(Figs. 18, 19, 61, 87)
HOLOTYPE WORKER. TL 6.05, HL 1.54, HW 1.63, FC 1.25, CS 1.58, SL 0.83, SI 1 51, SI 2 52, PML 1.20, PW 1.43, PMD 1.63, PMI 2 114, ML 1.48, PTLL 0.43, PTLH 0.63, PTDW 0.58, PPLL 0.45, PPLH 0.64, PPI 71, PPDW 0.55, PT / PP 105.
Mandible with four teeth. Clypeus in full face view surpassing anterolateral frontal corners, acutely bidentate, with an additional short acute medial denticle, accompanied by a low crest. Head only moderately wider than long (CI 106), rear margin shallowly concave. Frontal carinae evenly and rather broadly narrowing towards clypeus (FI 130). Antennal scrobe in lateral view surpassing middle of length of head posteriorly, distinctly transversely carinulate in posterior half, with additional microreticulation, posteriorly distinctly demarcated from remainder of head. Genae rugose, ventrolateral sides of head rugoreticulate, preoccipital lobes reticulate. Compound eyes of moderate size (EL 0.27, REL 0.18, with 16 ommatidia in the longest row) in lateral view situated in front of middle of lateral sides of head, dorsal ocular margin not reaching ventral scrobal margin.
Promesonotum wider than long (PMI 119), outline broadly translucently flanged, concealing lateral sides of mesosoma and propodeal declivity. Propodeal spines relatively short (PSL 0.51), acute and slightly arcuate and diverging, when seen in dorsal view.
Petiole distinctly higher than long (PTI 68), in profile with anterior face straight and unsculptured, posterior face convex, distinctly and regularly costate. Postpetiole elongately nodiform, with ventral medium sized tooth, rugose throughout.
First gastral tergite with dense microreticulum, basally with additional carinulae, with relatively short stiff decumbent and additional longer erect hairs. Dorsum of head longitudinally costulate anteriorly, posteriorly distinctly reticulate, interspaces with additional distinct microreticulum, with short decumbent hairs and longer stiff erect differently sized pilosity. Promesonotal shield rugoreticulate, pilosity similar to that of head.
Brown to fuscous with the gaster, legs and antennae slightly brighter.
WORKERS (n = 6). TL 4.75 - 6.05, HL 1.23 - 1.54, HW 1.33 - 1.63, FC 0.98 - 1.25, FI 129 - 137], CI 106 - 109, CS 1.28 - 1.58, SL 0.67 - 0.83, SI 1 50 - 52, SI 2 52 - 55, PML 0.93 - 1.20, PW 1.18 - 1.43, PMI 118 - 127, PMD 1.33 - 1.63, PMI 2 109 - 114, ML 1.15 - 1.48, PSL 0.48 - 0.55, PTLL 0.35 - 0.43, PTLH 0.50 - 0.63, PTI 68 - 77, PTDW 0.46 - 0.58, PPLL 0.36 - 0.45, PPLH 0.48 - 0.64, PPI 68 - 76, PPDW 0.45 - 0.55, PT / PP 100 - 105, EL 0.21 - 0.27, REL 0.16 - 0.18, with 13 - 17 ommatidia in the longest row
ETYMOLOGY
The name refers to the tridentate clypeal projection.
ADDITIONAL MATERIAL EXAMINED
Queensland : Emerald , 15. xii. 1972 ( B. B. Lowery ) ; Moonie , 60 mls NGoondiwindi , 4. i. 1965 ( B. B. Lowery ) ; N ofBowen , xi. 1957 ( Darlington ) ; Allinga , Chinchilla , 31. vii. 1986 ( G. Lithgow ) . Northern Territory : Kunnoth Polk nr. Alice Springs , x. 1974 & 24. - 26. ix. 1980 ( P. J. M. Greenslade ). (13 workers, 1 gyne in ANIC , MCZC , NHMW , QMBA ) .
DISCUSSION
Superficially this taxon somewhat resembles M. wilsoni and M. mars , but is readily separated by the clypeus and, in addition by the translucently margined promesonotal shield.
Paratypes and additional other material from Queensland resemble the type. Specimens from Northern Territory show a slightly longer and thinner pilosity and the dorsal surface of the head is shiny with the microsculpture less developed. Known from coastal and south-central Queensland, with a single sample taken at Alice Springs. The disjunct occurrence of M. tricuspidatus most likely is only due to the lack of additional samples. This gap might be closed as soon as new material shows up.
