Tyrannosaurus bataar Maleev 1955

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.