Strumigenys dictynna

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Strumigenys dictynna
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. dictynna
Binomial name
Strumigenys dictynna
(Bolton, 2000)

Strumigenys dictynna casent0900103 p 1 high.jpg

Strumigenys dictynna casent0900103 d 1 high.jpg

Specimen Labels

The type material was sampled from sifted litter.

Identification

Bolton (2000) – A member of the Strumigenys baudueri-group. The Afrotropical members of the group can be divided into two complexes on antennomere count. The central and west African species Strumigenys tacta and Strumigenys vodensa have 4, whilst the South African Strumigenys agnosta and dictynna have 6 antennomeres. The two South African species form a close pair, differentiated by the comparative table given under agnosta.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: South Africa (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.

  • dictynna. Pyramica dictynna Bolton, 2000: 294 (w.) SOUTH AFRICA. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 118

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 2.1, HL 0.53, HW 0.36, CI 68, ML 0.08, MI 16, SL 0.27, SI 75, PW 0.25, AL 0.56. Dorsum of clypeus with appressed small spatulate hairs that are directed anteromedially in the zone immediately behind the anterior margin, and directed medially behind this zone. Lateral margins of clypeus in full-face view without freely projecting haris but with a few appressed small spatulate hairs present. Ground pilosity of cephalic dorsum narrowly spatulate, decumbent to appressed. Standing hairs on cephalic dorsum restricted to a pair of long fine hairs close to the occipital margin medially and a more lateral pair that are directed dorsolaterally from close to the occipital corners. Dorsolateral margins of head in full-face view with a pair of flagellate hairs situated posteriorly on the occipital lobes. The dorsal pair of hairs at the occipital corners may also be visible in full-face view, projecting laterally behind the flagellate pair. Clypeus finely reticulate-punctate, the cephalic dorsum finely punctate-rugulose. A distinct longitudinal impression present dorsally, running from the posterior margin of the clypeus almost to the highest point of the vertex. Eye of moderate size, with 4 ommatidia across the greatest diameter. Pronotal dorsum with sparse vestigial traces of longitudinal costulae and faint scattered vestiges of punctulae; mostly shining. Mesonotum and anterior half of propodeal dorsum reticulate-punctate, the postpetiole glassy smooth. Propodeum armed with short triangular teeth subtended by a narrow lamella. Erect simple hairs present on dorsal alitrunk and waist segments; many appear feebly flagellate but some are truncated apically. Similar hairs present on first gastral tergite, most are truncated apically.

Paratypes. TL 2.0-2.1, HL 0.52-0.54, HW 0.36-0.38, CI 68-70, ML 0.08, MI 16-20, SL 0.26-0.29, SI 72-76, PW 0.23-0.25, AL 0.55-0.58 (8 measured).

Type Material

Holotype worker, South Africa: South Cape Prov., Tsitsikama, Lottering For. Res., 12.xii.1979, E-Y 1419, sifting (S. Endrody-Younga) (Transvaal Museum).

Paratypes. 11 workers with same data as holotype (TVM, South African Museum, The Natural History Museum, Museum of Comparative Zoology).

References

  • Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria”. 99:1-191.
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 294, worker described)