Strumigenys adrasora

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

Strumigenys adrasora casent0102628 profile 1.jpg

Strumigenys adrasora casent0102628 dorsal 1.jpg

Specimen labels

Few biological details are known about this species. One worker was collected in a pitfall trap sample from a primary forest.

Identification

A member of the Strumigenys scotti-group.

Bolton (1983) - The non-paratypic material is lighter than the type-series, being yellowish brown with a dark brown gaster, but otherwise matches the species description. S. adrasora is diagnosed by its poorly defined to vestigial preocular impression, reduced spongiform appendages on the pedicel segments and narrow hairs on the upper scrobe margins. The variably developed preocular notch is similar to Strumigenys rukha and Strumigenys ettillax. S. adrasora is separated from all of these forms by its reduced spongiform appendages on the pedicel segments.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Burundi, Rwanda (type locality), Uganda, United Republic of Tanzania.


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.

  • adrasora. Strumigenys adrasora Bolton, 1983: 364, fig. 68 (w.) RWANDA. See also: Bolton, 2000: 607.

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 2.4, HL 0.60, HW 0.45, CI 75, ML 0.32, MI 53, SL 0.33, SI 73, PW 0.29, AL 0.58.

Mandibles in full-face view evenly shallowly bowed outwards. Apical fork of each mandible consisting of two spiniform teeth, the upper largest, without intercalary teeth or denticles. Each mandibular blade with 2 preapical teeth, the proximal the largest. The distal tooth approximately half the length of the proximal and slightly shorter to about equal in length to the distance separating their bases. Upper scrobe margins not bordered by a projecting flange, the eyes visible in full-face view. Maximum diameter of eye slightly greater than maximum width of scape. Preocular notch present but small and shallow, not continued onto the ventral surface of the head as a transverse impression or groove. Antennal scapes slender, very shallowly curved basally, their leading edges equipped with a row of elongate narrowly spatulate hairs which are curved apically. Upper scrobe margins with an anteriorly curved row of elongate spatulate hairs which are narrow, only fractionally broader than those on the scapes. 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. Cephalic ground-pilosity of inconspicuous simple short hairs anteriorly but with the hairs tending to become narrowly spatulate on the occipital lobes. Dorsum of head reticulate-punctate. Pranotal humeri each with a single long fine flagellate hair. Mesonotum with a single pair of standing hairs. Dorsal alitrunk otherwise only with sparse minute ground-pilosity which is appressed. Metanotal groove obsolete, scarcely discernible on the dorsal alitrunk and not impressed in profile. Posterior portion of mesonotum only shallowly depressed behind the level of the standing hairs. Propodeal teeth lamellate and narrowly triangular, the infradental lamella narrow, engaging one-quarter or less of the length of the tooth. Sides of pronotum with faint sculpture anteriorly and posteriorly but smooth medially. Pleurae mostly glassy smooth but with peripheral weak punctulation. Sides of propodeum below the level of the spiracle punctate. Pronotum dorsally very finely longitudinally striolate-costulate, the remainder of the dorsal alitrunk punctate. Petiole node punctate dorsally, the postpetiole mostly smooth but with faint vestiges of shagreening towards the sides. Spongiform appendages of pedicel segments very reduced, the subpetiolar strip vestigial, commencing only at the midlength of the peduncle. Ventral lobe of postpetiole small, in profile distinctly smaller than the exposed portion of the postpetiole and about the same size as the lateral spongiform lobe. In dorsal view the petiole node with a narrow posterior collar, the postpetiole with a narrow posterior strip; the sides in front of the midlength not showing projecting spongiform tissue. Base of first gastral tergite with a narrow lamellate strip from which the basigastral costulae arise. Petiole, postpetiole and first gastral tergite with stout standing hairs, most of which are thickened apically. Colour blackish brown to black.

Paratype. TL 2.3-2.4, HL 0.59-0.62, HW 0.44-0.47, CI 73-78, ML 0.30-0.33, MI 50-54, SL 0.33-0.36, SI 72-77, PW 0.29-0.31, AL 0.58-0.62 (10 measured).

As holotype but in some the preocular notch is vestigial and very difficult to see, to all intents and purposes absent. In most the distal preapical tooth is as described above but in a few is distinctly shorter than the distance separating the bases of the two preapical teeth. The subpetiolar spongiform appendage may be reduced to a small lobe under the node or reduced to a narrow short carina. In a few individuals the propodeal teeth are almost free of the infradental lamellae.

Type Material

Holotype worker, Rwanda: Rangiro, ix.1976 (P. Werner) (Musee d'Histoire Naturelle Genève). Paratypes. 26 workers with same data as holotype (MHNG; Museum of Comparative Zoology; The Natural History Museum; Ecole Nationale Superieure Agronomique).

References