Strumigenys ninda

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Strumigenys ninda
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. ninda
Binomial name
Strumigenys ninda
(Bolton, 1983)

Pyramica ninda casent0102550 profile 1.jpg

Pyramica ninda casent0102550 dorsal 1.jpg

Specimen labels

Known from both natural and disturbed forest habitats, specimens have been found in litter samples.

Identification

Bolton (2000) - A member of the mandibularis complex in the Strumigenys emarginata group. Characters of mandibularis-complex. Cephalic dorsum without standing hairs. Clypeal dorsum not depressed anteromedially. Leading edge of scape rounded at subbasal angle, not right-angled. Basigastral costulae radiate from each side of a median costula-free area. Colour usually dark brown to blackish, only rarely lighter.

Bolton (1983) - The non-paratypic material from Ivory Coast has the alitrunk light brown and the gaster much darker brown, and has a single pair of stout erect hairs close to the base of the first gastral tergite. Such hairs are absent in the type-series but are frequently seen in Ghanaian and Nigerian specimens. The colour of the Ghana material is intermediate between that of the holotype and the lighter Ivory Coast samples.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Central African Republic, Chad, Gabon, Ghana, Ivory Coast.


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

Nomenclature

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

  • ninda. Smithistruma ninda Bolton, 1983: 284, fig. 2 (w.) CAMEROUN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 125. See also: Bolton, 2000: 304.

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 1.8, HL 0.52, HW 0.38, CI 73, ML 0.04, MI 8, SL 0.20, SI 53, PW 0.24, AL 0.48.

Anterior clypeal margin deeply concave medially, the concavity fringed with 4 pairs of scale-like hairs which project over the mandibles. Sides of clypeus distinctly convergent anteriorly, fringed by a continuous row of spatulate to spoon-shaped hairs which are curved anteriorly. Mandibles closed in holotype but from a paratype the dentition consisting of a high narrowly triangular basal lamella which is blunted apically and distinctly longer than the largest tooth. A minute diastema separates the basal lamella from the principal row of 5 relatively stout teeth, and these are followed distally by two slightly smaller teeth, 4 minute denticles and a small apical tooth. Dorsum of clypeus and cephalic dorsum without standing hairs of any description, with widely scattered and somewhat flattened minute appressed hairs which are directed anteriorly. Antennae with 4 segments. Scape narrow at base, bent and suddenly broadened in its basal quarter; the leading edge broadly convex at the bend and equipped with a row of freely projecting spatulate to spoon-shaped hairs, but the margin not projecting forward into a broad free lobe or strong angle. Maximum diameter of eye 0.13 X HW. Dorsum of head finely and densely reticulate-punctate, the sculpture becoming finer and more granular anteriorly. Clypeal dorsum granular to merely shagreened. Pronotum without a median longitudinal ridge or carina dorsally, not marginate laterally, the dorsum shallowly transversely convex and rounding broadly and evenly into the sides. With the alitrunk in profile the mesonotum forming a shallow convexity separate from that of the pronotum and propodeum, the metanotal groove extremely faintly indicated on the dorsum, not impressed in profile. Propodeal teeth short and triangular, the anterior half or slightly more of the ventral margin confluent with the broad infradental lamellae. Dorsal surfaces of alitrunk, petiole and first gastral tergite only with very sparse minute appressed pubescence, without standing hairs of any description. Posterior border of postpetiole with a single pair of feebly clavate standing hairs and similar hairs are present on the gastral tergites behind the first. Sides of alitrunk smooth, with a few feeble marginal punctures. Dorsal alitrunk smooth except for a narrow band of punctures just behind the anterior pronotal margin. The alitrunk frequently with a dull slightly rough appearance due to a superficial waxy deposit which when removed leaves the surface smooth and highly polished. Petiole and postpetiole unsculptured dorsally, the first gastral tergite unsculptured except for the basigastral costulae which arise on each side of a central clear area. Spongiform appendages of pedicel segments moderately developed in profile. In dorsal view the petiole node with a distinct spongiform strip posteriorly. Anterior margin of postpetiole with a strip which is about half the width of that on the petiole. Posterior margin of postpetiole with a spongiform strip which is broadest laterally and narrowed centrally. Base of first gastral tergite with a laminar strip which is broadest laterally where it is traversed by the basigastral costulae. Colour dark brown.

Paratypes. TL 1.7-1.8, HL 0.48-0.52, HW 0.37-0.38, CI 73-79, ML 0.03-0.05, MI 7-10, SL 0.18-0.20, SI 50-54, PW 0.22-0.24, AL 0.47-0.50 (9 measured).

As holotype, the maximum diameter of the eye 0.12-0.14 X HW.

Type Material

Holotype worker, Cameroun: Nkoemvon, 28.ix.1980, no. N 33 (D. Jackson) (The Natural History Museum). Paratypes. 6 workers with same data as holotype; 3 workers with same data but 6.x.1980, no. N 34; 1 worker with same data but l.viii.1980, no. N 18 (BMNH; Museum of Comparative Zoology; Musee d'Histoire Naturelle Genève; Ecole Nationale Superieure Agronomique).

References