Leptogenys coerulescens

Leptogenys coerulescens
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Ponerinae
Tribe:	Ponerini
Genus:	Leptogenys
Species group:	attenuata
Species:	L. coerulescens
Binomial name
	Leptogenys coerulescens; Emery, 1895 Specimen labels

Collection data indicate that this species forages on the forest floor and on low vegetation as well as through the leaf litter. Leptogenys coerulescens nests mainly under the ground and in rotten logs, but occasionally in rotten tree stumps, under rootmat ground layers or under rocks.

Identification

A member of the attenuata species group. Rakotonirina and Fisher (2014) - One of the largest species; third antennal segment less than twice the length of second segment; in full-face view, eye not breaking outline of side of head; mandible punctulate, interspersed with short, fine longitudinal striation or dense and fine elongate punctures.

One of the largest species (HW: 1.52–1.74, PW: 1.23–1.46) in the attenuata group, L. coerulescens can be recognized by its size, the location of the eye and the presence of punctures with fine striation on the mandible. Two extremes characterize the variation within this species. One extreme is represented by specimens sampled from the dry forest habitats. The dorsal outline of the propodeum in profile is slightly convex and the petiole in dorsal view is shorter and anteriorly more slender. This variant is most similar to the type specimens.The second extreme, collected from rainforest areas, is characterized by a straight propodeal dorsum, and a more elongate and anteriorly robust petiolar node. Across the range of this species, both the shape of the propodeum and the form of the petiolar node show continuous variation and transitional states. Phenotypic variants within this species occur along ecological gradients across the forest habitats of Daraina in the northeast of Madagascar and in the disjunct forests of Ambilanivy, Anabohazo, Manongarivo and Ankarana in the northwest of the island. These results illustrate the importance of recognizing habitats that harbor distinct allopatric populations and maximizing the protection of contiguous environmental gradients to maintain the viability of morphologically diverse populations.

Keys including this Species

Key to Malagasy Leptogenys

Distribution

Northern Madagascar.

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.

Habitat

Although the distribution of L. coerulescens is limited to northern Madagascar, this species occupies a wide range of habitats including lowland and montane rainforests as well as littoral and dry forest habitats adjacent to these mesic forests.

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

Images from AntWeb


Paralectotype of Leptogenys coerulescens. Worker. Specimen code casent0102025. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MSNG, Genoa, Italy.


Paralectotype of Leptogenys coerulescens. Worker. Specimen code casent0102026. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MSNG, Genoa, Italy.


Lectotype of Leptogenys coerulescens. Worker. Specimen code casent0102027. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by MSNG, Genoa, Italy.


Worker. Specimen code casent0102413. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by NHMUK, London, UK.

Nomenclature

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

coerulescens. Leptogenys coerulescens Emery, 1895f: 339 (w.) MADAGASCAR. See also: Bolton, 1975a: 296.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Rakotonirina and Fisher (2014) - (25 specimens). HW: 1.52–1.74, HL: 1.92–2.15, CI: 76–84, SL: 2.33–2.71, SI: 145–163, PW: 1.23–1.46, WL: 3.22–3.73, PNH: 1.09–1.25, PNL: 0.92–1.13, PNW: 0.86–1.06, DNI: 84–105, LNI: 100–121.

Head more or less elongate, width greatest at about mid-length immediately posterior to eye; sides distinctly convex; posterior margin straight. In full-face view, eye not breaking outline of side of head; size larger, maximum diameter roughly one-fourth the length of side of head. Antennal scape long, distal half surpassing posterior margin of head. Third antennal segment less than twice the length of second. With mesosoma in profile propodeal dorsum slightly convex; propodeal lobe absent or with blunt angle; opening of propodeal spiracle circular. In dorsal view, petiolar node more or less elongate but slightly broader posteriorly than anteriorly. With petiole in profile, node about as high as long. Mandible finely punctate, with fine and short longitudinal striation or dense elongate punctures. Declivitous surface most often smooth, rarely transversely rugulose or with striation. Remainder of body dorsum smooth and shining. Dorsum of head, mesosoma, petiolar node and gaster covered with whitish-yellow, standing short hairs and pubescence. Color black with bluish reflection or opalescence, apical portion of appendages reddish brown or ferruginous red.

Queen

Rakotonirina and Fisher (2014) - (3 specimens): HW: 1.52–1.64, HL: 1.90–1.97, CI: 80–84, SL: 2.14–2.41, SI: 141–147, PW: 1.21–1.31, WL: 3.08–3.18, PNH: 1.05–1.17, PNL: 0.75–0.82, PNW: 1.01–1.06, DNI: 124–146, LNI: 134–153. As in worker but with broader head and shorter antennal scape. No trace of ocelli. Mesosoma slightly rounded and much shorter, without wing sclerites. Hairs and pubescence more slender and abundant.

Type Material

Rakotonirina and Fisher (2014) - Lectotype worker, present designation, Madagascar, Diego-Suarez (Alluaud, 1893), AntWeb CASENT0102027 top worker specimen of two workers on a pin (Museo Civico di Storia Naturale, Genoa). Paralectotype workers, with same data but specimen coded as CASENT0102026 and CASENT0102025 (MSNG) [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 296, see also)
Emery, C. 1895g. Mission scientifique de M. Ch. Alluaud dans le territoire de Diego-Suarez (Madagascar-nord) (Avril-août 1893). Formicides. Ann. Soc. Entomol. Belg. 39: 336-345 (page 339, worker described)
Rakotonirina, J.C. & Fisher, B.L. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836, 1-163.

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.
Emery C. 1895. Mission scientifique de M. Ch. Alluaud dans le territoire de Diego-Suarez (Madagascar-nord) (Avril-août 1893). Formicides. Annales de la Société Entomologique de Belgique 39: 336-345.
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.
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