Strumigenys nambao

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

Strumigenys nambao casent0005609 profile 1.jpg

Strumigenys nambao casent0005609 dorsal 1.jpg

Specimen labels

The holotype was collected in a rainforest litter sample.

Identification

Bolton (2000) - A member of the lysis complex in the Strumigenys arnoldi-group. S. nambao forms a close species pair with Strumigenys norax within the lysis-complex. Characters isolating nambao are discussed under Strumigenys norax.

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.

  • nambao. Strumigenys nambao Fisher, in Bolton, 2000: 624, fig. 395 (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 2.8, HL 0.69, HW 0.56, CI 82, ML 0.38, MI 55, SL 0.46, SI 81, PW 0.32, AL 0.7l. Characters of lysis-complex. Each mandible with 2 preapical teeth, situated in the apical third; proximal preapical tooth much longer than distal. Upper scrobe margin without a projecting lamellate rim throughout its length; scrobe margin weakly marginate to rounded above vertical preocular groove on side of head. Eye small, convex and plainly visible in full-face view; maximum diameter of eye less than maximum width of scape. Scape short, more or less straight, widest in the midsection; hairs on leading edge fine, slightly thickened apically. Cephalic dorsum densely clothed with short curved narrowly clavate ground-pilosity; upper scrobe margin fringed with appressed clavate hairs. Cephalic dorsum with 6 stout standing hairs arranged in a transverse row close to the occipital margin; 3 (occasionally 2 or 4) pairs of stiff erect hairs posteriorly on dorsolateral margin, and 1 pair on vertex. Pronotal humeral hair filiform, stiffly projecting; humeral angles rounded. Anterior margin of mesonotum with 1 pair of stout filiform hairs, situated on anterior margin. Propodeum with one pairs of short, fine, posteriorly curved hairs at anterior base of propodeal spines. Alitrunk dorsum with inconspicuous, short curved fine ground-pilosity. Dorsum of alitrunk in outline convex anteriorly, posterior alitrunk more or less flat to gradually sloping down to declivity. Metanotal groove not or minutely impressed. Anterior mesonotum without a minute carina above the mesothoracic spiracle. Propodeal spines narrowly triangular, almost spiniform; lamella on declivity a very narrow strip. Alitrunk dorsum reticulate punctate. Side of pronotum and pleurae partially smooth with peripheral punctulate sculpture. Petiole node in dorsal view about as broad as long. Postpetiole disc reticulate-punctate. In profile ventral spongiform tissue of petiolar peduncle a narrow strip along the base of the peduncle, depth of strip less than the width of the mandible blade when viewed in profile. Ventral spongiform lobe of postpetiole moderately developed. Basigastral costulae short and distinct. Dorsal surface of petiole with one pair of anteriorly projecting stout, narrowly clavate hairs; postpetiole and gaster with stout standing hairs which are thickened apically. Colour light yellowish brown to medium brown.

Paratype. TL 2.6-2.8, HL 0.64-0.68, HW 0.51-0.55, CI 79-81, ML 0.35-0.39, MI 55-57, SL 0.42-0.49, SI 81-90, PW 0.29-0.33, AL 0.64-0.70 (4 measured). As holotype.

Measurements of this material extend the range shown by the type-series: HL 0.63-0.69, HW 0.52-0.57, CI 81-83, ML 0.35-0.38, MI 55-56, SL 0.42-0.47, SI 81-84 (3 measured).

Type Material

Holotype worker, Madagascar: Provo Antsiranana, R.S. Manongarivo, 10.8 km. 229° SW Antanambao, 400 m., 13°57.7'S, 48°26.0'E, 8.xi.1998, sifted litter (leaf mold, rotten wood), rainforest #1996 (1)-1 (B. L. Fisher) (Museum of Comparative Zoology).

Paratypes. 20 workers with same data as holotype but coded (2)-1, (8)-5, (14)-1, (30)-2, (44)-1, (44)-3, (44)-5, (46)-3, (50)-1, (50)-5; (56)-2, (75)-2 (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 666, worker described)