The Puerto Rican long-nosed bat (Monophyllus plethodon frater) is known only from a skull fragment excavated in the large Cathedral Cave near Morovis, Puerto Rico, by Dr. H. E. Anthony prior to 1917. This species was never observed or documented live.
The discovery of a fossilized skull of the Puerto Rican long-snouted bat (Monophyllus plethodon frater) in the Cathedral Cave near Morovis, Puerto Rico, by Dr. H. E. Anthony before 1917, highlights the species' elusive nature, as it has never been observed or documented alive.