Mesostruma laevigata

In WA this ant has been collected from bark traps on Powderbark Wandoo trunks at Dryandra. (Heterick 2009)

Identification
Mesostruma laevigata can be recognisable by the presence of sharp angles or short teeth on the pronotal corners and the wing-like projections on the lateral surfaces of the postpetiole. The only other species with pronotal teeth or spines, M. eccentrica, lacks postpetiolar wings.

Distribution
Heterick (2009) - Widely distributed throughout southern Australia.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  laevigata. Mesostruma laevigata Brown, 1952g: 12, fig. 1 (w.q.) AUSTRALIA. Wheeler, G.C. & Wheeler, J. 1955a: 130 (l.). See also: Taylor, 1973: 28; Shattuck, in Bolton, 2000: 51.

Worker
Holotype and 14 paratypes. Weakly polymorphic. TL 2.9 to 4.2 mm.; HL 0.66 to 0.89 mm.; WL 0.72 to 1.12 mm.; CI 85 (smaller individuals) to 93 (larger individuals); MI 37 to 44 (70% of individuals 39 to 41, mean 40, no correlation between MI and HL or CI). Present series, from a single nest, too small and so not suitable for statistical analysis, but shows slight tendency toward division into large, broad-headed and small, narrow-headed castes.

Head shape as in fig.; narrower than in turneri, with larger but only weakly convex eyes. Humeral angles acutely subdentate. Propodeal lamellae as in figure. the upper and lower angles varying slightly in prominence; translucent, without distinct trace of solid tooth in upper angle. Petiole narrower and relatively Jess massive than that of turneri; posterior descending face of node weakly or not at all convex seen in profile.

Body over-all much more smooth and shining than in turneri, with the spaces between the foveolae, especially on the thorax, petiole and postpetiole wider and smooth and polished for the most part. Gastric dorsum smooth and shining, with a few minute, indistinct vestiges of longitudinal costulae or striae in the articular groove between postpetiole and gaster. Colour medium ferrugineous yellow, gaster lighter, clear honey-yellow.

Shattuck (2000) - TL 2.9 - 4.2, HL 0.66 - 0.90, HW 0.57 - 0.82, CI 85 - 93, ML 0.26 - 0.36, MI 34 - 44, SL 0.43 - 0.51, SI 59 - 63, PW 0.37 - 0.60, AL 0.72 - 1.12. Head longer than broad (CI 85 - 93), its posterior margin weakly and broadly concave. In dorsal view the anterolateral corners of pronotum armed with sharp angles or short teeth. Dorsum of mesosoma with shallow foveolate punctures of varying densities (more widely spaced medially, more densely spaced posterolaterally), the area between the punctures with weak, indistinct sculpturing. Propodeal lamellae well developed. Sculpturing on the metaplerual gland bulb reticulcate-punctate. Lateral surfaces of postpetiole with well developed wings. First gastral segment immediately posterior of the postpetiole with short, evenly spaced distinct rugae. Body colour dark yellow-red to dark red-brown, often with light infuscation; mandibles, legs and gaster slightly lighter.

Queen
Gynetype and one paragynetype. TL 4.7, 5.4 mm.; HL 0.92, 0.93 mm.; WL 1.36, l.40 mm.; CI 91, 93; MI 37, 39. Dealate. Differing only in the usual features of full sexuality from the workers.

Type Material
Sea Lake, Victoria (J. C. Goudie). Sea Lake is in northwestern Victoria, in the dry Mallee District. Dominant vegetation in this region is the shrubby mallee (Eucalyptus dumosa and related forms), but I have no information as to the precise type of nest site. The holotype and gynetype, pith paratypes, returned to Mr. John Clark, for eventual placement in the Commonwealth Scientific and Industrial Research Organization collection at Canberra; paratypes also in the collections of the Museum of Comparative Zoology. Harvard University, the U.S. National Museum, the South Australian Museum, and elsewhere.