Mesozoic Era Animals List: Amazing Animals That Lived In The Mesozoic Era

Mesozoic Era Animals

Examples of Mesozoic Era animals include dinosaurs, pterosaurs, ammonites, sharks, plesiosaurs, ichthyosaurs, mosasaurs, pseudosuchians, insects, and early mammals. Although dinosaurs were the dominant land animals of the Mesozoic Era, many other important animal groups evolved and thrived during this time.

On this page is a list of Mesozoic Era animals with pictures, facts, and links to further information…


Introduction

Ichthyosaur
Ichthyosaurs were ocean predators in the Mesozoic Era.

The Mesozoic Era began 251.902 mya (million years ago) and lasted for 185.9 million years. For much of this time, reptiles were the dominant vertebrate animals, not just on land (in the form of dinosaurs), but also in the air (in the form of pterosaurs) and in the sea (in the form of plesiosaurs, ichthyosaurs and mosasaurs).

The Mesozoic Era has been termed the “Age of Reptiles” due to the dominance of this group of animals.

The Mesozoic Era ended 66 mya (million years ago) with a mass extinction event thought to have been caused by a meteor strike.

Below is a list of animals from the Mesozoic Era. The list includes only Mesozoic Era animals that are not dinosaurs; so if you want to discover the dinosaurs of the Mesozoic Era, check out these pages instead:

Page Index

The Mesozoic Era is divided into three periods: Triassic, Jurassic and Cretaceous. You can use the index below to see Mesozoic animals from each of these periods, or scroll down to see all of the animals.


Mesozoic Era Animals List

Mesozoic Animals From The Triassic Period

Ceratites

  • Type of animal: Cephalopod, Ammonite
Ceratites Ammonites
Photo: Ghedoghedo, CC BY-SA 4.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)

Ceratites was a genus of ammonite that lived in the early and middle Triassic Period. It belonged to a larger group of ammonites, the order Ceratitida. Most Triassic ammonites belonged to this group.

Ammonites became extinct at the end of the Mesozoic Era.


Effigia

  • Type of animal: Pseudosuchian archosaur
Effigia Mesozoic Reptile
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)

Effigia was a 10 ft. / 3 m long, fast-moving, bipedal reptile. Despite closely resembling dinosaurs of family Ornithomimidae, it was a pseudosuchian.

Pseudosuchians were a group of reptiles that competed with early dinosaurs in the Triassic Period. They include the ancestors of today’s crocodiles.

Effigia lacked teeth, and instead broke its food apart with a beak. It is believed to have been an omnivore, feeding on vegetation and small animals.

This Mesozoic animal was discovered in the Ghost Ranch Quarry, a fossil hotspot located in New Mexico, USA.


Eudimorphodon

The Earliest Known Pterosaur Eudimorphodon
Photo: Tommy from Arad, CC BY 2.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Pterosaur

Eudimorphodon is one of the earliest-known pterosaurs. This flying reptile of the Late Triassic Period was first discovered in what is now Italy.

This Triassic pterosaur had a wingspan of 3.3 ft / 1 meter and was equipped with claws for climbing on cliffs.

Fossilized fish scales have been found with Eudimorphodon fossils, suggesting that the pterosaur was a fish-eater.


Hybodus

Hybodus Mesozoic Shark
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Fish, Shark

Hybodus was a 6.5 ft / 2 m long shark that first appeared in the Permian Period and became extinct in the Late Cretaceous Period.

Like modern sharks, Hybodus replaced its teeth continuously throughout its lifetime. It had two dorsal fins, each of which was supported by a spine, which may have provided protection from other marine predators of the Mesozoic Era.


Lystrosaurus

Lystrosaurus Mesozoic Animal
Image: Dmitry Bogdanov, CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Dicynodont

Lystrosaurus, a pig-like herbivore, was one of the few animals to survive the Permian-Triassic Extinction Event that occurred immediately before the Mesozoic Era. It was the most common land vertebrate of the Early Triassic.

The powerful forelimbs of Lystrosaurus suggest it may have been a burrower. It had two tusks, and, like all dicynodonts, a hard beak for eating tough vegetation.


