On Saturdays when I was a boy of 14 or 15, it was my habit to ride my red Roadmaster bicycle to the various thrift shops in my home town. One afternoon, at Clarice's Values, I unearthed a beat-up ...

For decades, biologists thought that early tetrapods, ancient vertebrates that started conquering the land over 300 million years ago, developed like modern amphibians—beginning their lives as purely ...