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Oldest Coelurosaurian Found
The July 16, 1998 issue of Nature announces a new therizinosaur (no
name given) (Nature 394, 234-235) "The Oldest Coelurosaurian" - Xijin
Zhao, Xing Xu.
"This discovery extends the age range of these unusual animals,
previously known only from the Cretaceous period (Albian-Maastrichtian
stage1), back by another 94 million years. This is the oldest definitive
record of a coelurosaurian theropod, which therefore minimizes the
divergence time for members of the group. Most important, it contradicts
the theory that the non-avian Coelurosauria occur too late in the fossil
record to be related to birds."
"This specimen (V11579, held at the Institute of Vertebrate
Paleontology and Paleoanthropology, Beijing), consisting of most
of the left dentary and part of the splenial, was collected from
the bottom of dull, purplish beds of the Lower Lufeng Formation of
Eshan County, Yunnan."
"The therizinosauroid affinities of the specimen are indicated by the
presence of a broad and flat shelf lateral to the tooth row and the
few, large nutrient foramina below it; the downturned anterior end of
the dentary; the decrease in the size of teeth posteriorly; the large
number and small size of the teeth; and the morphology of the
"The new specimen is therefore the oldest fossil definitively referable
to Coelurosauria, extending the record of this group back by roughly
30 million years."