Futabasaurus

{{Short description|Extinct genus of reptiles}}

{{For|the informally named dinosaur|List of informally named dinosaurs}}

{{Speciesbox

| image = National Museum of Nature and Science- Futabasaurus.jpg

| image_caption = Reconstructed skeleton at National Science Museum, Tokyo

| fossil_range = Late Cretaceous (Santonian) {{fossil_range|86.3|85}}

| 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

Image:Futabasaurus suzukii.png]]

Futabasaurus has been estimated over {{convert|6|m|ft}} in length, possibly within the range of {{convert|6.4|-|9.2|m|ft}}.{{cite journal | first1 = J.P. | last1 = O'Gorman | title = 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 | journal = Ameghiniana | volume = 53 | issue = 3 | pages = 245–268 | url = http://www.bioone.org/doi/abs/10.5710/AMGH.29.11.2015.2928 | doi = 10.5710/AMGH.29.11.2015.2928 | year = 2016| s2cid = 133139689 | hdl = 11336/54311 | hdl-access = free }} 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

Image:National Museum of Nature and Science- Futabasaurus at Japan Gallery.jpg 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. Many of the bones of the type specimen show signs of apparent scavenging or predation by sharks,{{cite journal |last=Sato |first=Tamaki |author2=Hasegawa, Yoshikazu |author3= Manabe, Makoto | year=2006 |title=A new elasmosaurid plesiosaur from the Upper Cretaceous of Fukushima, Japan |journal=Palaeontology |volume=49 |issue=3 |pages=467–484 |doi=10.1111/j.1475-4983.2006.00554.x|doi-access=free |bibcode=2006Palgy..49..467S }} specifically Cretalamna.{{cite journal|author1=Shimada, K.|author2=Tsuihiji, T.|author3=Sato, T.|author4=Hasegawa, Y.|year=2010|title=A remarkable case of a shark-bitten elasmosaurid plesiosaur|journal=Journal of Vertebrate Paleontology|volume=30|issue=2|pages=592–597|doi=10.1080/02724631003621920|bibcode=2010JVPal..30..592S |s2cid=128760390 }}

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.{{cite web|url=http://archosaur.us/theropoddatabase/Neotheropoda.htm#Futabasaurus |title=Neotheropoda |last=Mortimer |first=Michael |year=2008 |work=The Theropod Database |access-date=2009-11-17 |url-status=dead |archive-url=https://web.archive.org/web/20130929081120/http://archosaur.us/theropoddatabase/Neotheropoda.htm |archive-date=2013-09-29 }}

Classification

File:Палеонтологический музей Орлова (20221008135801).jpgs and ammonites in the background)]]

The following cladogram shows the placement of Futabasaurus within Elasmosauridae following an analysis by Rodrigo A. Otero, 2016:{{cite journal|last1=Otero|first1=R. A.|title=Taxonomic reassessment of Hydralmosaurus as Styxosaurus: new insights on the elasmosaurid neck evolution throughout the Cretaceous|journal=PeerJ|date=2016|volume=4|pages=e1777|doi=10.7717/peerj.1777|pmid=27019781|pmc=4806632 |doi-access=free }}

File:Fossil of Futabasaurus suzukii 02.jpg

{{clade| style=font-size:85%; line-height:85%;

|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 }} }} }} }} }} }} }} }} }} }}

See also

References

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