Strumigenys labaris

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

Known from rainforest and montane forest litter-samples.

Identification

Bolton (2000) - A member of the sphera complex in the Strumigenys arnoldi-group. S. labaris is most similar to Strumigenys admixta in the sphera-complex. In both species the upper scrobe margin has a distinct, broad lamellate rim or flange throughout its length. They are most easily distinguished by the shape of the postbuccal margin with head in ventral view. In labaris, the posterior and lateral margins of the postbuccal groove are rounded to bluntly marginate, and the posterolateral face of groove is more or less vertical or gently sloping, never concave. In admixta, the posterolateral and lateral margins of postbuccal groove have a lamellate rim and the posterolateral face of the groove is concave.

Keys including this Species

Key to Malagasy Strumigenys

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -13.998° to -14.75°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

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 Strumigenys 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.

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Castes

Worker

Images from AntWeb


Paratype of Strumigenys labaris. Worker. Specimen code casent0005565. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.


Worker. Specimen code casent0173614. Photographer April Nobile, uploaded by California Academy of Sciences.	Owned by CAS, San Francisco, CA, USA.

Nomenclature

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

labaris. Strumigenys labaris Fisher, in Bolton, 2000: 662 (w.) 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 3.4, HL 0.85, HW 0.75, CI 88, ML 0.43, MI 51, SL 0.56, SI 74, PW 0.41, AL 0.83. Characters of sphera-complex. Each mandible with 1 preapical tooth, distance from preapical tooth to apicodorsal tooth approximately equal to length of preapical tooth. Upper scrobe margin bordered by a projecting laminar rim or flange throughout its length, eyes partially visible in full-face view. Eye very small, convex, its maximum diameter distinctly less than maximum width scape. Scape narrowed near base, slightly expanded and flattened in basal third; hairs on leading edge narrowly spatulate. Cephalic dorsum clothed with curved narrowly spatulate ground-pilosity; upper scrobe margin with hairs that are similar in size and shape to those on the dorsum. Cephalic dorsum with 4 pairs of long standing narrowly remiform hairs arranged as follows: transverse row of 3 pairs close to the occipital margin and 1 pair of erect hairs on vertex. Pronotal humeral hair absent; humeral angles rounded, posterolateral margin of pronotum bluntly marginate. Anterior margin of mesonotum with 1 pair of stout standing hairs. Propodeal spines with 1 pair of fine short, posteriorly curved hairs near anterior base. Alitrunk dorsum with very short curved ground-pilosity and concentrated on promesonotum. Dorsum of alitrunk in outline convex anteriorly, posterior mesonotum sharply depressed, propodeum gradually sloping to declivity. Metanotal groove represented by a shallow impression. Propodeal spines short, triangular, posterior margin with a narrow spongiform strip; propodeal lamella absent. Alitrunk dorsum densely reticulate-punctate. Sides of pronotum with faint longitudinally striolate sculpture anteriorly. Pleurae mostly smooth and shiny with reticulate-punctate sculpture peripherally. Petiole node in dorsal view approximately as long as broad. Postpetiole disc with weak longitudinally striolate sculpture on a fine punctulate surface. In profile ventral spongiform tissue of petiolar peduncle a narrow curtain that is continuous along the base of the peduncle, depth of curtain is distinctly greater than maximum width of eye. Ventral spongiform lobe of postpetiole moderately developed. Basigastral costulae short and sharply defined. Dorsal surface of petiole, postpetiole, and gaster with stout standing remiform to narrowly spatulate hairs which are slightly thickened apically. Colour medium brown.

Paratype. TL 3.0-3.4, HL 0.78-0.86, HW 0.66-0.75, CI 84-89, ML 0.39-0.45, MI 49-54, SL 0.52-0.57, SI 74-80, PW 0.35-0.40, AL 0.73-0.84 (6 measured). As holotype.

Measurements of this material extend the range shown by the type-series: HL 0.70-0.80, HW 0.58-0.67, CI 83, ML 0.37-0.42, MI 52-55, SL 0.46-54, SI 78-84 (3 measured).

Type Material

Holotype worker, Madagascar: 11.0 km. WSW Befingotra, Res. Anjanaharibe-Sud, 14°45'S, 49°27'E, 1565 m., 16.xi.1994, sifted litter (leaf mold, rotten wood), montane rainforest #1232 (4)-5. (B. L. Fisher) (Museum of Comparative Zoology). Paratypes. 6 workers with same data as holotype but coded (31)-4, (40)-4 (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 662, worker described)

References based on Global Ant Biodiversity Informatics

Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
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.