Mixosaurus

Mixosaurus
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Ichthyosaur

Mixosaurus was a member of a group of marine reptiles known as ichthyosaurs. Ichthyosaurs are descended from terrestrial (land) reptiles that gradually evolved to live in the sea.

Early ichthyosaurs had long, eel-shaped bodies, whereas later species were more fish-like in appearance.

Mixosaurus is seen as a transitional animal between the earlier and later ichthyosaurs – its name means “mixed lizard”.


Nothosaurus

Nothosaurus
Model created by Adam Procházka, Baden-Baden, Germany for Staatliches Museum für Naturkunde Karlsruhe, Germany. Foto: H. Zell, CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Nothosaur

Nothosaurus was a semi-aquatic marine reptile whose lifestyle is thought to resemble that of modern-day seals. With webbed feet and long tail, It was a capable swimmer, yet was able to haul itself out of the water to rest.


Postosuchus

Postosuchus

  • Type of animal: Pseudosuchian archosaur

Postosuchus was a fearsome Mesozoic predator that lived in North America in the Late Triassic Period. It belonged to the family Rauisuchidae.

An apex predator, Postosuchus grew up to 15 ft / 4.5 m in length and preyed on smaller reptiles, including dinosaurs.


Thrinaxodon

Thrinaxodon
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Cynodont

Cynodonts were a group of animals that appeared in the Late Permian. Although early cynodonts resembled reptiles, the group includes the ancestors of all mammals.

Thrinaxodon was a cynodont that lived in the Early Triassic. It was the size of a cat and possibly had hair. Its posture was less sprawling, and more mammal-like, than that of its ancestors. It was likely an active predator.


Triadobatrachus

Triadobatrachus
Pavel.Riha.CB, CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Amphibian

Triadobatrachus was an amphibian that live in the Early Triassic Period. It was a frog-like animal thought to be a transitional fossil between the first frogs and earlier amphibians.


Mesozoic Animals From The Jurassic Period

Dactylioceras

Dactylioceras ammonite
Dactylioceras commune. Photo: James St. John (jsj1771), (cropped / resized by ActiveWild.com) CC BY 2.0
  • Type of animal: Cephalopod, Ammonite

Dactylioceras is a genus of small ammonite with a heavily ribbed shell. It was abundant in Europe, and can be used to date other fossils from the Early Jurassic Period.


Eocarcinus

Eocarcinus prehistoric crab
Image: Gerhard Scholtz, CC BY 4.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Crustacean, crab

Eocarcinus is a decapod crustacean from the Early Jurassic. It is either one of the very first crabs, or a close relation of early crab-like crustaceans. (Decapoda is a group of crustaceans that includes animals such as crabs, lobsters and prawns.)


Fruitafossor

Fruitafossor
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Mammal

Fruitafossor was a mammal from the Late Jurassic. It had strong forelimbs – a probable adaptation for digging. Its teeth are similar to those of modern-day insect-eating animals such as armadillos and aardvarks. Fruitafossor probably ate termites and other insects, digging in the ground to reach its prey.


Ichthyosaurus

Ichthyosaurus

  • Type of animal: Ichthyosaur

Ichthyosaurus was an aquatic reptile that lived in the Late Triassic Period. It was 6 to 11 ft. (2 to 3.3 m) in length, and bore a striking resemblance to today’s dolphins. This is an example of convergent evolution – the process by which two unrelated species evolve similar characteristics.


Kayentachelys

Kayentachelys Mesozoic Turtle
Image: NobuTamura, CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Turtle

Although not the earliest turtle (turtles are thought to have appeared in the Triassic Period with animals such as Odontochelys), Kayentachelys is the first to be found in large numbers.

This small turtle lived in the Early Jurassic, and was discovered in (and named after) the Kayenta Formation in Arizona, USA.


Leedsichthys

Leedsichthys - largest fish that ever lived
Image: Dmitry Bogdanov [CC BY 3.0] (cropped / resized by ActiveWild.com)
  • Type of animal: Ray-Finned Fish

Leedsichthys is thought to be the largest bony fish that ever lived, with an estimated maximum length of 72 ft. / 22m. Even today’s whale shark, which is a shark, not a bony fish, rarely, if ever, attains such a length.

