In the previous article, we discussed the period of dinosaurs’ greatest dominance- the Jurassic. In the next one, we will talk about their extinction. However, now let’s stop for a moment and explore this fascinating group, which like no other extinct life form found its way in pop culture.

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What Were Dinosaurs?

You probably heard about dinosaurs before, however, not everyone knows what exactly that group includes. To clarify, the most recent common ancestors of birds and Triceratops, or Megalosaurus and Iguanodon (which R.Owen found when he discovered dinosaurs). Both theories lead to two major groups of dinosaurs: Saurischia and Ornithischia. The first one consists of lizard-like creatures and traditionally all meat-eaters. The most simple way to differentiate them from the second group is by their hips. Lizard-hipped (which is a direct translation of their name from Greek) dinosaurs had hip bones similar to today’s lizards and reptile. On the other hand, Ornithischia was ‘bird-hipped’ because their hips were very similar to modern birds. Moreover, the second group contains mostly herbivores like Stegosaurus or Triceratops. The only line of dinosaurs that survive until today is birds.

The only line of dinosaurs that survive until today is birds.
The only line of dinosaurs that survive until today is birds.
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The Largest and the Smallest

As we established in the previous article, dinosaurs dominated the entire planet during the Jurassic period. It would not have happened without certain adaptations. As mammals today, they differed a lot from each other. Scientists know more than a thousand species of dinosaurs, however, it’s possibly just a fraction. The modern line of birds consists of over ten thousand species! Probably all species laid eggs, had dynamic metabolism, and possibly knew many social interactions. Some, mostly carnivores, were bipeds which enabled them to have two limbs ‘free’ for other activities. Others used all four legs for moving or could switch to either method. Their size was also very diverse- from 0.57 cm hummingbird to almost 40 m sauropods (making them the largest-ever land animals). In between them, there are and were species of many sizes and shapes. Other important adaptations were products of the epidermis, like unguis, or bone structures, like horns.

Dinosaurs: Discussion and Controversy 1

Dinosaurs were creatures of many sizes and shapes.
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Pterosaurs- First Rulers of the Air

Pterosaurs are reptiles, not dinosaurs, however, they are for sure worth mentioning. They are the first found flying vertebrates and they were also a very diverse group, closely related to dinosaurs and birds. Their wings were made of membranes made of layers of tissues, which stretched in the air. They did not have feathers, instead, they had various kinds of pycnofibers, some very similar to feather-like structures. They had many adaptations to flight, for example, very fast metabolism and even more air sacs in bones than today’s birds. Some were so huge, that we may think they were too large to fly. Quetzalcoatlus is a pterosaur with an extremely long neck, the biggest known flying creature. It had a wingspan of 11 m, height between 11 and 15 meters, and weighed about 200 kg. Similarly to dinosaurs, they conquered most of the world’s ecosystems and often dominated in their niches.

Dinosaurs: Discussion and Controversy 2
Despite their sometimes huge sizes, pterosaurs could fly.

Dinosaurs Feathers Case

Most visualizations of dinosaurs present them with a very reptile-like appearance. However, they differed a lot from modern reptiles, looks included. For the most time, only dinosaurs very closely related to birds were considered feathered creatures. It was in the first decades of the 200’s when scientists discovered that many more dinosaurs could have feathers (or at least feather-like structures). Fossils of the Yutyrannus proved that even huge tyrannosaurus had them! The first theory suggested, that dinosaurs split into two groups we discussed before in the Triassic and one of them was fluffy. However, fossils found later showed that both could have feathers. With more studies, there were many more dinosaur species were found to have a cover. Only further studies and fossils can provide evidence for how many species were feathered. However, there is a rising possibility, that most of them had body coverage.

Yutyrannus - a 30m high tyrannosaur with impressive set of feathers, a kind of dinosaurs
Yutyrannus – a 30m high tyrannosaur with an impressive set of feathers.
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Read the previous in the series: The Jurassic Period (The Age of the Dinosaurs)

Author’s message

I hope that the article helped you learn about dinosaurs and gave you a new outlook on pterosaurs. If you enjoyed it, please share it with your family and friends. In the next one, we will discuss the most recent mass extinction. Until then, if you have any questions, please feel free to contact me. You can use the contact form below or find my email in the team’s section of the page.

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[…] wiped out nearly 75% of life on the planet and specifically led to the extinction of non-avian dinosaurs. With progress, questions about the origin and frequency of similar impactors have always been […]


[…] In the previous article, we focused on dinosaurs and pterosaurs that ruled the Earth in Mesozoic. Now it is time to talk about the Cretaceous period, to discuss their last years on Earth and their extinction. […]

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