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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.