Strumigenys datissa

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

Nothing is known about the biology of Strumigenys datissa.

Identification

Bolton (2000) - A member of the truncatidens complex in the Strumigenys emarginata group. Characters of truncatidens-complex. In full-face view dorsolateral margin of head behind level of apex of scrobe without laterally projecting hairs. Mesonotum without standing hairs. Disc of postpetiole sharply longitudinally costulate. Head and alitrunk dark brown to blackish brown.

Bolton (1983) - The truncatidens-complex of this group contains five species. Four of these, Strumigenys gatuda, Strumigenys hensekta, Strumigenys dendexa (= truncatidens) and Strumigenys truncatidens, possess conspicuously projecting hairs on the sides of the occipital lobes. In datissa, however, such projecting hairs are absent, any hairs which occur on the sides of the occipital lobes being small and curved, usually closely adherent to the head and not freely projecting. S. datissa is also separated from gatuda, dendexa and hensekta by having the postpetiolar disc longitudinally costulate; it is glassy smooth in the last three named. A few specimens of truncatidens do show costulae either on part or all of the postpetiole but here the mesonotum has a pair of long erect hairs which are not seen in datissa.

Keys including this Species

• Key to Afrotropical Strumigenys (as Pyramica)

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Rwanda (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

Expand 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. ‎

Nomenclature

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

• datissa. Smithistruma datissa Bolton, 1983: 289, fig. 9 (w.) RWANDA. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 118. See also: Bolton, 2000: 301.

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 2.7, HL 0.70, HW 0.54, CI 77, ML 0.12, MI 17, SL 0.34, SI 63, PW 0.34, AL 0.74.

Mandibles armed with 5 relatively large teeth following the basal lamella (which is concealed by the clypeus in the holotype). Distal to the 5 principal teeth are 2 slightly smaller teeth, a row of four denticles and a small apical tooth. Anterior clypeal margin broadly and evenly concave between the anterolateral corners, the margin equipped with 10 scale-like hairs which project forward over the mandibles. These hairs become gradually larger away from the midline but the outermost, at the anterolateral corner, is much the largest and forms an intermediate between the shorter hairs on the anterior margin and the large spatulate to spoon-shaped anteriorly curved hairs which form a fringe on the lateral clypeal margins. In full-face view the preocular laminae slightly divergent anteriorly. Clypeal dorsum more or less smooth centrally but feebly sculptured laterally and anteriorly. Cephalic dorsum densely shallowly reticulate-punctate everywhere. Dorsum of head with numerous small, widely spaced flattened hairs which are subdecumbent to decumbent and are mostly directed anteriorly. In full-face view the sides of the head with a few such hairs projecting, curved anteriorly, most conspicuous on the sides of the occipital lobes. Flagellate hairs absent. Antennal scapes narrow basally, shallowly bent at about the basal third and broadest at this point. The leading edges of the scapes evenly curved at the bend and equipped with a row of projecting spatulate to broadly clavate hairs and an interspersed row of shorter much finer simple hairs. Maximum diameter of eye about O·13xHW, approximately equal to the maximum width of the scape. Head in profile roughly wedge-shaped, the vertex forming a high narrowly rounded convexity, the ventral surface evenly shallowly convex. Pronotal dorsum without a median longitudinal ridge or carina, not sharply marginate laterally. Alitrunk without flagellate hairs. With the alitrunk in profile the posterior part of the pronotum and anteriormost section of the mesonotum raised into a broad shallowly convex tumulus, the remainder of the mesonotum and the propodeum, which form a single surface without trace of a metanotal groove, markedly depressed below the level of this tumulus. Propodeal teeth short and broadly triangular, the infradental lamellae narrow but clearly visible. Dorsal alitrunk with scattered short flattened hairs which are decumbent to appressed, without standing pilosity of any description. Petiole and postpetiole dorsally with similar but extremely sparse hairs, the latter also with 4 clavate suberect hairs projecting from the posterior margin. In the holotype a single clavate hair is also present on the left side of the postpetiolar disc, appressed to the surface; this is not matched in the paratypes. First gastral tergite with numerous suberect to erect stout hairs which are simple to weakly clavate apically. Pronotal dorsum predominantly broadly reticulate-punctate but anteriorly and laterally the margins of the punctures tending to run together and form very fine rugulae. Mesonotum and propodeal dorsum more sharply punctate, the sculpture on the latter running between the propodeal teeth and ending about half way down the declivity. Petiole dorsum minutely rugulose, the disc of the postpetiole finely longitudinally costulate. Basigastral costulae sharply developed and conspicuous, the tergite otherwise unsculptured. Alitrunk pleurae mostly smooth centrally but punctulate marginally, a line of punctures separating meso- and metapleuron and a relatively densely punctured patch on the mesopleuron behind the upper half of the front coxa. Spongiform appendages of pedicel segments moderately large in profile. In dorsal view the petiole node with a posterior spongiform strip which is continued down the sides. Postpetiole with a narrow spongiform strip anteriorly and a broader strip bordering the posterior margin which is slightly narrowed medially. Colour dark brown.

Paratypes. TL 2.6-2.7, HL 0.70, HW 0.54, CI 77, ML 0.12, MI 17, SL 0.34, SI 63, PW 0.32-0.34, AL 0.73-0.74 (2 measured).

As holotype but maximum diameter of eye 0.13-0.15 X HW.

Type Material

Holotype worker, Rwanda: Rangiro, ix.1976 (P. Werner) (Musee d'Histoire Naturelle Genève). Paratypes. 2 workers with same data as holotype (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. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology 46:267-416. (page 289, fig. 9 worker described)
• Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History. 33:1639-1689. (page 1673, combination in Pyramica)
• Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 301, redescription of worker)

References based on Global Ant Biodiversity Informatics

• Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65