A homocercal tail is a caudal fin composed of two lobes of equal proportion. Homocercal tails are the most common caudal fin type in fish but can come in many symmetrical shapes. A homocercal tail is contrasted with a heterocercal tail which has unequal lobes.
A heterocercal tail is a caudal fin composed of two asymmetrical lobes. Often, such as the case in many sharks, the vertebral column passes through the upper lobe, making it the larger of the two lobes. A heterocercal tail is contrasted with a homocercal tail which has equal lobes.
The caudal fin, or tail, of a fish is the only fin to be connected to the vertebral column. It is the primary means of locomotion for most fish. Unlike many marine mammals with tails that use an up-and-down motion, fish generally use a side-to-side thrust of their caudal fin for propulsion. The shape of the … [Read more…]