The towering 'zebra stripped' Therizinosaurus from
the painting is an enigmatic dinosaur known only from several parts of
the skeleton including a powerful 75 cm. core of a hand claw (With a horny
sheath, it would have reached a meter in length).
This reconstruction is based on the comparative studies with several Therizinosaur
relatives called Segnosaurs and it has been inspired by a recent drawing
by Gregory S. Paul. The Segnosaurians were a group of strange theropods
with backward facing pubis and ischium and hand-folding mechanisms similar
to Dromaeosaurs, but that had beaks and cheeks, were probably herbivorous
and had massive guts. Colours and skin patterns are (as in every dinosaur)
Tarbosaurus is the Asian Tyrannosaurus (virtually the same animal as T. rex although it might have been longer and not as stocky).
Avimimus is one of the many bird-like theropods found in Asia in recent times (described by S. Kurzanov) with long powerful legs, short beak and arms that are probably modified wings.
Just for size comparison sake and as a guide while examining the illustration, a human being would have reached just over the knee of the Tarbosaurus!