Cephalocarida facts for kids

Cephalocarida is a special group, or class, of crustaceans. These tiny creatures look a bit like shrimp and live on the bottom of the ocean. They are often called horseshoe shrimps because of their shape. Scientists first found them in 1955.

There are only twelve known species of cephalocaridans, and they all belong to one family called Hutchinsoniellidae. Even though we haven't found any fossils of them, many experts believe they are very ancient or primitive among crustaceans. This means they might be similar to some of the first crustaceans that ever lived.

What Are Cephalocaridans Like?

These small crustaceans are usually about 2 to 4 millimeters long. That's less than half a centimeter! They have a long body and no eyes. They live in muddy places on the ocean floor.

Their body parts are quite simple. For example, their mouthparts, called maxillae, look and work a lot like their legs. In many other crustaceans, these parts are very specialized. This simple design might be another sign that they are an ancient group.

Their body has ten segments in the middle part, called the thorax. The back part, or abdomen, has a tail-like end called a telson. However, the abdomen does not have any other legs or appendages.

Where Do Cephalocaridans Live and What Do They Eat?

You can find cephalocaridans in many different ocean environments. They live from the intertidal zone (the area between high and low tide) all the way down to depths of 1500 meters. They can be found in all sorts of sediments, like mud or sand.

These tiny creatures eat detritus, which is dead plant and animal matter found in the ocean. To get their food, they create water currents using their legs, which are called thoracic appendages. This is similar to how some other crustaceans, like branchiopods, feed.

The water currents help bring food particles towards them. The food then moves forward along a special groove on their underside, leading right to their mouthparts.

See Also

In Spanish: Cefalocáridos para niños