An Ultimate Guide to Nothosaurus: The False Reptile

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Name Meaning“False lizard”HeightN/A
PronunciationNo-tho-SAWR-uhsLength5–7 meters (16–23 feet)
EraMesozoicEarly-Middle TriassicWeight100–200 kilograms (220–440 lbs)
ClassificationSauropterygia, Nothosauroidea & NothosauridaeLocationEurope, Asia, and North Africa

Nothosaurus Reptile Pictures

Nothosaurus | Warpaintcobra via iStock

The Nothosaurus

Gage Beasley Prehistoric's Nothosaurus Concept
Gage Beasley Prehistoric’s Nothosaurus Concept

Nothosaurus is a genus of extinct marine reptiles alive during the Triassic Period, approximately 241 to 200 million years ago.

It lived in parts of North Africa, Europe, and Asia and was among the most abundant marine reptiles of the Triassic, along with others like the primitive ichthyosaurs

Unlike the other popular groups of marine reptiles that were fully aquatic, Nothosaurus lived a semi-oceanic lifestyle.

Like modern seals, this reptile spent significant time on land but was well-adapted to life in the ocean. 

The name Nothosaurus translates as false lizard and is a reference to the reptile’s unique adaptation to terrestrial life. 

Marine reptiles were not very popular when the first fossil of the Nothosaurus was discovered in the early 1800s. 

As a result, the paleontologists that described the Nothosaurus weren’t certain of how to classify it because it looked like a land-dwelling animal but was not quite like them. 

This is why it got the name “false lizard.” 

A carnivorous reptile, Nothosaurus, attacks smaller marine dinosaurs, Shonisaurus, in a Cretaceous ocean
A carnivorous reptile, Nothosaurus, attacks smaller marine dinosaurs, Shonisaurus, in a Cretaceous ocean | CoreyFord via iStock

Nothosaurus was a formidable predator in the marine environment of the Triassic. 

It was around for nearly 50 million years, diversifying into many new species. 

It remains one of the most well-known marine reptiles of Earth’s prehistoric seas thanks to an abundance of fossil remains, including a few complete and well-articulated skeletons. 

In this article, we’ll discuss some of the most interesting facts about this ancient lizard, describing various aspects of its appearance and how it lived. 

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

Nothosaurus was a moderately-sized marine animal. 

Although it was not as big as later Mesozoic Era reptiles like the plesiosaurs and pliosaurs, it still reached lengths of about four meters (13 feet) on average. 

Some species in the Nothosaurus genus may have reached lengths of about five to seven meters (16–23 feet).

Gage Beasley Prehistoric's Nothosaurus Concept
Gage Beasley Prehistoric’s Nothosaurus Size Comparison Chart

As an animal well-adapted to a marine lifestyle, Nothosaurus had a streamlined body. 

It also had a long neck and tail, with a relatively small head. 

The tail and its long, webbed feet tail helped the Nothosaurus propel its slender body through water. 

The Nothosaurus’ snout was long and narrow. 

The jaws were lined with rows of fang-like teeth that were effective for holding on to prey. 

There were two nostrils on the top end of the Nothosaurus’ snout, which suggests that the reptile breathed air.

Habitat and Distribution

Nothosaurus had a relatively wide geographic distribution during the Triassic Period. 

Fossils of this reptile have been found in various locations across the globe, including parts of present-day Africa, Europe, Asia, and North America. 

Nothosaurus preferred marine and near-marine habitats. 

It spent significant time in nearshore environments but also ventured out into the shallow seas, lagoons, and estuaries of the Triassic, where it hunted for prey.

This reptile had a streamlined body, long tail, and paddle-like limbs, which suggests that it was well-adapted to life in the water. 

It isn’t clear how far from shore the Nothosaurus could swim and the depth it could reach.

When it wasn’t hunting prey in the sea, Nothosaurus probably spent time on land, but it probably didn’t go far inland enough to lose sight of the sea.‭ 

Two Nothosaurus dinosaurs growl at each other on a Triassic beach
Two Nothosaurus dinosaurs growl at each other on a Triassic beach | CoreyFord via iStock

The climate of the Triassic Period was generally warm and humid. 

However, there were variations from one region to the other. 

The supercontinent Pangaea was still intact during the Triassic when this reptile was alive. 

The single landmass was surrounded by a vast ocean that formed shallow seas and lagoons along the coastlines of the continent.

