Researchers discover a 520 million year old brain in a tiny larva. The discovery provides insights into the early evolution of complex nervous systems.
Durham/Yunnan – Scientists have made another spectacular discovery: Was it recently the possibly oldest cave painting in the worldwhich caused a sensation, the oldest known brain has now been found in the tiny fossil of a larva from the Cambrian period (around 500 million years ago).
This amazingly well-preserved fossil provides valuable clues to the evolution of arthropods, one of the most successful and diverse groups of animals. The results, which were recently published in the journal “Nature” provide deep insight into the formation of complex nervous systems.
An extraordinary brain discovery from the Cambrian period
The find dates back to the Cambrian period, which took place around 520 million years ago. This era is known for the “Cambrian explosion”, which saw a sudden increase in the diversity and complexity of life on Earth. The animal groups that emerged at that time included arthropods, whose modern descendants are insects, spiders and crabs. The body structure of these animals, characterized by jointed legs and an external skeleton, enabled them to be widely ecologically adaptable.
The fossil of the larva was discovered in the Yu’anshan Formation in China and is characterized by exceptionally good preservation. The researchers speak of an “Orsten-like preservation”, named after a particular fossil deposit. Orstens are in geoscience, according to spectrumgeological layers that have become known for the three-dimensional preservation of microscopic organisms from the Cambrian period.
The term is derived from the Swedish word for a particular limestone in which these fossils are found. These fossil deposits are unique because they often preserve not only hard parts, but also tiny details such as hair, spines or mouthparts. The fossil finds from Orsten therefore offer profound insights into the early developmental stages of animals and make a significant contribution to understanding evolution during this period.
Evolution of arthropods: A 520 million year old brain discovered
The larva found in the Yu’anshan Formation in southern China is According to the studyonly a few millimeters in size, but it reveals a well-preserved brain divided into several sections. This structure gives scientists valuable information on how complex nervous systems have developed over the course of evolution. The larval brain shows clear segmentation, similar to that of modern arthropods, which suggests that early representatives of this animal group already had highly developed nervous systems.
Particularly noteworthy is the so-called “protocerebrum”, a brain region responsible for controlling the first limbs and eyes. This region was already well developed in the tiny larva and suggests that the evolution of complex brains took place earlier than previously thought.
Orsten fossils: Fossil larva reveals the oldest known brain in Earth’s history
The discovery caused a similar stir as the discovery of two species of worm in a cave on Mallorca – with a red glowing brain.
This discovery provides new information about the evolution of arthropods, which, according to Natureis the most diverse group of living creatures on Earth today. Their ability to adapt to different habitats – from the deepest oceans to the highest mountains – is based on their unique body structure and specialized organs. The discovery of the larva confirms that even the early arthropods had highly developed structures that enabled them to survive in different ecological niches.
The discovery of the larva also sheds light on the development of the circulatory system and digestive organs of these animals. The researchers found evidence of specialized glands in the larva’s digestive tract, suggesting that it may have been a predator. These glands closely resemble those of modern arthropods, showing that the blueprint of this organ system was already established early in evolution.
The brain of the discovered larva is a striking example of how Orsten fossils provide new insights into the evolution of complex organisms. The find helps to better understand the evolution of arthropods and to trace the development of the first nervous systems. An unforgettable discovery also occurred in June 2024, when a team of researchers came across a 78 million year old dinosaur fossil encountered. (ls)
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