Triassic Park

In the Liber campaign, humans never settled the Great Swamp. The Gharial, Quisloi, Skresh, and Tegano are all amphibious-to-reptilian. The Skitterwings look mammalian - but they are Fey, so for all we know, mosquitoes are intrusive. It doesn't look good for the Great Apes, either. Nor for any mammals, even monotremes: the adjacent Tisyah took a separate evolutionary road from the then-reptilian synapsids. Also missing: dinosaurs, including birds.

In multiverse terms, Kham's biology is separate from our world's as if the two worlds diverged before the Permian / Triassic. [10/19/2020 - better, internal to Triassic: preCarnian.]

Kham's continent is like the shared southern America-Africa supercontinent of the Triassic, with a warm Pacific and without the Andes. In our world's Jurassic, America broke off west and the rest of Africa started moving north. This didn't happen to Kham's continent. In deep time, the opposite happened here: two ancient cratons met and uplifted that western watershed, now eroded back to Appalachian heights. Other splits perhaps applied instead - or maybe, like for our long Eurasia, they didn't. As mentioned, I claim confidence in Kham's north, west, and south but I have no idea about its east.

Some components of the D&D slate have inhabited at least the planet: hill giants and trolls preceded the Qor (p. 89), orcs roam the tundra (p. 130). Men are here too - the Kham is a human empire. Many mammalian humanoids here are monsters that the Kham's geneticists created through Low Beast Magic. The Nange and Temple-Sentinels came out of a different and earlier empire's work.

When I say "two worlds" I mean, worlds. The Kham continent is such an ultra-Australia it cannot share a planet with any continent like ours. Every mammal and every bird here who is not a para-mammal like the Tisyah, descends from some conjunction with a mainstream D&D plane.