Sea angels are fascinating creatures that are often confused with jellyfish, but they are actually a type of sea slug. Classified into six different families, these small free-swimming creatures belong to the clade Gymnosomata within the larger mollusc clade Heterobranchia. They are also known as pelagic opisthobranchs, which means they are sea slugs that swim freely in the open ocean.
Sea angels were previously thought to be a type of pteropod, which is another group of free-swimming sea slugs. However, recent research has shown that sea angels are a distinct group with their own unique characteristics. Unlike pteropods, sea angels have no shell and their bodies are covered in a series of wing-like appendages that they use to swim through the water.
Sea angels can be found in oceans all over the world, from the Arctic to the Antarctic. They come in a range of sizes, from just a few millimeters to several centimeters in length. Their bodies are often transparent or translucent, which can make them difficult to spot in the water.
One of the most interesting things about sea angels is their diet. They feed on a variety of small animals, including other sea slugs and even jellyfish. To catch their prey, sea angels use a pair of specialized tentacles that are covered in tiny hooks. These hooks help them to grab onto their prey and bring it towards their mouth.
Despite their small size, sea angels are an important part of the ocean ecosystem. They serve as a food source for larger predators, and they also help to control the populations of other small animals. However, like many other marine creatures, sea angels are facing threats from human activities such as overfishing, pollution, and climate change.
In conclusion, sea angels are a fascinating group of sea slugs that are often confused with jellyfish. Classified into six different families, these pelagic opisthobranchs are important members of the ocean ecosystem. Despite their small size, they play an important role in the food chain and help to control populations of other small animals. As with many other marine creatures, it is important that we work to protect sea angels and their habitats from the threats posed by human activities.