Chelaner nigriceps

Beyond some clues from label data (rainforest, moss on rocks & trees, pyrethrum, Berlesate) little is known about the biology of .

Identification
Heterick (2001) - A member of the rubriceps group. As the name suggests, the black head of this species is diagnostic, and clearly separates it from the otherwise similar Chelaner leae and Chelaner centrale. The strongly indented anteromedial clypeal margin found in C. nigriceps is reminiscent of Chelaner forcipatum (New Caledonia).

Distribution
This rainforest member of the rubriceps-group appears to have a restricted distribution in Northeast Queensland. Since the time of the study, an additional specimen has been identified among material collected by Prof. R. Kitching through canopy fogging in Eungella National Park.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  nigriceps. Monomorium nigriceps Heterick, 2001: 434, fig. 44 (w.) AUSTRALIA.
 * Combination in Chelaner: Sparks et al., 2019: 233.

Worker
Holotype. HML 1.77; HL 0.62; HW 0.53; CeI 85; SL 0.41; CeI 78; PW 0.36. Worker measurements. HML 1.69-1.78; HL 0.60-0.64; HW 0.52-0.54; CeI 84-87; SL 0.41-0.54; SI 78-83; PW 0.34-0.37 (4 measured).

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

Head. Head square or rectangular. Compound eyes elliptical; (viewed from front) compound eyes set in anterior half of head capsule. Anteromedial clypeal margin emarginate, median clypeal carinae produced as pair of bluntly rounded denticles. Posteromedial clypeal margin level with posterior surface of antennal fossae. Palp formula unknown. Apical and basal mandibular margins meeting in curve.

Alitrunk. Dorsal promesonotal face evenly convex. Metanotal groove present as distinct and deeply impressed trough between promesonotum and propodeum. Propodeal sculpture present as faint microreticulation with few striae, mainly on lower lateral surface; processes absent (propodeum angulate in profile). Propodeal angle present; length ratio of dorsal face to declivitous face near 2: 1; declivitous face of propodeum longitudinally concave between its lateral margins. Propodeal setulae decumbent and subdecumbent.

Petiole and postpetiole. Petiolar node cuneate, dorsally rounded; sculpture absent, petiolar node smooth and shining. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 4:3 to near 1: 1. Ventral lobe always absent. Height ratio of petiole to postpetiole near 4:3; height-length ratio of postpetiole near 2:1 to near 4:3.

General characters. Colour of alitrunk, petiole, postpetiole and appendages orange, head and gaster dark chocolate. Worker caste monomorphic.

Type Material
Holotype. Worker (top point), Queensland, Windsor Tableland, 8.i.1989, E. Schmid & ANZSES, 1186 m, site 9 pyrethrum. Paratypes. Queensland: 1 + 2 workers, with same data as the holotype (ANIC, ); 1 worker, Thornton Peak, 11 miles NE Daintree, 1.xii.1983, Monteith, Yeates & Thompson, QM berlesate no. 605, rainforest 1100 m, moss on rocks and trees.



Etymology
Latin: “black-headed”.