Henodus, the "Single Tooth," is a prehistoric placodont that is famous for its resemblance to a modern sea turtle. Its iconic flat face and shell allows it to stand out compared to true prehistoric turtles, even though it is relatively small at only a meter long. Its shell was very wide and featured an intricate mosaic pattern due to the large amount of pieces that constituted it. Like a turtle, this shell was attached to its spine, meaning it could not leave its shell. Its dopey little limbs, accustomed to swimming, were virtually useless on land. Henodus likely spent all its time in brackish and freshwater lagoons in prehistoric Germany, where quiet waters wouldn't sweep it away. Living in the Triassic Period, it was one of the few Mesozoic creatures that figured out the art of filter-feeding. Sometimes thought to have used its two teeth to munch on crustaceans, it is now more commonly accepted that Henodus used baleen-like structures in its mouth to filter out algae from the surrounding waters. It may have also had an expandable throat that allowed it to suck in the water more easily.