Strumigenys livens

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

Strumigenys livens casent0005577 profile 1.jpg

Strumigenys livens casent0005577 dorsal 1.jpg

Specimen labels

Known from montane forest litter-samples.

Identification

Bolton (2000) - A member of the scotti complex in the Strumigenys scotti-group. S. livens is closely related to Strumigenys lexex; see under the latter for discussion of distinguishing characters.

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

Nomenclature

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

  • livens. Strumigenys livens Fisher, in Bolton, 2000: 688 (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 0.57, HW 0.45, CI 79, ML 0.31, MI 54, SL 0.37, SI 83, PW 0.27, AL 0.60. Characters of scotti-complex. Mandibles in full-face view with outer margins very shallowly and evenly convex, width approximately constant from the level of the proximal preapical tooth to near the base. Upper scrobe margin shallowly concave immediately behind the frontal lobe, posteriorly evenly and shallowly convex in full-face view, not bordered by a rim or flange except immediately behind the frontal lobes, the eyes visible. Maximum diameter of eye approximately equal to or slightly greater than maximum width of scape, with 5-6 ommatidia in longest row. Scape subcylindrical, curved and narrowed near the base; hairs on leading edge of scape slender, slightly flattened or spoon-shaped apically. Cephalic dorsum densely clothed with short, slender filiform ground-pilosity. The upper scrobe margin fringed with hairs which are more sharply curved but otherwise similar in shape and size as those on the leading edge of the scape. 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; humeral angles bluntly marginate. Mesonotum with a pair of standing filiform to narrowly remiform hairs on anterior margin, a shorter more posteriorly situated pair of erect filiform hairs, and with an even shorter pair of erect fine hairs on posterior margin. Propodeum with one pair of short, fine, posteriorly curved hairs immediately anterior of propodeal spines. Dorsal alitrunk with inconspicuous, sparse, appressed fine ground pilosity.

Dorsum of alitrunk in outline convex anteriorly and posteriorly gently sloping to the declivity. Metanotal groove shallowly impressed. Anterior mesonotum with a thin carina above a narrow mesothoracic spiracle; mesopleural gland set in a small circular notch. Propodeal tooth triangular, pointed apically, and subtended by a very narrow lamella. Pronotal dorsum longitudinally rugulose-striolate; mesonotal and propodeal dorsa reticulate-punctate. Sides of alitrunk glassy smooth. Postpetiole disc more or less smooth, faintly longitudinally striolate. In profile ventral spongiform tissue of petiolar peduncle a narrow irregular strip along the base of the peduncle, usually widest in the posterior third, the deepest point in the anterior two-thirds less than or approximately equal to the maximum width of eye. Ventral spongiform tissue of postpetiole moderately developed. Basigastral costulae short and sharply defined, radiating on each side of a broad central clear area. Petiolar disc with two pairs of filiform hairs, postpetiole with three pairs of erects hairs of similar length, dorsal surface of gaster with standing filiform hairs which are slightly thickened apically. Colour light brown.

Paratypes. TL 2.2-2.6, HL 0.51-0.60, HW 0.42-0.47, CI 77-82, ML 0.28-0.33, MI 53-56, SL 0.35-0.40, SI 82-86, PW 0.23-0.30, AL 0.56-0.65 (6 measured). As holotype.

Type Material

Holotype worker, Madagascar: 40 km. S Ambalavao, Res. Andringitra, 22°13'S, 46°58'E, 1275 m., 15.x.1993, sifted litter (leaf mold rotten wood), montane rainforest #793 (4)-9 (B. L. Fisher) (Museum of Comparative Zoology).

Paratypes. 7 workers and 2 queens (dealate) with same data as holotype but coded (7)-7, (8)-10, (9)-10, (10)-11, (20)-9, (34)-9 (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 688, worker described)