Ancient Fish Reveals Origins of Human Hands

The blueprint for your hand was first sketched out inside a fish's fin. Scientists just

found an incredibly complete fossil of a 374-million-year-old fish called Elpistostege. Using high-energy

CT scans, they peeked inside its pectoral fin and were shocked. They found the earliest

version of a hand, with tiny, organized bones forming primitive digits and a wrist.

But the fin was still a fin, covered in fin rays for swimming. This means the basic

architecture for our hands evolved while our ancestors were still fully aquatic,

completely blurring the line between fish and land animals.