Chelaner flavoniger

Unlike the closely related Chelaner longinode, Chelaner flavonigrum seems to have a restricted distribution in the Murchison district, Western Australia, with just two collections taken east of Geraldton at the time of this study. Since then additional worker material has been collected from nests on the Canna townsite, 15 km S of Tardun. (Heterick 2001)

Identification
Heterick (2001) - A member of the longinode group. Features of colour (bicoloured yellow and dark brown as opposed to a combination of various shades of red and brown) and head shape (trapezoid versus square or rectangular) most clearly separate C. flavonigrum from Chelaner longinode.

Distribution
Heterick (2009) - Known only from in and around the Geraldton region, in the mid-north WA. Specimens in the Curtin Ant Collection come from Canna and the Kalbarri NP.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  flavonigrum. Monomorium flavonigrum Heterick, 2001: 392, figs. 31, 65, 71 (w.q.) AUSTRALIA.
 * Combination in Chelaner: Sparks et al., 2019: 232.

Worker
Holotype. HML 2.83; HL 0.97; HW 0.87; CeI 90; SL 0.83; SI 95; PW 0.60. Others. HML 2.55-2.82; HL 0.90-1.00; HW 0.91-0.96; Cel 89-100; SL 0.75-0.86; SI 85-92; PW 0.48-0.58; (12 measured).

As for the worker of M. longinode, but with the following apomorphies.

Head. Head trapezoid, narrowest towards vertex; frons longitudinally striate with combination of appressed setulae and erect and suberect setae. (Viewed laterally) compound eyes set anterior of midline of head capsule.

Alitrunk. Promesonotal sculpture present in form of microreticulation, striolae and striae on the mesopleuron, and striolae on posterodorsal promesonotal surface; dorsal promesonotal face evenly convex; erect and suberect promesonotal setae 5-10. Propodeal sculpture present as uniform microreticulation, with few or no striae or costulae; dorsal propodeal face gently convex; processes absent (propodeum smoothly rounded in profile or with slight hump at propodeal angle). Propodeal angle present; declivitous face of propodeum flat. Erect and suberect propodeal setae absent or very sparse; propodeal setulae absent. Propodeal spiracle lateral and nearer declivitous face of propodeum than metanotal groove.

Petiole and postpetiole. Petiolar spiracle ventral and slightly anteriad of petiolar node. Petiolar sculpture present in form of microreticulation. Anteroventral process always absent or vestigial. Height ratio of petiole to postpetiole near 3:4 to near 1 : 1; height-length ratio of postpetiole near 4:3 to near 1: 1. Sculpture present in form of microreticulation.

Gaster. Pilosity of first gastral tergite consisting entirely of well-spaced appressed setulae.

General characters. Colour of head orange, alitrunk petiole and postpetiole dark brown to black, gaster bright gamboge yellow, legs brown. Worker caste monomorphic.

Queen
Ergatoid. HML 3.39; HL 1.03; HW 1.09; Cel 105; SL 0.88; SI 81; PW 0.88 (1 measured).

As for the worker, but differing in the following particulars:

Head. Head square or rectangular. (Viewed from front) compound eyes set in anterior half of head capsule; (viewed laterally) compound eyes set at midline of head capsule.

Alitrunk. Mesoscutum in profile evenly convex. Mesoscutal pilosity consisting of dense in curved setulae and setae; dorsal appearance of mesoscutum finely microreticulate. Propodeal sculpture present as uniform rugosity, with well defined costulae on declivitous face of propodeum; dorsal propodeal face flattened. Propodeal angle absent. Erect and suberect propodeal setae 5-10; propodeal setulae decumbent and subdecumbent.

Petiole and postpetiole. Petiolar spiracle 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 2: 1. Anteroventral process of petiole a pronounced spur. Height ratio of petiole to postpetiole near 1 : 1; height-length ratio of postpetiole near 2:1. Sculpture absent on dorsum, at least: postpetiole mainly smooth and shining, faintly shagreenate on sides.

Gaster. Pilosity of first gastral tergite consisting entirely of erect and suberect setae.

General characters. Colour of head and gaster orange; alitrunk, petiole and postpetiole brown. Brachypterous alates not seen for this species.

Type Material
Holotype. Worker (top rectangle), Western Australia, Woongondy [= Wongoondy], 19.v.1963, C. Mercovich. Paratypes. Western Australia: 2 workers and 1 ergatoid with same data as holotype (ANIC); 8 workers, Tardun, 90 miles E of Geraldton (via Mullewa), 10.i.1963, C. Mercovich, 400 ft, semi-arid mallee ; 2 workers, Tardun, 10.i.1963, C. Mercovich.



Etymology
Latin: “yellow-and-black”.