Satsuma-utsunomiya-ryu

[2] It is the oldest known elasmosaurid plesiosaur fossil in East Asia, dating back to approximately 100 million years ago.

[4][5] The specimen of Satsuma-utsunomiya-ryu (SU01) was discovered from the Hegushi Formation of the Goshoura Group (lower Cenomanian, Upper Cretaceous) of Shishijima Island, Kagoshima Prefecture in 2004 by Satoshi Utsunomiya.

Features like ornamentation on tooth surfaces and the structure of cervical vertebrae, suggest that Satsuma-unomiya-ryu belongs to the Elasmosauridae and may represent a new species.

It is the oldest member of the family from East Asia and it offers crucial insights into the presence of elasmosaurid in the northwestern Pacific during the early Late Cretaceous.

[1] In 2021, Ustunomiya and Yasuhisa Nakajima reported presence of "pellet" around its throat region.