These provided suitable habitats for marine reptiles like the Nothosaurus

Behavior and Diet

Nothosaurus is often described as the seal of the Triassic Period. 

That’s because it was fully adapted to an aquatic lifestyle but still held on to some terrestrial adaptations. 

Nothosaurus catching an unaware Ceolophysis
Nothosaurus catching an unaware Ceolophysis | Arthur Dorety via GettyImages

In the water, this reptile was an active swimmer. 

It moved by undulating its slender body while steering its body through the water using its webbed feet. 

Its streamlined body shape made it possible to navigate the water with relative speed and agility.

On land, Nothosaurus moved by waddling its paddles through the soft sediments. 

Given the shape of its limbs, its locomotion on land was likely slow and awkward. 

Nothosaurus was an active predator of shallow-marine ecosystems. 

It was capable of killing prey underwater using its long and narrow jaws. 

The Nothosaurus’ jaws were filled with rows of long-thin teeth that intermeshed to form an effective trap for any prey caught in them. 

Nothosaurus showing its powerful jaws
Nothosaurus showing its powerful jaws | CoreyFord via iStock

In June 2014, scientists in China found trackways that have been identified as paddle prints left behind by Nothosaurus or a very similar semi-aquatic reptile in the seabed.

This suggests that the Nothosaurus probably agitated the soft seabed by making rowing motions with its paddle-like feet. 

This helped to churn up lobster, fish, and other marine animals that may be sheltered in the bottom sediment. 

In addition to being an active fish eater, Nothosaurus may have also preyed on small marine reptiles. 

Fossils of the Lariosaurus, a close relative of the Nothosaurus, have been found with bones of juvenile placodonts in its stomach, suggesting that it hunted small marine reptiles for food. 

Life Cycle

Nothosaurus reproduced sexually. 

Male and female individuals came together in the water during certain times of the year. 

A male Nothosaurus walking to find food
A male Nothosaurus walking to find food | CoreyFord via iStock

They probably had reproductive aggregations during mating season, but there’s no conclusive evidence for this.

After mating, the female Nothosaurus would have laid eggs like other reptiles. 

Although some marine reptiles, such as ichthyosaurs and plesiosaurs, gave birth to live young in the water, semi-aquatic forms like the Nothosaurus spent a lot of time on land. 

This suggests that their life cycle was probably more similar to that of present-day reptiles like turtles and crocodiles.

Their eggs were laid in nests dug into the sand on land near the coastline. 

To increase the chances of survival for the egg, Nothosaurus females would have picked a well-protected area suitable for incubation. 

Females likely returned to the water after laying their eggs, leaving them to hatch on their own with no parental care. 

After a few weeks, hatchlings would emerge from the eggs as a miniature version of adult Nothosaurus

They were significantly smaller but still possessed the basic body structure of the adults, with adaptations needed for an aquatic lifestyle. 

A juvenile Nothosaurus swimming
A juvenile Nothosaurus swimming | Adam Procházka via Wikipedia CC BY-SA 3.0

Nothosaurus juveniles were on their own from the onset. 

They probably lived in shallow marine environments where they learned to swim and hunt for prey. 

Although the growth rate of Nothosaurus individuals isn’t precisely known, they likely experienced a period of rapid growth during their early years, which slowed down after reaching maturity.  

Evolution and History

Nothosaurus belonged to the sauropterygian group of marine reptiles. 

This group of reptiles evolved from terrestrial ancestors that returned to the water shortly after the devastating end-Permian extinction about 247 million years ago.

Nothosaurus underwater
Nothosaurus underwater | Julian Johnson Mortimer via Dinosaurs 101

Experts think a rise in the sea level during the Early Triassic Period forced the ancestors of the Nothosaurus to enter into shallow water in a region of present-day Israel. 

From there, new species evolved, which includes the Nothosaurus

The earliest ancestors of the Nothosaurus and other sauropterygian reptiles were small lizard-like animals such as the Pachypleurosaurus

They only measured about 60 centimeters but soon evolved into larger sizes like the Nothosaurus, dominating the shallow marine ecosystem of the Triassic as one of the most successful marine predators. 

Their streamlined body, long neck, and long tail were useful adaptations that allowed efficient locomotion through the water.

They also evolved specialized paddle-like limbs that were not very efficient for locomotion on land but helped with steering in the water. 

Nothosaurus also displayed adaptations that made it an effective marine hunter. 

