Chelaner macarthuri

Known only from three workers from two widely separated collections. The Poochera specimen was taken in a pitfall trap [A. McArthur, personal communication].

Identification
Heterick (2001) - A member of the rubriceps group. Monomorium macarthuri is an attractive species characterised by an unusually large, round postpetiole. This condition is normally associated with the genus Cardiocondyla, and is not found in any other Australian Monomorium.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  macarthuri. Monomorium macarthuri Heterick, 2001: 432, figs. 48, 82, 83 (w.) AUSTRALIA.

Worker
Holotype. HML 2.05; HL 0.74; HW 0.60; CeI 81; SL 0.54; SI 90; PW 0.47. Others. HML 1.95-2.02; HL 0.64; HW 0.52; Cel 80; SL 0.46-0.47; SI 89-91; PW 0.41-0.43 (2 measured).

As for the worker of Monomorium longiceps, but with the following apomorphies. Head. Frons of head capsule smooth and shining with scattered foveae and striolae, pilosity combination of incurved decumbent and subdecumbent setulae and erect and suberect setae. Compound eyes elliptical; (viewed laterally) compound eyes set posterior of midline of head capsule. Anteromedial clypeal margin straight or slightly emarginate, median clypeal carinae not produced as teeth or denticles. Frontal lobes parallel, sinuate. Mandibles (viewed from front) triangular and smooth, with piliferous punctures.

Alitrunk. Promesonotal sculpture present in form of scattered foveae and striolae, mainly on the mesopleuron, and mesopleural striae. Mesonotal suture absent. Metanotal groove present as feebly impressed furrow between promesonotum and propodeum. Dorsal propodeal face strongly convex; processes absent (propodeum smoothly rounded in profile or with slight hump at propodeal angle). Propodeal angle absent. Erect and suberect propodeal setae 5-10.

Petiole and postpetiole. Petiolar node cuboidal. Height ratio of petiole to postpetiole near 3:4 to near 1:1. Sculpture present in form of microreticulation. Ventral process vestigial.

General characters. Colour alitrunk, petiole and postpetiole reddish-orange, head, gaster and appendages gamboge yellow. Worker caste monomorphic.

Type Material
Holotype. 1 worker, South Australia, Maggea, 25.ix.1974, P. J. M. Greenslade. Paratypes. South Australia: 1 worker with same data as the holotype (ANIC); 1 worker, Poochera 32°45'S, 134°50'E, SAM Notho [Nothomyrmecia] search.



Etymology
Named in honour of Mr. A. J. McArthur, of the South Australian Museum.