(Figs. 48, 49, 75, 84)
HOLOTYPE WORKER. TL 6.0, HL 1.40, HW 1.70, FC 1.35, CS 1.55, SL 1.0, SI 1 59, SI 2 65, PML 1.25, PW 1.58, PMD 1.76, PMI 2 112, ML 1.55, PTLL 0.44, PTLH 0.63, PTDW 0.56, PPLL 0.41, PPLH 0.59, PPI 70, PPDW 0.61, PT / PP 92.
Mandible with five teeth. In full face view clypeus distinctly carinulate, oblique anterior margin broadly and deeply excavated, anterolateral corners produced into acute teeth, weakly surpassing anterolateral frontal corners. Head wider than long (CI 121), preoccipital margin only shallowly concave. Frontal carinae markedly narrower than head width (FI 126), weakly sinuately narrowing towards clypeus. With head in profile antennal scrobe reaching far beyond middle of lateral side of head, distinctly transversely carinulate with additional shagreening, well defined posteriorly by a carina against remainder of head. Genae rugose, ventrolateral sides of head and preoccipital lobes coarsely reticulate. Eyes moderately large (EL 0.35, REL 0.25, with 19 ommatidia in the longest row), situated slightly in front of middle of lateral sides of head, the dorsal ocular margin confluent with the ventral scrobal margin. Dorsal surface of head coarsely rugoreticulate, interspaces glossy.
Promesonotal shield moderately wider than long (PMI 126), mesonotum indented with mesonotal projections well developed and rather acute, translucently fused. Propodeal spines moderately long (PSL 0.55), situated at about middle of lateral sides of the propodeal declivity, narrow and acute, in dorsal view markedly arcuate and diverging.
Petiole in lateral view narrowly trapezoid, higher than long (PTI 70), dorsum convex and reticulate, posterior face rugose. Postpetiole nodular with small anterio-basal tooth.
First gastral tergite entirely microreticulate. Dorsal surfaces covered with short decumbent and longer erect thin whitish hairs.
Distinctly bicolored as in preceding species.
WORKER (n = 8). TL 4.90 - 6.50, HL 1.25 - 1.45, HW 1.43 - 1.73, FC 1.15 - 1.45, FI 123 - 128, CI 114 - 125, CS 1.34 - 1.59, SL 0.85 - 1.0, SI 1 57 - 61, SI 2 61 - 66, PML 0.95 - 1.25, PW 1.30 - 1.58, PMI 126 - 148, PMD 1.43 - 1.76, PMI 2 107 - 112, ML 1.20 - 1.55, PSL 0.45 - 0.61, PTLL 0.40 - 0.45, PTLH 0.60 - 0.65, PTI 64 - 70, PTDW 0.48 - 0.56, PPLL 0.38 - 0.41, PPLH 0.53 - 0.63, PPI 63 - 71, PPDW 0.54 - 0.63, PT / PP 84 - 95, EL 0.29 - 0.35, REL 0.22 - 0.25, with 17 - 19 ommatidia in the longest row.
ETYMOLOGY
Named for Archie McArthur, great (old) man from Adelaide, who I had the honor and pleasure to meet in Vienna during his trip to Europe in early spring 2004. He sent hundreds of pitfall samples which included most important material for this study and which certainly will bring to light further interesting data.
ADDITIONAL MATERIAL EXAMINED
Northern Territory : 9 km ECurtin Springs , 20. xi. 1977 ( J. E. Feehan ) . New South Wales : 2 mi. WJacob's Well , 23. xi. 1949 ( T. Greaves ) . South Australia : 26.3 km ENEMimili , 25. - 31. x. 1998 (coll. unknown) ; 48.9 km SEMount Lindsay , 26. x. 1996 (coll. unknown) ; 8 km NWMorgan , 15. xii. 1976 ( P. J. M. Greenslade ) ; Victoria Desert , 10 km EEmu , 11. x. 1976 ( P. J. M. Greenslade ) ; 35 km SArraby , Leap yr. Bore , viii. 1975 ( Forrest ) . Victoria : Linga ( F. E. Wilson ) ; M. Western Australia : Morawa , 1961 ( G. H. Lowe ) . State unknown: ' Cent Australia' (coll. unknown) (37 workers in ANIC , NHMW , QMBA , SAMA , USNM , WAMP ) .
DISCUSSION
M. mcarthuri is well defined among related species by the mandibular dentition and by the widely concave clypeal structure. Specimens from Morowa (WA) have the promesonotal shield more distinctly indented between anterior and posterolateral mesonotal projections and the cephalic index markedly lower (CI 114; 118 - 125 in others). Widely distributed throughout central and southern Australia, with a single sample from Western Australia.
