Strumigenys dextra

Strumigenys dextra
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. dextra
Binomial name
	Strumigenys dextra; Brown, 1954 Specimen Labels

Known from more than twenty collections, all from wet forest litter samples.

Identification

Bolton (1983, 2000) - A member of the dextra complex in the Strumigenys arnoldi-group. In the dextra-complex three other species beside dextra have lost the distal preapical tooth of the left mandible, Strumigenys irrorata, Strumigenys katapelta and Strumigenys paranax. The first of these is distinguished from dextra and the rest by also lacking the distal preapical tooth on the right mandible so that both blades have only a single preapical tooth. S. katapelta is the only species of the four which possesses intercalary teeth between the spiniform teeth of the apical forks, and paranax is easily separated from dextra by its possession of a straight stout projecting hair at the humeri where dextra has a long fine flagellate hair present.

Elsewhere in the genus Strumigenys bernardi, Strumigenys sarissa and Strumigenys londianensis also have only a single preapical tooth on the left mandible, but in all of these there is a large and very distinct preocular notch present.

Keys including this Species

Key to Afrotropical Strumigenys

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 2.06889° to -2.283333333°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Afrotropical Region: Angola, Cameroun, Central African Republic, Democratic Republic of Congo, Equatorial Guinea, Gabon, Kenya, Uganda (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

Nomenclature

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

dextra. Strumigenys dextra Brown, 1954k: 27 (w.) UGANDA. See also: Bolton, 1983: 368; Bolton, 2000: 592.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (1983) - TL 1.6-1.8, HL 0.41-0.47, HW 0.31-0.34, CI 71-77, ML 0.16-0.19, MI 38-42, SL 0.22-0.25, SI 68-75, PW 0.21-0.24, AL 0.40-0.48 (10 measured).

Mandibles relatively slender, shallowly and evenly curved along the outer margins. Apical fork of each mandible of two teeth, without intercalary teeth or denticles. Preapical armament of left mandible of a single tooth, the right mandible with 2 preapical teeth. Upper scrobe margins concealing the eyes in full-face view. Eyes small, with only 3--5 ommatidia, the maximum diameter of the eye distinctly less than the maximum width of the scape. Pre ocular notch absent, the ventral surface of the head without a transverse preocular groove or impression on each side. Antennal scape shallowly curved basally, somewhat expanded in the median third, the leading edges with a row of apically curved narrow spoon-shaped hairs. Ground-pilosity of cephalic dorsum reduced, consisting of a few inconspicuous small spatulate haits. Upper scrobe margins with a triple row of larger narrowly spoon-shaped hairs. Dorsum of head with 6 standing hairs arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Pronotal humeri each with a single fine flagellate hair. Mesonotum with a single pair of standing stout hairs which are clavate apically. Ground-pilosity of dorsal alitrunk of inconspicuous narrowly spatulate hairs like those on dorsum of head. In profile the mesonotum feebly or not depressed behind the level of the standing hairs. Propodeal teeth short and subtended by moderately developed infradental lamellae. Sides of pronotum almost smooth to weakly longitudinally rugulose. Pleurae and sides of propodeum smooth except for weak peripheral punctures. Dorsal alitrunk with sparse widely separated longitudinal rugulae on pronotum, the spaces between the rugulae smooth or with vestiges of superficial sculpture. Remainder of dorsal alitrunk reticulate-punctate. Dorsum of petiole node punctate, the postpetiole smooth. Spongiform appendages of pedicel segments only moderately developed. In profile the petiole with a narrow ventral strip and small lateral appendage on the node. Ventral spongiform lobe of postpetiole equal to or Slightly smaller than the exposed area of the postpetiolar disc in profile. Basigastral costulae short but sharply defined, arising across the width of the first tergite basally, not radiating on each side of a broad central clear area. Dorsal surfaces of petiole, postpetiole and gaster with stout standing hairs which are narrowly clavate apically. Colour dull yellow.

Type Material

Bolton (1983) - Holotype and paratype workers, UGANDA: 5 miles (8 km) N. Kamapala, Kawanda Exp. Sta., 15.ii.1949, no. SS 30, soil sample under elephant grass (G. Salt) (Museum of Comparative Zoology) [examined].

References

Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology. 46:267-416. (page 368, redescription of worker)
Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 592, redescription of worker)
Brown, W. L., Jr. 1954k. The ant genus Strumigenys Fred. Smith in the Ethiopian and Malagasy regions. Bulletin of the Museum of Comparative Zoology 112: 1-34 PDf (page 27, worker described)

References based on Global Ant Biodiversity Informatics

Bolton B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology 46: 267-416.
Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
Brown W. L. Jr. 1954. The ant genus Strumigenys Fred. Smith in the Ethiopian and Malagasy regions. Bulletin of the Museum of Comparative Zoology 112: 1-34.
Fisher B. L. 2004. Diversity patterns of ants (Hymenoptera: Formicidae) along an elevational gradient on Monts Doudou in southwestern Gabon. Memoirs of the California Academy of Sciences 28: 269-286.
Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
IZIKO South Africa Museum Collection