Triassic Animals – Discover The Animals That Lived With The Dinosaurs In The Triassic Period

Not all Triassic animals were dinosaurs! On this page you’ll find a list of animals that lived in the Triassic Period that were not dinosaurs.

Triassic Animals: Introduction

The Triassic Period saw the appearance not only of the first dinosaurs, but also of the first true mammals. Other well-known animals that first appeared in the Triassic Period include the pterosaurs – the world’s first flying vertebrates, and the fearsome marine reptiles known as ichthyosaurs.

Although dinosaurs appeared during the Triassic Period, they wouldn’t become the dominant land animals until the Jurassic Period. Instead, the top Triassic land predators were another group of reptiles: the pseudosuchians. For most of the period the dominant land herbivores were the dicynodonts, a group of animals related to the ancestors of mammals.

On this page you’ll meet pseudosuchians, dicynodonts, and a host of other Triassic animals.

Triassic Animals: Page Index

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The Triassic Period: Background Information

The Triassic Period is the first of the three periods that make up the Mesozoic Era (just as years can be divided into months, eras can be divided into periods). It began 251.9 million years ago (Mya), and ended 201.3 Mya. It was preceded by the Permian Period and followed by the Jurassic Period.

The Triassic Period lasted around 50.6 million years. As you can imagine, during this vast amount of time Earth underwent huge changes, including the appearance and extinction of many animal species.

Permian–Triassic Extinction Event

The boundary between the Permian and Triassic Periods was marked by the worst extinction event the world has ever known. The Permian–Triassic Extinction Event resulted in the extinction of around 90% of all species.

This global extinction is thought to have been triggered by huge volcanic eruptions, causing devastating lava flows, a rise in global temperature and a poisoning of the atmosphere.

It would take 10 million years for the world’s biodiversity to recover.

The end of the Triassic Period was also marked by a global extinction event. The Triassic-Jurassic Extinction Event saw the extinction of the dinosaurs’ main rivals, allowing the dinosaurs to become dominant on land.

Triassic Animals: Reptiles

The Mesozoic Era is known as the ‘Age of Reptiles’ for good reason; the Triassic Period saw reptiles outcompete their vertebrate rivals to become the dominant animals on land and in the sea.

In the Early Triassic the group of reptiles known as archosaurs split into two groups: Pseudosuchia and Avemetatarsalia.

Although it would be the avemetatarsalians – in the shape of dinosaurs – which would eventually rise to dominance later in the Mesozoic Era, in the Triassic Period the pseudosuchians were the dominant meat-eaters on land.

(Incidentally, both groups still exist: avemetatarsalians in the shape of birds and pseudosuchians in the shape of crocodiles, alligators and gharials.)



Saurosuchus. Photo: Kentaro Ohno [CC BY 2.0]
With an estimated body length of 6 - 9 meters (20 - 30 ft.), Saurosuchus was a huge, crocodile-like predator of the Late Triassic Period.

Saurosuchus had a mouth full of serrated teeth and armor-plated skin. It walked on four straight legs. It is highly likely that this fearsome reptile was an apex predator. Saurosuchus specimens have been found in northwestern Argentina.


Postosuchus kirkpatricki
Postosuchus kirkpatricki

Like Saurosuchus, Postosuchus was a large, predatory pseudosuchian archosaur. Both Postosuchus and Saurosuchus are currently placed in the same family, Rauisuchidae.

Postosuchus lived in the southern United States during the Late Triassic. It was 4 to 5 meters (13 to 16 ft.) in length, and its relatively short fore limbs suggest that it walked bipedally (on two legs). One of the largest carnivorous around at the time, it is likely to have been an apex predator.


Silesaurus. Image: Dmitry Bogdanov [CC BY-SA 3.0]
Silesaurus was a 2.3 m (7.5 ft.) long reptile that lived in Poland during the Late Triassic. It was a lightly-built, fast-moving animal that walked on its hind legs.

Coprolites (fossilized droppings) found in the vicinity of Silesaurus specimens suggest that the reptile may have been an insectivore (insect eater). Seemingly lacking teeth, Silesaurus may have had a bird-like beak for capturing its insect prey. (The artist's impression above shows Silesaurus with teeth.)

Reptiles such as Silesaurus were the closest relatives of the dinosaurs. Only slight anatomical differences separate them from ‘true’ dinosaurs.


