Ostracoderm
by Corey B.
The ostracoderm is a bony, armored, jawless fish that lives at the bottom of the ocean. The cool things about my animal are that it uses a suction to capture its prey and it has sensors on the front of its face to detect vibrations in the water. I think my animal is cool and I hope you think so too.
According to our cladogram it had only developed one trait. The group trait it has developed is a vertebrate. A vertebrate is an animal with a backbone and skull, which gives my animal the ability to move faster. After that trait it didn’t develop any more traits.
My animal’s closest relative on our cladogram is actually all of them. This is because my animal branched off before any of the other animals did so all of the other animals are equally related to it. They all share the same advanced trait, and that is a backbone and skull. The biggest difference between my animal and the others is a jaw. A gnathostome’s trait is a jaw used for catching prey. To find my closest relatives first I had to trace the branch of my animal to find the last node my animal branched off of. Secondly I traced all of the other branches that came off my animal’s most advanced trait. All of the animals that branch off of the most advanced trait are my animal’s closest relatives. My animal is most closely related to all of them because the paths of every other animal leads to where mine branched off. At the American Museum of Natural History (AMNH) their cladogram was a little different, but my ostracoderm was still the closest relative to all of them and the only trait they shared was a backbone and skull. Once again the biggest difference between my animal and the others was a jaw.
My animal is a lot different from all of the other fishes today. It had hard bony armor all over that kept it safe from other predators. Because of the heavy armor it wasn’t the fastest swimmer, but it could swim. It was about a foot long like a lot of fish, and fossils were found in North America and Europe. The ostracoderm had a sensor on the front of its skull which allowed it to detect vibrations in the water. This is how we developed the sense of touch. It used its jawless mouth to create a suction that would suck up food.
Last updated April 7, 2007.