Hypotheticals

The People Of The Wind, IV.

Phillipe Rochefort and his Cynthian crew member watch a taped lecture about the enemy:

"'Otherwise the pre-Ythrian must have appeared fairly similar to Terran birds.' Pictures of various hypothetical extinct creatures went by." (p. 483)

There is some scope for alternative versions of reality here. Images of Ythrian organisms that had appeared in an animated adaptation could reappear as "hypothetical extinct creatures" as viewed by Rochefort in a live action adaptation.

I think that something like this was done in a Superman comic. Kryptonian organisms that had been real in an earlier version of the story reappeared as speculative reconstructions in a TV documentary about Krypton that was viewed by the characters in a much later version. A series that continues for decades can either ignore its earlier episodes or refer back to them in interesting ways. A series written by a single author usually does not last long enough for that to happen but screen adaptations can produce some interesting variations - as well as outright travesties.