College of Marine Sciences & Maritime Studies

Q&A: Discussing Ancient Sea Monsters With Dr. Christopher Smith

"Paleo Hall at Houston Museum of Natural Science" by Kim Alaniz is licensed under CC BY 2.0. To view a copy of this license, visit tx.ag/creativecommonslicense

In the spirit of Halloween, bldg. 311 sat down to talk with Dr. Christopher Smith, a marine science professor in the College of Marine Sciences and Maritime Studies and instructor for the Ancient Sea Monsters class. Though it might sound scary, Smith’s class uses the history of our oceans to better inform us of what the future holds by focusing on the paleontology, evolution and extinction of prehistoric marine reptiles.

How does the study of “Ancient Sea Monsters” inform our understanding of modern marine animals? 

There is a common phrase in my field, “The past is the key to the present,” that nicely sums matters up. Understanding the evolutionary history of ancient organisms can only improve our understanding of modern organisms. For example, understanding how groups like Ichthyosaurs, Plesiosaurs, and Mosasaurs  came to be so successful in the Mesozoic seas can enhance our understanding of how modern groups such as whales and dolphins achieved the same success in similar roles in the ocean ecosystem. On the flip side, a better understanding of why those ancient groups went extinct can help us understand potential threats to our modern ocean ecosystems as well.

Paleontology and more specifically, the study of ancient extinct animals like these sea reptiles, will always be important because understanding the history of our planet should be one of our utmost concerns in science. The better we understand our planet’s history, the more nuance we have for understanding current issues facing our planet.

What are the major differences between prehistoric marine reptiles and modern marine reptiles that we see today? 

The most obvious difference is size of course. The most famous Mesozoic marine reptiles, like Plesiosaurs and Mosasaurs, could achieve enormous sizes that only a few species today, such as the saltwater crocodile or leatherback sea turtle could even be compared to. Modern marine reptiles are also far less ubiquitous and diverse in today’s oceans. In the Mesozoic era, Ichthyosaurs, Plesiosaurs, and Mosasaurs,  and other marine reptile groups were extremely common and occupied the top levels of the ancient ocean food chains. Modern marine reptiles did not evolve from these famous extinct lineages, but many of them were around in the Mesozoic. Crocodilians and sea turtles have an extensive fossil history going back to the Mesozoic. In contrast, sea snakes and marine iguanas are both fairly recent, evolutionary speaking.

How do we know what prehistoric marine reptiles looked like and how they lived?

We have vast amounts of fossil remains for these animals that give us, at least for some species, a fairly accurate idea of how they looked. Behavior can be trickier to parse, but there are many clues we can use to deduce life habits of these animals as well. For example, in many cases, the stomach contents of these animals have been preserved, giving us a window into their diets. Often, wounds and scars can be identified on fossil bones as evidence of attacks from predators or even rivals of the same species. We can also look at modern animals with similar body plans, like whales and dolphins, for insight into how they may have swam, hunted or otherwise behaved. 

Do you have a favorite topic to cover in the class?

While the “big three” groups (Mosasaurs, Ichthyosaurs, and Plesiosaurs)  are always fun to cover, I find my favorite group to cover are the Pliosaurs . Pliosaurs were close relatives of Plesiosaurs  that grew to truly enormous sizes and were the unquestioned top predators of the Jurassic oceans. Often, the students have less of a knowledge base with these creatures, so they usually end up even more fascinated by them.

Are there any recent findings or discoveries in the field that you can share?

There are new discoveries in paleontology made almost every day. With every new skeleton or other fossil we find, new information comes to light. For example, I was just reading about a new species of Mosasaur  found in North Dakota last year that scientists have named Jormungandr, inspired by the legendary serpent from Norse mythology.

Very cool! It sounds like an exciting field of study. Can you tell us why you decided to go into the discipline? 

Paleontology is a subject that has fascinated me since I was a small child. When I was just 4 years old, Jurassic Park was in its initial theatrical run and my parents made the admittedly questionable decision to take me to see it. As they’re fond of telling people, I was the one child in the room completely unafraid of the dinosaurs on screen. That turned out to be an omen of things to come. Often children grow out of their “dinosaur/fossil” phase. I just never did. While the ancient sea reptiles were NOT dinosaurs (one of the biggest things I try to instill in my students), they are often closely associated with them because they ruled the oceans at the same time dinosaurs ruled the land.

---

For students wanting to take the class, Ancient Sea Monsters will be offered again in the spring of 2025.