The Times Australia
The Times World News

.
The Times Real Estate

.

a look inside the extraordinary preservation of a 310-million-year-old nervous system

  • Written by John Paterson, Professor of Earth Sciences, University of New England

Charles Darwin famously discussed the “imperfections” of the geological record in his book On The Origin of Species. He correctly pointed out that unless conditions are just right, it’s unlikely for organisms to be preserved as fossils, even those with bones and shells.

He also said “no organism wholly soft can be preserved”.

Read more: Guide to the classics: Darwin's On the Origin of Species[1]

However, after more than a century of fossil hunting since his book was published, we now know the preservation of soft creatures is indeed possible — including some of the most fragile animals, such as jellyfish[2].

But what about the really delicate anatomy of animals, such as their internal organs? Can they be fossilised too?

Our study, published today in Geology[3], shows how even the intricate brains of ancient aquatic arthropods[4] (invertebrates with jointed legs) can be preserved in remarkable detail.

The discovery of a 310 million-year-old horseshoe crab[5] in the US, complete with its brain intact, adds to a recent string of fossil finds which have unearthed some of the oldest arthropods with a preserved central nervous system[6].

The horseshoe crab fossil we document in our study sheds new light on how these fragile organs — typically prone to very rapid decay — can be preserved with such fidelity.

a look inside the extraordinary preservation of a 310-million-year-old nervous system (A) Specimen of the fossil horseshoe crab Euproops danae from Mazon Creek, Illinois, USA, preserved with its brain intact. (B) Close-up of brain, as indicated by box in image (A). (C) Reconstruction of Euproops danae, including the position and anatomy of the brain. Russell Bicknell

Brain freeze: how to fossilise an arthropod brain

Most of our knowledge of prehistoric arthropod brains has been sourced from two key types of fossil deposit: amber and those of Burgess Shale-type.

Amber[7] is fossilised resin that oozes through tree bark and is known to trap a variety of organisms. The entombed individuals[8] are commonly represented by arthropods such as insects — made famous in the original Jurassic Park[9] movie.

These fossils preserve an incredible amount of anatomical detail, as well as behaviours[10], mainly because very little decay takes place after the organism is rapidly trapped in the resin.

a look inside the extraordinary preservation of a 310-million-year-old nervous system A centipede and a neighbouring ant suspended in roughly 23 million-year-old Mexican amber. Greg Edgecombe

Using sophisticated imaging technology on these amber fossils, palaeontologists can study tiny arthropod brains in 3D at minuscule scales[11]. However, the oldest arthropods in amber[12] only extend back to the Triassic Period (around 230 million years ago).

Burgess Shale-type deposits[13] are much older, being Cambrian in age (typically 500 to 520 million years old). They contain an abundance of exceptionally preserved marine arthropods.

These fossils are very important as they represent what are unmistakably some of the oldest animals, and can therefore inform us on their origins and earliest evolutionary history. Their remains are primarily preserved as carbon films in mudstone.

a look inside the extraordinary preservation of a 310-million-year-old nervous system The Cambrian arthropod Chengjiangocaris kunmingensis from China. See the bead-like ventral nerve cord preserved in the fossil (A) and its central position in the reconstruction (B). Javier Ortega-Hernández

The fossilisation process starts with storm-induced mudflows that sweep up the delicate animals and bury them in the seafloor in low oxygen conditions. Over time, the mud turns to stone and is compressed, leaving the animals pancaked in the rocks.

Many Burgess Shale-type arthropod specimens preserve internal organs, especially the gut. But fewer show parts of the central nervous system, such as the optic nerves, ventral nerve cord or the brain.

Mind-boggling preservation

Our new fossil demonstrates arthropod brains can be preserved in an entirely different way. The specimen of the horseshoe crab, Euproops danae, comes from the world-famous Mazon Creek deposit[14] of Illinois, in the US. Fossils from this deposit are preserved within concretions made of an iron carbonate mineral called siderite.

Some of the Mazon Creek animals, such as the bizarre “Tully Monster”[15], are entirely soft-bodied. This suggests special conditions must have been in place to preserve them.

We have shown, for the first time, that the Mazon Creek animals were not only moulded by the rapid formation of siderite that entombed their entire bodies, but also that the siderite quickly encased their internal soft tissues before they could decompose.

Notably, the brain of Euproops is replicated by a white-coloured clay mineral called kaolinite. This mineral cast would have formed later within the void left by the brain, long after it had decayed. Without this conspicuous white mineral, we may have never spotted the brain.

A fossil no-brainer

One of the challenges of interpreting ancient arthropod anatomy is the lack of close modern relatives available for comparison. But luckily for us, Euproops can be compared to the four species of living horseshoe crabs.

