Rangeomorphs are considered to be one of the Earth’s first complex animals. They lived in the ocean about 565 million years ago. However, little was known about their reproductive life until now. A group of scientists led by Emily Mitchell of Cambridge University has found that these early organisms had a highly complicated sex life.

Revealed: How Rangeomorphs, The World's First Animals, Reproduced

These creatures were immobile and lacked organs

Findings of the study were published in the latest issue of the journal Nature Communications. Rangeomorphs have little in common with modern creatures because they looked more like plants. They lacked organs, mouth, or the ability to move around. Researchers said these early animals absorbed nutrients from the water.

Since these animals were immobile, well-preserved fossils reveal their whole ecosystem as they lived and died. It allowed researchers to analyze them in clusters to find out how they populated the Earth more than 500 million years ago. Scientists used statistical analysis, computer simulations, and high-resolution GPS to determine the reproductive strategy genus Fractofusus, a type of rangeomorph, used.

Rangeomorphs used two-pronged reproduction strategy

They found that rangeomorphs used a two-pronged approach. Scientists believe rangeomorphs might have been the first group to develop such a complex reproductive strategy. In one method, the ancient animal would send out “grandparent,” much like tiny seeds or buds, into the water column to colonize new areas. The grandparents would then produce “parents” or “children” using stolons.

In another, rangeomorphs sprouted young from their body in pretty much the same way as strawberries grow today. Combined, these two methods allowed rangeomorphs to rule the sea. These creatures prospered during the late Ediacaran period between 580 million and 541 million years ago. However, they vanished at the beginning of the Cambrian period about 540 million years ago.

Rangeomorphs measured between 4 inches and 2 meters in length. Researchers said findings of the study would help them understand the origin of modern marine life.