Chelaner parantarcticus

Chelaner parantarcticum is evidently a very rare or localised ant, known from a single series at the time of this study. More recently, additional specimens have been unearthed among material collected by Professor R. Kitching from fogged canopies in the Werrikimbe and Styx River districts, New South Wales. (Heterick 2001)

Identification
Heterick (2001) - A member of the rubriceps group. Chelaner parantarcticum is remarkably similar to some series of New Zealand's Chelaner antarcticum. Most notably, the elongate, parallel clypeal teeth of the Australian ant closely match those in New Zealand material. However, the colour of C. parantarcticum is not like any of the New Zealand series examined for this work. The latter specimens are a variable dull amber to chocolate. The strongly defined transverse costulae found on the declivitous face of the propodeum of C. parantarcticum are lacking in C. antarcticum, the average scape index is lower, and the petiolar node is rather more cuboidal than in the New Zealand species. Moreover, the shape of the postpetiolar node links C. parantarcticum with the C. rubriceps complex.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  parantarcticum. Monomorium parantarcticum Heterick, 2001: 434, figs. 47, 96, 103 (w.) AUSTRALIA.
 * Combination in Chelaner: Sparks et al., 2019: 233.

Worker
Holotype. HML 2.97; HL 1.05; HW 0.87; CeI 84; SL; 0.75; SI 86; PW 0.61. Paratypes. HML 2.66-3.03; HL 0.95-1.05; HW 0.80-0.90; CeI 84-87; SL 0.67-0.74; SI 82-83; PW 0.55-0.60.

As for the worker of Chelaner rubriceps, but with the following apomorphies.

Head. Head square or rectangular; vertex planar; frons smooth and shining with combination of incurved decumbent and subdecumbent setulae and erect and suberect setae. (Viewed laterally) compound eyes set anterior of midline of head capsule. Anteromedial clypeal margin emarginate, median clypeal carinae produced apically as pair of pronounced teeth. Mandibles (viewed from front) triangular and smooth, with piliferous punctures.

Alitrunk. Promesonotal setulae decumbent and subdecumbent. Metanotal groove present as distinct and deeply impressed trough between promesonotum and propodeum. Propodeal sculpture present on lower lateral surfaces only, dorsal surface smooth and shining; strongly defined costulae present on declivitous face of propodeum. Dorsal propodeal face sloping posteriad, with wedge-shaped flattening or shallow depression that is widest between propodeal angles; propodeal processes absent (propodeum smoothly rounded in profile). Propodeal angle absent; declivitous face of propodeum longitudinally concave between its lateral margins. Erect and suberect propodeal setae 5-10.

Petiole and postpetiole. Petiolar spiracle lateral and in anterior sector of petiolar node, or lateral and slightly anteriad of petiolar node. Petiolar node cuboidal. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 1:1 to near 3:4. Anteroventral process always present as pronounced spur. Height ratio of petiole to postpetiole near 1:1 to near 4:3; height-length ratio of postpetiole near 2:1.

General characters. Colour brick red, legs tan; gaster with vague, transverse brown band at junction of first and second gastral tergites. Worker caste monomorphic.

Etymology
Greek: “close to antarcticum” (NZ species Chelaner antarcticum)