Even to the untrained eye, a comparison of the fossil’s nervous system with that of a modern horseshoe crab (below) leaves little question that the same structures are found in both species, despite them being separated by 310 million years.

a look inside the extraordinary preservation of a 310-million-year-old nervous system (A) The fossil and (B and C) interpretive drawings of the Euproops danae brain, and (D) the brain of a modern juvenile horseshoe crab, Limulus polyphemus. (A-C) Russell Bicknell, (D) Steffen Harzsch

The fossil and living nervous systems match up in their arrangements of nerves to the eyes and appendages, and show the same central opening for the oesophagus to pass through.

Uncovering these exceptional specimens gives palaeontologists a rare glimpse into the deep past, enhancing our understanding of the biology and evolution of long-extinct animals. It seems Charles Darwin need not have been so pessimistic about the fossil record after all.

Read more: Our 500 million-year-old nervous system fossil shines a light on animal evolution[16]

References

  1. ^ Guide to the classics: Darwin's On the Origin of Species (theconversation.com)
  2. ^ jellyfish (www.nationalgeographic.com)
  3. ^ Geology (doi.org)
  4. ^ arthropods (australian.museum)
  5. ^ horseshoe crab (theconversation.com)
  6. ^ central nervous system (www.britannica.com)
  7. ^ Amber (www.britannica.com)
  8. ^ entombed individuals (cosmosmagazine.com)
  9. ^ Jurassic Park (www.youtube.com)
  10. ^ behaviours (eartharchives.org)
  11. ^ in 3D at minuscule scales (link.springer.com)
  12. ^ oldest arthropods in amber (www.amnh.org)
  13. ^ Burgess Shale-type deposits (burgess-shale.rom.on.ca)
  14. ^ Mazon Creek deposit (pubs.geoscienceworld.org)
  15. ^ “Tully Monster” (theconversation.com)
  16. ^ Our 500 million-year-old nervous system fossil shines a light on animal evolution (theconversation.com)

Read more https://theconversation.com/ancient-brains-a-look-inside-the-extraordinary-preservation-of-a-310-million-year-old-nervous-system-164321

The Times Features

Itinerary to Maximize Your Two-Week Adventure in Vietnam and Cambodia

Two weeks may not seem like much, but it’s just the right time for travelers to explore the best of Vietnam and Cambodia. From the bustling streets of Hanoi to the magnificent te...

How to Protect Your Garden Trees from Wind Damage in Australia

In Australia's expansive landscape, garden trees hold noteworthy significance. They not only enhance the aesthetic appeal of our homes but also play an integral role in the local...

Brisbane Homeowners Warned: Non-Compliant Flexible Hoses Pose High Flood Risk

As a homeowner in Brisbane, when you think of the potential for flood damage to your home, you probably think of weather events. But you should know that there may be a tickin...

Argan Oil-Infused Moroccanoil Shampoo: Nourish and Revitalize Your Hair

Are you ready to transform your hair from dull and lifeless to vibrant and full of life? Look no further than the luxurious embrace of Argan Oil-Infused Moroccanoil Shampoo! In a...

Building A Strong Foundation For Any Structure

Building a home or commercial building can be very exciting. The possibilities are endless and the future is interesting. You can always change aspects of the building to meet the ...

The Role of a Family Dentist: Why Every Household Needs One

source A family dentist isn’t like your regular dentist who may specialise in a particular age group and whom you visit only when something goes wrong. A family dentist takes proa...

Times Magazine

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

How AI-Driven SEO Enhancements Can Improve Headless CMS Content Visibility

Whereas SEO (search engine optimization) is critical in the digital landscape for making connections to content, much of it is still done manually keyword research, metatags, final tweaks at publication requiring a human element that takes extensiv...

Crypto Expert John Fenga Reveals How Blockchain is Revolutionising Charity

One of the most persistent challenges in the charity sector is trust. Donors often wonder whether their contributions are being used effectively or if overhead costs consume a significant portion. Traditional fundraising methods can be opaque, with...

Navigating Parenting Arrangements in Australia: A Legal Guide for Parents

Understanding Parenting Arrangements in Australia. Child custody disputes are often one of the most emotionally charged aspects of separation or divorce. Parents naturally want what is best for their children, but the legal process of determining ...

Blocky Adventures: A Minecraft Movie Celebration for Your Wrist

The Minecraft movie is almost here—and it’s time to get excited! With the film set to hit theaters on April 4, 2025, fans have a brand-new reason to celebrate. To honor the upcoming blockbuster, watchfaces.co has released a special Minecraft-inspir...

The Ultimate Guide to Apple Watch Faces & Trending Wallpapers

In today’s digital world, personalization is everything. Your smartwatch isn’t just a timepiece—it’s an extension of your style. Thanks to innovative third-party developers, customizing your Apple Watch has reached new heights with stunning designs...

LayBy Shopping