How a 380 Million Years Old Fossil Is Shaking Up Our Understanding of Evolution

A recent discovery reveals that the secret to understanding evolution may be hidden in the unexpected movements of Earth itself.

We recently went to see the “Back to the Future” musical at the Kennedy Center. Fun fact: It had been our anniversary, but we both forgot, so we made up for it by doing something fun together.

After the show was over, we had an interesting conversation. For the second movie, the characters travel to the future in 2015. Released in 1989, the director and scriptwriters had to put their thinking hats on to predict how they imagined society would look like 25 years later.

What shocked us the most was what they got right and what they got wrong. For example, they pictured flying cars and supersonic shoes and people dressed in shiny metallic clothes, none of which was happening almost 10 years ago. We still love cotton and linen, and we are far from flying over anything.

On the flip side, restaurant scenes show the same square and bulky TVs that we watched in the 90s, with no flat screens. Nobody carries a smartphone and spends their entire day glued to a tiny screen.

Indeed, it is very hard to predict what will stay, what will change, and in what direction in our society. Similarly, it is very hard for scientists to predict how a biological species (or family of species) will evolve (or have evolved) over time. What we think is a very useful innovation may be detrimental, while what we think will offer disadvantages sticks around for millions of years.

Want an example? Read today’s story!

When most of us think about ancient fish, we might imagine something long extinct, fossilized in rock and distant from our modern world. But coelacanths, a type of deep-sea fish, flip that expectation on its head.

Once thought to have vanished around 66 million years ago, they shocked the scientific community when a live specimen was discovered off South Africa in 1938. The story of how it was found is quite fascinating, so I recommend that you watch the video below before you continue reading this, so that you have a background of what we knew about the coelacanth before this most recent discovery.

But let’s proceed. Known for their ‘living fossil’ status, coelacanths haven’t changed much in appearance over millions of years. However, a new fossil discovery is prompting scientists to reconsider how these creatures evolved and what drove their diversification. As usual, new discoveries make us rethingk what we know.

Researchers recently found a remarkably well-preserved fossil from the Late Devonian Gogo Formation in Western Australia. Named Ngamugawi wirngarri, this new species is the best-preserved coelacanth from the Devonian period, around 380 million years ago, and fills a crucial gap in our understanding of how this group evolved.

This find is so significant that it has made us rethink the evolutionary forces that shaped not only coelacanths but potentially other ancient lineages.

But first, let’s look at how they did the study, shall we?

The research team undertook an extensive analysis of both the new fossil and hundreds of known coelacanth species from over 410 million years of history.

Using a combination of high-resolution scans, detailed anatomical studies, and evolutionary modeling, they pieced together the phylogenetic tree of coelacanths. This allowed them to examine how different species are related, track their rates of evolutionary change (a tricky calculation paleontologists love to make), and explore potential environmental factors that influenced their evolution.

And what did they find? Well, as it turns out, their evolution was likely driven by something quite unexpected!

One of the most striking findings from this research is that the greatest influence on coelacanth evolution wasn’t what one might expect. While factors like ocean temperature, oxygen levels, and atmospheric carbon dioxide were considered, the data pointed elsewhere: tectonic activity.

Yes, tectonic activity. The continents moving in relation to one another over time.

The research reveals that periods of increased tectonic movement were closely linked to bursts of evolutionary change in coelacanths. As tectonic plates shifted and moved around, they transformed habitats and created new environments, which likely triggered the appearance of new coelacanth species.

As the authors explain, “New species of coelacanth were more likely to evolve during periods of heightened tectonic activity, as seismic movement transformed habitats.”

This suggests that environmental shifts and the creation of new ecological niches due to tectonics played a far greater role in coelacanth evolution than previously thought.

The study also highlighted the relatively slow pace of coelacanth evolution, with the exception of a few periods of rapid change. The researchers found that while coelacanths as a group have evolved slowly over time, they haven’t been entirely static.

For example, although their body shapes remained relatively consistent, finer aspects of their anatomy and proportions have continued to change. In fact, the modern coelacanth species, Latimeria chalumnae and Latimeria menadoensis, the ones that we once thought were extinct, show some distinct differences from their ancient relatives, even if they look quite similar on the surface.

The team’s detailed analysis also revealed an interesting divergence in how different traits have evolved over time. The major morphological features — those big innovations like new structures or major changes in body plans — essentially stopped evolving after the Cretaceous period.

Yep, right when dinosaurs disappear.

However, smaller, continuous traits, such as body proportions, continued to change at typical rates. In layman’s terms, while coelacanths stopped developing new “parts,” the fine-tuning of what they already had kept going. They kept getting better.

But what about the whole “living fossil” thing?

The label of “living fossil” has been commonly applied to coelacanths, implying that they have remained virtually unchanged for millions of years.

But the new findings call for a more nuanced perspective. While Latimeria has essentially ceased evolving new features, the proportions of its body and the details of its DNA are still changing slightly. This means that, while their outward appearance might seem frozen in time, coelacanths are still evolving — just in more subtle ways.

In fact, this reevaluation of coelacanth evolution highlights the importance of looking beyond just the outward appearance of species when considering how they have evolved over time. It emphasizes that even species that seem to have “paused” their evolution in some respects are often still experiencing shifts and adjustments that keep them dynamically adapting to their environments.

In a way, if something important works and keeps you alive for offer 380 million years, why change it, right?

But what does this study tell us we didn’t know about before about evolutionary dynamics?

The discovery of Ngamugawi wirngarri and the findings from this study not only reshape our understanding of coelacanths but also broaden our perspective on how geological processes like tectonics can influence evolution.

Instead of seeing evolutionary change as solely driven by things like temperature or atmospheric conditions, it appears that Earth’s shifting plates and the ever-changing landscape, which may play a role in isolating members of the same species, play a crucial role in opening up new opportunities for species to diversify and evolve.

For those intrigued by how ancient life forms are connected to today’s biodiversity, this research shows that even some of the most seemingly “unchanging” creatures have complex evolutionary stories to tell. And for coelacanths, their story is still unfolding.