Utatsusaurus fossil map
Where fossils of Utatsusaurus have been found, shown on the Earth as it looked about 252 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 252 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Ichthyosaurs |
|---|---|
| Lived | 251.902–247 million years ago |
| Periods | Triassic |
| Family | Utatsusauridae |
| Named by | Shikama and Kamei 1978 |
| Fossil records | 5 occurrences at 5 locations (PBDB) |
| Found in | Japan, Canada, United States |
| Rock formations | Sulphur Mountain, Osawa, txn:38872, Prida |
About Utatsusaurus
Utatsusaurus hataii is the earliest-known ichthyopterygian which lived in the Early Triassic period (c. 245–250 million years ago). It was nearly 2.5–3 metres (8.2–9.8 ft) long with a slender body. The first specimen was found in Utatsu-cho (now part of Minamisanriku-cho), Miyagi Prefecture, Japan. It is the only described species in the genus Utatsusaurus and the only member of the family Utatsusauridae. The name Utatsusaurus was given after the city. The fossils have been found from the Early Triassic Osawa Formation of Miyagi Prefecture, Japan and British Columbia, Canada.
Utatsusaurus is one of the most primitive grades of ichthyosaurs, a basal ichthyosaur.
Text in “About” is quoted from the Wikipedia article Utatsusaurus (revision 1371814978), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q20672904.
