I mean, it's pretty obvious from their anatomy. They are Archosaurs, like the Crocodilians, however they are not Dinosaurs. Flying reptiles are scientifically known as Pterosaurs, and are adapted to an aerial lifestyle like birds. Pteranodons, Pterodactyls, and other flying reptiles are all Pterosaurs , it's incorrect to call them Dinosaurs.


I'm pretty sure most people know this by now, but in case you don't, Dinosaurs are still among us today in the form of birds (Avians). They are a branch of the Dinosaur group called Maniraptora (Avialae - "bird wings") that managed to survive K-Pg (the Cretaceous-Paleogene Mass Extinction, 66 million years ago) and adapt to their new environment. Popular Maniraptorans such as the Dromaeosaurs which include the Velociraptor and the Utahraptor are extinct - only Avialae survived. This also touches on another shorter point of mine: Birds are not Tyrannosaurs. Maniraptorans are a different group from Tyrannosaurs, even though they're closely related. So you could say that birds are related to Tyrannosaurs but not that they are Tyrannosaurs.


I can't stress how important this is. If you are genuinely into dinosaurs, you must know a few base groups so that you don't mix up completely different species.

First of all, you start off with two base groups within Dinosauria: Ornithischia ("bird-hipped") and Saurischia ("lizard-hipped"). This is all based on a simple anatomical difference between their hip bones and how the ischium is oriented, yet it is the foundation for the entire Dinosaur taxonomy.

Within Ornithischia, you've got 3 large base groups: Thyreophora - "shield-bearers" (which has the Ankylosaurs and the Stegosaurs) , Ornithopoda - "bird-footed" (which has the Hadrosaurs - "duck-billed reptiles" such as the Parasaurolophus and Maiasaura, as well as the Iguanodons) , and Marginocephalia - "margin-head" (which has all the Ceratopsians like the Triceratops, and the Pachycephalosaurs) .

Moving into Saurischia, things get a little more complex. In this one, you need to differentiate between Theropods and non-Theropods. For simplicity's sake, we will only take the Sauropods as the non-Theropods, and take the major Theropods separately. Sauropoda - "lizard-footed", includes all the dinosaurs with the elongated necks, such as the Brachiosaurus and the Diplodocus. For the Theropods , you've got 3 large base groups which have their own subgroups:

1. Ceratosauria - "horned lizards" (these guys are among the oldest of the Theropods and include families such as Ceratosauridae and Abelisauridae ) ;

2. Tyrannoraptora (more accurately, Coelurosauria) - this one includes several large major groups such as Tyrannosauroidea (which has subgroups like Tyrannosauridae - where the T.rex and Tarbosaurus are, Megaraptora, and many others) , Compsognathidae (for the little scavengers you know from Jurassic Park) , Ornithomimosauria - "bird-mimic lizards" (for dinosaurs like Struthiomimus, Gallimimus and Deinocheirus) , and Maniraptora (which includes the infamous Therizinosaurs, Oviraptors, Dromaeosaurs, and the ones we know today - Avians)

3. Carnosauria (informal) - this is a very large group that is meant to classify a lot of the different theropods not in the previous groups. It contains the Spinosaurids (Spinosaurus, Baryonyx, Suchomimus, etc), the Megalosaurids (Megalosaurus, Torvosaurus, etc) , and the Allosauroidea superfamily (which contains the Metriacanthosaurids, Allosaurids and Carcharodontosaurids) .

- Example classification : Let's say you want to know exactly where the Giganotosaurus from Jurassic World Dominion is located among all of these groups, so that you know what other species he's closely related to, but without unnecessary complexities.

It is a Dinosaur (obviously), and you look at the hip and ischium and determine that it is a Saurischian . Since it's obviously not a Sauropod, you can easily place it in Theropoda . You compare its cranium with other Theropod dinosaurs and find that the elongated, "saw" shape closely matches that of the Allosaurus, so you can place it within Carnosauria (informal) and then Allosauroidea . Now, you observe that its skeleton is far, far larger than both Allosaurids and Metriacanthosaurids, closely matching that of several Charcharodontosaurs. You could also take the shape of the Giganotosaurus' teeth, which look like those of a shark, to place it in Charcharodontosauridae (shark-toothed lizards). Further down, you know that Giganotosaurus isn't a Charcharodontosaurus, so you place it into its own, smaller group called a tribe - Giganotosaurini . Now you get to the genus: Giganotosaurus, but to reach rock bottom of classification you also need the species. Since there's only one discovered species of this genus, you simply put it as Giganotosaurus (genus) carolinii (species).

Now you arrange this nicely in a short form: Dinosauria -> Saurischia -> Theropoda -> Carnosauria (informal) -> Allosauroidea (superfamily) -> Carcharodontosauridae (family) -> Giganotosaurini (tribe) -> Giganotosaurus (genus) - Giganotosaurus carolinii (species).

