Biologists have discovered six new species of miniature frogs in Mexico

MEXICO (KFSN) -- Biologists have discovered six new species of miniature frogs in Mexico.

Each of the new species is smaller than a penny when fully grown.

They've gone unnoticed for centuries because they are tiny and brown. Plus they look similar to other frogs.

But these amphibians don't develop from tadpoles. Instead, they emerge from eggs as perfect miniature frogs.

Scientists from London's Natural History Museum and the Universities of Cambridge and Texas collaborated on the discovery.