† protopteranadj. and n.Obsoleterare(a) adj. of or relating to the former order Protopteri (equivalent to the subclass Dipnoi, comprising the lungfishes);(b) n. a fish of the former order Protopteri; a lungfish.Apparently only attested in dictionaries or glossaries.
ΚΠ
1890 Cent. Dict.Protopteran, a. same as protopterous; n. a member of the Protopteri.