New species of coelacanth shows rapid evolution after mass extinction

In a groundbreaking study, scientists from the Museum of Natural History of Geneva and the University of Geneva (UNIGE) have unveiled fascinating insights into a new species of coelacanth dating back to the Middle Triassic period. Coelacanths are known as “living fossils” due to their ancient lineage and slow evolutionary changes over the course of 420 million years.

The research focused on fossils discovered in the Grisons and Ticino regions of Switzerland, both from the same geological era. These peculiar fish, which exhibit a remarkable morphology, shed light on the period following a mass extinction event that occurred 252 million years ago, decimating over 80% of marine species.

Coelacanths are extraordinary creatures that offer valuable clues about the ancestors of terrestrial vertebrates, including humans. Their unique fins and other characteristics place them closer to land-dwelling vertebrates than to typical fish. Therefore, studying coelacanths allows us to gain insights into what our ancient fish ancestor might have looked like.

Among the exciting findings was the identification of a new species, Foreyia maxkuhni, from coelacanth fossils discovered in the Grisons region. These specimens display a peculiar appearance, featuring a compact body and a dome-shaped skull.

The researchers were prompted to expand their investigation to coelacanth fossils found in the UNESCO World Heritage site of Monte San Giorgio in Ticino, which are of the same age as those in Grisons. These ancient specimens, preserved in the Paleontological Museum of Zurich since the mid-20th century, have never been thoroughly studied due to their complex interpretation.

The study’s results, published in the journal Scientific Reports, provide valuable insights into the rapid formation of several coelacanth species following the mass extinction event. This discovery challenges the common notion that coelacanths evolved slowly over time. Instead, it suggests a burst of diversification during a critical period of Earth’s history.

The new species’ strange characteristics and its implication in the evolution of coelacanths make it a significant addition to the field of paleontology. The study serves as a testament to the enduring fascination with these “living fossils” and their crucial role in understanding the history of life on our planet.

A new species of coelacanth

Christophe Ferrante, a researcher at the UNIGE Faculty of Science, made a significant breakthrough during his doctoral thesis by unveiling a new species of coelacanth named Rieppelia heinzfurreri. Interestingly, this species is evolutionarily closely related to the Foreyia species found in the Grisons region. However, while some characteristics of Rieppelia resemble those of Foreyia, others are remarkably reversed, presenting intriguing differences such as variations in fin size and opercle dimensions.

The study conducted by Ferrante reveals an exciting phenomenon: both Rieppelia heinzfurreri and Foreyia maxkuhni, along with two other coelacanth species with more conventional traits, are part of a small evolutionary radiation. This phenomenon involves the rapid emergence of several species within a confined period and geographical area. Remarkably, this is the first time such an occurrence has been identified in coelacanths.

The research sheds light on an important period in Earth’s history. Approximately 252 million years ago, our planet experienced a catastrophic mass extinction event, with over 80% of marine species vanishing due to massive volcanic eruptions in Siberia. Remarkably, the Swiss coelacanths, living about 10 million years after this catastrophic event, managed to thrive in the unique conditions of the post-extinction environment, giving rise to distinct and unusual forms throughout their evolutionary journey. These niche habitats later became inhabited by other groups, including major bony ray-finned fish that continue to occupy these ecological spaces today.

To further unravel the mysteries of these postapocalyptic coelacanths from the Triassic era, Lionel Cavin’s team at the Natural History Museum in Geneva continues their research by describing new fossils found in various locations worldwide. Additionally, they are exploring potential genetic characteristics that may be responsible for these peculiar forms, drawing comparisons with the genomes of present-day vertebrates.

The discoveries made by Ferrante and the ongoing research led by Cavin’s team showcase the remarkable resilience and adaptability of these ancient coelacanths. They provide us with valuable insights into the evolutionary processes that shaped life on Earth after one of the most significant mass extinctions in history.

Source: University of Geneva

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