Those of you who like to dive and enjoy the underwater beauty may be familiar with this one creature. They look like lilies with long petals waving with the ocean currents. Did you know that they are actually animals, not plants?
It’s called sea lily. Even though their name is similar to a flower, they are a type of animal Echinodermata, the same as starfish, sea pigs, and sea cucumbers. Even though it looks like it doesn’t move on its own, this animal is actively looking for food with its arms, you know.
Uniquely, this animal has no head and no brain. So, how do these animals breathe? What’s the food? Check out the explanation about sea lilies below, come on!
1. “Flowers” with animal anatomy
collection of sea lilies or feather stars in Bunaken, Sulawesi (commons.wikimedia.org/Bernard DUPONT)
Sea lilies, or as they are formally called crinoidis a type of animal Echinodermata besides starfish, sea pigs, and sea cucumbers. Unlike animals in general, the body of a sea lily actually resembles a flower.
His body is divided into three main parts; stalk, calyx, and arms. Even though it looks like a small body, sea lilies have the anatomy of animals in general, you know.
The digestive system, central nervous system, and reproductive organs are found in calyx, the area of the midsection of the body where the body cavity is located. His nervous system spreads throughout his body down to the tips of his arms.
2. There are two types, one with stems like flowers
types of sea lilies that live on the seabed (commons.wikimedia.org/NOAA Okeanos Explorer Program, INDEX-SATAL 2010)
crinoid actually divided into two groups, there are sea lilies (sea lily) and feather stars (feather star). Sea lilies have stalks to anchor their bodies to the seabed. Hence, they are most numerous in the deep sea region.
According to Charles Messing, a professor from Nova Southeastern University, the shallowest species of sea lily is named Metacrinus round. This species of sea lily lives at a depth of 100 meters off the coast of Japan, he wrote on the website NOAA Ocean Exploration.
Over time, some sea lilies have evolved to shed their stalks as adults. In this way, they can move freely in the sea to find food. Well, this type is called a feather star or feather star. They are most commonly found in shallow water.
While sea lilies have stalks, feather stars have evolved to grow tiny legs that are named cirri. With these tiny legs, star feathers can grip the ocean floor or wherever it is attached. They can swim freely as they please.
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3. One of the most ancient sea creatures
sea lilies or feather stars on coral reefs (commons.wikimedia.org/Holobionics)
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From its appearance alone, it can be seen that sea lilies are one of the most ancient sea creatures. Many of the fossils are hundreds of millions of years old.
Reported Fossilerasea lilies or crinoid It is thought to have appeared during the Ordovician era (a period in the Paleozoic era) about 488 million years ago. Some of the survivors of the mass extinction in the Permian period (the very last period of the Paleozoic era) became the ancestors of the sea lilies you can see in the seas today.
In the past, the number of sea lilies was very abundant. They cover the ocean floor like a rug. This can be seen from the large number of skeletal fossils that can be found in many places around the world. It is estimated that more than 6,000 species of sea lilies have lived on earth!
4. Many are nocturnal
sea lilies on the coral reefs of Raja Ampat (commons.wikimedia.org/pete Weis)
Evening is the perfect time to see sea lilies in person. The reason is, most of them like to hunt after sunset.
During the day, you can find them hiding in rock crevices and coral reefs. As evening approaches, they come out to roost somewhere and stretch out their arms to catch food.
If you notice, the arms of sea lilies have a kind of tiny hairs they call pinnules or pinula. Reported dtmag.com, these hairs are coated with a sticky liquid to trap food in the form of plankton and organic particles from the bodies of dead sea creatures. This food is then transferred relay by the pinula into the mouth which is located in the middle calyx.
Also Read: 5 Facts about Atoll Islands, Coral Rings in the Middle of the Sea
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