An article published in the journal “Scientific Reports” describes the discovery of two species of algae dated over 555 million years ago, during the period known as the Ediacaran. These are some of the oldest multicellular life forms ever found and their fossils are very rare because those soft bodies are difficult to preserve. For this reason each new discovery provides new information on the development of multicellular organisms.

The paleontologist Stephen Dornbos of the University of Wisconsin-Milwaukee led a team that discovered two new species of algae during a search for fossils dating back to the Ediacaran period in western Mongolia. There they found Burgess Shale-type deposit, where there were conditions that allowed the preservation of the organisms’ soft tissues.

This type of deposit was more common in the Cambrian period and it’s for this reason that today we have many fossils from that era. Deposits of that type from the previous period, the Ediacaran, are rare and the fossils found are generally algae or other organisms difficult to classify. In many cases, the interpretations on their nature are sources of controversy for a long time.

The research in western Mongolia was accomplished the first fossils wer discovered in summer 2014. Excavations started in summer 2015 and led to the identification of two species of algae. The most widespread was called Chinggiskhaania bifurcata while the other, of which three specimens were found, was called Zuunartsphyton delicatum.

The fossils were subjected to various analyzes using a scanning electron microscope that showed that they are composed of clay minerals and specifically aluminosilicates and by a bit of carbon. It’s a composition comparable to that of the Burgess Shale Cambrian fossils.

These fossils were found under the most ancient fossil traces in that region, dated around 555 million years ago. This suggests that these algae are a bit older. That means that those are some of the most ancient multicellular life forms found so far.

The limited amount of fossils dating back to the Ediacaran period makes their classification difficult so every new discovery helps to make new step forward. The discovery of a new deposit of Burgess Shale-type fossils dating back to that period gives paleontologists new hope for a greater understanding of a crucial period in the evolution of life on Earth.