"Satsuma-utsunomiya-ryu" is an undescribed plesiosaur known from Kyushu, Japan.[1] This nickname is named after the former province name of the discovery site and the discoverer, Satoshi Utsunomiya.[2] It is the oldest known elasmosaurid plesiosaur fossil in East Asia, dating back to approximately 100 million years ago. It is permanently exhibited at the Kagoshima Prefectural Museum.[3]
Furthermore, the world's first plesiosaur "pellet" was found in the throat area.[4][5]
Description edit
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. He worked on cleaning, research and publication later.[1] Since another findings of plesiosaur fossils are mostly from Hokkaido and Tohoku (like Futabasaurus and "Hobetsu-araki-ryu"), it is significant as the first discovery of plesiosaur fossil from Kyushu.
The known materials include the mandible, tongue bone (first record from Japan), fragments of the skull, 40 cervical vertebrae, and a limb bone. This specimen was possibly a juvenile, based on the structure of the vertebrae. 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.[4]
See also edit
- Satsuma-yokuryu, a pterosaur from same site
References edit
- ^ a b c 宇都宮, 聡 (2019-03-31). 鹿児島県長島町獅子島の上部白亜系御所浦層群から産出した 東アジア最古のエラスモサウルス科（爬虫綱，長頚竜目）(Oldest Elasmosauridae (Plesiosauria) in East Asia from the Upper Cretaceous Goshoura Group, Shishijima Island, Southwestern Japan) (Thesis) (in Japanese). Osaka Museum of Natural History.
- ^ "2004 年に鹿児島県長島町獅子島でクビナガリュウの化石が発見 (The finding of plesiosaur fossil from Shishijima, Nagashima-cho, Kagoshima prefecture in 2004)" (PDF). 鹿児島県立博物館 鹿博だより No.101. Kagoshima Prefectural Museum. March 20, 2020. Retrieved August 11, 2023.
- ^ "Kagoshima Prefectural Museum Guide Map" (PDF). Kagoshima Prefectural Museum. Kagoshima Prefectural Museum Guide Map. Retrieved August 11, 2023.
- ^ a b "１億年前の首長竜に現代の鳥に似た習性 ─ 世界初、未消化で吐き出した"ペリット"を発見 ─｜東京都市大学". www.tcu.ac.jp. Retrieved 2024-02-14.
- ^ 中島保寿; 宇都宮聡; 多久島徹 (2021). "エラスモサウルス科首長竜類の咽頭内容物". 日本古生物学会例会講演予稿集 (in Japanese). 170th (CD-ROM): 24.