Researchers Name New Extinct Softshell Turtle Species

Fossils found in North Dakota's Brule Formation reveal a previously unknown softshell turtle that lived in North America during the Oligocene.

Updated on Nov. 10, 2026 in Reptiles

Isometric editorial illustration of layered pale sediment bluffs over flat prairie with a bold geometric turtle shell form embedded in a strata band. — Researchers named Rafetus lysoni, a newly identified extinct softshell turtle species, from fossils found in southwestern North Dakota, published November 2, 2026. AI Illustration. Upload story photo >

Researchers have identified Rafetus lysoni, a new extinct species of softshell turtle, from fossils discovered in southwestern North Dakota. The findings were published in the Swiss Journal of Palaeontology on November 2, 2026.

Why it matters

The discovery expands the known Oligocene fossil record of North American softshell turtles, which had previously been documented only from two figured shell fragments. It also links the North American fossils to a genus whose living members are found in Eurasia.

The study examined five fossil specimens, with the largest shell estimated at roughly 52 cm along its midline, based on the preserved portion and comparison with a smaller, more complete shell. The skull measures about 9 cm from snout tip to base and about 12 cm including a bony projection at the back, while the precise evolutionary relationships remain under investigation.

The players

Tyler R. Lyson

Tyler R. Lyson is a North Dakota-based paleontologist for whom the new turtle species is named.

Swiss Journal of Palaeontology

The Swiss Journal of Palaeontology is a scientific journal that published the peer-reviewed findings describing the new species.

The details

The fossil material includes a nearly complete skull, a lower jawbone, and three partial shells found in the Brule Formation in southwestern North Dakota, including remains from the Fitterer Ranch area. The species shows reduced development of the nuchal callosity compared with other softshell turtles and narrower areas of thickened bone along the sides of the shell, and it is named after North Dakota-based paleontologist Tyler R. Lyson.

• The softshell turtle lived in North America during the Oligocene period.
• Findings were published in the Swiss Journal of Palaeontology on November 2, 2026.

Legacy Record

Before this discovery, the Oligocene North American softshell turtle record rested on just two figured shell fragments. The newly described Rafetus lysoni, represented by a nearly complete skull and multiple shell elements, substantially expands that sparse fossil picture.

The discovery is primarily a scientific advance rather than one with near-term practical applications for everyday life. Its value lies in refining how researchers understand the distribution and evolution of softshell turtles across ancient North America.

The takeaway

Fossil finds can rewrite entire regional chapters of evolutionary history from only a handful of specimens. This discovery shows how careful study of existing collections can reveal species that were previously overlooked.