(Figs. 8, 9, 56, 89)
HOLOTYPE WORKER. TL 5.15, HL 1.50, HW 1.58, FC 1.25, CS 1.54, SL 0.75, SI 1 48, SI 2 49, PML 1.02, PW 1.25, PMD 1.30, PMI 2 104, ML 1.25, PTLL 0.38, PTLH 0.53, PTDW 0.55, PPLL 0.35, PPLH 0.50, PPI 70, PPDW 0.54, PT / PP 102.33.
Mandible with three teeth. In full face view the clypeal elaboration distinctly exceeding anterolateral frontal corners, with a dorsal median bicarinate, anteriorly concave flat projection and lateral even longer arcuate acute denticles, the latter situated ventrally to the median projection. Head only moderately wider than long (CI 105), almost square, preoccipital margin distinctly concave. Frontal carinae sinuately narrowed towards clypeus, not as narrow as in former species (FI 126). Antennal scrobe in lateral view posteriorly surpassing middle of length of head, distinctly transversely carinulate at rear, without additional shagreening. Genae and ventrolateral sides of head carinate to rugose, preoccipital lobes reticulate. Eyes small (EL 0.26, REL 0.17, with 15 ommatidia in the longest row), in lateral view situated in anterior half of lateral sides of head, dorsal ocular margin never reaching ventral scrobal margin. Surface of head between ridges of rugo-reticulation with microsculpture.
Promesonotal shield wider than long (PMI 123), only narrowly translucently margined. Mesonotum posteriorly markedly converging, with the posterolateral projections acute and stout, the posterior medial projections bluntly rounded. Propodeal declivity partly visible from above. Propodeal spines rather short (0.44) situated above middle of length of declivity, when seen from above acute, straight and considerably divering. Petiole in lateral view higher than long (PTI 71), somewhat tectiform, anterior and posterior faces meeting in an acute angle with anterior petiolar face angulate, posterior face convex.
Postpetiole elongately nodiform to drop-shaped with a medium-sized anterio-basal tooth. Gaster entirely microreticulate, with faint basal striation. Surface covered with moderately dense regular pilosity consisting of shorter decumbent hairs and longer erect ones, in general pilosity on dorsal head shorter than on mesosoma and gaster.
Concolorous brown to dark-brown.
WORKERS (n = 7). TL 5.15 - 6.35, HL 1.48 - 1.70, HW 1.58 - 1.80, FC 1.25 - 1.35, FI 126 - 133, CI 103 - 110, CS 1.53 - 1.74, SL 0.75 - 0.88, SI 1 47 - 50, SI 2 49 - 52, PML 1.02 - 1.15, PW 1.25 - 1.5, PMI 119 - 136, PMD 1.3 - 1.5, PMI 2 98 - 106, ML 1.25 - 1.50, PSL 0.43 - 0.50, PTLL 0.38 - 0.45, PTLH 0.53 - 0.64, PTI 67 - 74, PTDW 0.55 - 0.65, PPLL 0.35 - 0.43, PPLH 0.50 - 0.61, PPI 61 - 77, PPDW 0.53 - 0.64, PT / PP 100 - 110, EL 0.25 - 0.29, REL 0.16 - 0.18, with 15 - 17 ommatidia in the longest row.
ETYMOLOGY
The name refers to the type locality.
ADDITIONAL MATERIAL EXAMINED
Northern Territory : Groote Eylandt , vii. 1983 ( J. D. Majer ) ; Nourlangie Rock , 17. viii. 1983 ( P. S. Ward ) ; Mudginberri , 18. vii. 1976 ( R. Mercer ) ; Koolpinyah , 1933 ( C. Barrett ) ; Larrimah , 16. vii. 1981 ( B. B. Lowery ) ; Mataranka Homestead , 22. viii. 1981 ( B. B. Lowery ) ; 20 km WKatherine , 1. vii. 1985 ( B. B. Lowery ) ; 23 km SWKatherine , 24. x. 1977 , 27 km SWKatherine , 25. x. 1977 , 30 km SWKatherine , 10. iv. 1978 ( P. J. M. Greenslade ) ; Berrimah , Darwin distr ., 8. vii. 1951 ( W. L. Brown ). (43 workers in ANIC , JDMP , MCZC , NHMW , PSWC , USNM ) .
DISCUSSION
M. berrimah is a quite uniform taxon within its limited range, but shows variation in the clypeal elaboration to some extent, concerning both size and occasional additional lateral carinae. However, its structural distinctness in combination with the relatively small size (HW 1.60 - 1.80), the non-striate gaster and the petiolar shape separate M. berrimah easily from other related group members. Small M. unicolor workers, that might show a similar clypeal structure are readily separated by their striate gaster. Hitherto known from Top End, Northern Territory.
