Entoprocta

These tiny sea animals are called goblet worms.

They look like little cups on long stalks. They live in the water.

Most of them live in groups. They stay in one place. They use tiny hairs to catch food. These hairs make a water flow.

The water carries food to their mouths. This helps them eat.

Some worms can move very slowly. They can also make clones. A clone is a copy of the worm.

They are very small and soft. It is hard to find their fossils. They are amazing little creatures.

Goblet worms are small animals that live in the water.

Most of them stay in one place. They have a body shaped like a cup. This cup sits on a long stalk. The cup has a crown of tentacles. These tentacles are solid parts of their body.

Tiny hairs called cilia cover their tentacles. These hairs move to make water currents. The water carries food toward the mouth. The mouth and the anus are both inside the crown. This is how they get their name. Entoprocta means "anus inside."

Many goblet worms live in colonies. A colony is a large group of animals. The members are called zooids. They are not fully independent. They can grow new members from their stalks. They can also make clones. A clone is an exact copy of an animal.

Some species can move very slowly. They use a muscular foot to creep. They can even somersault to move. Most of these animals live in the sea. Fossils of these worms are very rare. This is because they are soft. The oldest fossils are from the Late Jurassic period.

Entoprocts are tiny aquatic animals often called goblet worms.

Most of these animals live in the sea. They are mostly sessile, which means they stay attached to one spot. A mature worm has a body shaped like a cup. This cup sits on a long, muscular stalk. The rim of the cup has a crown of 8 to 30 solid tentacles. These tentacles help the animal find food in the water.

These worms use a clever way to eat. Tiny hairs called cilia cover their tentacles and body parts. The cilia move in a way that creates water currents. These currents pull food particles into the crown of tentacles. Some species even use sticky threads to catch larger pieces of food. Once the food is trapped, the cilia move it toward the mouth. The mouth and the anus are both located inside the crown. This is why the name Entoprocta means "anus inside."

Scientists have worked hard to understand where these animals fit in nature. In 1870, the name Entoprocta was first used. In 1929, the name Kamptozoa was also assigned. For a long time, people thought they were a class of animals. Since 1996, many studies have grouped them with molluscs and annelids. However, a 2008 study suggested they are closely related to bryozoans. Other researchers place them in a group called Tetraneuralia.

There are about 150 known species of entoprocts. These species are divided into four main families. These are Barentsiidae, Pedicellinidae, Loxokalypodidae, and Loxosomatidae. Most entoprocts live in colonies. The individual members of a colony are called zooids. These zooids are not fully independent animals. They can grow new members from their stalks or from tubes called stolons. Some solitary species can move by creeping or even somersaulting.

Finding fossils of these animals is a very hard job. This is because they are small and have soft bodies. For a long time, people thought a fossil called Dinomischus was an entoproct. It was found in the Burgess Shale in Canada. However, experts later decided it was not a true entoproct. The earliest confirmed fossils come from the Late Jurassic period in England. Some fossils of a species called Cotyledion tylodes were found in China. These fossils are 520 million years old.

Entoprocta, often called goblet worms, are a phylum of aquatic animals. Most species are sessile, meaning they remain attached to a surface. They are mostly marine, though some live in freshwater. There are about 150 recognized species in this group. They are organized into four main families: Barentsiidae, Pedicellinidae, Loxokalypodidae, and Loxosomatidae. These animals are important for understanding how complex body plans evolve.

A mature entoproct has a very specific shape. The body consists of a goblet-shaped calyx. This calyx sits on a long, muscular stalk. The rim of the calyx holds a crown of 8 to 30 solid tentacles. These tentacles are extensions of the body wall. The mouth and the anus both sit inside this crown. The name Entoprocta actually means "anus inside." This distinguishes them from bryozoans, which have an anus outside their tentacle crown.

Feeding in entoprocts is a highly organized process involving cilia. Cilia are tiny, hair-like structures that move in waves. Two main types of feeding occur. First, they use ciliary sieving. One band of cilia creates a water current. A second band of cilia acts as a sieve to trap food. Second, they use downstream collecting. In this method, the same cilia that create the current also trap the particles. The current flows into the crown at the base of the tentacles. It then exits above the center of the crown. Some species even use sticky threads to capture large particles.

Many entoprocts live in colonies rather than alone. The individual members of a colony are called zooids. These zooids are not fully independent animals. They grow from shared attachment plates or from stolons. Stolons are tube-like networks that run across a surface. In solitary species, the stalk may end in a muscular sucker or a flexible foot. Some solitary species can even move by creeping or somersaulting. These animals lack a coelom, which is an internal fluid-filled cavity. Their internal organs are embedded in connective tissue.

Reproduction in entoprocts is quite diverse. Most species are simultaneous hermaphrodites. This means one individual has both male and female reproductive organs. They have gonads located between the atrium and the stomach. Some species release eggs into the water to hatch as planktonic larvae. Other species brood their eggs in a special chamber. Some use placenta-like organs to nourish these developing eggs. When a larva settles on a surface, it undergoes metamorphosis. During this change, the internal gut can rotate by up to 180 degrees. This ensures the mouth and anus face upward.

Understanding the history of entoprocts is difficult because they are soft-bodied. Soft tissues rarely leave fossils. For a long time, scientists studied a fossil called Dinomischus from the Burgess Shale. It was found in Canada and lived during the Mid-Cambrian period. Many thought it was an early entoproct. However, researchers later concluded it was not a true member of the phylum. The earliest confirmed fossils come from the Late Jurassic in England. These fossils resemble the modern genus Barentsia.

There is also evidence of even older relatives. Fossils of a species called Cotyledon tylodes were found in China. These fossils are 520 million years old. This species was larger than modern entoprocts, reaching up to 56 mm in height. It was also armored with scale-like structures called sclerites. This suggests that early ancestors lived during the Cambrian explosion. Scientists continue to debate the exact family tree of these animals. Some studies link them to the Trochozoa, which includes molluscs and annelids. Other research suggests they are closely related to bryozoans or belong to a clade called Tetraneuralia.