4/16/2023 0 Comments Brain warp![]() ![]() In 2009, Alan Pradel, from France’s Muséum National d'Histoire Naturelle, in Paris, and his team made an exceptional discovery: a fossilised brain preserved in a 300 million-year-old cartilaginous fish. Hearts are made of muscle that can be more easily fossilised compared to brains, which are made of much softer material, and so very rarely ever fossilise. Because of this, palaeontologists are usually only left with the hard skeletal remains, and almost never get to see organs, such as the heart or brain.īut there are some remarkable exceptions such as a recently discovered 120 million-year-old fossilised heart. But how much did their brains evolve in the process? The hunt for fossil brainsĪfter an animal has died, soft tissue such as muscle breaks down quickly and doesn’t get a chance to fossilise. ![]() Lungfish can be thought of as our fishy cousins, who can provide great insight into the anatomical changes in our ancient ancestors as they first crawled out of water onto land, some 370 million years ago. Lungfish have long fascinated researchers due to their close relationship with the tetrapods – the land-dwelling animals with a backbone, which includes ourselves. This is in great contrast to their close relative the coelacanth whose brain fills a very small percentage of its cranial cavity (thought to be only 1%). Recent work shows that a group of fish called lungfish also have relatively large brains, one that fills more than 80% of the cranial cavity. There are some groups of fish, such as some sharks and rays, that actually have a very large brain size relative to their body mass. But the picture of how brains evolved, as restored from the spaces inside fossil skulls, might not be as simple as once thought. This enables us to see inside fossil skulls and start piecing together the evolutionary history of the vertebrate brain.Fish have relatively small brains, especially in comparison to birds and mammals. We now routinely scan our specimens using CT scan machines, like those used in hospitals, to reveal internal features without destroying the specimen. Palaeontologists have recently found a way around this dilemma. Although this method can reveal amazing results, it requires destroying rare and irreplaceable specimens. These were fossils that had been split in half with hammers or serially ground away to reveal glimpses of the internal anatomy. Until recently, only a few endocasts were known. The site is world renowned because 385 million-year-old fish fossils can be prepared out of limestone to yield beautifully preserved three-dimensional skulls. The fossils from Gogo are truly exceptional. To do this, you need some very well-preserved (uncrushed) fossils such as those coming from the world famous Gogo Formation in the Kimberley region of Western Australia. Like the coelacanth, this fish had a very small brain, housed within a much larger skull cavity.Īs actual fossilised brains are so frightfully rare, palaeontologists must instead look at the cranial endocast, a mould of the internal cavity that once housed the brain, to reconstruct brain shape. ![]() After an animal has died, soft tissue such as muscle breaks down quickly and doesn’t get a chance to fossilise. ![]()
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