These sharks are some of the commonest sharks alive today. They first appeared during the early Cretaceous, though some teeth dating to the late Jurassic that possibly belong to Lamniformes have been found. As with most cartilaginous fish, preservation isn't that good, but on occasion beautiful specimens have been found. These early forms were the †Alopiidae. These aren't that well known, with only jaws and teeth that have been found. However, the jaws are remarkably similar to crocodile sharks in our world, and the teeth are rather larger compared to most modern Lamniformes, which suggests that they ate small fish. From the jaws it is presumed that they grew up to a metre long. The jaw structure and teeth show that they are the ancestors to all Lamniformes. Their fossil record lasted only into the Albian epoch.
†Cretoxyrhinidae are a recently described group of Lamniformes that have been dated from the Santonian epoch to the Eocene epoch of North America. These are much mo