Until recently, only a single specimen from this family was known.
Only two specimens were known, and these have now disappeared.
Only a single specimen, collected in the 19th century, is known.
This is still considered to be one of the finest specimens known.
Only 20 specimens of this species are known to have been collected.
One specimen is known to have been introduced to Europe.
More than thirty specimens of all ages are known to science.
Several specimens are known and the largest was a little over 12 feet (3.8 m) long.
No specimens of the publication are known to have survived.
As only one specimen is known to survive, it seems that this was not a successful issue.
