Complex sentence: Several hypothetical extinct ara species have been postulated based on very little evidence, and they may have been subspecies, or familiar parrots that were imported onto an Island and later presumed to have a separate identity.
Split into simpler sentences: Several hypothetical extinct members of the genus have been postulated based on very little evidence. They may have been subspecies, or familiar parrots that were imported onto an Island and later presumed to have a separate identity.