NOTE: This is a very barebones classification system I just explained here. Real taxonomy is far more difficult, so if you really want to know all there is about the different dinosaur species, you'll need to spend a lot of time reading articles about it. For the average dinosaur enthusiast, I'd recommend simply learning the basic level of classification to have some idea of the different groups. You must learn to differentiate the groups from one another, for example knowing that a Tyrannosaur is not an Allosaur. If you master this ability, then you're golden.

You can't learn paleontology without geology. They go hand in hand, so if you are a dinosaur enthusiast and know all the different classifications and intricacies, but at the same time have no idea about the geological periods of our planet, you're only exploring half of the science.

The geological time scale is classified by different groups that form a hierarchy: Eons are the longest, and encompass Eras, which in turn cover Periods, which in turn hold Epochs.

First of all, it is essential to know that Earth was formed 4.6 billion years ago (Bya). That's when our space rock became a planet orbiting our star. The time period between that and the 4 billion year mark is called the Hadean Eon - a very hot, uninhabitable portion in our history that marks the primordial stages of our planet. The first forms of life appeared some time between 4 and 3.8 Bya (prokaryotes living around deep ocean geothermal vents), thus marking the end of the Hadean Eon , and the beginning of the Archean Eon (4 - 2.5 Bya). After that comes the Proterozoic Eon (2.5 Bya - 540 Mya), marked by the introduction of oxygen into our planet's atmosphere and the appearance of multi-celular eukaryotic life such as algae and sea sponges.

Moving on to our current eon, the Phanerozoic Eon , it began with the single most important event in life's history: the Cambrian Explosion (540 million years ago), which marks the beginning of complex organisms and their true spread across the planet, particularly within the Animal kingdom. The Phanerozoic Eon starts off with the Paleozoic Era (540 - 250 Mya), which in turn contains 6 geological Periods (the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and the Permian).

The Paleozoic Era ends with the Permian-Triassic Mass Extinction , which was the most devastating event in life's history where most life was wiped out in only a few million years. This creates the split between it and the Mesozoic Era (250 - 66 Mya), which contains three Periods: the Triassic (250 - 200 Mya), the Jurassic (200 - 145 Mya), and the Cretaceous (145 - 66 Mya). The Mesozoic Era ends with the well known Cretaceous-Paleogene Mass Extinction (K-Pg), which is set off by a massive asteroid impacting the Yucatan Peninsula and creating the Chicxulub Crater, wiping out all non-Avian Dinosaurs and most other life in the chain reaction of devastation that followed.

Humanity sits within the Cenozoic Era (66 Mya - present), and it also contains 3 Periods: the Paleogene (66 - 23 Mya), the Neogene (23 - 2.5 Mya), and the Quaternary (2.5 Mya - present)


The first vertebrate Animals to exist on our planet were fully aquatic, and, for simplicity, represent the Fish class we know today, and are known to have appeared shortly after the Cambrian Explosion approximately 518 Mya. Fish primarily diversified during the Ordovician, Silurian, and Devonian Periods of the Paleozoic Era (between 460 and 350 Mya), which created the Sarcopterygii branch ("lobe-finned fishes"). This is the group from which the first Tetrapods ("four-limbed" vertebrates) appeared.

Tetrapoda , which was initially only comprised of Amphibians, took shape 350 Mya during the early Carnoniferous Period of the Paleozoic Era - the first Animals to dwell on land. Later on, these Amphibians branched out into multiple groups, including the Amniotes 318 Mya, which are characterized by a more complex embryonic system, internal fertilization, and thicker skin designed for water retention.

Amniotes split into two main groups only a few million years later: Synapsida - containing true Mammals + all Pseudo-mammals (false mammals), and Sauropsida . Unlike its sister group, Sauropsida is broadly equivalent to the Reptilia class, as the vast majority of organisms within are considered true Reptiles. On the other hand, Synapsida is quite diverse, and true Mammals only appeared around 225 Mya during the Triassic Period of the Mesozoic Era.


In case you already knew all this stuff and more, you're certainly among the very few people who actually appreciate these sciences for what they are, and spend time sorting out the truth from the lies propagated by popular media nowadays. If you didn't know these things, that's fine. Most of the world's population will have no idea about this stuff, since it takes real work to learn logically and interpret it properly. However, I hope that this short explanation of these complex topics will at least encourage you to research more and expand your knowledge as I did. You will make mistakes and mix stuff up, and that's natural. You learn from them and perfect what you know. If you're a dinosaur enthusiast, I feel like you're missing out on all the wonderful aspects of paleontology if you don't have this scientific foundation to build upon, and I highly recommend you learn these topics on at least a basic level. As always, for any experts on the field, if I made mistakes in here feel free to correct me in the comments and I'll modify it accordingly. Do note that it's a very simplified explanation, though, and I'm aware that there's a whole host of complexities in the classification that I chose not to include here.