptogenys Roger (Hymenoptera: Formicidae) in the Ethiopian region with a review of the Malagasy species. Bull. Br. Mus. (Nat. Hist.) Entomol. 31: 235-305 (page 297, Raised to species)
Rakotonirina, J.C. & Fisher, B.L. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836, 1-163.
Santschi, F. 1912b. Fourmis d'Afrique et de Madagascar. Ann. Soc. Entomol. Belg. 56: 150-167 (page 150, worker described)

References based on Global Ant Biodiversity Informatics

Bolton B. 1975. A revision of the ant genus Leptogenys Roger (Hymenoptera: Formicidae) in the Ethiopian region with a review of the Malagasy species. Bulletin of the British Museum (Natural History). Entomology 31: 235-305.
Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
Rakotonirina J. C., and B. L. Fisher. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836 (1): 001163.
Santschi F. 1912. Fourmis d'Afrique et de Madagascar. Annales de la Société Entomologique de Belgique 56: 150-167.
Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. IX. A synonymic list of the ants of the Malagasy region. Bulletin of the American Museum of Natural History 45: 1005-1055