Futabasaurus

---

title: "Futabasaurus" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["late-cretaceous-plesiosaurs", "fossil-taxa-described-in-2006", "plesiosaurs-of-asia", "extinct-animals-of-japan", "elasmosauridae", "fossils-of-japan", "sauropterygian-genera", "santonian-life"] description: "Extinct genus of reptiles" topic_path: "geography/japan" source: "https://en.wikipedia.org/wiki/Futabasaurus" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of reptiles ::

| image = National Museum of Nature and Science- Futabasaurus.jpg | image_caption = Reconstructed skeleton at National Science Museum, Tokyo | fossil_range = Late Cretaceous (Santonian) | genus = Futabasaurus | parent_authority = Sato, Hasegawa & Manabe, 2006 | authority = Sato, Hasegawa & Manabe, 2006 | species = suzukii

Futabasaurus is a genus of plesiosaur from the Late Cretaceous of Fukushima, Japan. It was described and named in 2006, and was assigned to the family Elasmosauridae. The genus contains one species, F. suzukii.

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/f/fb/Futabasaurus_suzukii.png" caption="[[Life restoration"] ::

Futabasaurus has been estimated over 6 m in length, It can be distinguished from other elasmosaurids by the following characteristics: there is a long distance between the eye sockets and nostrils; the interclavicles and clavicles are fused, and the anterior edge is bent; the humerus is relatively long; and the femora are slim and show prominent muscle scars.

Discovery and naming

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b8/National_Museum_of_Nature_and_Science-_Futabasaurus_at_Japan_Gallery.jpg" caption="Cast of fossils of ''[[Futabasaurus suzukii]]'' exhibited at the [[National Museum of Nature and Science"] ::

Futabasaurus is the first elasmosaurid found in Japan. It was originally known as either "Wellesisaurus sudzuki" or "Futaba-ryu" before publication. The type specimen of Futabasaurus was found in the Irimazawa Member of the Tamayama Formation, in the Futaba Group of Fukushima Prefecture, Japan. The rocks in which it were found date to the Inoceramus amakusensis zone of the early Santonian. The fossils were found by Tadashi Suzuki, then a high school student. specifically Cretalamna.

The genus Futabasaurus was named after the Futaba Group, in which it was discovered; the specific name is derived from the family name of its discoverer, Suzuki.

The name "Futabasaurus" has also been used for an unrelated theropod dinosaur, from the Late Cretaceous Ashizawa Formation of Japan. However, this dinosaur was not officially named, and remains a nomen nudum.

Classification

::figure[src="https://upload.wikimedia.org/wikipedia/commons/a/a2/Палеонтологический_музей_Орлова_(20221008135801).jpg" caption="Pre-2006 skeletal mount which is informally labelled as "Wellesisaurus sudzuki" (with a large stone containing [[crinoid]]s and [[ammonite]]s in the background)"] ::

The following cladogram shows the placement of Futabasaurus within Elasmosauridae following an analysis by Rodrigo A. Otero, 2016: ::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b6/Fossil_of_Futabasaurus_suzukii_02.jpg" caption="Fossils"] ::

|label1=Elasmosauridae |1={{clade |1=Eromangasaurus carinognathus |2={{clade |1=Callawayasaurus colombiensis |2={{clade |1=Libonectes morgani |2={{clade |1={{clade |1=Tuarangisaurus keyesi |2=Thalassomedon haningtoni }} |2={{clade |1=CM Zfr 115 |2={{clade |1=Hydrotherosaurus alexandrae |2=Futabasaurus suzukii }} }} |3={{clade |label1=Aristonectinae |1={{clade |1=Kaiwhekea katiki |2={{clade |1=Alexandronectes zealandiensis |2={{clade |1=Morturneria seymourensis |2={{clade |1=Aristonectes parvidens |2=Aristonectes quiriquinensis }} }} }} }} |label2=Elasmosaurinae |2={{clade |1=Terminonatator pointeixensis |2={{clade |1={{clade |1=Elasmosaurus platyurus |2=Albertonectes vanderveldei }} |2={{clade |1=Styxosaurus sp. (="Hydralmosaurus serpentinus") |2={{clade |1=Styxosaurus snowii |2=Styxosaurus browni }} }} }} }} }} }} }} }} }} }}

In Popular Culture

In the anime movie, Doraemon: Nobita's Dinosaur, Nobita finds a fossilized futabasaurus egg. Using Doraemon's tools, he makes the egg viable, hatches the egg, and raises it to adulthood before returning it to its time period.

References

References

1. (2016). "A Small Body Sized Non-Aristonectine Elasmosaurid (Sauropterygia, Plesiosauria) from the Late Cretaceous of Patagonia with Comments on the Relationships of the Patagonian and Antarctic Elasmosaurids". Ameghiniana.
2. (2010). "A remarkable case of a shark-bitten elasmosaurid plesiosaur". Journal of Vertebrate Paleontology.
3. Mortimer, Michael. (2008). "Neotheropoda". The Theropod Database.
4. (2016). "Taxonomic reassessment of ''Hydralmosaurus'' as ''Styxosaurus'': new insights on the elasmosaurid neck evolution throughout the Cretaceous". PeerJ.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::