Complex sentence: Coquí is the local name used for the most common group of tree frogs found in the Virgin Islands and neighboring Commonwealth of Puerto Rico; of the sixteen species once recorded on Puerto Rico, it is estimated that three species became extinct in the late 1900s.
Split into simpler sentences: Coquí is the local name used for the most common group of tree frogs found in the Virgin Islands and neighboring Commonwealth of Puerto Rico. Of the sixteen species once recorded on Puerto Rico, it is estimated that three species became extinct in the late 1900s.