Ancient Mollusk Tells a Contrary Story
A fossil unearthed in Great Britain may end a long-running debate about the mollusks, one of life’s most diverse invertebrate groups: Which evolved first, shelled forms like clams and snails, or their shell-less, worm-like relatives?
The small new fossil, found in marine rocks along the English-Welsh border, provides the best fossil evidence yet that the simpler worm-like mollusks evolved from their more anatomically complex shelled brethren, rather than the other way around. (more…)