The dinosaur kingdom has two primary orders, namely, Ornithischia and Saurischia. We’ll be looking at the Saurischia order in detail in this article, investigating the sub-groups and families within it. We’ll also discuss some of the top dino species that it contains.
So, what sets the Saurischians apart from the Ornithischians? When did the Saurischia dinosaur order live, and how do they fit into the seven major groups? Stay tuned as we answer all these questions and more!
What is the Saurischia order?
The name Saurischia can mean two things, depending on who you ask. It either means “reptile hips” or “lizard hip joint.” When Harry Seeley decided to classify dinosaurs into two orders in 1888, he decided to base it on the two different hip structures. Some paleontologists feel that Saurischia should be a clade that’s unranked instead of an order.
Unlike the Ornithischians, you’ll find most of the carnivores in the Saurischia order. Birds are mostly descendants of the therapods, while there are massive sauropod herbivores within it too. There’s also a discussion that ornithischians, avalian saurischians (bird predecessors), and therizinosaurians eventually had similar hip structures, which is called convergent evolution.
Before we head into groups, we need to quickly highlight the Eusaurischia clade. Scientists place theropods and sauropods within this Saurischia order clade to split the two divisions. If there are any dinosaurs that don’t fit into the classifications of these groups, they fall outside Eusaurischia within the order.
Which characteristics define Saurischia?
The top characteristic that defines the Saurischia order is the hip structure, or pelvis to be more specific. In the Ornithischia order, the pubic bone points forward and backward and is parallel to the ischium. For Saurischians, the pubis only points forward while the ischium faces back with the ilium above them.
While Ornithischian characteristics focus more on the head and jaw, the Saurischia order looks more towards the hands, fingers, and neck. These dinosaurs had hands that could more easily grasp items, while they also had asymmetrical fingers. The sauropods were well-known for having lengthy, mobile necks to help them eat from tall trees.
Finally, we need to point out the distinction that the Saurischia order contains all the carnivorous dinosaurs in the therapod group. You’ll recognize some popular names here, such as Tyrannosaurus Rex, Carnotaurus, and Compsognathus.
The Sub-Groups of the Saurischia Order
It’s time to dig a little deeper into the Saurischia order. In this section, we’ll look at some groups and sub-groups that lead to the dinosaur families, as we don’t have specific sections for these groups. You’ll get an idea of how they’re grouped together in various relationships.
There are some clades and species that fall outside of the larger orders, as they remain unranked at the moment. While we won’t cover them here in detail, we’ll be sure to include them when we discuss the different species.
The name Therapod literally means wild beast (thēríon) and foot (podós), relating to the wild nature of the carnivores in this group and the distinction of the feet. The limbs had three toes, while the bones were hollow.
While most of the Therapods were carnivorous, there were small populations of herbivores, piscivores, omnivores, and insectivores. They lived mostly from the Late Triassic period in the Carnian Age to the Late Cretaceous. It was from the Jurassic period that some of the Therapods evolved to form the avians that were the descendants of birds today.
We’ll provide a more detailed discussion on Therapods in a different article. For now, let’s look at some of the significant sub-groups that belonged to the Saurischia order under Theropoda.
As one of the Neotheropoda clades, these dinosaurs lived between Late Triassic and Early Jurassic. They were completely carnivorous, with cranial crests that were the main characteristic of the Coelophysoidea. Popular genera that fall in this clade included Dilophosaurus, Sarcosaurus, Gojirasaurus, and the Coelophysidae family, although there is some debate about some of the species labelled in it.
This clade also consists of carnivore dinosaurs, with the chief traits being the medium to large size with shortened forearms. The skulls also had unique ornamental designs, as can be seen with the Carnotaurus genus. The three main families within it include Ceratosauridae, Abelisauridae, and Noasauridae, each with distinctive features that we’ll analyze on the separate family pages to come. Other popular dinosaurs in Ceratosauria include Majungasaurus, Ceratosaurus, Indosaurus, and Abelisaurus.
