Simplify the following text for a Grade 6 native English-speaking person.
Original: In addition , some suggest that the Bronze-tailed Barbthroat ( T. n. loehkeni ) should also be considered a valid species and include the doubtful Christina 's Barbthroat ( T. n. christinae ) as a subspecies .
Simplified: Not only that , but some suggest that the Bronze-tailed Barbthroat ( T. n. loehkeni ) should also be thought a valid species and have the doubtful Christina 's Barbthroat ( T. n. christinae ) as a subspecies .