Although not explicit in the first book in this series, the Quintaglios are descended from Earth's dinosaurs. However, this is NOT the model I used for the Quintaglios. Rather, the Quintaglios evolved from dwarf tyrannosaurs. Unlike troodontids, which kill with their clawed feet, all tyrannosaurs, including Quintaglios, kill with their powerful jaws. Quintaglios vary from tyrannosaurs in several significant ways, however.
Tyrannosaurs have tiny arms, with only two clawed fingers.
All terrestrial vertebrates on Earth now have or evolved from creatures with five digits on each hand or foot. In the case of the Quintaglios, the development of the third, fourth, and fifth fingers is no longer suppressed. Unlike humans, though, most Quintaglios are left-handed. Skin Quintaglio hide is much tougher than human skin. It is dry and leathery.