The theme that dinosaurs (or some other pre-60-million-years-ago reptilian species of Earth) may have evolved into intelligent beings who then had an encounter with men is pretty widely used ("West of Eden", "ST: Voyager", "Dr. Who" to name 3 random examples covered on SFF alone).
Q1: What was the first SciFi/Fantasy work to include intelligent beings evolved from Earth prehistoric reptiles?
Q2: What was the first SciFi (or even Fantasy) work to include intelligent beings evolved from Earth prehistoric reptiles, with added requirement of them existing contemporaneously - and meeting - with modern or future humans? (could be the same or later work than Q1).
They must have evolved directly from reptiles who lived 65+ million years ago on Earth. Not of extraterrestrial origin. No alien planets where humans somehow exist.
It's fine if the species migrated OFF earth since then (ala Voyager) or even were somehow time-shifted to the future as a way to explain why they haven't met humans in the historic past. BUT, in that case, the intelligence must still have evolved while they were on Earth, in prehistoric times, before such a space/time move.
Specifically for Q1, it's acceptable if the intelligent species went exitinct before humans arose; or if humans never evolved in the first place.
Pretty much any reptiles are OK (not just Dinosauria clade), with the exception of a trixy answer of "humans and all mammals evolved from Therapsids who were reptiles".
Intelligence must have evolved naturally during pre-historic times (e.g. before Australopitecus arose), with an entire species being intelligent (in other words, "nuclear tests made Godzilla smart" or "mad human/alien scientist raised intelligent raptor clone" one-offs don't count).
"Intelligent" means "tool using", at least on the level or Homo Erectus; not "Jurassic Park" level "raptors were smart".
Dragons (of magical fantasy type) do NOT count unless the work in question explicitly explains how they have evolved from real Earth reptiles. So no Tolkien or Le Guin.
It's OK if the work takes place on "alternate" Earth where Dinosaurs were not wiped out during Cretaceous–Paleogene extinction event; but again the intelligence must have evolved millions of years ago.