Strumigenys seti

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

Pyramica seti casent0005457 profile 1.jpg

Pyramica seti casent0005457 dorsal 1.jpg

Specimen labels

Broadly distributed across Madagascar, this species has been found in montane rainforest and tropical dry forest on tsing. Most specimens have been collected in litter samples.

Identification

Bolton (2000) - A member of the exiguaevitae complex in the Strumigenys leptothrix-group. By far the most densely hairy species of the exiguaevitae-complex, seti is immediately isolated by the pilosity of its head, promesonotum and legs, as described. In particular this is the only known member of the complex to have laterally projecting straight simple hairs on the dorsolateral margin of the head behind the level of the eye. Beside this diagnostic pilosity the antennal scape is shorter here that in Strumigenys hathor (SI 80 or more); the latter also has the lateral spongiform lobes of the petiole vestigial and its scrobes lack a sharply defined posterior margin. Strumigenys exiguaevitae and Strumigenys serket are also differentiated from set; as the lateral spongiform lobes of their petioles are much more strongly developed, and they share a very diagnostic arrangement of erect hairs on the cephalic dorsum where only 4 are present, arranged at the comers of a small square around the highest point of the vertex.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • seti. Pyramica seti Bolton, 2000: 349 (w.q.) MADAGASCAR. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 127

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 3.1, HL 0.78, HW 0.56, CI 72, ML 0.12, MI 15, SL 0.36, SI 64, PW 0.38, AL 0.90. Characters of hoplites-complex. With head in full-face view the side behind the level of the eye with several short straight freely projecting simple hairs. Dorsum of head from just in front of highest point of vertex to occipital margin with numerous simple short straight erect hairs. Posterior margin of scrobe bounded by a fine rim or carina. Eye with 6 ommatidia in the longest row. Promesonotum with numerous short simple hairs that are erect to suberect; conspicuously more than 3 pairs in all. Similar hairs present on waist segments and numerous on first gastral tergite. Each femur ventrally with a spaced row of suberect to subdecumbent outstanding simple hairs; similar hairs sparsely and irregularly present on other surfaces of femora and on other leg segments. Pronotal dorsum with a weak median longitudinal carina, best developed anteriorly; carina may extend onto anterior mesonotum. In dorsal view the sides of the mesonotum and propodeum marginate, the junction of pronotum and mesonotum marked by a fine transversely arched carina. Propodeal teeth short and triangular, engaging the lamella for most of their length and but with their apices free. Lateral spongiform lobes of petiole weakly developed. In profile the lateral lobe broadest posteriorly, petering out anteriorly well before the level of the anterior face of the node. In dorsal view the lobes rapidly narrowing anteriorly, fading out well behind the anterior margin of the node. Ventral spongiform curtain of petiole, and ventral and lateral lobes of postpetiole, large. Sculpture virtually absent; petiole with superficial fine punctulation and a few weak rugulae.

Paratypes. TL 3.0-3.3, HL 0.73-0.81, HW 0.51-0.61, CI 70-75, ML 0.10-0.12, MI 14-16, SL 0.32-0.36, SI 59-65, PW 0.34-0.40, AL 0.85-0.96 (10 measured). As holotype but eye with 5-6 ommatidia in the longest row. Median dorsal carina of pronotum variably developed. In most it extends the anterior two-thirds of the sclerite, but almost effaced in a few. Arched transverse carina separating pronotum and mesonotum dorsally may be faint or interrupted medially. One paratype ((9)-1) has a vestigial wing-bud on each side of the mesothorax.

Type Material

Holotype worker, Madagascar: 11.0 km. WSW Befingotra, Res. Anjanaharibe-Sud, 14°45'S, 49°27'E, 1565 m., 16.xi.1994, sifted litter (leaf mold, rotten wood) montane rainforest, #1232 (25)-1 (B.L. Fisher) (Museum of Comparative Zoology).

Paratypes. 13 workers and 1 queen (dealate) with same data as holotype; all series #1232 but coded (4)-1, (7)-1, (9)-1, (10)-1, (11)-1 [queen], (15)-1, (16)-1, (31)-1, (36)-1, (L.O.)-1 (University of California, Davis, The Natural History Museum).

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. 65:1-1028.8 (page 349, worker described)