Strumigenys korahyla

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

Strumigenys korahyla casent0900625 p 1 high.jpg

Strumigenys korahyla casent0900625 d 1 high.jpg

Specimen Labels

Known from a number of wet forest habitats. All of the specimens have been found in litter samples.

Identification

Bolton (1983, 2000) - A member of the havilandi complex in the Strumigenys arnoldi-group. Among the species of the group with small to minute eyes, lack of a preocular notch and ventral preocular impression, and scale-like cephalic ground-pilosity, only two species have elongate mandibles and scapes.

Apart from this korahyla is distinguished by its complete preapical dentition of 2 teeth on each mandible, lack of intercalary or adventitious teeth in the mandibular apical fork, lack of pronotal flagellate hairs at the humeri, slender antennal scapes and hairs on the leading edges of the scapes which are much smaller than those on the upper scrobe margins.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Gabon, Ghana, Kenya, Uganda.


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.

  • korahyla. Strumigenys korahyla Bolton, 1983: 376, fig. 64 (w.) CAMEROUN. See also: Bolton, 2000: 594.

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 2.3, HL 0.62, HW 0.44, CI 71, ML 0.30, MI 48, SL 0.36, SI 82, PW 0.29, AL 0.60.

Mandibles slender and moderately long, the blades broadening slightly from base to apex in full-face view, not bowed outwards. Apical fork of each mandible of 2 spiniform teeth, without intercalary teeth or denticles. Preapical armament of 2 teeth on each mandible, the proximal tooth about one-third longer than the distal and the distance separating their bases equal to or slightly greater than the length of the distal pre apical tooth. Upper scrobe margins bordered by a broad translucent rim or flange, the eyes not visible in full-face view. Eyes very small, with only 4-5 ommatidia, their maximum diameter distinctly less than the maximum width of the scape. Preocular notch absent, the ventral surface of the head without a preocular groove or impression on each side. Antennal scapes long and slender, approximately straight, very narrow in the basal eighth then with the anterior margin suddenly broadened. Beyond this the scape evenly tapering towards the apex. Leading edges of scapes with a series of small apically curved spoon-shaped hairs which are very obviously much smaller than those on the upper scrobe margins. Dorsum of head from the posterior clypeal margin to the midlength with large anteriorly curved shallowly spoon-shaped hairs which appear scale-like in full-face view. Similar but even larger hairs are present fringing the upper scrobe margins. Behind the midlength of the head the hairs of the cephalic ground-pilosity are much smaller and contrast with the larger anterior hairs. Dorsum of head with a transverse row of 4 clavate standing hairs close to the occipital margin, and with a pair of similar but smaller hairs close to the highest point of the vertex (this abraded in the holotype but present in the paratypes). Dorsum of head densely punctate, the walls of the punctures aligned in places on the occipital lobes and showing as fine rugulae. Pronotal humeri hairless. Mesonotum with a single pair of clavate hairs. Metanotal groove represented by a faint line across the dorsum, extremely weakly impressed in profile. Mesonotum slightly depressed behind the level of the hairs, the base of the declivous portion forming a shallow transverse impression. Propodeal teeth triangular and acute, subtended by narrow infradental lamellae. Sides of pronotum sculptured, remainder of sides of alitrunk smooth except for weak peripheral punctures. Pronotal dorsum longitudinally rugulose, the remainder of the dorsal alitrunk reticulate-punctate. Dorsum of petiole node reticulate-punctate, the postpetiole smooth. Spongiform appendages of pedicel segments moderately developed. In profile the petiole with a straight ventral strip and small lateral appendages. Postpetiole with a small lateral spongiform lobe and a slightly larger ventral lobe, the latter, however, slightly smaller than the exposed area of the postpetiolar disc in profile. In dorsal view the postpetiolar disc about 1.5 X broader than the petiole node. Basigastral costulae short and widely spaced, but sharply defined. Dorsal surfaces of petiole, postpetiole and gaster with stout clavate hairs. Colour brownish yellow.

Paratypes. TL 2.2-2.3, HL 0.61-0.64, HW 0.41-0.43, CI 67, ML 0.30-0.32, MI 49-50, SL 0.35-0.36, SI 84-85, PW 0.27-0.28, AL 0.58-0.60 (2 measured). As holotype.

Type Material

Holotype worker, Cameroun: nr Yaounde, series MT (G. Terron) (Ecole Nationale Superieure Agronomique). Paratypes. 2 workers with same data as holotype but one series OV, the other series EP (ENSA; The Natural History Museum).

References