Complex sentence: The Liverpool Pigeon, another extinct species from an unknown locality, has only a slightly similarity (due to the neck feathers) to the Nicobar Pigeon and might belong in this genus too despite it is not supported by all scientists.
Split into simpler sentences: The Liverpool Pigeon, another extinct species from an unknown locality, has only a slightly similarity to the Nicobar Pigeon due to its neck feathers. It might belong in this genus too despite it is not supported by all scientists.