Strumigenys pretoriae

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Strumigenys pretoriae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. pretoriae
Binomial name
Strumigenys pretoriae
Arnold, 1949

Strumigenys pretoriae casent0249038 p 1 high.jpg

Strumigenys pretoriae casent0249038 d 1 high.jpg

Specimen Labels

Brown (1954) reported the large eyes may be correlated with a epigaeic foraging habitats or even an arboreal existence. This conjecture was partly supported by the type being collected while beating vegetation for thrips. This ant has subsequently been collected in a grassland pitfall trap.

Identification

Bolton (2000) - A member of the pretoriae complex in the Strumigenys arnoldi-group. In the other two species of this complex, Strumigenys dromoshaula and Strumigenys shaula, the eyes are smaller, though still relatively large (ca 0.18 X HW) by Afrotropical standards. Both also have a pair of erect short hairs near the highest point of the vertex, have a conspicuously flagellate pronotal humeral hair and have ground-pilosity of the cephalic dorsum of small inconspicuous hairs. In dromoshaula the preocular impression in the ventral surface of the head forms a broad shallow dish-like depression with rounded and only weakly defined margins. In shaula the impression takes the form of a sharply defined and sharp-edged narrow transverse groove.

Bolton (1983) - S. pretoriae is immediately separated from its Afrotropical congeners by its very large eyes; no other species even approaches the ocular development seen here. Its closest relatives are Strumigenys shaula, Strumigenys dromoshaula and Strumigenys dyshaula but in all of these the pronotal humeri are equipped with flagellate hairs and the cephalic dorsum lacks the dense scale-like ground-pilosity characteristic of pretoriae.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Botswana, South Africa (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • pretoriae. Strumigenys pretoriae Arnold, 1949: 267, fig. 8 (w.) SOUTH AFRICA. See also: Brown, 1954k: 15; Bolton, 1983: 385; Bolton, 2000: 603.

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 2.3-3.0, HL 0.59-0.70, HW 0.43-0.54, CI 71-77, ML 0.26-0.31, MI 40-44, SL 0.33-0.40, SI 69-77 PW 0.27-0.33, AL 0.58-0.70 (5 measured).

Mandibular blades broad and powerful, the outer margins shallowly convex. Apical fork of each mandible of 2 teeth, without intercalary teeth or denticles. Each mandibular blade with 2 preapical teeth, crowded close to the mandibular apex, the proximal teeth larger than the distal. Upper scrobe margins in full-face view constricted immediately behind the frontal lobes; behind the constriction diverging posteriorly in an almost straight line on each side which passes directly above the inner margin of the eye on each side so that the latter is clearly visible in full-face view. Eyes very large, larger than in any other Afrotropical Strumigenys, their maximum diameter 0·23-0·24xHW; in full-face view the maximum eye diameter more than twice the width of the scape at its broadest. Preocular notch present, the anteriormost portion of the eye detached from the side of the head. Preocular notch continued onto ventral surface of head as an extensive impressed area. Antennal scapes quite slender, very feebly bent in the basal third, the leading edges with a row of apically curved spoon-shaped hairs. Dorsum of head clothed with short broad spoon-shaped hairs which are curved anteriorly and appear scale-like in full-face view. Hairs bordering the upper scrobe margins the same as those on the cephalic dorsum but slightly larger. Vertex of head with 4 simple standing hairs arranged in a transverse row close to the occipital margin, without a pair situated anterior to this row. Dorsum of head densely reticulate-punctate. Pronotal humeri without flagellate or any other kind of projecting hairs. Mesonotum with a single pair of standing hairs. Ground-pilosity of dorsal alitrunk of small broadly spoon-shaped to scale-like hairs, like those on the head but not so dense. In profile the posterior portion of the mesonotum slightly depressed, the metanotal groove minutely impressed. Propodeal teeth lamellate, subtended by broad infradental lamellae which are confluent with the basal margins of the teeth for about half of their length. Central areas of pleurae smooth but peripherally with punctate sculpture. Sides of pronotum with faint striolate markings. Pronotal dorsum finely longitudinally rugulose, the remainder of the dorsal alitrunk finely reticulate-punctate. Petiole node superficially reticulate-punctate, the postpetiole smooth or with traces of faint longitudinal costulae or striolae. Spongiform appendages of pedicel segments strongly developed. In profile the petiole with a large ventral strip which is almost as deep as the peduncle at its midlength; the lateral lobe extensive. Ventral and lateral lobes of postpetiole large and spongiform, the former larger than the exposed area of the postpetiolar disc in profile. Sides of postpetiok surrounded by projecting spongiform material in dorsal view. Base of first gastral tergite with a lamellate transverse strip from the more lateral portions of which the dense and sharply defined basigastral costulae arise. Petiole, postpetiole and gaster with standing hairs which are more or less simple or slightly expanded apically. Colour dull yellow to light yellowish brown.

Type Material

Bolton (1983) - Syntype workers, SOUTH AFRICA: Transvaal, Pretoria, 22.i.1946 (E. K. Hartwig) (South African Museum) [examined].

References