Pygmy seahorses, about the size of a fingernail, are some of the smallest vertebrates in the world. First discovered in 1969, little was known about the creatures. But in the early 2000s ...

(CNN) — Pygmy seahorses, about the size of a fingernail, are some of the smallest vertebrates in the world. First discovered in 1969, little was known about the creatures. But in the early 2000s ...