Pacific lamprey; Entosphenus tridentatus “More than 360 million years ago, a dead lamprey

Pacific lamprey; Entosphenus tridentatus“More than 360 million years ago, a dead lamprey sank down onto the seabed and was buried by layers and layers of sand, which eventually hardened into rock. Why this particular lamprey’s cartilage was preserved so well is unknown, but humans were able to discover it and prove that lampreys lived that long ago.They still are. They and hagfish, also primitive eel-like cartilaginous fishes, make up Cyclostomata, the jawless fishes. They were the first vertebrate chordates, chordates with backbones (like us!) instead of a notochord, to evolve.Although most people who know what they are think they’re creepy, I actually really like them, because they haven’t, unlike us, changed very much from our common ancestor hundreds of millions of years ago. Also, they go back to their birthplace to spawn, just like salmon, and even build a nest.Did you know? In Chinese, lampreys are called “eight eyed eel” because of their seven external gill slits plus their eyes! What a tongue twister!” Baapooh Chung, Secondary School Student. -- source link

More pics about