Chelaner anthracinus

The type material was captured in a pitfall trap. Only a few stray workers have been collected and little is known about the biology of this ant.

Identification
Heterick (2001) - A member of the bicorne group. This inconspicuous species strongly resembles minor workers of Chelaner rufonigrum, but can be distinguished from them on the basis of eye shape (elongate versus elliptical or ovoid).

Heterick (2009) - Similar in size to many ants in the M. monomorium group, this is an uncommon, elongate-eyed species.

Distribution
Heterick (2009) - Most specimens have come from within the semi- arid areas of the SWBP, WA but the ant has also been collected from Bush Bay, in the Carnarvon district, just north of the Province.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  anthracinum. Monomorium anthracinum Heterick, 2001: 370, figs. 21, 55 (w.) AUSTRALIA.
 * Combination in Chelaner: Sparks et al., 2019: 232.

Worker
Holotype. HML 1.24; HL 0.48; HW 0.44; Cel 90; SL. 0.28; SI 68; PW 0.28. Other. HML 1.28-1.47; HL 0.52-0.57; HW 0.46-0.52; 89-91; SL 0.30-0.33; SI 64-65; PW 0.28-0.33 (2 measured).

As for minor worker of Monomorium rufonigrum but with the following apomorphies.

Head. Vertex of head planar; frons smooth and shining with incurved decumbent and subdecumbent setulae. Compound eyes elongate, much longer than wide; (viewed laterally) compound eyes set posterior of midline of head capsule; eye large, eye width greater than 1.5 x greatest width of antennal scape. Posteromedial clypeal margin situated between anterior and posterior surfaces of antennal fossae. Mandibles smooth with piliferous punctures.

Alitrunk. Promesonotal sculpture present in form of uniform microreticulation with few mesopleural striolae; dorsal promesonotal face convex anteriad, otherwise flattened; setulae decumbent and subdecumbent. Propodeal angle present; length ratio of dorsal face to declivitous face near 4:3 to near 1:1. Erect and suberect propodeal setae 5-10; propodeal setulae absent.

Petiole and postpetiole. Petiolar spiracle lateral and slightly anteriad of petiolar node. Petiolar node tumular and inclined anteriad. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 4:3. Anteroventral process always present as pronounced spur. Ventral lobe always absent. Height ratio of petiole to postpetiole near 1: 1; height-length ratio of postpetiole near 4:3. Sculpture present in form ofmicroreticulation.

General characters. Colour dark chocolate, mandibles orange. Worker caste monomorphic

Etymology
Greek: “coal-black”.