Tetramorium viehmeyeri

A species of semi-arid habitats (Heterick 2009).

Identification
Heterick (2009) - I am retaining the distinctive nature of the clypeus in the (SWBP) key as a diagnostic feature for the species. There is some question as to the nature of the variation of this character in T. viehmeyeri (see the taxonomy section below). In other respects, what I think is likely to be T. viehmeyeri has dark red workers with lighter-coloured gasters.

Distribution
Nominal T. viehmeyeri in the Curtin Ant Collection from WA have mostly been collected in the Newman area in the Pilbara, but several specimens of this species have been collected at Westonia within the SWBP.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  viehmeyeri. Tetramorium (Xiphomyrmex) viehmeyeri Forel, 1907h: 275 (q.) AUSTRALIA. Bolton, 1977: 142 (w.). Combination in Xiphomyrmex: Viehmeyer, 1925a: 29; in Tetramorium: Bolton, 1977: 142. Senior synonym of venustus: Bolton, 1977: 142.
 * venustus. Xiphomyrmex viehmeyeri var. venustus Wheeler, W.M. 1934d: 147 (q.) AUSTRALIA. Junior synonym of viehmeyeri: Bolton, 1977: 142.

Heterick (2009) - Tetramorium viehmeyeri is somewhat problematic. The holotype female may well have been destroyed in WW II (Taylor and Brown 1985). The dealated queen holotype of Tetramorium viehmeyeri venustus Wheeler (WAM) is headless. This taxon was synonymised with T. viehmeyeri by Bolton (1977). However, three worker specimens on the same pin from the Mt Magnet area (in the ANIC Collection), identified by R. W. Taylor as T. viehmeyeri, do not show the supposedly characteristic clypeal feature very well, i.e., one worker does, two do not. I suspect the structure of the clypeus may be variable. More material is needed to clarify the morphological variation and limits of this species.

The synonymy of the supposed subspecies Tetramorium viehmeyeri venustus with the type species is questionable, not least because of the different phytogeographic region represented (the Swan Coastal Plain in the South-West Botanical Province versus the semi-arid Murchison in the Eremaean Botanical Province). No workers belonging to this subspecies ever appear to have been collected, ''T. viehmeyeri venustus'' having been described from a single, dealated queen. This ant is possibly something else, the most probable candidate being Tetramorium impressum (queens and workers of which also share the narrow petiole and often an anteromedial clypeal notch with T . viehmeyeri, the bicoloured appearance of many T . impressum specimens also agreeing with Wheeler’s (1934) description). Since the whereabouts of the type specimen of Tetramorium viehmeyeri venustus are now known, this type can be compared with indubitable queen material of Tetramorium viehmeyeri, should the identity of such material be established.

Worker
Bolton (1977) - TL 3.5-4.0, HL 0.78-0.90, HW 0.72-0.84, CI 90-93, SL 0.60-0.70, SI 83-86, PW 0.56-0.64, AL 0.92-1.12 (9 measured).

Mandibles striate. Anterior clypeal margin with a distinct median notch or impression. Anterior half to two-thirds of median portion of clypeus descending very steeply, almost vertical, this descending portion conspicuously transversely concave. Median clypeal carina absent from descending portion, short, present on the posterior portion and curve of the clypeus only, sometimes very faint. Frontal carinae with a raised, semi-translucent narrow flange which is distinct to the level of the posterior margins of the eyes, behind this the frontal carinae being scarcely stronger than the other sculpture. Scrobes narrow and shallow, for scape only. Eyes large and strongly convex, the maximum diameter c. 0.20-0.24 at HW 0.72-0.84 respectively. Propodeal spines narrow and acute; metapleural lobes triangular, dentiform. Node of petiole in profile angular, the tergal portion about as long as high. In dorsal view the node as broad as or slightly broader than long. Dorsum of head with spaced-out fine longitudinal rugulae, the spaces between them finely and densely reticulate-punctate. Scrobes reticulate-punctate. Dorsal alitrunk with a disorganized rugoreticulum on the pronotum, the constituents of which are sharply defined. Elsewhere on dorsal alitrunk cross-meshes are reduced in number or absent. Petiole and postpetiole finely rugulose, the spaces here and on the alitrunk densely punctulate, but much more conspicuously so on the alitrunk. Gaster smooth or with a very faint shagreening near the base of the first tergite. Hairs numerous on all dorsal surfaces of head and ali trunk, and with shorter subdecumbent hairs on scapes and legs. Colour yellow-brown, the gaster and appendages yellow.

Type Material
Bolton (1977) - Holotype female, Australia: S. Western Australia, Day Dawn, Stat. 76 (Michaelsen & Hartmeyer) (location of type not known).