Turneria bidentata

Turneria bidentata occurs in the Top End of the Northern Territory and along the east Australian coast from the Cape York Peninsula to extreme north-eastern New South Wales. It is a twig-nesting species that is reasonably common although it is infrequently encountered because of its arboreal nesting habits. It is known to nest in a wide range of tree and shrub species.

Identification
Cephalic index (head length/head width) < 0.88, relative eye length (eye length/head width) > 0.40, frontal lobes without erect hairs, lateral areas of head moderately imbricate and with integument opaque, area between propodeal protuberances concave. In lateral profile, the concave region of the declivitous face of the propodeum is more rounded than in other species.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  bidentata. Turneria bidentata Forel, 1895f: 419 (w.) AUSTRALIA. Shattuck, 1990: 108 (q.m.).

Description
The clypeus possesses 8 to 14 erect hairs. Color varies from uniform dark brown or black to strongly bicolored with the head, alitrunk, legs and petiole yellow and the gaster brown. In lighter colored individuals, the dorsum of the head may be slightly darker than the mesosoma.

Worker measurements (n=25): OOD 0.15-0.21, EL 0.24-0.28, OCD 0.10-0.13, CL 0.13-0.19, HL 0.65-0.75, LES 0.03-0.05, EW 0.11-0.15, ES 0.24-0.28, HW 0.55-0.66, SL 0.41-0.46, PnL 0.30-0.42, ML 0.27-0.37, PpL 0.23-0.30, PnW 0.36-0.43, MW 0.23-0.30, PpW 0.25-0.29, PO -0.01-0.04, FFL 0.41-0.53, FFW 0.16-0.21, MH 0.31-0.39, PpH 0.22-0.29, CI 0.80-0.88, OI 0.43-0.57, REL 0.40-0.48, SI 0.70-0.79, FI 0.34-0.48, PI 0.63-0.71, PpI 0.87-1.10, ROOD 0.28-0.33, POI -0.04-0.17, RPO -0.02-0.07, RMW 0.42-0.47, RLES 0.05-0.09, RES 0.41-0.45, RFFL 0.66-0.94.

Body color in this species is highly variable. Populations from the vicinity of Cairns are uniform dark brown, Mackay-area populations are strongly bicolored, while southern collections from Burleigh Heads are yellowish brown with the gaster slightly darker; in extreme cases some workers are yellow-brown with a black gaster. None of these populations diverge in any of other morphological traits, although the Cairns-vicinity specimens average slightly, but insignificantly, smaller. For most traits all known specimens broadly overlap. The Cairns-vicinity populations diverge slightly from the more southern ones in two metric traits, MW and PpH, as follows: MW 0.23-0.27 vs. 0.25-0.30 and PpH 0.22-0.25 vs. 0.23-0.29. The broad overlap in the ranges of these characters make them of little value in separating these populations.

The convexity of the area between the propodeal spiracles (when viewed dorsally), a character used to separate this species from the Papua New Guinea-based T. arbusta by Shattuck (1990), is now known to vary more than originally thought, being less concave in some specimens, especially those from the Northern Territory (Shattuck 2011). However, this region is still concave and the separation from T. arbusta is supported by this character as well as differences in head shape (more elongate in T. bidentata and broader in T. arbusta) and scape length (averaging shorter in T. bidentata, longer in T. arbusta). Together, these characters suggest that these species are distinct and both are best regarded as valid species.

References based on Global Ant Biodiversity Informatics

 * CSIRO Collection
 * Forel A. 1895. Nouvelles fourmis d'Australie, récoltées à The Ridge, Mackay, Queensland, par M. Gilbert Turner. Ann. Soc. Entomol. Belg. 39: 417-428.
 * Reichel H., and A. N. Andersen. 1996. The rainforest ant fauna of Australia's Northern Territory. Australian Journal of Zoology 44: 81-95.
 * Shattuck S. O. 1990. Revision of the dolichoderine ant genus Turneria (Hymenoptera: Formicidae). Systematic Entomology 15:101-117.
 * Shattuck S. O. 2011. Turneria rosschinga sp.n. (Hymenoptera: Formicidae), a new dolichoderine ant from Australia. Myrmecological News 15: 125-128.