Strumigenys dyshaula

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

Strumigenys dyshaula casent0102647 profile 1.jpg

Strumigenys dyshaula casent0102647 dorsal 1.jpg

Specimen labels

Known from various forest habitats, with specimens found in litter samples and rotten wood.

Identification

Bolton (2000) - A member of the Strumigenys scotti-group. Outer margin of mandible bowed outwards; mandible broadest at about its midlength. Proximal preapical tooth of left mandible spiniform, distinctly longer than maximum width of mandible. Distal preapical tooth of left mandible very small, its basal width much less than that of proximal tooth and its length less than half that of the proximal. Preocular notch small but distinct. Curved hairs that fringe upper scrobe margin broadly spatulate to spoon-shaped, much larger than those on leading edge of scape.

Bolton (1983) - Of the species possessing a preocular notch and relativelly large eyes a number of forms do not have the preocular notch extended onto the ventral surface of the head as a transverse impression. Among the six species in this category Strumigenys dyshaula is distinguished by having a postpetiole whose sides are not completely lapped around by spongiform tissue, having the ventral lobe of the postpetiole well developed, having six standing hairs on the cephalic dorsum and having basigastral costulae which do not arise as a regular row across the width of the tergite but rather radiate out from each side of a central clear area.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun, United Republic of Tanzania, Zambia, Zimbabwe (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

Nomenclature

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

  • dyshaula. Strumigenys dyshaula Bolton, 1983: 370, fig. 55 (w.q.) ZIMBABWE. See also: Bolton, 2000: 608.

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 2.0, HL 0.53, HW 0.40, CI 75, ML 0.25, MI 47, SL 0.28, SI 70, PW 0.26, AL 0.50.

Mandibles in full-face view with the outer margins shallowly convex. Apex of each mandible with a fork of two spiniform teeth, without intercalary teeth or denticles. Preapical armament of 2 teeth on each mandible, situated in the apical third of the length of the blade, the proximal pre apical tooth distinctly larger than the distal. Upper scrobe margins evenly divergent posteriorly, shallowly convex and bordered by a thin projecting rim or flange. Eyes visible in full-face view, not wholly hidden by the upper scrobe margins. Preocular notch present but only weakly developed, merely an impression in the side of the head immediately in front of the eyes; the anterior portion of the eye not detached from the side of the head. Preocular notch ending below at the ventrolateral cephalic margin, not extending onto the ventral surface of the head as a transverse groove or impression. Maximum diameter of eye greater than the maximum width of the scape. Antennal scapes very shallowly curved in the basal third, broadest just distal of the midlength, the leading edges with a row of narrow spoon-shaped hairs which are curved apically and are distinctly smaller than those on the upper scrobe margins. Occipital margin of head narrowly and deeply impressed in full-face view. Ground-pilosity of cephalic dorsum consisting of inconspicuous minute spatulate hairs which are closely applied to the surface. Upper scrobe margins with a row of large spoon-shaped hairs which are curved anteriorly and very distinct. 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. Head reticulate-punctate. Pronotal humeri each with a fine flagellate hair. Mesonotum with a single pair of standing hairs. Ground-pilosity of dorsal alitrunk of sparse closely applied hairs similar to those on the head. Posterior portion of mesonotum depressed behind the level of the standing hairs. Metanotal groove forming a line across the dorsum but not impressed in profile. Propodeal teeth triangular and subtended by infradental lamellae. Pleurae mostly smooth:with weak peripheral punctulation which is best developed laterodorsally. Sides of propodeum with a fine punctulate strip above and below the spiracle, otherwise smooth. Sides of pronotum with vestigial striolate and punctulate sculpture. Pronotal dorsum with feeble longitudinal costulae or striae, the remainder of the dorsal alitrunk finely reticulate-punctate. Dorsum of petiole node broader than long and superficially punctate, the postpetiole smooth. Spongiform appendages of pedicel segments moderately developed. In profile the petiole with a shallow ventral process which is about half as deep as the depth of the peduncle at its midlength. Lateral lobe of petiole node bluntly triangular. Ventral and lateral spongiform lobes of postpetiole about equal in size, the former about equal to the exposed portion of the postpetiolar disc in profile. In dorsal view the postpetiole with a lamellar posterior strip which abuts a similar strip traversing the base of the first gastral tergite. Basigastral costulae dense and sharply defined, radiating from each side of a central clear area which is free of costulae. Secondary costulae present which' arise between the main costulae, these latter originating on the basal strip and the secondaries arising some distance behind it. Petiole, postpetiole and gaster with stout standing hairs which are broadened to narrowly clavate apically. Colour dull yellow.

Paratypes. TL 2.0-2.1, HL 0.54-0.56, HW 0·40-0.43, CI 74-78, ML 0.25-0.27, MI 46-48, SL 0.28-0.31, SI 70-74, PW 0.26-0.28, AL 0.50-0.54 (7 measured). As holotype.

Type Material

Holotype worker, Zimbabwe: Victoria Falls, spray forest, rotten wood M440, 7.iii.1969 (W. L. Brown) (Museum of Comparative Zoology). Paratypes. 8 workers and 1 female with some data as holotype (MCZ; The Natural History Museum; Musee d'Histoire Naturelle Genève).

References