Beorn (tardigrade)

Beorn leggi is an extinct species of tardigrade and the first known fossil tardigrade, discovered c. 1940 and described in 1964 from Late Cretaceous amber from Manitoba, Canada. It is the only species in the genus Beorn, and family Beornidae. It is one of two fossil tardigrades known from the Cretaceous, the other being Milnesium swolenskyi from the Turonian New Jersey amber.

In addition to some other finds from the Cretaceous and the Cambrian period, Beorn is an example of the early existence of tardigrades in earth's history, and its largely modern appearance suggests that tardigrades must have diversified considerably before this time.

The species was first described in 1964 by Kenneth W. Cooper. The type specimen is now in the Museum of Comparative Zoology at Harvard University. The generic name Beorn was chosen by Cooper in reference to a character of the same name from the children's book The Hobbit by J. R. R. Tolkien, which can occur both in the shape of a man and that of a bear. The specific name leggi refers to Cooper's student William M. Legg who in the summer of 1940 created the large collection of amber in which the fossil tardigrade was found. He died in 1953 before finishing his thesis at Princeton University. Cooper, his friend and scientific mentor, named Beorn leggi after him.