Megamouth shark "M. applegatei" – have also recently been proposed on the basis of fossilized tooth remains. However, the Cretaceous-aged "M. comanchensis" has been recently reclassified as an odontaspid shark in the genus "Pseudomegachasma", and is in fact unrelated to the megamouth shark despite similar teeth morphology. The appearance of the megamouth is distinctive, but little else is known about it. It has a brownish-black colour on top, is white underneath, and has an asymmetrical tail with a long upper lobe, similar to that of the thresher shark. The interior of its gill slits are lined with finger-like gill rakers that capture
Robot fish instead of forward swimming only. The shapes and sizes of fins vary drastically in living fish, but they all help to accomplish a high level of propulsion through the water. In order for robot fish to achieve the same type of rapid and maneuverable propulsion, robot fish need multiple control surfaces. The propulsive performance is related to the position, mobility, and hydrodynamic characteristics of the control surfaces. The key to controlling a multi-joint robotic fish is creating a simplified mechanism that is able to generate a reasonable amount of control. Designers should consider some important factors, including lateral body motions,