Phytosaurs were large, semi-aquatic predatory reptiles that looked – and acted – like modern-day crocodiles. Their long snouts were filled with hundreds of sharp teeth, which were likely to have evolved for catching fish.

Phytosaurs appeared during the Middle Triassic and, like most non-dinosaur archosaurs, failed to make it through the Triassic-Jurassic Extinction Event.


Placerias vs Redondasaurus
This museum exhibit shows Redondasaurus attacking a Placerias. Photo: Christopher Holden [CC BY-SA 2.0]
Redondasaurus had the typical long, thin snout of a Phytosaur. This predatory reptile of the Late Triassic was found in New Mexico.


Hyperodapedon huxleyi(syn. Paradapedon), a rhynchosaur from the late Triassic of India. Image by Nobu Tamura [CC BY 3.0]
Rhynchosaurs were herbivores equipped with sharp beaks for cutting foliage and large claws on their hind feet, which may have been used for digging.

Although they weren’t archosaurs, Rhynchosaurs shared the same ancestors as the group that gave rise to both the dinosaurs and the crocodile-like pseudosuchians.

Rhynchosaurs were found in many parts of the world. They were present from the Early Triassic and became extinct in the Late Jurassic.

Triassic Animals: The Early Relatives of Mammals & The First True Mammals


Synapsida, the branch of animals that included the ancestors of mammals, had split from Diapsida – the branch that included the ancestors of reptiles – in the Late Carboniferous Period, around 50 million years before the start of the Triassic Period.

A subgroup of synapsids known as therapsids appeared around 30 million years ago, during the Permian Period.

Earlier synapsids walked on bent legs that projected outwards from the sides of the body. As therapsids evolved, their legs moved to the base of the body and projected downwards.

This adaptation provided a greater load-bearing ability and more efficient movement. It was also seen in the archosaurs.

The synapsids fared poorly during the Permian-Triassic Extinction Event, with only three main groups – the dicynodonts, therocephalians, and cynodonts – surviving into the Triassic Period.


Dicynodonts were herbivores that were equipped with beaks for cutting through foliage. Many species had two tusk-like teeth. (The name dicynodont means ‘two dog tooth’.)

Towards the end of the Permian Period dicynodonts became the most common land vertebrates.

There were many different types of dicynodont. Although their number was greatly reduced in the Permian-Triassic mass extinction, several dicynodont groups made it through to the Triassic Period.


Lystrosaurus. Image by Dmitry Bogdanov [CC BY-SA 3.0]
Lystrosaurus was a pig-sized dicynodont. Due to the powerful build of its forelimbs and the shape of its skull it is thought that Lystrosaurus was a burrower that may have excavated a new home every night. Like other dicynodonts, it had a beak-like mouth and two tusk-like teeth.

After surviving the Permian-Triassic mass extinction, Lystrosaurus became the most common land vertebrate of the Early Triassic. Lystrosaurus specimens are most abundant in Africa, and have also been found in Asia, Europe and Antarctica.


Dinodontosaurus. Image by Dmitry Bogdanov [CC BY 3.0]
Dinodontosaurus was a large plant-eating dicynodont that lived during the Middle and Late Triassic Period. One of the largest dicynodonts, it grew to almost 8ft. (2.4 m) in length and was found in what is now Brazil.

The remains of ten infant Dinodontosauruses were found together at one excavation site. This suggests that these Triassic animals lived in family groups for some of their lives.


Lisowicia. Image by Dmitry Bogdanov [CC BY 3.0]
Lisowicia is the largest known dicynodont – and the largest animal that wasn’t a dinosaur – of the Triassic Period. This elephant-sized, 9 tonne plant-eater lived in Poland during the Late Triassic Period.

Unlike other dicynodonts, Lisowacia’s limbs projected straight down from its body, rather than projecting outwards from the sides.


Placerias hesternus

Placerias was a dicyndont that lived in the Late Jurassic. Its remains have been found in Arizona and Carolina.

Placerias was one of the largest herbivorous animals of the time, growing up to 3 meters (10 ft.) in length and weighing around 1 tonne. It was a herd animal, and may have been semi-aquatic, using the water as a refuge from predators such as Postosuchus.



Microgomphodon. Image by Dmitry Bogdanov [CC BY 3.0]
Microgomphodon was a therocephalian that lived in the Middle Triassic. Remains of this dog-like relative of early mammals have been found in southern Africa. It is one of the last-known therocephalians (the group became extinct during the Middle Triassic).


