Sapients! - The Sentient Chelonian

This concept is part of a small-scale project, tentatively called "Sapients!", which Cheetanzee (formerly known as Chimpeetah) and I are currently working on.
The project follows a simple notion - Show a set of modern animals and conceptualize an evolutionary pathway if they managed to acquire human level intelligence, no matter how strange and outlandish they may appear.

The idea behind this was to create a hypothetical, turtle-derived sophont, without resorting to conventional cliches.
150 million years into the future, the Antarctic continent has drifted upwards towards the Indian Ocean, reaching a tropical climate. During this time the dominant land vertebrates have been birds... and turtles.
Over millions and millions of years of evolution in isolation, the descendants of some pleurodile turtle radiated into a great panoply of forms - many strange and outlandish. This sophont is the result of that radiation.
At first sight the most remarkable features of this chelonian are its bipedal stance, light build and agility.
The closest relatives of this animal are tree-creeping creatures, belonging to a group of therizinosaur-like semi-bipedal herbivorous chelonians. Like all the advanced Antarctic chelonians (characterized by their vertical limbs and rudimentary endothermy), these descend from a swift, and probably arboreal turtle form. From this creature, this sophont inherited its reduced and flexible shell, which is composed of a leathery tegument and bordered with bony protrusions".
From the much more recent arboreal ancestors, this sentient chelonian has inherited long and prehensile and opposable fingers forming a pincer-like structure. At some point during its recent evolutionary history these creatures abandoned tree-life and became terrestrial again, this time acquiring a full bipedal stance… and intelligence.

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Concepts designed so far:

Sentient Slug: fav.me/d54zip8
Sentient Clam: fav.me/d54zgt2
Sentient Snake: electreel.deviantart.com/art/S…