These are fragments of fossilized bones from a softshell turtle, or Trionychidae, a specific taxonomic family of turtles. Turtles are one of the oldest groups of reptiles. Softshell turtles differ from other turtles because of the layer of skin over their shells compared to the other turtles with hard scales (scutes). Each fossilized bone fragment measures around 4.5 cm x 4 cm x 1.5 cm in size or less.
- Catalog Number:
- 401524
- Object/Specimen Description:
- Specimen Count:
- 27
- Collector:
- A. Bolton
- Locality:
- US High Plains and Rocky Mountains (ID, MT, ND, SD, WY, CO)
- Collecting Date:
- 22 Jul 2014
- Collecting Locality:
- North America, United States, Montana, Fallon County
- Cabinet:
- 07
- Drawer/Shelf:
- 07
- Special Instructions:
- Ask a staff person for assistance
- Upper Level Taxonomy:
- Animalia, Chordata, Vertebrata, Tetrapoda, Reptilia, Testudines, Cryptodira, Trionychidae
Fossil marine sea turtle, now extinct (Protostega gigas)
Photo by Chip Clark, Smithsonian, National Museum of Natural History
Turtles first appeared on Earth in the Triassic, before the rise of the dinosaurs. The earliest turtle found in the fossil record is an odd-looking animal called Odontochelys semitestacea, discovered in China and dated to about 220 million years old. It appeared to have lived in water and had just a bottom shell (“semi” = half; “stacea” =shelled). Unlike modern turtles, it had a jaw full of teeth. In contrast, another fossil turtle, Proganochelys, dated to a bit later, resembles a modern turtle with a full shell (although it did have a few teeth still, in the middle of its mouth). Paleontologists are not sure whether land turtles evolved from aquatic half-shelled turtles like Odontochelys, or whether Odontochelys evolved from full-shelled ancestors living on land. They are searching for an ancestor to both Odontochelys and Proganochelys to help solve this mystery.