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In Images: The Tracks of an Ancient Sea Monster

Trackmarks uncovered

nothosaur tracks being excavated

(Image credit: © Chengdu Center of China Geological Survey)

In 2009, researchers uncovered track marks made by Triassic era marine reptiles. Here, students and farmers help excavate the track marks made by paddle-limbed creatures called nothosaurs 245 million years ago.

Long-standing debate

images of nothosaur track

(Image credit: © Chengdu Center of China Geological Survey)

The tracks could help resolve a long-standing debate: how nothosaurs swam.

Rowing limbs

illustration of a nothosaur

(Image credit: Original artwork © Brian Choo, 2014)

The new analysis shows the nothosaurs, like the Lariosaurus shown here, probably used a rowing motion.

Tasty snack

Live lobsters caught in Bar Harbor, Maine.

(Image credit: Natalia Bratslavsky | Shutterstock)

Nothosaurs probably ate the lobster and fish that dwelled on the seabed surface, and their paddle-like rowing dredged them up from the soupy sediments.

Ancient sea monster

prehistoric ichthyosaur sea monster, illustration,

(Image credit: Art by Raul Martin, © 2013 National Geographic Magazine, Reproduced with permission (ONE-TIME USE))

The researchers ruled out other sea creatures, such ichtyosaurs and other marine reptiles based on size and anatomy.

Other monsters

illustration of a mosasaur

(Image credit: Tibor Pecsics)

Nothosaurs could range from 13-feet long to a measly 2-feet long. For comparison, mosasaurs that terrorized the sea during the Cretaceous Era (pictured here) were 20 feet (6 meters) long.

Tia Ghose
Tia has interned at Science News,, and the Milwaukee Journal Sentinel and has written for the Center for Investigative Reporting, Scientific American, and ScienceNow. She has a master's degree in bioengineering from the University of Washington and a graduate certificate in science writing from the University of California Santa Cruz.