Dinosaurs are a group of reptiles that appeared more than 230 million years ago. These animals diversified throughout the Mesozoic, giving rise to very different types of dinosaurs that colonized the entire planet and dominated the Earth.
As a result of their diversification, animals of all sizes, shapes and diets arose that inhabited both the land and the air. Do you want to meet them? Do not miss this article on our site about the types of dinosaurs that existed: characteristics, names and photos.
Dinosaur Characteristics
The superorder Dinosauria is a group of sauropsid animals that appeared during the Cretaceous period, about 230-240 million years ago. Later, they became the dominant land animals of the Mesozoic. Here are some characteristics of dinosaurs:
- Taxonomy: Dinosaurs are sauropsid vertebrates, like all reptiles and birds. Within these, they are diapsids, since they have two temporal pits in the skull, unlike turtles (anapsids). Furthermore, they are archosaurs, like today's crocodiles and pterosaurs.
- Size: The size of dinosaurs varies from 15 centimeters, in the case of many theropods, to 50 meters long, in large herbivores.
- Anatomy: The pelvic structure of these reptiles allowed them to walk upright, with their entire body supported by very strong legs that were located below. In addition, the presence of a very heavy tail made it much easier for them to balance and, in some cases, allowed them to bipedalize.
- Metabolism – Many of the types of dinosaurs that existed may have had a high metabolism and endothermy (warm blooded), like birds. Others, however, would be closer to modern reptiles and would have ectothermy (cold blood).
- Reproduction: they were oviparous animals and built nests in which they took care of their eggs.
- Social Behavior: Some discoveries suggest that many dinosaurs formed herds and cared for each other's young. Others, however, would be solitary animals.
Dinosaur feeding
It is believed that all types of dinosaurs that ever existed originated from carnivorous bipedal reptiles That is, the most primitive dinosaurs, with very likely, they ate meat. However, with the great diversification that took place, there came to be dinosaurs with all kinds of food: generalist herbivores, insectivores, piscivores, frugivores, folivores…
As we will now see, in both the ornithischian and saurischian groups there were many types of herbivorous dinosaurs. However, the vast majority of carnivores belonged to the group of saurischians.
Types of dinosaurs that ever existed
In 1887, Harry Seeley determined that dinosaurs could be divided into two main groups that are still used today, although there are doubts about if it is the most correct. According to this paleontologist, these are the two types of dinosaurs that existed:
- Ornithischians (Ornithischia): They are known as bird-hipped dinosaurs because their pelvic structure was rectangular in shape. This characteristic is due to the fact that its pubis was oriented towards the rear of the body. All ornithischians became extinct during the third great extinction.
- Saurischia (Saurischia): these are the lizard-hipped dinosaurs. His pubis, unlike in the previous case, was oriented towards the cranial area, so his pelvis had a triangular shape. Some saurischians survived the third great extinction: the ancestors of birds, now considered dinosaurs.
Types of ornithischian dinosaurs
Ornithischian dinosaurs were all herbivorous and can be divided into two suborders: thyreophorans and neornitischians.
Dinosaurs Thyreophores
Of all the types of dinosaurs that existed, the members of the suborder Thyreophora are probably the most unknowns. This group includes both bipedal (the most primitive) and quadrupedal herbivorous dinosaurs. With variable sizes, its main characteristic is the possession of a bone armor on the back with all kinds of ornaments, such as spines or bone plates.
Examples of Thyreophores
- Chialingosaurus: they were 4 meter long dinosaurs covered by bony plates and spikes.
- Ankylosaurus: This armored dinosaur was about 6 meters long and had a club on its tail.
- Scelidosaurus: they are dinosaurs with a small head, a very long tail and a back covered by bony shields.
Neornitischian dinosaurs
The suborder Neornithischia is a group of dinosaurs characterized by having sharp teeth with thick enamel, which suggests that they were specialized in feeding on hard plants.
However, this group is very diverse and includes many of the types of dinosaurs that ever existed. So let's focus on telling something more about some representative genres.
Examples of Neornitischians
- Iguanodon: It is the best known representative of the Ornithopoda infraorder. It is a very robust dinosaur, with strong legs and a powerful chewing jaw. These animals could reach 10 meters in length, although other ornithopods were very small (1.5 meters).
- Pachycephalosaurus: Like the rest of the members of the infraorder Pachycephalosauria, this dinosaur had a cranial dome. It is thought that they could have used it to charge other individuals of the same species, as musk oxen do now.
- Triceratops: This genus of the infraorder Ceratopsia had a posterior cranial platform and three horns on its face. They were quadrupedal dinosaurs, unlike other ceratopsians, which were smaller and bipedal.
Types of saurischian dinosaurs
Saurischians include all types of carnivorous dinosaurs and some herbivores. Among them, we find the following groups: theropods and sauropodomorphs.
Theropod dinosaurs
Theropods (suborder Theropoda) are bipedal dinosaurs. The most ancient were carnivores and predators, such as the well-known Velociraptor. Later, they diversified, giving rise to herbivores and omnivores.
These animals are characterized by having only three functional fingers on each limb and pneumatized or hollow bones. As a result, they were very agile animals and some acquired the ability to fly.
Theropod dinosaurs gave rise to all kinds of flying dinosaurs. Some of them survived the great extinction of the Cretaceous/Tertiary boundary; it's about the ancestors of birds Today, theropods are not considered extinct, but birds are part of this group of dinosaurs.
Examples of theropods
Some examples of theropod dinosaurs are:
- Tyrannosaurus: It was a large predator of 12 meters in length, well known on the big screen.
- Velociraptor: this carnivore, 1.8 meters long, had large claws.
- Gigantoraptor: it is a feathered but non-flying dinosaur that was about 8 meters long.
- Archaeopterix: It is one of the oldest known birds. It had teeth and was no more than half a meter tall.
Sauropodomorph dinosaurs
The suborder Sauropodomorpha is a group of large herbivorous quadrupedal dinosaurs with very long necks and tails. However, the most ancient were carnivorous, bipedal and smaller than a human.
Sauropodomorphs include the largest land animals that have ever existed, with individuals up to 32 meters in length The largest Small ones were agile runners, which allowed them to escape from predators. The largest, for their part, formed herds in which the adults protected the young. In addition, they had large tails that they could use as a whip.
Examples of sauropodomorphs
- Saturnalia: he was one of the first members of this group and was less than half a meter tall.
- Apatosaurus: this long neck had a length of up to 22 meters and is the genus to which Little Foot, the protagonist of The Enchanted Valley, belongs (or The Land Before Time).
- Diplodocus: is the genus of the largest known dinosaurs, with individuals up to 32 meters long.
Other large reptiles of the Mesozoic
Dinosaurs have often been called the many groups of reptiles that lived with them during the Mesozoic. However, due to their anatomical and taxonomic differences, we cannot include them within the types of dinosaurs that existed. These are the following groups of reptiles:
- Pterosaurs: they were the great flying reptiles of the Mesozoic. Along with dinosaurs and crocodiles, they belonged to the group of archosaurs.
- Plesiosaurs and Ichthyosaurs: they were two groups of marine reptiles. They are known as some types of marine dinosaurs, but, although they are diapsid, they are not closely related to dinosaurs.
- Mosasaurs: they are also diapsids, but they belong to the superorder Lepidosauria, like modern lizards and snakes. They are also known as marine “dinosaurs.”
- Pelycosaurs: They were a group of synapsids more closely related to mammals than to reptiles.
