A version of this article appears in print on , Section D, Page 2 of the New York edition with the headline: Paleozoic Passion: Before There Were Birds or Bees, How Trilobites Reproduced. Order ...

Trilobites are one of the most common fossils we know, but normally only their hard exoskeleton is preserved. Now, researchers have discovered a site that was buried by a Pompeii-style volcanic ...

With appendages growing out of its head and an armored mouth, an ancient shrimplike creature was thought to be the quintessential apex predator of its time.