Leptogenys corniculans

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Leptogenys corniculans
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Leptogenys
Species: L. corniculans
Binomial name
Leptogenys corniculans
Lattke, 2011

Leptogenys corniculans P.jpg

Leptogenys corniculans D.jpg

Specimen Label

An apparent endemic to the Atlantic Forests of Bahia, Brazil.

Identification

Lattke (2011) - Head rectangular in full-face view; with head in oblique anterolateral view, anterolateral cephalic margin appears flattened, eye straddling blunt crest along dorsal edge; median clypeal lobe narrow, propodeal teeth triangular and well developed; body black, legs brown.

This is an apparent endemic to the Atlantic Forests of Bahia, and quite easy to distinguish, especially on account of the well-developed propodeal teeth, which are almost as long as the second antennal segment. It would seem close to the pusilla group species on account of size, shape of the basal mandibular margin, mandibular setae, slender median clypeal lobe, small eye, transverse mesonotum and other characters, but it would be separated from the nearest pusilla group members by the Andes and the whole Amazon Basin. The well-developed propodeal spines are quite unlike any pusilla group species but even if this could be considered an autopomorphy of the species, the head shape is very unlike the pusilla species. In L. corniculans the head seems to have been partially flattened dorsoventrally close to the eye. If the head is seen in an oblique anterolateral view, a pinched aspect of the anterolateral cephalic margins becomes apparent with the eye straddling the formed blunt crest on its dorsal edge.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

The biology of Leptogenys corniculans is poorly known.

The Leptogenys genus page has more details about the general biology of ants in this genus, some of which is summarized in what follows. New World species have relatively small ranges, generally occur in humid forests and prey on isopods. Colonies may occur in high densities on a local scale, with up to 5 or 6 species present. Nest size tends to be small with just 20 or 30 individuals in a mature colony. Nests of most species may be found in rotten wood on the ground, usually within cavities in logs or large branches, and also beneath bark. Wood-soil and rock-soil interfaces are another common nesting location, as well as rock crevices, and a few species may nest directly in the soil. Reproduction is most commonly via ergatoid females and, in many species, may include egg-laying workers.

Castes

Queens and males are unknown.

Nomenclature

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

  • corniculans. Leptogenys corniculans Lattke, 2011: 190, fig. 33 (w.) BRAZIL.

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

Description

Worker

Metrics, holotype: HL 0.85; HW 0.53; ML 0.32; EL 0.10; SL 0.68; PW 0.50; WL 1.15; PH 0.47; PL 0.43; DPW 0.28 mm. CI 0.63; MI 0.59; OI 0.19; SI 1.28; LPI 1.08; DPI 0.65.

Head rectangular in full-face view, widest posterad of eyes, lateral cephalic margin mostly straight to weakly convex, posterior margin weakly concave, vertexal carina well developed, narrow, visible along all of posterior cephalic margin; median clypeal lobe longer than wide, apex pointed, without setae, with 2 preapical long hairs; lateral clypeal lobe narrow, weakly projecting anterad. Compound eye small, not more than 6 ommatidia in length, lens of ommatidia indistinct, eye placed laterally on head, distance from ocular midpoint to mandibular insertion greater than that from eye to mid-distance of lateral cephalic margin, eye in dorsal cephalic view weakly convex. Cephalic dorsum mostly smooth and shining except for scattered piligerous punctulae. Scape surpasses posterior cephalic border by under 2 × its apical width, antennal segments I–IV subequal in length, longer than wide, width of each segment more than one-half respective length. Scape mostly smooth and shining with scattered punctae, abundant mostly decumbent to subdecumbent pilosity, no appressed pubescence. Mandible elongate, basal and external margins subparallel, basal margin sinuate with row of 3 setae close to base; masticatory margin edentate except for apical tooth, mandibular dorsum mostly smooth and shining except for scattered piligerous punctae.

Mesosoma with mostly continuously broadly convex dorsal margin in lateral view, metanotal groove barely impressed; pronotal margin with brief, straight anterior margin and broadly convex dorsal margin; pronotum mostly smooth and shining with scattered punctae anterad, meso- and metapleuron colliculate, small rugulose area present posterad of propodeal spiracle; declivitous margin jagged anterad of tooth, propodeal tooth elongate and triangular. Mesometapleural suture distinct; metapleural-propodeal suture absent, brief ledge extends anterad of propodeal spiracle to same level of posteroventral mesopleural corner, mesopleuron subrectangular, propodeal spiracle broadly elliptical, facing posterolaterad. Width of mesonotum more than twice its length, metanotal groove distinct but finely impressed.

Petiolar node subquadrate in lateral view with vertical anterior margin half as long as posterior margin; dorsal margin convex, node highest posterad, posterior margin broadly convex. Subpetiolar process subquadrate, posterior margin longer than anterior margin. Node in dorsal view longer than wide, anterior margin broadly convex, width of anterior margin more than half the width of broadly convex posterior margin, lateral margin straight to weakly concave. Cross-section of node V-shaped, with straight lateral margins. Node mostly smooth and shining with weak colliculae lateroventrad and striae anteroventrad. Anterior margin of abdominal segment III broadly convex in lateral view, dorsal margin convex, constriction between abdominal segments III and IV well developed. Gaster mostly smooth and shining with scattered piligerous punctulae; pro- and metatibial apices without apical setae; mesotibia with single apical seta. Head and body without pubescence, only scattered pilosity. Body mostly black; mandibles, antennae, legs and gastral apex brown.

Type Material

Holotype worker. Brazil, Bahia, Laboratório de Mirmecologia CEPEC / CPDC, Ilhéus, 1987, J.H. Delabie leg. One worker deposited in CEPEC.

Etymology

The species name alludes to the slender propodeal teeth of the ant. It is derived from the Latin for horn shaped, corniculatus.

References