(Figs. 50, 51, 76, 88)
HOLOTYPE WORKER. TL 4.15, HL 1.05, HW 1.15, FC 0.80, CS 1.10, SL 0.59, SI 1 51, SI 2 53, PML 0.65, PW 0.93, PMD 1.05, PMI 2 114, ML 0.93, PTLL 0.29, PTLH 0.44, PTDW 0.36, PPLL 0.28, PPLH 0.43, PPI 64.71, PPDW 0.40, PT / PP 91.
Mandible with four teeth. In full face view anterior clypeal margin with few carinulae, bifurcate with anterolateral corners produced into long acute teeth; the latter distinctly surpassing the anterolateral frontal corners. Head almost square, only little wider than long (CI 110), preoccipital margin very shallowly concave. Frontal carinae markedly narrower than head width (FI 144), sinuately converging towards clypeus. With head in profile antennal scrobe reaching beyond middle of lateral side of head, weakly transversely carinulate with distinct additional shagreening, distinctly defined posteriorly against remainder of head. Genae and anterior ventrolateral section of head carinate, preoccipital lobes coarsely reticulate. Eyes relatively large and rather flat (EL 0.27, REL 0.29, with 14 ommatidia in the longest row), situated slightly in front of middle of lateral sides of head, the dorsal ocular margin touching the ventral scrobal margin. Dorsal surface of head densely rugoreticulate, interspaces microsculptured.
Promesonotal shield rugoreticulate, short and distinctly vaulted (PMI 142), somewhat square with bluntly reduced projections. Propodeal spines medium sized in relation to small body (PSL 0.35), situated rather high on lateral sides of the propodeal declivity, acute and in dorsal view slightly arcuate and diverging.
Petiole in lateral view trapezoid, higher than long (PTI 66), dorsum convex and reticulate. Postpetiole reticulate, nodular with triangular antero-basal tooth.
First gastral tergite regularly and densely microreticulate, basally with few additional carinulae. Dorsal surfaces covered with short decumbent and longer erect thin whitish hairs. Distinctly bicolored.
WORKERS (n = 21). TL 3.90 - 4.80, HL 0.99 - 1.20, HW 1.10 - 1.35, FC 0.80 - 0.94, FI 131 - 146, CI 107 - 115, CS 1.04 - 1.28, SL 0.59 - 0.65, SI 1 48 - 53, SI 2 51 - 56, PML 0.65 - 0.88, PW 0.93 - 1.08, PMI 120 - 142, PMD 1.05 - 1.20, PMI 2 107 - 116, ML 0.88 - 1.08, PSL 0.33 - 0.40, PTLL 0.26 - 0.35, PTLH 0.41 - 0.50, PTI 58 - 70, PTDW 0.33 - 0.41, PPLL 0.25 - 0.33, PPLH 0.38 - 0.50, PPI 58 - 70, PPDW 0.38 - 0.46, PT / PP 81 - 97, EL 0.27 - 0.32, REL 0.26 - 0.29. with 14 - 17 ommatidia in the longest row.
ETYMOLOGY
The name refers to the horn-shaped anterolateral clypeal projections (' taurus', Latin for bull).
ADDITIONAL MATERIAL EXAMINED
Northern Territory : 15 km SWKatherine , 7. iv. 1978 ( P. J. M. Greenslade ) ; Tanami Rd98 km WStuart Hwy. , 7. vii. 2003 ( R. R. Snelling ) ; TanamiRd 35 km WStuart Hwy. , 5. vii. 2003 ( R. R. Snelling ) . Queensland : Sandringham , 18. - 25. ii. 198 ( P. J. M. Greenslade ) . New South Wales : N. Nyngan ' Kapunda' , 6. v. 1987 ( P. J. M. Greenslade ) ; c. 45 km W by S ofWilcania , 11. xii. 1973 ( R. J. Kohout ) ; 8 km SConargo , 8. v. 1979 ( B. B. Lowery ) ; Lightning Ridge , 10. v. 1961 ( B. B. Lowery ) . Victoria : Patho ( H. A. Potter ) . South Australia : 2.5 km NWNinety Nine Dam , Anna Creek Stn. , 1. - 5. iii. 1996 (coll. unknown) ; Top Camp Well , Hamilton Stn. , 14. - 17. xi. 1995 (coll. unknown) ; Innamincka , 9.5 km NWPatchawara bore , 10. - 14. xi. 1995 (coll. unknown) ; 4.3 km NEArmistice bore , Anna Creek Stn. , 1. - 5. iii. 1996 (coll. unknown) ; Cordillo Downs Stn. , 3.7 km WFrew well (coll. unknown) ; Murnpeowie , Mount Moolawatana , 16. - 17. xi. 1994 ( R. Tynan ) ; Andamooka , 5.6 km WNWNetting Dam , 10. - 14. xi. 1996 (coll. unknown) ; 3 km EMyra Mitta bore , 28. iv. 1995 ( T. Robinson ) ; Nilpinna Stn. , 4.1 km SSE , Arckaringa WH , 15. - 20. ix. 1996 (coll. unknown) ; 5.2 km ESEStrangeways Springs , Stuart Creek Stn. , 25. - 30. ix. 1995 (coll. unknown) ; Stuart Creek Stn. , 7.5 km Esheep camp WH (coll. unknown) ; Anna Creek Stn. , 28 km WNWBackadinna Dam , 2. - 6. x. 1995 (coll. unknown) ; Anna Creek Stn. , 15.6 km SWBackadinna Hill , 2. - 6. x. 1995 (coll. unknown) ; Peake Stn. , 0.9 km NEFour Hills Trig , 1. - 5. iii. 1996 (coll. unknown) ; 8 km NWApollo Bore , iv. 1995 (coll. unknown) ; 7.5 km NWApollo Bore , iv. 1995 (coll. unknown) ; Lake Eyre north , 20. vi. 1991 ( P. & I. Gee ) ; Screech-Owl Creek , 27. iv. 1995 (coll. unknown) ; 15 km SEBalcanoona HS , 19. vii. 1997 (coll. unknown) ; 3.8 km ESECoppertop Hill , Peak Stn. , 1. - 5. iii. 1996 (coll. unknown) ; Woorana WH , 6.2 km SMacumba , 21. - 25. ix. 1996 (coll. unknown) . Western Australia : 8 km EGascoyne junction , road turn-off, 4. vii. 1981 ( B. Heterick ). (82 workers, 2 gynes, in ANIC , JDMP , LACM , NHMW , SAMA ) .
DISCUSSION
M. taurus shows very little variability throughout its wide range. However, specimens from a single sample taken at Katherine, Northern Territory are uniformly ferrugineous and have the frontal striation more delicate. Southeastern-most samples, namely from Nyngan, Conargo, Lightning Ridge and Patho differ by the clypeal bifurcation less acutely developed, by the petiole more angulate in profile and by the markedly smaller eyes (REL 0.21 - 0.24), with 13 - 15 ommatidia in the longest row). Both forms are at least very closely related and are here tentatively added to taurus . Further material will be needed to decide whether these samples belong to taxa different from taurus . Occuring more or less sympatric with angustinodis and variabilis in central and south-east Australia, except two remote collection sites in the far west and one in the north, respectively. This small species is very distinctive by the large eyes, the clypeal bifurcation and the square promesonotal shield with its reduced blunt projections.
