T-Rex: Photography only goes back a century or so! We know what folks looked like then...

T-Rex: ...but we DON'T know what they looked like BEFORE then!!

T-Rex: MAYBE before photos everyone was all gross with tentacles coming out of their mouth, Cthulhu style??
Dromiceiomimus: If that were the case, I'm pretty sure it would've been represented in paintings and whatnot.
T-Rex: But maybe not, if they were all embarrassed!!
T-Rex: On account of their tentacles?

Utahraptor: Okay, well, it'd at least be in the newspapers of the time.
T-Rex: Aha! Not NECESSARILY!

T-Rex: MAYBE it was SO universal and established by then that it wasn't even worth REPORTING on anymore!! The news doesn't say "HOLD THE FRONT PAGE - NOTHING CHANGED TODAY"!
Utahraptor: And then when it went away, NOBODY wrote it down?
T-Rex: Oh, uh, THOSE records got lost.

Off panel: Well, I suppose there IS a small but non-zero chance, in the same way there's a small but non-zero chance a bunch of comets could spell out "HOITY TOITY IBBIT BOITY" in the sky.
T-Rex: Man - if I ever saw that, my mouth tentacles would be going HOG WILD