GIANT SEA REPTILES OF THE DINOSAUR AGE at the Natural History Museum of Los Angeles County, CA

Mosasaur skeleton from Kansas at the Natural History Museum of Los Angeles County

Several years ago, when I was researching my book about giant sea reptiles, I visited the Natural History Museum of Los Angeles County in Exposition Park to view the fossil skeleton of a mosasaur. The huge mouth and sharp teeth made me glad that I wasn't meeting this creature in real life! In the late Cretaceous Period, about 80 million years ago, these huge reptiles were the supreme predators of the sea. But, like the dinosaurs, mosasaurs became extinct 65 million years ago. We know about them from their fossil remains.

Fossils of mosasaurs have been found all over the world, including Antarctica. A recent discovery in Hungary reveals that mosasaurs lived in both freshwater and saltwater. They swam in North America’s inland sea, and their fossils are especially numerous in Kansas and South Dakota. The largest known species, Tylosaurus, grew to be up to 50 feet long and weighed up to 11 tons.

Mosasaurs were excellent swimmers and propelled themselves through the water with a side-to-side motion of their long tails. Most of them ambushed their prey, making a swift attack and catching it by surprise. Bite marks on fossil nautiloids show that they were preyed upon by sea reptiles like mosasaurs.

Chambered nautiluses are still swimming in the ocean today.

Mosasaurs probably ate anything they could find, including other mosasaurs. The preserved stomach contents of a Tylosaurus found in South Dakota contains the remains of a smaller mosasaur, a bird, a fish, and what may have been a shark.

Mosasaurs, along with the icthyosaurs and plesiosaurs, also extinct, were the largest reptiles ever known to swim the Earth’s oceans. They are part of the amazing diversity of life during the Dinosaur Age.

You can read more about these fascinating animals in my book Giant Sea Reptiles of the Dinosaur Age, illustrated with beautiful water color paintings by Laurie Caple.

MARY ANNING's Amazing Fossils at the Natural History Museum, London

"Mary Anning" at the Museum of Natural History, London

In 1811, Mary Anning and her older brother Joseph discovered a strange-looking skull eroding out of the cliffs of Lyme Regis on England’s Dorset coast.  The fossil turned out to be the head of an ichthyosaur, a sea-going contemporary of the dinosaurs.  (At the time the word “dinosaur” had not yet been coined.)  This was the first of Mary Anning's many remarkable discoveries, now on display at the British Natural History Museum in London.

Meeting Mary Anning

On a recent trip to London, I visited the museum, and as I walked along the gallery where Mary Anning’s fossils are displayed, who should I see, but Mary Anning herself!  Of course, it was not the real Mary Anning, who lived from 1799 to 1847, but a character actor, who was delighted to interact with me and other visitors as if we were still in the early 19th century.  For me, this was a special treat, as I had researched Mary Anning’s life and written about her discoveries in two of my books, Giant Sea Reptiles of the Dinosaur Age and Pterosaurs: Rulers of the Skies in the Dinosaur Age.

Ichthyosaur fossil, 203 - 194 million years old. Like reptiles that live on land, ichthyosaurs needed to breathe air.  Their nostrils were located in front of their eyes.

Fossil hunting in Britain had its “golden age” in the first half of the nineteenth century.  People collected fossils for fun and profit as well as for academic study.  Mary Anning collected fossils from the rocks along the shore near Lyme Regis and sold them to support her family.  She had little formal education, but an uncanny ability to find fossils.  The ichthyosaur skeleton, and many of Mary’s other finds, were used by leading scientists of the time as a basis for their new theories about Earth’s history.

Ichthyosaur head. The large eye of an ichthyosaur was surrounded by a doughnut-shaped bone called the sclerotic ring.  Large eyes enabled ichthyosaurs to see well in dim ocean depths.

The cliffs at Lyme Regis, on England’s southern coast, are filled with the remains of marine animals that had lived 200 million years earlier, during Jurassic times, when this region was a shallow sea.  When Mary Anning’s brother Joseph first saw the ichthyosaur skull, he thought it was a crocodile.  Later, after a fierce storm washed away more of the cliff, Mary discovered the neck and shoulders of the animal’s skeleton. At the time, she was only thirteen years old.  She and her brother excavated the bones and sold them to a fossil collector from London, who thought they belonged to a giant fish.  At the time, little was known about prehistoric sea reptiles.  It was not until several years later, after similar fossils had been found, that the skeleton was correctly identified as that of an ichthyosaur.  Because these strange animals seemed to be part fish and part reptile, they were given a scientific name meaning “fish lizard.”

Plesiosaur skeleton, 203 - 194 million years old.  Collected by Mary Anning in 1824.

In addition to her discoveries of at least three ichthyosaur skeletons, Mary Anning found fossils of two plesiosaurs and a pterodactyl, as well as numerous fish, ammonites (spiral-shelled mollusks that are ancient relatives of the chambered nautilus), brittle stars, and other marine animals, including many belemnites.  Like squid, belemnites had ink sacs.  One of the belemnites she found was complete with its fossil ink!

Ammonites from Lyme Regis

Mary Anning collected fossils for many of the leading scientists of the day and her work helped develop new ideas about what the world was like in prehistoric times.  As a woman and without a formal education, she was not recognized in her time.  Today, she is given credit for some of the most amazing fossil discoveries ever made.

Recommended book:
I recently read about Mary Anning in the book, Remarkable Creatures: A Novel by Tracy Chevalier.  This fictionalized story of Mary Anning and her relationship with the Philpot sisters who helped promote her work, brings the town of Lyme Regis to life and makes you appreciate the difficulty of fossil collecting and the amazing contribution Mary Anning has made to our understanding of prehistoric life.  The book is also a window on the social and religious conventions of the time and how Mary Anning’s  fossils challenged many of those ideas.