Podcast Summary: The First Sharks The Ancients
Host: Tristan Hughes
Guest: Professor John Long, Flinders University, Adelaide, Australia
Release Date: July 17, 2025

Introduction

In a special episode of The Ancients, host Tristan Hughes welcomes Professor John Long, a leading expert on prehistoric sharks from Flinders University. Together, they delve into the ancient origins and evolutionary journey of sharks, tracing their lineage from the earliest scales to the formidable predators that roamed the oceans before the age of dinosaurs.

Origins of Sharks

Timestamp: [04:25]

Tristan introduces the topic by highlighting the ancient lineage of sharks, noting their existence predates many other life forms:

Professor John Long: “Sharks. They're older than the rings of Saturn. They're older than trees. 300 million years ago, sharks enjoyed a golden age.”

The conversation begins with an exploration of the earliest sharks, emphasizing their ancient origins and the limited fossil evidence available from those times.

Fossil Evidence and Early Research

Timestamp: [05:23]

Professor Long explains the critical role fossils play in understanding shark evolution:

Professor John Long: “Fossils are the main tool of research for learning about these earlier specimens of sharks, for following the whole evolutionary cycle.”

He underscores the importance of fossilized scales and teeth in reconstructing the history and diversity of early sharks.

Development During the Devonian Period

Timestamp: [07:03]

The discussion moves to the Devonian period, a pivotal era for shark evolution:

Professor John Long: “During the Devonian period, which started 419 million years ago and ended 60 million years later, we start getting abundant shark fossils from marine and freshwater deposits.”

Tristan and Professor Long explore how sharks evolved from small, meter-long predators to larger, more formidable creatures by the end of the Devonian, becoming the apex predators of their time.

The Devonian Revolution

Timestamp: [10:03]

Professor Long describes the Devonian as a revolutionary period for life on Earth:

Professor John Long: “The Devonian was the revolution that really started it all. Plants took over the land and grew to forests, fish evolved limbs and started walking on land, and sharks developed complex teeth and cartilage structures.”

This era not only saw significant advancements in shark physiology but also dramatic changes in the Earth's ecosystems, setting the stage for future evolutionary developments.

The Golden Age of Sharks: Carboniferous Period

Timestamp: [18:18]

Transitioning to the Carboniferous period, Professor Long labels it the “golden age of sharks”:

Professor John Long: “In the Carboniferous period, sharks diversified rapidly and grew larger, becoming the most abundant fishes in our seas and rivers, more so than the bony fish that dominate our oceans today.”

He highlights notable fossil sites like Bear Gulch in Montana, where thousands of well-preserved shark fossils provide a window into this diverse and prolific period.

Shark Diversity and Adaptations

Timestamp: [23:20]

The Carboniferous period showcased a remarkable diversity of shark species, each adapted to different ecological niches:

Professor John Long: “There were filter-feeding sharks, predatory sharks with serrated teeth like great white sharks, and even bizarre forms like eniopterygians with antler-like fins and club-shaped tails.”

These adaptations allowed sharks to exploit a wide range of feeding strategies, from crushing clams to hunting giant cephalopods like ammonites.

Significant Fossil Discoveries

Timestamp: [42:14]

Professor Long shares insights from his extensive fieldwork, including discoveries in the Gogo fossil site in Australia:

Professor John Long: “We discovered Gogosalacus, a shark with three-dimensional preserved jaws and teeth, showing that early sharks had more bone in their skeletons before specializing in cartilage.”

He also recounts expeditions to Antarctica where significant Devonian shark fossils were unearthed, further enriching our understanding of early shark morphology and diversity.

Migrations and Survival Through Extinctions

Timestamp: [49:06]

The conversation addresses how sharks survived major extinction events:

Professor John Long: “Sharks occupied diverse environments, including deep waters and freshwater systems, which helped them survive extinction events that heavily impacted shallow marine habitats.”

This adaptability ensured the persistence of various shark lineages through turbulent periods in Earth's history.

Evolutionary Legacy and Modern Sharks

Timestamp: [53:59]

Professor Long traces the lineage from ancient sharks to modern species, culminating in the emergence of Neo Salakians in the Jurassic period:

Professor John Long: “The Neo Salakians are the beginning of the modern lineage of sharks that populate today's oceans, emerging prominently in the Jurassic period.”

He contrasts this with the later dominance of large predatory reptiles, showcasing the dynamic shifts in marine ecosystems over millions of years.

Conclusion: The Enduring Legacy of Sharks

In wrapping up, Tristan and Professor Long reflect on the remarkable evolutionary journey of sharks, emphasizing their resilience and adaptability:

Professor John Long: “Sharks have been one of the great survivors of Earth's history, adapting to changing environments and emerging as dominant predators time and again.”

Tristan hints at future episodes, promising to explore the next chapter in shark evolution—the rise of the Megalodon.

Final Thoughts

This episode of The Ancients provides an enthralling journey through time, offering listeners a comprehensive look at the origins, evolution, and enduring legacy of sharks. Professor John Long's expertise and engaging narrative bring to life the secrets of these ancient predators, making complex paleontological concepts accessible and fascinating.

Notable Quotes:

• John Long [04:25]: “Sharks. They're older than the rings of Saturn. They're older than trees.”
• Christian Dropo [07:03]: “The Devonian was the revolution that really started it all.”
• John Long [18:18]: “In the Carboniferous period, sharks diversified rapidly and grew larger, becoming the most abundant fishes in our seas and rivers.”
• Christian Dropo [23:20]: “There were filter-feeding sharks, predatory sharks with serrated teeth like great white sharks, and even bizarre forms like eniopterygians with antler-like fins and club-shaped tails.”
• John Long [42:14]: “We discovered Gogosalacus, a shark with three-dimensional preserved jaws and teeth.”
• Christian Dropo [49:06]: “Sharks occupied diverse environments, including deep waters and freshwater systems, which helped them survive extinction events.”
• John Long [53:59]: “The Neo Salakians are the beginning of the modern lineage of sharks that populate today's oceans.”

This summary encapsulates the key discussions and insights from the episode, providing a detailed and engaging overview for listeners new and old.