(The bony fish are one of two major groups of living fish, the other being the sharks and rays, which have cartilaginous skeletons.)

Like today’s baleen whales, Leedsichthys fed by filtering plankton from huge mouthfuls of seawater.

Leedsichthys lived in the Middle and Late Jurassic period, and has been found in what is now Northern Europe and Chile.


Liopleurodon

Liopleurodon

  • Type of animal: Pliosaur

Liopleurodon was an apex predator that swam in the oceans of the Middle and Late Jurassic Period.

The maximum length of Liopleurodon was once thought to be in the region of 80 ft. / 25 m. Today, liopleurodon’s maximum size is believed to be somewhat shorter, at between 20 and 23 ft / 6 and 7 m – around the size of a modern killer whale.

Pliosaurs were plesiosaurs with short necks and powerful, tooth-filled jaws.


Plesiosaurus

Plesiosaurus

  • Type of animal: Plesiosaur

Plesiosaurus was the first plesiosaur to be named (by paleontologists Henry De la Beche and William Conybeare in 1821). It gives its name to the entire order, Plesiosauria. Today, over 100 species of plesiosaurs have been discovered.

Plesiosaurus was 10 to 16.4 ft. / 3 to 5 meters in length and had a long neck and a small head. Like other plesiosaurs, it propelled itself through the water with two pairs of flippers.

All plesiosaurs are believed to have given birth to live young (rather than laying eggs) and may have been warm-blooded.


Protosuchus

Protosuchus
Image: Nobu Tamura (http://spinops.blogspot.com), CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Protosuchid

Between the Triassic and Jurassic Periods Earth underwent a mass extinction in which most of the dinosaurs’ main reptilian competitors – the pseudosuchians – became extinct.

The only group of pseudosuchians to survive were the crocodylomorphs – a group that contained the ancestors of today’s crocodiles, alligators and caimans.

One such animal was Protosuchus – a 3.3 ft. / 1 m long predator that resembled a modern crocodile but with longer legs. With an upright stance, Protosuchus would have been a fast runner that likely hunted on land rather than in the water.


Pterodactylus

Pterodactylus

  • Type of animal: Pterosaur

Pterodactylus was a pterosaur with a wingspan of around 3.4 ft / 1.04 meters. Pterodactylus was the first pterosaur to be discovered and identified as a flying reptile.

Because Pterodactylus is so well-known, the name “Pterodactyl” is often used (incorrectly) to refer to any Pterosaur.

A recent analysis of Pterodactylus’ teeth suggest that this Mesozoic Era animal mainly preyed on invertebrates.


Mesozoic Animals From The Cretaceous Period

Deinosuchus

Deinosuchus
Image: Daderot, CC0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Crocodilian

They may have ruled most of the land, but the dinosaurs of the Cretaceous Period didn’t have it all their own way: the top predator in some North American aquatic habitats was the mighty Deinosuchus – one of the largest crocodilians ever to have lived.

Looking much like a modern crocodilian, and having a similar lifestyle, Deinosuchus reached lengths of 39 ft. / 12 meters – twice the size of today’s largest crocodile, the saltwater crocodile.

Deinosuchus is one of the earliest members of the superfamily Alligatoroidea, which contains animals more closely related to today’s alligators than to other crocodilians.


Elasmosaurus

Elasmosaurus
Image: DiBgd [CC BY-SA 4.0] (cropped / resized by ActiveWild.com)
  • Type of animal: Plesiosaur

Even expert paleontologists like Edward Drinker Cope make mistakes: when he first identified the fossilized remains of Elasmosaurus, Cope thought that the animal’s ridiculously long neck was its tail.

It was an easy mistake to make: Elasmosaurus has 72 neck vertebrae; only one other animal (Albertonectes, another plesiosaur) has more.

Elasmosaurus swam in the shallow waters of the Western Interior Seaway, an inland sea that split North America into two separate landmasses during the Late Cretaceous.


Kronosaurus

Kronosaurus
Image by Saúl Velasco Martel [CC BY-SA 3.0] (cropped / resized by ActiveWild.com)
  • Type of animal: Pliosaur

Kronosaurus was one of the largest pliosaurs, with a maximum estimated length of around 36 ft. / 10.9 m.

