Complex sentence: Another challenge is deciding when to recognize a new species, for example when new data indicate that one previously described species actually may include two or more separately evolving groups, each of which could possibly be recognized as a separate species.
Split into simpler sentences: Another challenge is deciding when to recognize a new species. A related question arises when new data indicate that one previously described species actually may include two or more separately evolving groups, each of which could possibly be recognized as a separate species.