Pseudonotoncus eurysikos

Pseudonotoncus eurysikos has been found primarily within dry sclerophyll forests in cool climate areas. It is likely this species is suited to cool areas with low rainfall. The majority of samples for this species are from forests near Melbourne, with single specimens from Black Mountain in the Australian Capital Territory, and Armidale in New South Wales. Very little is known of their nesting and foraging habits. Brown (1955) described this species (as P. hirsutus) at Arthurs Seat, Victoria as nesting in soil without covering or detectable craters and with workers and dealate females foraging on nearby shrubs for nectar and honeydew.

Identification
Petiole approximately square in dorsal view; in lateral view almost as long as high and with the anterior face rounding gradually into the domed dorsal face. Dorsal surface of petiole with course longitudinal rugae.

Pseudonotoncus eurysikos is similar to Pseudonotoncus hirsutus in all features except the size of the petiole (PetNL > 0.31 mm, PetW > 0.39 mm, LPetI > 57 vs. PetNL < 0.26 mm, PetW < 0.39 mm, LPetI < 56 in P. hirsutus) and the presence of course rugae on the upper petiolar surface (this surface is at most weakly sculptured in P. hirsutus).


 * Petiole approximately square in dorsal view; in lateral view almost as long as high, the anterior face rounding gradually into the domed dorsal face. Dorsal surface of petiole with course longitudinal rugae . . . . . Pseudonotoncus eurysikos


 * Petiole broader than long in dorsal view; in lateral view much higher than long, the anterior face separated from the flat dorsal face by a rounded angle. Dorsal surface of petiole smooth or with small foveate depressions . . . . . Pseudonotoncus hirsutus

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Known only from the worker caste.

Nomenclature

 *  eurysikos. Pseudonotoncus eurysikos Shattuck & O'Reilly, 2013: 289, fig. 1 (w.) AUSTRALIA.

Description
Worker description. Body uniform chocolate brown. Head in frontal view with sides tapering slightly anteriorly, as wide as long. Mandibles with six teeth, the first, second and fourth larger than the remaining. Clypeus with a central carina, tapering anteriorly into a central tooth. Frontal carinae short and sharply margined. Eyes large, convex, positioned one third from posterior margin of head, one and a half times longer than wide. Ocelli small but distinct. Scapes extending one third their length beyond posterior margin of the head. Mesosoma strongly rugose-punctate, the rugae more strongly developed and longitudinal laterally and on the mesonotum, more weakly developed dorsally on the pronotum and propodeum. In dorsal view pronotum transversely convex, twice as wide as long and wider than mesonotum and propodeum. Promesonotal suture convex and deeply impressed. Mesonotum and propodeum in dorsal view similar in width and very slightly convex. Mesonotum slightly longer than broad. Propodeum roughly square in dorsal view, with well developed, slightly curved spines at the angle and with two small spines just above the metapleural gland bulbs. Petiolar node higher than long, with a rounded dorsal surface and two posterior facing spines which are half as long as the width between their bases. In dorsal view petiolar node approximately square, with complex longitudinal rugae. Gaster simple, first segment (abdominal segment III) extending to half its length. Legs slender; tibiae and femora somewhat spindle-shaped and with numerous erect hairs.

Measurements. Worker (n=8) - CI 97–108; PetW 0.39–0.56mm; HL 0.96–1.23mm; HTL 1.02–1.15mm; HW 1.03–1.22mm; LPetI 57–67; ML 1.37–1.85mm; PetH 0.51–0.63mm; PetNL 0.31–0.40mm; SI 82–96; SL 0.90–1.05mm.

References based on Global Ant Biodiversity Informatics

 * Shattuck S. O., and A. J. O'Reilly. 2013. Revision of the Australian endemic ant genera Pseudonotoncus and Teratomyrmex (Hymenoptera: Formicidae: Formicinae). Zootaxa 3669 (3): 287301.