The incredible appearance of molas suggests that half of their body is missing, but they have existed in this form for over twelve million years, according to fossil evidence.
Some species of molas actually have a recognizable tail when they are very young, but as they start to develop into adult fish this feature is lost. The tail ends up retained once more into the figure and is traded by a pseudotail, called the clavus. The large dorsal (back) and anal (belly) fins, along with the clavus, help the molas to swim, pushing its body through the water.
