Final answer:
The finger bone found in Siberia is a Denisovan phalanx bone, providing insight into this ancient hominin group that lived between 500,000 and 30,000 years ago.
Step-by-step explanation:
The finger bone found in Siberia is best described as a phalanx bone from the Denisovans, an archaic group of hominins related to modern humans and Neanderthals. Denisovan remains are limited, but include one finger bone, three teeth, some long bone fragments, a partial jawbone, and a parietal bone skull fragment. The fossils are dated to between 500,000 and 30,000 years ago. The finger bone from Denisova Cave in Siberia provided significant insights into the Denisovans and their genetic relationship to modern humans and Neanderthals.