Tyrannosaurus bataar Maleev 1955a

Holtz, T. R., 2001, The phylogeny and taxonomy of the Tyrannosauridae, Mesozoic Vertebrate Life, Bloomington: Indiana University Press, pp. 64-83 : 70

Tyrannosaurus bataar Maleev 1955a :

As used here, this species includes several specimens previously referred to other taxa: Tarbosaurus efremoui Maleev 1995b , Gorgosaurus lancinator Maleev 1955b , and Maleevosaurus novojilovi ( Maleev 1955b) . As with Currie (in press), and Carr (1999),the present study considers these taxa a growth series of a single species, rather than two ( Carpenter 1992) or three ( Olshevsky et al., 1995 a, b) different genera. Tyrannosaurus bataar is from the Nemegt Formation (Early Maastrichtian) of Mongolia: numerous isolated elements and teeth from comparable aged units in China might be referable to T. bataar .

The hypothesis of Olshevsky et al. (1995a, b) that T bataar isless closely related to Tyrannosaurus rex than the latter is to other North American tyrannosaurines is not supported: instead numerous synapomorphies strongly unite the Asian taxon with Tyrannosaurus rex . Given the number of these similarities, the original name Tyrannosaurus bataar is retained. However the use of the name Tarbosaurus bataar (as in Russell 1970; Molnar et al. 1990; Currie in press) would be no less appropriate phylogenetically. The juvenile and subadult material demonstrates some of the autapomorphies found in the adults: the type skull of " Gorgosaurus lancinator " shows 12.0 and73.1;the type material of " Maleeuosauruzs " shows 84.2 and 102.1. T.bataar is characterized by the most reduced foreiimbs known within Tyrannosauridae : the general theropod reduction in digital and metacarpal elements from digit V toward digit I ( Wagner and Gauthier 1999) is seen developed further in this species than in other tyrannosaurids.