Strumigenys langrandi

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Strumigenys langrandi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. langrandi
Binomial name
Strumigenys langrandi
Fisher, 2000

Strumigenys langrandi casent0005566 profile 1.jpg

Strumigenys langrandi casent0005566 dorsal 1.jpg

Specimen labels

Known from montane forest litter-sampling.

Identification

Bolton (2000) - A member of the scotti complex in the Strumigenys scotti-group. S. langrandi, Strumigenys odacon and Strumigenys ravola are distinguished from other species in scotti-complex by having mesonotum with two pairs of erect hairs, and ventral spongiform tissue of petiolar peduncle a well developed curtain that is continuous along the base of the peduncle. S. langrandi is separated from the other two by the absence of short hairs on the anterior half of first gastral sternite. S. ravola is distinguished by the presence of dense reticulate-punctuate sculpture on pronotum, while in odacon and ravola, the pronotal dorsum is longitudinally striolate on a smooth surface or with superficial punctulate sculpture.

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

Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species.

Castes

Worker

Queen

Nomenclature

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

  • langrandi. Strumigenys langrandi Fisher, in Bolton, 2000: 686 (w.q.) MADAGASCAR.

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

Description

Worker

Holotype. TL 2.4, HL 0.58, HW 0.44, CI 76, ML 0.27, MI 47, SL 0.33, SI 76, PW 0.29, AL 0.59. Characters of scotti-complex. Mandibles in full-face view short, with outer margins shallowly and evenly convex and sharply narrowed at base. Upper scrobe margin evenly and shallowly convex in full-face view, not bordered by a rim or flange, the eyes visible. Maximum diameter of eye slightly greater than maximum width of scape, with 4-5 ommatidia in longest row. Scape subcylindrical, curved and narrowed near base; hairs on leading edge slender filiform to narrowly spatulate. Cephalic dorsum densely clothed with erect to suberect filiform ground-pilosity. Upper scrobe margins fringed with spatulate hairs; in full-face view hairs on upper scrobe margin decumbent and sharply bent at basal third, not projecting well beyond the scrobe margin. Cephalic dorsum with 6 standing filiform hairs arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Pronotal humeral hair flagellate. Mesonotum with two pairs of standing filiform to narrowly remiform hairs: a pair on anterior margin, and a second pair situated on central lateral margin. Propodeum with one pair of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Ground-pilosity on dorsal alitrunk inconspicuous and more or less absent, consisting of short suberect to decumbent fine filiform hairs. Dorsum of alitrunk in outline convex anteriorly and more or less flat to shallowly convex posteriorly. Metanotal groove without a conspicuous impression. Anterior mesonotum with a narrow carina above the mesothoracic spiracle; mesopleural gland set in a conspicuous circular notch. Propodeal tooth triangular, lamellate, pointed apically, and subtended by a narrow lamella. Pronotal dorsum longitudinally striolate; mesonotal and propodeal dorsa reticulate-punctate. Sides of pronotum superficially longitudinally striolate. Pleurae and side of propodeum glassy smooth and peripherally punctulate. Postpetiole disc more or less smooth. In profile ventral spongiform tissue of petiolar peduncle a well developed curtain that is continuous along the base of the peduncle. Ventral spongiform tissue of postpetiole well developed. Basigastral costulae well developed and sharply defined, radiating on each side of a broad central clear area. Dorsal surface of petiole, postpetiole, and gaster with standing filiform hairs which are slightly thickened apically. Anterior half of first gastral sternite without erect hairs. Colour light brown.

Paratype. TL 2.4-2.6, HL 0.56-0.59, HW 0.44-0.45, CI 76-80, ML 0.27-0.28, MI 46-49, SL 0.34-0.35, SI 77-78, PW 0.28-0.30, AL 0.60-0.64 (3 measured). One paratype without proximal preapical tooth on left mandible, otherwise as holotype.

Type Material

Holotype worker, Madagascar: Stn Forestiere Manjakatompo, 19°21'S, 47°10'E, 1600 m., 20.ii.1993, sifted litter (leaf mold, rotten wood), montane rainforest, #11971-11 (P. S. Ward) (Museum of Comparative Zoology).

Paratypes. 3 worker and 1 queen (alate) with same data as holotype (The Natural History Museum, South African Museum).

References

  • Fisher, B.L. 2000. The Malagasy fauna of Strumigenys. Pp. 612-696 in: Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 686, worker described)