Hypsidoris was about 20 centimetres (7.9 in) long, and looked similar to the modern catfish, also possessing sensitive barbels used to detect prey in murky waters. It also had a vibration-sensitive organ called the Weberian apparatus, which consisted of specialized vertebrae at the front of the spinal column which passed vibrations to the inner ear, using the swim bladder as a resonance chamber. For defense against predators, Hypsidoris had large spines at the front of each pectoral fin. Like modern catfish, it would probably have eaten smaller fish, along with crayfish and other bottom-dwelling creatures.[1]