Like all pliosaurs, Kronosaurus was a plesiosaur with a short neck. It swam with is four large flippers, and is thought to have fed mainly on large fish.


Mosasaurus

Mosasaurus hoffmanni.
Image by Dmitry Bogdanov.
  • Type of animal: Mosasaur

Mosasaurus was a huge swimming lizard that appeared in the Late Cretaceous period. This 56 ft. / 17.1 m long aquatic reptile was an apex predator that used bursts of high speed to catch large prey animals such as turtles, sharks and even other mosasaurs.

Mosasaurs belong to the order Squamata – the order to which today’s lizards and snakes belong. Mosasaurs evolved from aquatic lizards and became the dominant marine predators at the very end of the Mesozoic Era.


Pteranodon

Pteranodon
Pteranodon
  • Type of animal: Pterosaur

With a wingspan of around 23 ft./ 7 m, Pteranodon was one of the largest-known Pterosaurs.

Like all of the later pterosaurs, Pteranodon lacked both teeth and a tail. Its head was adorned with a large crest.  It soared in the Late Cretaceous skies of North America and fed on fish.


Quetzalcoatlus

Quetzalcoatlus
Quetzalcoatlus. Image by Johnson Mortimer (cropped / resized by ActiveWild) [CC BY 3.0]
  • Type of animal: Pterosaur

Pteranodon may have been big, but it was dwarfed by Quetzalcoatlus. With a wingspan of around 36 ft. / 11 m, this huge reptile is among the largest flying animals ever to have lived.

Quetzalcoatlus was discovered in Texas, USA. It is thought to have hunted on land by stalking small vertebrate prey.


Scaphites

Scaphites ammonite
Ammonite of genus Scaphites. Photo by: Hectonichus, (cropped/resized by ActiveWild.com) CC BY-SA 3.0
  • Type of animal: Cephalopod, Ammonite

Scaphites was a common ammonite of the Late Cretaceous Period. It has a distinctive “hooked” shape, and was around 8” / 20 cm in width.

There is some evidence that some Scaphites survived the Cretaceous-Paleogene Extinction Event at the end of the Mesozoic Era and lived for some time into the Paleocene.


Simosuchus

Simosuchus
Image: Smokeybjb, CC BY-SA 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Crocodylomorph

Simosuchus was a 3.3 ft. / 1 m long Crocodylomorph that lived in what is now Madagascar in the Late Cretaceous.

The body of this Mesozoic reptile resembled that of a modern crocodile, but, unlike other crocodiles, its snout was short and wide. This, and its leaf-shaped teeth, suggest that Simosuchus may have been a herbivore.


Squalicorax

Squalicorax Mesozoic Shark
Creator: Dmitry Bogdanov, CC BY 3.0, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Fish, Shark

Swimming in the oceans throughout the Cretaceous Period was Squalicorax, otherwise known as the crow shark. Growing up to 16.4 ft. / 5m in length, the crow shark likely predated other fish, as well as reptiles such as mosasaurs.

A Squalicorax tooth was found embedded in the foot of a hadrosaurid dinosaur. This suggests that Squalicorax was to some extent a scavenger, as hadrosaurids lived on land. The shark would have been feeding on the body of a hadrosaurid that had ended up in the ocean.


Xiphactinus

Xiphactinus
Image: ДиБгд at Russian Wikipedia, Public domain, via Wikimedia Commons (cropped / resized by ActiveWild.com)
  • Type of animal: Fish

Growing to around 20 ft. / 6 m in length, Xiphactinus was a fearsome Mesozoic fish whose fossilized remains have been found in North and South America, Europe and Australia.

Xiphactinus had a forked tail and was built for speed. With a mouthful of sharp teeth, it would have been a formidable predator. Several Xiphactinus fossils have been found with the remains of other fish in their stomachs.


Further Reading: Discover More With Active Wild

You can see more Mesazoic Era animals on the following pages:

What is an Era? What does “Cretaceous Period” mean? Find out here: Geologic Timescale Facts

Discover amazing dinosaurs on this page: Dinosaur List with Pictures & Facts

Find out more about dinosaurs and prehistoric life:

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