Today on Animal Fact Files we’re discussing entoprocts.
These animals are also known as goblet worms because they look like a drinking goblet with
their cup-shaped “head” on top of their long stalk. Unsurprisingly, entoprocts are
classified in the phylum Entoprocta and there are approximately 150 currently identified species.
The name "Kamptozoa '' is sometimes applied to the phylum instead, and sometimes it’s the name of the
phylum and entoprocts are classified as a class of that phylum. So it’s not fully settled. For this
reason, it's debated if these animals are closely related to bryozoans, or the moss animals, which
we've discussed in a previous episode. Bryozoans are also known as ectoprocts, in opposition to the
entoprocts we're describing today. This naming is in reference to the position of their anus.
Both bryozoans and entoprocts have a similar shape. Their mouths are surrounded by up to 36
sticky tentacles. In the case of bryozoans, the ectoprocts, their anus is located outside of this
ring of tentacles; the anus in entoprocts is located inside this ring of tentacles
near their mouth. So they have a u-shaped gut! The tentacles in entoprocts are solid but they're
hollow in bryozoans. In both groups of animals, the tentacles help filter water and direct food
to the animal's mouth and waste away from them. Water comes up from the entoproct's stalk, through
the tentacles, and out - ensuring that waste material doesn't contaminate the food particles
stuck to the mucousy tentacles. In bryozoans, the water moves in the opposite direction! Both
ectoprocts and entoprocts are filter feeders and eat tiny particles floating in the water column.
Entoprocts are almost entirely sessile meaning they spend their entire lives in a single spot
once they've settled. They begin life as an egg. They breed when it's warm and those in tropical
areas may breed year round. Sperm is released into the water column where it can be drawn
into the female's body to fertilize her eggs. Most entoprocts have both male and female organs,
however, most do not present both sets of sexual organs at the same time.
They'll start out as either male or female and eventually change, sometimes years later, into
the other. All of them can reproduce asexually, as well. They do this by budding, much like a hydra
who creates clones of itself. These clones become part of the colony in which the entoproct lives.
Entoproct larvae hatch from eggs and swim freely for up to seven
months before settling to the bottom of the water column. Some larvae, however,
are brooded in the mother's body and some crawl along the bottom instead of swimming.
Most species are found no more than 165 feet (50m) below the water's surface but some live over
1,650 feet (500m) down. Nearly all the entoproct species are marine animals, however, they do live
in brackish water environments and a handful have been observed in freshwater environments, as well.
They're known from every ocean and continent except Antarctica. Once settled on a hard surface
like rock or abandoned shell the entoproct remains there for life. Some also settle on other animals
like sponges and coral. There are a few species known to move slowly in a somersault fashion,
but these are an exception. There are solitary and colonial entoproct species. Most species
only reach about 1 millimeter in length, though some can reach almost 7 millimeters!
Predators to entoprocts include nudibranchs, flatworms, crustaceans, and mollusks.
Fascinatingly, one entoproct species hitches rides on hellgrammites to move about their environment!
For more facts on entoprocts, check out the links below. Give a thumbs up if
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