Nothosaurus hunting another reptile species
Nothosaurus hunting another reptile species | Stocktrek Images via GettyImages

For instance, they had air passages separated from their food passages. 

This adaptation made it possible to hunt and feed in the water. 

The Nothosaurus’ dentition was also well-suited for capturing and holding on to slippery prey such as fish, which formed the bulk of the reptile’s diet. 

As they continued to adapt to their aquatic environment, experts think the Nothosaurus or one of its close relatives evolved into Liopleurodon and other pliosaurs that became the dominant predators of the Jurassic seas.  

Interactions With Other Species

Nothosaurus lived in both marine and terrestrial environments, which means it would have interacted with other animals both on land and in water. 

Nothosaurus actively finding prey in the water
Nothosaurus actively finding prey in the water | Johnson-Mortimer via Dinosaurs 101

As an active predator, Nothosaurus would have preyed on various marine organisms, including different species of fish and cephalopods such as squid and ammonites. 

Smaller marine reptiles and other vertebrates were probably on the menu as well. 

The Nothosaurus relied on its ability to swim swiftly as well as its unique dentition to capture and consume these prey animals. 

During the Early Triassic Period, both the marine and terrestrial ecosystems were still recovering from the end-Permian extinction event, meaning there weren’t a lot of massive predators around. 

In the marine ecosystem, Nothosaurus likely faced competition for food and other resources from other marine reptiles, such as the ichthyosaurs. 

A school of Ichthyosaurs swims over a bed of seaweed in the Jurassic seas
A school of Ichthyosaurs swims over a bed of seaweed in the Jurassic seas | Daniel Eskridge via iStock

Large predator fish species like the ancient sharks were also present.  

In addition to competing for food, these large predators may have also hunted smaller Nothosaurus individuals. 

Nothosaurus’ ability to return to land would have helped evade marine predators that could potentially prey on it. 

However, the archosaur reptiles (ancestors of the dinosaurs) and other large reptiles were present on land during the Triassic. 

They may have patrolled the coastal areas where the Nothosaurus lived, killing them for food during such encounters. 

Cultural Significance

Although not very popular with the general public, Nothosaurus is well known to paleontologists.

It is also one of the most important marine reptiles ever discovered because it represents an essential node in the evolution of marine reptiles. 

Antique illustration, geology, and fossils: Tusk and vertebra of Nothosaurus | ilbusca via iStock

Since the discovery of the first species in the genus, more than ten new species have been identified and studied. 

Nothosaurus is representative of the entire sauropterygian group, and studying the fossils of this reptile contributes to our understanding of the diversity of this group of marine reptiles. 

Nothosaurus also lived during an important period of the Earth’s paleontological history. 

Evolving just shortly after the Permian-Triassic extinction event, Nothosaurus helps us reconstruct how the Earth’s ecosystem looked like in the first few million years after life on Earth was almost completely wiped out. 

The discovery of this reptile’s fossils in multiple locations all over the world also aids our knowledge of prehistoric life in these regions during the early years of the Triassic Period.


Nothosaurus was a semi-oceanic reptile that lived during the Triassic Period. 

It is a member of an extinct group of reptiles that returned to the ocean about 245 million years ago known as the sauropterygians 

Nothosaurus was an odd-looking creature characterized by a slender body, long neck and tail, and paddle-like limbs. 

These adaptations allowed the “false lizard” to live and hunt in aquatic environments. 

But the Nothosaurus was not entirely aquatic. 

It spent a considerable amount of time out on land but probably didn’t venture far from shore. 

It was a prolific marine predator, feeding on fish, cephalopods, and other invertebrates. 

The Nothosaurus eventually went extinct during the Triassic-Jurassic extinction event along with all the other sauropterygians except the plesiosaurs. 


Did Nothosaurus live with dinosaurs?

Nothosaurus lived during the Triassic Period, which predated the time of dinosaurs’ dominance. 

While some early dinosaur species may have coexisted with Nothosaurus, the peak of dinosaur diversification occurred in the later Jurassic and Cretaceous periods.

Why did Nothosaurus go extinct?

Nothosaurus went extinct about 210 million years ago, during the end-Triassic extinction event. 

Experts think a combination of factors, such as a decline in food sources, competition with other predators, and climate change, may have contributed to their decline. 

Where was the first Nothosaurus fossil found? 

The first Nothosaurus specimen was found in the Muschelkalk, in Germany. 

This was in the year 1833. 

The genus was named the following year. 


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