Strumigenys oxysma

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

Pyramica oxysma casent0102552 profile 1.jpg

Pyramica oxysma casent0102552 dorsal 1.jpg

Specimen labels

Specimens have been collected in montane rainforest and podocarp forest, from a litter-sample, rotten wood and at a rotten fruit bait.

Identification

Bolton (2000) - A member of the Strumigenys oxysma-group. Dorsolateral margin of head in full-face view with 3-4 laterally projecting fine flagellate hairs; 2-3 of these arise from the upper scrobe margin and one from the side of the occipital lobe close to the occipital corner. Four pairs of flagellate hairs arise from dorsum of head. Clypeus in full-face view with 2 pairs of claviform hairs that project laterally from the outline in its anterior half, the apices of these hairs thickened and sharply curved posteriorly. Dorsum of clypeus with similarly shaped hairs that are elevated and curve posteromedially or medially without breaking the lateral outline.

Bolton (1983) - The only closely related species is Strumigenys anarta. The two species can be separated as follows: in anarta the clypeal dorsum has 18 recurved hairs, the upper scrobe margins lack flagellate hairs, the cephalic dorsum lacks flagellate hairs, and the first gastral tergite has only 4 standing hairs arranged in a transverse row close to the base of the sclerite. In contrast Strumigenys oxysma has 12 recurved hairs on the clypeal dorsum, has 3 pairs of flagellate hairs on the upper scrobe margins, has flagellate hairs present on the cephalic dorsum, and has 12 or more standing hairs on the first gastral tergite which are distributed all over the sclerite.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Lesotho, South Africa (type locality).


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.

  • oxysma. Smithistruma oxysma Bolton, 1983: 315, fig. 19 (w.q.) SOUTH AFRICA. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 125. See also: Bolton, 2000: 325.

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 0.58, HW 0.36, CI 62, ML 0.07, MI 12, SL 0.27, SI 75, PW 0.22, AL 0.54.

Principal dental row of mandible with 7 teeth followed by 4 minute denticles and a small apical tooth. Basal lamella of mandible (concealed by clypeus in holotype) a long low rounded lobe which is only as high as the basalmost tooth; without a diastema between the basal lamella and the basal most tooth. In full-face view the clypeus with shallowly convex sides which are evenly convergent anteriorly and with a strongly convex anterior margin which is narrowly rounded medially; the anterior margin on each side of the midpoint forms a single evenly convex line which is continuous with the lateral margins, without trace of anterolateral angles. Outer margins of the fully closed mandibles forming a more or less continuous line with the outer margins of the clypeus in full-face view. Clypeal margins without a fringe of curved spatulate to spoon-shaped hairs but one or two simple short hairs may occur laterally. The dorsum of the clypeus along the anterior margin with three pairs of flattened, apically gradually clavate, recurved hairs. The innermost pair arises very close to the clypeal apex and curves up and back without breaking the clypeal outline. The two outer pairs curve outwards as well as upwards and back and project beyond the clypeal outline in full-face view. Dorsum of clypeus behind the anterior margin also with 6 hairs which are similar in shape to those just described, arranged in a transverse band of 4 behind the midlength which curve backwards and towards the midline, and a pair close to the posterior clypeal margin which are strongly arched towards the midline and only feebly curved backwards. Ground-pilosity of cephalic dorsum of numerous simple to very narrowly spatulate fine hairs which are subdecumbent to decumbent and generally curved towards the highest point of the vertex. Upper scrobe margins with three pairs of flagellate hairs; the posterior occipital lobes with a pair of flagellate hairs; 4 other pairs of flagellate hairs present on the dorsum of the head, making a total of 16 cephalic flagellate hairs. Antennal scapes slender and more or less cylindrical, slightly narrowed basally and very weakly bent at the basal quarter. Leading edges of scapes without strong freely projecting hairs, only with decumbent fine pubescence. Maximum diameter of eye 0.11 x HW. Clypeal dorsum very finely punctate-granular, the cephalic dorsum strongly reticulate-punctate. Anterior border of pronotum transversely marginate; sides of pronotum not marginate but sides of mesonotum and propodeum angular. A mid-dorsal longitudinal ridge or carina present on pronotum and mesonotum, absent from propodeal dorsum. With the alitrunk in profile the metanotal groove absent and the propodeal teeth confluent with the broad and conspicuous infradental lamellae. Pronotal humeri with a pair of long flagellate hairs which are directed predominantly laterally. Pronotal dorsum behind the humeri with a pair of shorter flagellate hairs and with 2-3 pairs of anteriorly situated fine decumbent shorter hairs. Mesonotal dorsum with two pairs of fine hairs. Fine simple hairs numerous on dorsal surfaces of petiole and postpetiole, and such hairs widely distributed on the first gastral tergite where 12 or more are present. Sides of alitrunk unsculptured except for a few feeble longitudinal striae close to the anterior pronotal margination. Pronotum and mesonotum dorsally with scattered weak longitudinal rugulae or costulae most of which are short, the spaces between them mostly smooth on the pronotum but on the mesonotum with vestiges of punctate sculpture also visible. Propodeal dorsum smooth, with two weak rugulae running from the apex of the median mesonotal ridge across the dorsum to the bases of the propodeal teeth. Dorsum of petiole node densely punctate; disc of postpetiole smooth and shining. First gastral tergite unsculptured except for the basigastral costulae which arise in two patches, on each side of a median clear area. Spongiform appendages of pedicel segments strongly developed in profile. In dorsal view the petiole node bounded posteriorly by a narrow lamellate strip. Postpetiole in dorsal view with the anterior margin sharply concave medially and with a short narrow transverse lamella bordering the concave section. The ventrolaterally situated spongiform appendages of the postpetiole are visible in dorsal view, projecting anterolaterally and laterally beyond the outline of the disc. Posterior margin of postpetiole bordered by a lamellate strip which is very broad posterolaterally. First gastral tergite with a sinuous basal lamellar strip which has its anterior free border convex at the sides and concave medially, and which is traversed by the basigastral costulae. Colour glossy medium brown.

Paratypes. TL 1.9-2.1, HL 0.50-0.58, HW 0.32-0.38, CI 62-67, ML 0.06-0.08, MI 11-14, SL 0.25-0.30, SI 72-80, PW 0.21-0.26, AL 0.50-0.56 (15 measured).

Maximum diameter of eye 0.11-0.14 X HW. Mostly as holotype but propodeal dorsum may be unsculptured and the mesonotum may lack any trace of punctate sculpture. The long recurved hairs on the clypeus appear to be easily lost by abrasion, especially those of the anterior row, and the long flagellate hairs of the head may be flattened to the surface by accident of preservation.

Type Material

Holotype worker, South Africa: Natal, 75 km WSW. Estcourt, Cathedral Peaks Forest Sta., 7-31.xii.1979, Ber. 8, 17.xii.1979, podocarp forest rotted stump of Cussonia spicata (S. & 1. Peck) (Museum of Comparative Zoology). Paratypes. South Africa: 8 workers and 1 female with same data as holotype; 5 workers with same data but Ber. 19, 24.xii.1979, podocarp forest rotted wood, moss, fleshy and woody fungi, 1500 m; 2 workers with same data but Ber. 18, 24.xii.1979, podocarp forest rotted fruit bait 1500 m (MCZ; The Natural History Museum; Musee d'Histoire Naturelle Genève).

References