Cumacea

Small sea bugs live in the mud and sand.

They look like tiny shrimp. Some people call them comma shrimp.

These bugs have a big head part. It covers their parts for breathing and eating. They have a thin body and a tail.

Most of these bugs live in the ocean. They eat tiny bits of food from the sand. Some species live in much deeper water.

Males and females look different. The females are usually larger than the males.

Many fish like to eat them. This makes them a very important food. They live on every continent.

Cumaceans are small sea animals. Some people call them comma shrimp.

They live in mud and sand. Most live in the salty ocean. Some live in brackish water. This is water that is part salt and part fresh.

These animals have a unique look. They have a big head part called a carapace. This shell covers the parts they use to eat and breathe.

They also have a slim body and a forked tail.

Males and females look very different. This is called sexual dimorphism.

Females are usually larger than males. They also have a marsupium. This is a pouch used to carry babies. The babies are called mancae. They are almost fully grown when they leave the pouch.

Many fish eat cumaceans. This makes them a big part of the food chain. There are more than 1,500 known species. Many of these live in the deep sea. Deep-sea species live a long time. They have a slow metabolism. This is the way their bodies use power.

Fossils show they have been around for a very long time.

Cumaceans are tiny marine animals. Some people call them hooded shrimp or comma shrimp.

They live in soft places like mud and sand. Most live in the salty ocean. Some can live in brackish water, which is part salt and part fresh. There are more than 1,500 known species. You can find them on every continent.

As the ocean gets deeper, the number of different species grows.

These small creatures have a very special body. They have a large head shield called a carapace. This shell covers the parts they use to breathe and eat. The body also has a slim abdomen and a forked tail.

Most species have two eyes on the front of their head. In some, these eyes join together into one single lobe. They use six pairs of mouthparts to help them eat. Some species use their mouthparts to pierce and eat other tiny animals.

Males and females look very different from each other. This is called sexual dimorphism. Females are usually larger than the males. They also have a special pouch called a marsupium. The female carries her babies inside this pouch for a while. When the babies leave, they are called mancae. These young ones are almost fully grown already. They are only missing their very last pair of legs.

Scientists have studied these animals for a long time. Ivan Ivanovich Lepechin first described a species in 1780. Back then, people thought they were just young stages of other shrimp. In 1846, Henrik Nikolaj Krøyer realized they were their own separate group. Later, a German scientist named Carl Wilhelm Erich Zimmer studied them very closely.

Fossils show these animals have been around since the Mississippian age. Some fossils from the Jurassic period look just like the ones alive today.

Cumaceans play a big role in the ocean. They are an important food source for many kinds of fish. This makes them a key part of the marine food chain. Most species live for one year or less. However, species in the deep sea have a slower metabolism. This means their bodies use energy more slowly. Because of this, they likely live much longer than the ones in shallow water.

Cumacea is an order of small marine crustaceans. They are often called hooded shrimp or comma shrimp.

These animals have a very unique body plan. This makes them easy to tell apart from other crustaceans. They mostly live in marine environments. They prefer soft bottoms made of mud or sand.

Scientists have formally described more than 1,500 different species. The number of species increases as the ocean gets deeper.

The anatomy of a cumacean is quite distinct. They have a large head shield called a carapace. This carapace is made of several fused parts. It also includes the first three segments of the thorax. This shell protects the appendages used for breathing and feeding.

Most species have two eyes on the front of the head. Sometimes these eyes merge into one single dorsal eye lobe. The body also includes a slim abdomen and a forked tail. The abdomen, or pleon, consists of six cylindrical segments.

Feeding habits vary depending on where the species lives. Most cumaceans eat microorganisms and organic material from the sediment. Species in the mud often filter their food. Species in the sand browse individual grains. In the genus Campylaspis, the mandibles are very different. These are mouthparts used for biting or crushing. In this genus, they are transformed into piercing organs. These organs allow the animal to hunt small crustaceans and foraminiferans.

Cumaceans show a clear example of sexual dimorphism. This means males and females look very different. Females are generally larger than the males. They also have different ornaments like knobs and ridges on their carapace. The second antenna is also different between the sexes. It is strongly reduced in females but has many segments in males. Females possess a marsupium, which is a brood pouch.

They carry embryos inside this pouch for a period of time.

The development of a cumacean is called epimorphic. This is a form of incomplete metamorphosis. It means the number of body segments does not change as they grow. When the larvae leave the marsupium, they are called mancae. These mancae are almost fully grown. They are only missing their very last pair of legs. Most species live for one year or less and reproduce twice. However, deep-sea species have a slower metabolism. This slower rate of energy use means they likely live much longer.

Research into these animals began in 1780. Ivan Ivanovich Lepechin described the first species, then called Oniscus scorpioides. At that time, many scientists believed cumaceans were just larval stages of decapods. This changed in 1846 when Henrik Nikolaj Krøyer recognized them as a separate order. Later, the German zoologist Carl Wilhelm Erich Zimmer studied them very intensively.

Today, the order is divided into eight families. These include Nannastacidae, which has 426 species, and Bodotriidae, which has 379 species.

The fossil record for cumaceans is quite sparse. However, it stretches back to the Mississippian age. Some fossils from the early Jurassic look almost exactly like living forms. A special discovery was made in 2019 in Colombia. Scientists found Eobodotria in strata from the Middle Cretaceous. This fossil had exceptional detail preserved. It showed the gut, mouthparts, and even small eyes. This discovery helps scientists understand the history of the group.

Cumaceans are vital to the ocean. They are an important food source for many fish. This makes them a key part of the marine food chain.