Comb jellyfish may be the oldest group of animals in the world, scientists say. A study published in the journal Nature Ecology & Evolution presents new data that indicates these strange creatures appeared on Earth about 700 million years ago. That’s considerably earlier than previously thought.
Researchers used a new method to analyze genomes and phylogenetic trees to determine the ages of different groups of animals. They found that comb jellyfish were the first animals to appear on earth more than 100 million years earlier than previously thought.
Comb jellyfish have a unique body structure that differs from other animal groups. Unlike square jellyfish and coral polyps, they do not have a stable skeleton or hard shell. Instead, they have soft, jelly-like bodies that consist of transparent water layers called mesogloea.
Scalloped jellyfish also have a unique ability to move. Instead of using muscles like most animals, they move thanks to the rows of flashing cilia that cover their bodies.
Although comb jellyfish have been studied for more than 150 years, there are still many unknowns about their biology and evolution. However, the new study represents an important step in understanding the origin and evolution of this ancient group of animals.