Armored Fish Pioneered Sex As You Know It
Fossils suggest that long before birds and bees, vertebrates used internal fertilization.
The armor-coated swimmers, called antiarchs, lived around 385 million years ago. They were among the first vertebrates with jaws, and thanks to the discovery of some never before seen anatomy, paleontologists now know they were also the first to use internal fertilization to reproduce.
Flinders University paleontologist John Long and colleagues add new evidence that copulation goes far back in the vertebrate family tree. Previously, early fish like the antiarchs were thought to have relied on spawning: Females would drop their eggs into the water, and males would douse them with sperm.
But in 2008 Long and colleagues described another armored, 380-million-year-old fish they named Materpiscis—"mother fish"—that carried embryos inside its body. This required internal fertilization, and further discoveries of