The name Tetanurae means “stiff tails” and contains most of the Therapods, more than any other clade in the Saurischia order. These dinosaurs are more closely related to modern birds than Ceratosauria were. There were four main groups under it, namely:
- Megalosauroidea (which included Spinosaurus and Megalosaurus)
- Avetheropoda (modern bird descendants)
We’re drawing attention to this clade under Avetheropoda, as it contains many carnivore dinosaurs you’ll recognize. The name means “hollow tailed lizards”. Some of the more popular names include Compsognathidae, Tyrannosauridae, Ornithomimosauria, and Maniraptoriformes. That’s right; it’s in this section that you’ll find the almighty Tyrannosaurus Rex.
You’ll find the Maniraptora clade with the Maniraptoriformes group. The reason why we mentioned this clade specifically under the Coelurosauria is that it includes many avian species and non-avian dinosaurs you may recognize. We’re getting closer to the descendants of birds in the dino periods. Top groups you may know quite well include Therizinosauria, Deinonychosauria, and Oviraptorosauria. Ornithomimosauria is the sister group under Maniraptoriformes.
Also within Maniraptora is the Avialae clade It contains what we call the living dinosaurs, which refers to modern birds. Many scientists believe that Archaeopteryx was one of the earliest avians during the Mesozoic era. It’s also said that some of the species may have been able to fly already at that stage.
We finally turn our attention to the second Saurischia order group, the sauropods. Sauropodomorpha literally translates to “lizard-footed forms”. It mostly consists of massive herbivore dinosaurs with long necks that were quadruped. They existed from the late Triassic to the end of the Cretaceous.
The Sauropods dominated the land with their bulk and strength. They had access to trees that were quite high that smaller herbivores couldn’t get to, which means they regularly had food in the right regions. Some popular names in this group include Diplodocus, Argentinosaurus, Supersaurus, and Titanosaurus.
While we’ll cover some of the Sauropod groups in more detail, here’s a quick overview of what you’ll find.
The Sauropods have some genera and families that exist without proper clades, such as Saturnaliinae, Buriolestes, and Eoraptor. The most significant collection of Sauropods lies within Bagualosauria. Besides some random uncladed dinosaurs, like Bagualosaurus, Plateosauravus, and Thecodontosaurus, it also contains the Plateosauria sub-group.
The Plateosauria clade exists to hold one massive family and more groups within it. It was named as a placement for the Plateosaurus family, which was seen as separate from the other clades under Plateosauria. The other section that we need to note is the Massopoda clade.
As with the Plateosauria clade, Massopoda was formed to hold the Massospondylidae and another sub-group. The name means “lump foot”, with the list of dinosaurs including Yunnanosaurus, Jingshanosaurus, Glacialisaurus, and Massospondylus. Any other families or genera not in this or any of the above groups fall under Sauropodiformes.
Sauropodiformes is the final large clade, fallin under Massopoda. It contains all the massive herbivore dinosaurs not in the other Saurischia groups. There are plenty of genera in this section, including Lessemsaurus, Blikanasaurus, and Melanorosaurus. However, attention usually draws to the Sauropoda clade, as it holds popular names like Brachiosaurus, Brontosaurus, Diplodocus, and Apatosaurus.
Families within Saurischia
We’ve already mentioned some of the more popular families in the Saurischia order. You’ll notice we have a separate section for dinosaur families you can explore, so we don’t want to duplicate that information. You can explore them there, or feel free to click on any available links below if we’ve already covered them.
For now, here’s a quick summary of the more popular Saurischian families:
- Dromaeosauridae (velociraptors are here)
What are Some Dinosaur Examples of Saurischians?
We could spend all day here discussing several Saurischian dinosaurs that we love. Since we’ll have several sheets for each species, we’ll only provide short summaries of the more popular ones. We’re sure you’ll recognize all of them.
When you speak to most people about dinosaurs, then T. Rex or Tyrannosaurus Rex is the species that most of them will mention first. As the primary symbol for the Jurassic Park and Jurassic World brands, it became a household name almost instantly. However, there are so many other tyrannosaurids that many people don’t even know about.
