Researchers Report the Discovery of a Partial Femur from a Hadrosaur

Dinosaur fossils are exceptionally rare in Japan, so when one is discovered, it makes quite a story.  Japanese media have reported upon a paper delivered at last weekend’s meeting of the Palaeontological Society of Japan, which provided details of partial hadrosaurid femur that had been found on Kamikoshikijima Island, at the southernmost tip of the land of the rising sun.

The fossil was discovered two years ago (July 2016), its discovery was announced at the meeting by a team from Kumamoto University and the National Museum of Nature and Science (Tokyo).

The Partial Dinosaur Femur at the Dig Site

Fossil partial Hadrosaur femur (Japan).

The fossilised remains of the partial Hadrosaur femur in situ (tape measure provides scale).

Picture Credit: Satsuma-sendai City Government

Identifying the Fossil as a Duck-billed Dinosaur (Hadrosaur)

Whilst it may not be possible to assign a genus to this fossil, the single bone does at least permit scientists to assign it to the Hadrosauridae family.  The femur is similar in shape when compared to the thigh bones of better known hadrosaurids.  It lacks the pneumatic texture as seen within the bones of Theropod dinosaurs and the position of the fourth trochanter, a flange of bone on the femur associated with muscle attachment, is within the scope of placement associated with duck-billed dinosaurs.

The sediments in which the femur was found date from the Maastrichtian faunal stage of the Late Cretaceous, indicating that this herbivorous dinosaur roamed this part of the world some 70 million years ago.

Commenting on the importance of the fossil find, researcher Yuka Miyake, who made the initial discovery stated:

“It is a clue that may enable us to grasp the extent of the diversity of dinosaurs that flourished in Asia.”

The bone measures about 70 centimetres long, if it had been complete it would have measured around 1.2 metres in length.  The scientists estimate that the dinosaur would have measured in excess of ten metres.

An Illustration of Late Cretaceous Hadrosaurs

A typical Late Cretaceous hadrosaurid.

Typical Late Cretaceous (Maastrichtian faunal stage) hadrosaurids.

Picture Credit: Mike Fredericks

This is the tenth reported Hadrosauridae discovery from Japan.  However, this is the first time a dinosaur fossil has been found on Kamikoshikijima.  Sensibly, the researchers have refused to state the exact location of the fossil find, this will help to protect the fossil site.  The bone will go on public display at the city government’s Kashima branch office in Shimokoshikijima from the middle of next month.

To read other blog articles published by Everything Dinosaur about dinosaur fossil discoveries from Japan:

Tyrannosaurus Roamed Late Cretaceous Japan

Japan’s Most Complete Dinosaur Discovery

Fragments of Fossilised Teeth Hint at Late Cretaceous Japanese Theropod

Japanese Schoolboy Finds Dinosaur Toe Bone

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