A 1722 illustration by Jean-Baptiste Labat of three parrots on Guadeloupe. There are no remains of these species, so accurate taxonomic classification is impossible.

Several species have been assumed to exist, but due to a lack of physical evidence they can only be regarded as hypothetical or potential species. Hypothetical species are usually believed to be extinct. They have caused confusion, as they may have been a separate species, a subspecies, an introduced species or a misidentification. It can also refer to species that are hypothesised to have existed evolutionarily.

List of hypothetical species

Birds

Illustration of "Leguat's giant", a bird from Mauritius now believed by some researchers to be based on sightings of the greater flamingo

Non-avian dinosaurs

Mammals

Fish

Arthropods

Other invertebrates

Plants

See also