Tyrannosaurid Caudal Vertebra Found - Yezo Group, Ashibetsu, Hokkaido

A caudal vertebra believed to be from a tyrannosauroid (a member of the tyrannosaur family) was discovered in the Late Cretaceous (about 86.3-89.8 million years ago) Haborogawa Formation of the Yezo Group, which extends across Ashibetsu City, Hokkaido. Analysis by the Hokkaido University Museum and the Mikasa City Museum revealed a high probability that the fossil, discovered in 2016 by amateur fossil enthusiast Hidetoshi Ogawa while collecting shark teeth, belongs to a tyrannosauroid. The specimen was 89 mm.

Identification involved external morphological comparison and CT scanning.
Due to its elongated shape with a height-to-length ratio of 0.63, therizinosaurs and oviraptorosaurs were ruled out. The morphology of the articular surfaces did not match that of ornithomimosaurs. However, a comparison with tyrannosauroids showed a near-perfect match.

To date, tyrannosauroid fossils have been reported from four locations in Late Cretaceous strata in Japan. A fossil believed to be from a tyrannosauroid from a similar period (about 86.3-89.8 million years ago) has also been found in Fukushima Prefecture, suggesting that tyrannosauroid theropods inhabited the north-south extending region during this time.

Source - Hokkaido University PRESS RELEASE