"The worm-like creatures writhed in the dark waters, fins twitching and eyestalks roving. Each one sported a long, pincher-tipped proboscis lined with tiny, needle-like teeth. When paleontologists found fossils of these ancient horrors trapped in stone, they named them Tullimonstrum gregarium, or Tully monsters.
For roughly 60 years, no one could say for sure what the strange beasts actually were. Paleontologist Eugene Richardson, who gave the species its name in 1966, was so unsure of the creature's nature that he wasn't confident sticking it within any known lineage beyond "animal."
Now, an international team says they have at last cracked the mystery, and their answer overturns every other theory offered to date. Depending on who you asked, the Tully Monster could have been related to ribbon worms, snails, eel-like protovertebrates called conodonts or other ancient oddballs, like another nozzle-nosed creature called Opabinia. But based on studies of more than 1,200 fossil specimens, the researchers say the Tully Monster was really a vertebrate, specifically, a type of fish akin to modern lampreys. If they're right, the fossil changes what we know about the history of these aquatic bloodsuckers…"
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