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Re: Building Blocks of T. rex (sorry about the last one)



_Ornithomimus grandis_ is based on a large (60 cm long) third metatarsal from
the Eagle Sandstone that is presently lost. The Eagle Sandstone is much
earlier than Lance/Hell Creek, and indeed earlier than Judith River. The
fossil was, I believe, the geologically oldest undoubted tyrannosaurid
material from North America (although Mike Brett-Surman said it MAY have
belonged to a big ornithomimid), which makes it most unlikely to be a synonym
of _Tyrannosaurus rex_. The referred material, however, includes a right
metatarsal IV (USNM 2110) found by J. B. Hatcher along Lance Creek in 1890,
an incomplete right hind limb with a 104-cm femur (USNM 6183) found by him,
and a right ilium (USNM 8064) found by him and A. E. Sullins near the hind
limb but not part of the same individual, from Alkali Creek, all in Wyoming.
These three specimens may be referable to _Tyrannosaurus rex_, or to the
somewhat smaller Lance tyrannosaurid _Dinotyrannus_ (formerly
_Albertosaurus_) _megagracilis_. None is a type specimen, so _Tyrannosaurus
rex_ is safe.

_Manospondylus gigas_ is based on a giant caudal cervical or cranial dorsal
(Hi, Larry Witmer!) centrum (AMNH 3982; there were once two, but one is lost)
from a theropod at least as large as the largest _Tyrannosaurus rex_ known
from good skeletal material. But because more than one species of
_Tyrannosaurus_ may be present in the Lance, reference to the genotype
species _Tyrannosaurus rex_ is not certain enough to warrant changing the
generic or specific name. (If it were, I'd be the first in line with a
petition to suppress _Manospondylus gigas_.)

All these "lost" specimens make me wonder why anyone would want to turn
material over to a museum... (just kidding!!).

George O.