Peppered tree frog
This frog is in danger of dying out.  It might already be extinct.  Scientists have not seen this frog for sure since 1973.  Some scientists saw and heard a frog that looked like the peppered tree frog in the 1990s, but their voices sounded different.  In the 1990s, scientists decided that they needed to study the genes and DNA of this frog and its relatives before they could truly say which were separate species and which were not.  Its relatives are Ranoidea barringtonensis, Ranoidea pearsoniana, and Ranoidea phyllochroa.