Cynodontia is a branch of synapsids that includes mammals and the early relatives of mammals. Humans and all other mammals, living and extinct, are cynodonts.

Cynodonts appeared in the Late Permian and survived the Permian-Triassic Extinction Event. Although early Triassic cynodonts laid eggs, they were growing ever more mammal-like, and were probably warm-blooded.


Thrinaxodon. Image by Nobu Tamura [CC BY-SA 3.0]
Thrinaxodon was a 20” (50 cm) cynodont that lived in what is now southern African and Antarctica during the Early Triassic. It was large for a cynodont, and its posture was less sprawled that that of its ancestors.

Like modern mammals, thrinaxodon had a secondary palette – a bony plate that separates the nasal cavity from the mouth. This meant that thrinaxodon could continue to breathe while chewing its food.

Thrinaxodon probably had hair, and holes in its skull suggest that it may have had whiskers; this Triassic animal would have looked much more mammal-like than its earlier, more ‘reptile-like’ ancestors.


Morganucodon. Image: FunkMonk (Michael B. H.) Resized by ActiveWild [CC BY-SA 3.0]
Morganucodon is a small shrew-like animal that lived in the Late Triassic. It preyed mainly on insects, and is likely to have had a nocturnal, burrowing lifestyle.

Morganucodon specimens were first discovered in Wales, and have since been found on mainland Europe, North America and in China.

Marine Reptiles of the Triassic Period

Although they would rule on land, the dinosaurs never expanded into the oceans. Instead, various other groups of fearsome reptiles battled for marine supremacy during the Mesozoic Era. Several of these groups would appear during the Triassic Period...


Ichthyosaurs are a group of reptiles that lived in the sea during the Mesozoic Era. The ancestors of ichthyosaurs were land animals who gradually evolved into fully aquatic animals.

Ichthyosaurs – whose name means ‘fish lizards’ – first appeared during the Early Triassic.


Cymbospondylus. Image by Nobu Tamura [CC BY-SA 3.0]
Cymbospondylus was one of the first ichthyosaurs. Although fully-aquatic, it wasn’t as ‘fish-like’ as later ichthyosaurs. It lacked both a dorsal fin and a wide tail, and probably swam using eel-like undulations of its long, thin body and tail.

Cymbospondylus was one of the largest-known ichthyosaurs, reaching lengths of up to 10 m (33 ft.).



Despite being a reptile, ichthyosaurus looked very much like today’s sharks and dolphins. It had a streamlined, fish-like body, a large tail with which it propelled itself through the water, and a dorsal fin on its back that provided stability.

Ichthyosaurus had large eyes and probably hunted its prey – which included fish and squid – by sight.


Shortly after the Triassic Period began, a group of land reptiles evolved to live in the sea. This group was the Sauropterygia, whose name means ‘lizard flippers’.

The sauropterygians were the ancestors of several groups of Triassic marine animals, including the Nothosaurs, Placodonts and Pistosauroids (who themselves were the ancestors of Plesiosaurs).


Many reptiles of the Triassic Period have similar lifestyles to those of modern-day mammals. The plant-eating dicynodonts lived in herds, just like today’s cattle. The lifestyle of the nothosaurs can be compared to that of today’s seals and sea lions. These aquatic and semi-aquatic animals would have hunted in the sea and hauled themselves out of the water to rest on the shore.

Nothosaurs had streamlined bodies and long necks and tails. Their flipper-like feet had webbed toes.

The sharp teeth lining the mouths of nothosaurs suggest they hunted fish, squid, and marine reptiles.

Nothosaurs shared the same ancestors as the plesiosaurs, but were not themselves ancestors of the plesiosaurs.


Nothosaurus. Image by Nobu Tamura [CC BY 3.0]
Nothosaurus was a 4m (13 ft.) long semi-aquatic reptile that lived on the northern coasts of the Tethys Ocean (the large body of water partially enclosed by the C-shaped supercontinent Pangea).

Each of its four legs was equipped with long, webbed toes, which allowed the animal to both swim in the water and walk on land.

Its long, agile neck, long snout and thin, pointed teeth would have allowed it to capture fish and other marine animals.