The main characteristics of the Tyrannosaurus genus were the massive skull, long powerful tail, and short arms. With the discovery that some dinosaurs had feathers, it’s believed that some of the smaller tyrannosaurids had feathers on them. This genus seems to have appeared in the Late Cretaceous period just before the extinction-level event.
The Carnotaurus genus falls within the Abelisauridae family under the Furileusauria clade. These carnivore dinosaurs had a lighter build than the Tyrannosaurus, with small horns on the skull used for killing prey and fighting with others. Its diet mainly consisted of small to large animals, and it may have even hunted some of the larger sauropods.
With its strong legs and light build, scientists believe it was one of the fastest theropods that lived. As with the T. Rex, it existed during the Late Cretaceous period, so it didn’t experience as many ages as the sauropods.
If you’ve watched the first Jurassic Park, you may remember the frilled dinosaur that spat at the visitors. That was the Dilophosaurus. While the Velociraptor was more popular in the movie franchise, we love these small carnivores. The name means “two-crested lizard.”
While it may not have had frills, it certainly had two crests on the head. It’s unknown if the crests were used for display or battling other Dilophosaur dinosaurs. Despite their relatively small size, they may have hunted larger animals. It had four fingers on its hands with a long thin tail at the back.
Moving onto the Sauropods, we’ll start with the infamous Brontosaurus. Its name means “thunder lizard”, and it was one of the largest sauropods of its time. There was a time that scientists believed it was just another Apatosaurus species. Fortunately for us Brontosaurus lovers, it now falls as its own genus under the Apatosaurinae sub-family in the Diplodocidae family.
While no Brontosaurus skull has been discovered, paleontologists believe it’s similar to the cousin, Apatosaurus. It lived during the Late Jurassic period, but it didn’t make it into the Early Cretaceous. It’s probably one of the best-known Sauropods due to the Jurassic movies and games.
Most of the sauropod fossils found in North America belong to the Camarasaurus genus. Our first virtual encounter with this dinosaur was in the game Jurassic World Evolution, which is when we fell in love with it. The name means “chambered lizard”, referring to hollow chambers in the cervical vertebrae.
Camarasaurus could stretch its long neck horizontally to reach foliage over long distances or stretch it up vertically towards high treetops. There are four known species, with Camarasaurus supremus being the most popular. It also lived in the Late Jurassic with Brontosaurus.
Fans of the game ARK: Survival Evolved may recognize Diplodocus. The name roughly means “Double beam.” If you look at the skeletal structure of the tail, there were chevron bones with double beams, which were unique to these Sauropods. Its gigantic size may have intimidated even the largest carnivore hunters, while its tail had potent power.
With the front limbs being shorter than the hind, it had a more horizontal display than Brontosaurus and Camarasaurus. Based on fossils discovered so far, it’s the longest known dinosaur among the Saurischia order. While there are only three known species, it shares the Diplodocidae family with other well-known dino giants.
How does Saurischia fit into the 7 major dinosaur groups?
There are seven significant groups in the dinosaur kingdom. They don’t follow the general taxonomy as mentioned for the Saurischia and Ornithischia orders but give a list of the largest groups among them.
The seven major dinosaur groups are:
As you can tell from the highlighted sections, the Saurischia dinos only form two of the seven major dinosaur groups. That doesn’t mean they have less species and families within them. On the contrary, they seem to have more than the Ornithischia order.
Final Thoughts on the Saurischia Order
We’ve been on an exciting journey with you discussing the various dinosaur orders. It provides so much insight when you see how the various families are related in some way. It also helps to see where your favorite species are located in the classification system. Who knows how long it will stay this way, though.
I remember when Brontosaurus was thought to be the same as Apatosaurus, so it vanished from the taxonomy. Then, they realized that it wasn’t the same, so Brontosaurus was placed under the Apatosaurinae sub-family. We’re all still learning as we uncover more dinosaur fossils. We’ll try to keep our site updated if any more changes take place in the worlds of science and paleontology.