Strumigenys dotaja

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

Pyramica dotaja casent0102587 profile 1.jpg

Pyramica dotaja casent0102587 dorsal 1.jpg

Specimen labels

Specimens records show this is predominately (more than a dozen collections) a rainforest species that is collected in litter samples. One collection was taken in savanna from a sweep sample.

Identification

A member of the Strumigenys lujae-group.

Bolton (1983) - The presence of very long fine flagellate hairs on the mesonotum as well as on the pronotum immediately distinguishes dotaja from all other species as in those the mesonotum has one or more pairs of stout hairs which are thickened or clavate apically. The species Strumigenys lujae, Strumigenys serrula, Strumigenys concolor and Strumigenys maynei are also distinguished from dotaja by their possession of conspicuous pronotal sculpture, and Strumigenys maynei, Strumigenys sulumana and Strumigenys geoterra lack cephalic flagellate hairs. From Strumigenys ludovici samples in which the enlarged basal series of mandibular denticles is not very strongly developed dotaja differs in having the pleurae and propodeal dorsum smooth, as well as by having simple cephalic, petiolar, postpetiolar and gastral pilosity, all of which are clavate in ludovici. Strumigenys simoni, the closest relative of dotaja, is separated as follows.

dotaja simoni
Standing hairs behind highest point of cephalic vertex simple. Standing hairs behind highest point of cephalic vertex clavate.
Mesonotum with a pair of very long flagellate hairs similar to those on the pronotum. Mesonotum with a pair of stout clavate hairs contrasting with the flagellate. hairs on the pronotum.
Pilosity of petiole, postpetiole and gaster each of a single pair of simple curved hairs. Pilosity of petiole, postpetiole and gaster each of one or more pairs of clavate hairs.
Dorsum of propodeum and of petiolenode glassy smooth. Dorsum of propodeum punctate, very very rarely with a smooth median area; petiole node punctate dorsally even if only feebly so.
Disc of clypeus smooth (when clean). Disc of clypeus sculptured (when clean).
MI 38-43; ML is 0·48-0·S3xHW. MI 33-39; ML is 0·42-0·48xHW.
Pronotal dorsum glassy smooth. Pronotal dorsum at least with scattered vestiges of sculpture.

A single worker of simoni from Burundi (in MCZ) with very reduced sculpture is responsible for the qualifying ‘at least’ and ‘very rarely’ in the sculpture characters listed above. In this specimen the sculpture is more reduced than is usual in simoni and it is more like dotaja in this respect than any other sample examined. However, even in this individual the pilosity characters are absolutely those of simoni.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Democratic Republic of Congo, Gabon.


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.

  • dotaja. Serrastruma dotaja Bolton, 1983: 339, figs. 35, 38 (w.) CAMEROUN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 119. See also: Bolton, 2000: 313.

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

Description

Holotype. TL 23, HL 0.53, HW 0.42, CI 79, ML 0.22, MI 42, SL 0.36, SI 86, PW 0.32, AL 0.62.

Mandibular denticles small even and regular, without a basal series of 4-8 enlarged denticles; only the basalmost denticle enlarged. Upper scrobe margins narrow and petering out posteriorly, not composed of a broad continuous lamellate granular flange; equipped just behind the level of the eye with an extremely long flagellate hair which basally projects laterally from the margin. Clypeus smooth on the disc, with appressed small spatulate hairs, the anteriormost row of spatulate hairs situated on the false margin of the clypeus and freely projecting forwards over the mandibular bases. Ground-pilosity of head to highest point of vertex consisting only of sparse narrow inconspicuous hairs which are decumbent to appressed and directed anteriorly. Dorsum of head behind highest point of vertex with similar but slightly longer ground-pilosity and also with two pairs of anteriorly curved long simple hairs, one pair situated just behind the highest point and the other latero-occipitally. Dorsum and sides of head densely and strongly reticulate-punctate everywhere. Pronotum marginate anteriorly but laterally the sides of the alitrunk separated from the dorsum only by smoothly rounded blunt angles. In profile the pronotum and anterior part of the mesonotum forming an even shallow convexity, the posterior part of the mesonotum sloping down to the shallowly impressed metanotal groove. Propodeal dorsum curving down posteriorly to the bases of the strong propodeal teeth which are elevated and slightly upcurved. Infradental lamellae present down the depth of the propodeal declivity, its width equal to or slightly greater than the diameter of the propodeal spiracle. Sides of alitrunk glassy smooth, devoid of sculpture. Dorsal surfaces of pronotum, anterior mesonotum and propodeum glassy smooth. Posterior (sloping) portion of mesonotum smooth centrally but with some weak lateral punctulae and posteriorly with some irregular sculpture just in front of the metanotal groove. Propodeal declivity reticulate-punctate between the bases of the teeth. Pronotum and mesonotum each equipped with a pair of extremely long fine flagellate hairs, each hair arising from a small papilla. Dorsum of promesonotum otherwise only with very sparse short ground-pilosity which is subdecumbent. With the pedicel segments in profile the spongiform appendages well developed. Ventral petiolar process spongiform posteriorly but more solid and opaque anteriorly. Ventral and lateral spongiform lobes of postpetiole about equal in size, lateral appendage of petiole node smaller. In dorsal view both petiole and postpetiole smooth and very shiny, the former with a distinct spongiform strip running across the posterior face. Disc of postpetiole transversely roughly oval in dorsal view, the anterior face with a narrow transverse lamellate strip, the sides bordered with spongiform material which becomes broader posteriorly, and the posterior margin bordered with a broad spongiform strip the posterior margin of which is shallowly concave medially. Extreme base of first gastral tergite lamellate spongiform, with a continuous band of short basigastral costulae which do not run further back than the pair of long gastral hairs; remainder of tergite glassy smooth. Petiole and postpetiole each with a single pair of stout simple posteriorly curved long hairs. First gastral tergite with a single pair of simple hairs which are situated close to the base of the sclerite. Colour jet black, glossy behind the head, the appendages brown.

Paratypes. TL 2.3-2.5, HL 0.50-0.54, HW 0.41-0.43, CI 78-82, ML 0.20-0.23, MI 38-43, SL 0.34-0.37, SI 81-88, PW 0.31-0.34, AL 0.60-0.66 (20 measured).

As holotype but specimens from Gabon are slightly lighter in colour, blackish brown with somewhat lighter pedicel segments.

Type Material

Holotype worker, Cameroun: Nkoemvon, 16.iii.1980 (D. Jackson) (The Natural History Museum). Paratypes. Cameroun: 12 workers with same data as holotype; 3 workers with same data but 2S.xi.1980, N52. Gabon: 11 workers, Plateau d'Ipassa, 6, IPA CI9 (J. A. Barra); 1 worker with same data but IVIS, IPA 8 (BMNH; Museum of Comparative Zoology; Musee d'Histoire Naturelle Genève).

References