Ceresiosaurus. Image by Dmitry Bogdanov [CC BY 3.0]
Unlike those of Nothosaurus, the toe bones of Ceresiosaurus were fused together into flippers. The front pair of flippers was bigger than the hind pair, suggesting that they may have provided at least some of the power when the animal was swimming.

This 3m (10 ft.) long ocean predator lived during the Middle Triassic.


Pistosauridae was a family of animals that included the ancestors of the plesiosaurs.


Pistosaurus. Image by Nobu Tamura [CC BY-SA 3.0]
Pistosaurus was a 10 ft. (3m) marine reptile with a long neck, small head, long tail, and four flippers. Unlike most of the nothosaurs, it swam by powering itself through the water with its flippers, rather than by undulations of its body and tail.


Placodonts were semi-aquatic and aquatic marine reptiles that appeared in the Middle Triassic and became extinct at the end of the Late Triassic.

Towards the end of the Triassic Period many placodonts had evolved hard, turtle-like shells as protection against ichthyosaurs and nothosaurs.

Placodonts were equipped with large, flat teeth for crushing shellfish.


Placodus and Cyamodus
Placodus and Cyamodus. Image by DiBgd [CC BY-SA 4.0]
Placodus was a marine reptile that lived during the Middle Triassic. Its remains have been found in Central Europe and China.

It used its protruding front teeth to prize shellfish from rocks and its flat hind teeth to crush the shells of its prey.

Placodus had a long tail and webbed toes to propel it through the water. It resembled today’s marine iguana, and probably had a similar lifestyle, foraging in the sea and resting on the shore.


Henodus chelyops
Henodus chelyops. Image by Nobu Tamura [CC BY-SA 4.0]
Henodus was a placodont that lived in what is now Germany during the Late Triassic. It had a flat, square shell that was as wide as it was long. Its mouth was equipped with a flat beak and just two teeth. It may have been herbivorous, filtering plant matter from the water.


Pterosaurs are among the best-known Triassic animals. These winged, flying reptiles first appeared during the Late Triassic, and were present throughout the Mesozoic Era, only becoming extinct with the Cretaceous–Paleogene Extinction Event that also killed off the (non-avian) dinosaurs.

During the Mesozoic Era many different types of pterosaur came and went. Early specimens had long tails and teeth – features that had disappeared in many pterosaurs by the end of the Cretaceous Period.


Eudimorphodon. Resized & cropped. Original by Tommy [CC BY 2.0]
Eudimorphodon was a pterosaur that lived in Italy during the Late Triassic. It is one of the earliest-known pterosaurs.

Eudimorphodon had a wingspan of around 1 m (3.3 ft.), and was capable of true flight rather than merely gliding. Like many early pterosaurs it had a long tail, at the tip of which was a diamond-shaped vane which may have acted as a rudder.

Triassic Animals: Invertebrates

Groups of land animals such as millipedes, centipedes, arachnids (including spiders) and insects had already appeared millions of years before the beginning of the Triassic Period.

Ocean animals such as crustaceans, corals, ammonites, mollusks and sea urchins were also all long-established before the Triassic Period began.

During the Triassic Period these groups continued to evolve. Today’s spiders are divided between two groups: Mygalomorphae and Araneomorphae; these groups appeared during the Triassic Period. The earliest fly fossils date back to the Triassic Period (although it is thought that flies may have appeared even earlier).

Triassic Animals: Amphibians


Temnospondyli is a group of now-extinct four-legged amphibious animals. Although temnospondyls had scales and claws and resembled crocodiles, the group of animals to which they belong – Batrachomorpha – includes today’s amphibians and their ancestors.


Sclerothorax. Image by ДиБгд [CC BY-SA 3.0]
Sclerothorax was a temnospondyl found in Germany during the Early Triassic Period. It was around 1.3 m in length and had a shallow, wide head and a ridged back. Its skin contained bony plates.



Plagiosaurus was a temnospondyl from the Triassic Period whose remains have been found in France, Germany and Luxemburg. Its skin was reinforced with bony plates.

Like today’s mudpuppies, plagiosaurus is thought to have been entirely aquatic, retaining its external gills even after reaching adulthood.

Triassic Animals Conclusion

The Triassic Period was a momentous time for life on Earth. It saw the appearance of both the dinosaurs and of mammals. Pterosaurs and ichthyosaurs also made their first appearances, and reptiles became the dominant animals on land, in the sea, and in the air.

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