Strumigenys platyscapa group

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Strumigenys platyscapa group Bolton (2000)

Species

Neotropical-Nearctic

Worker Diagnosis

Apical fork of mandible with one intercalary small tooth. Mandible with a single small preapical tooth located near the apicodorsal tooth; no proximal denticle. MI 58-64.

Leading edge of scape with a continuous row of coarse flattened hairs, the apical portions of which are all curved toward the apex of the scape. Scape broad and dorsoventrally compressed, with a more or less flat dorsal surface; in section posterior edge of scape thickest, tapering anteriorly to a very thin extended leading edge. Scape short, SI 61-67.

Head relatively broad, CI 90-98, with occipital lobes that are strongly expanded laterally. In profile scrobe short, terminating at about level of eye, its ventral margin not at all defined behind eye.

Preocular lamella broad and prominent in full-face view; in profile terminating at the eye.

Ventrolateral margin of head constricted in front of eye. Postbuccal groove obsolete, very shallow.

Propodeum with a pair of narrow spines subtended by thin carinae on the declivity; without a sharp tooth or spine at base of declivity.

Ventral surface of petiole with a carina or vestigial strip of spongiform tissue that may be broken or incomplete. Lateral spongiform lobe of petiole and ventral lobe of postpetiole well developed, but lateral lobe of postpetiole narrow. Base of first gastral sternite with a narrow spongiform pad.

Pilosity. Pronotal humeral hair stout, may have a looped or short flagellate portion apically. Ground-pilosity of head and alitrunk of small spoon-shaped hairs; a conspicuous row present along upper scrobe margin in full-face view. Longer pilosity short and stout: dorsolateral margin of head with a single freely projecting flattened hair that is expanded apically. Cephalic dorsum with one pair of erect stout hairs, near the occipital margin. Mesonotum with a pair of short standing hairs. Waist segments with several, and first gastral tergite with many, curved stout remiform hairs.

Sculpture. Head and alitrunk reticulate-punctate; a few extremely feeble rugulae may occur on promesonotum and mesonotum has a short median carina. Mesopleuron and sometimes metapleuron with a smooth area. Disc of postpetiole mostly, and first gastral tergite entirely, smooth.

Notes

A single species, Strumigenys platyscapa, is included here. It is a moderately large size-variable form with particularly strongly dorsoventrally compressed scapes. When retracted the scape appears to fold against the head with its flattened dorsal surface facing outwards. There is no defined scrobe behind the level of the eye though the dorsolateral margin of the head is sharply developed.

Among the Neotropical fauna only Strumigenys deltisquama has similar but shorter and even more flattened scapes. However, the two are not closely related because in that species the mandible has two sharp preapical teeth and the scrobe is deep and strongly defined behind the level of the eye, among many other differences.

References

  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.