Many types of dinosaurs walked the planet before they went extinct. The Dinosauria clade had some members that were the size of a modern turkey and others that measured over 100 feet long. Ornithopods were a large clade or group of dinosaurs. The dinosaurs included in this clade are counted among the most successful herbivorous reptiles to live. So, what are ornithopods?
Discover what sets these dinosaurs apart from others and learn about three different members of the clade that once walked the Earth.
Understanding Dinosaur Clades
Dinosaurs are often categorized according to various elements of their physiology and their relationships with each other. In the past, scientists considered two major orders, Saurischia and Ornithischia. However, new research has led to scientists dividing the former into two parts, giving rise to three clades: Ornithischia, Theropoda, and Sauropodmorpha.
As one may infer from the name, ornithopods belong to the order Ornithischia. So, what are some of the distinctions between Ornithischia, Theropoda, and Sauropodmorpha? One of the most significant ways that dinosaurs have been divided is according to their hip structures.
In the case of Ornithischia, the key to their unique hip structure is found in their name. After all, Ornithischia roughly translates to “bird-hipped”, so the dinosaurs in this group have hips that are similar to birds. The pelvis of members of the order Ornithischia consists of a closed structure, meaning two bones, the pubis and ischium, are very close together.
This is very distinct compared to dinosaurs that have an open pubis and ischium. The clade Saurischia features dinosaurs that have a lizard-like hip, and this open structure is different than those in Ornithischia. Of course, scientists are still scrutinizing that clade entirely, but the hip differences help make members of the order distinct.
Yet, many dinosaurs have bird-like hips and are not considered ornithopods. For example, Triceratops and Ankylosaurus are two genera of dinosaurs that belong to the order Ornithischia, but they are not ornithopods. So, we must ask, what are ornithopods’ qualities that help scientists set them apart from others?
What Are Ornithopods?
Ornithopods are members of the clade Ornithischia, and they were mostly small to medium-sized herbivorous bipeds with bird-like hips and bird-like feet. Generally, they’re also described as lacking armor and a beak, helping to differentiate them from neoceratopsians, stegosaurs, and ankylosaurs.
The name of the clade to which ornithopods belong, Ornithopoda, roughly translates to “bird feet.” That name refers to advanced members of the clade having three forward-facing toes like those seen in Iguanodon. However, not all members of the clade have three toes. Particularly, early members of this family had four toes.
Early ornithopods were small bipedal creatures that measured about three feet long and ran swiftly. However, the members of this clade increased in size throughout their long existence, with some growing upwards of 50 feet and weighing about 36,000 pounds like Shantungosaurus giganteus.
Since ornithopods and the other dinosaur clades have been so broadly defined, a diverse assortment of dinosaurs belongs to this clade, differing in size, location, and looks.
When Did Ornithopods Live?
The first ornithopods may have been members of the genus Fabrosaurus, and they lived in the Early Jurassic period about 199 to 189 million years ago. Remains of these creatures have been found in the Kingdom of Lesotho in South Africa.
Ornithopods survived for over 100 million years, right up until the end of the dinosaurs. Members of the Hadrosauridae family lived until the Cretaceous–Paleogene Extinction Event that occurred roughly 66 million years ago and killed off the terrestrial dinosaurs. So, members of this clade survived for a very long time, and their diversity increased greatly during that extensive time.
What Did Ornithopods Eat?
Ornithopods were herbivorous dinosaurs that ate a wide variety of plants. The morphology of their mouths, chewing anatomy, and teeth changed greatly throughout their history. The fact that ornithopods became a dominant clade of dinosaurs on the planet during an era of monstrous carnivores contributes to the impressiveness of ornithopods.
3 Examples of Ornithopods
We’ve answered the question, what are ornithopods? Now it’s time to consider some examples of these dinosaurs. After all, many genera and species fit into the Ornithopoda clade, and they’re pretty diverse. Learn about some of the most well-known ornithopods!
Iguanodon is a genus of ornithopods known for the type species Iguanodon bernissartensis. Unlike early ornithopods, Iguanodon bernissartensis was a large herbivore that used both bipedal and quadrupedal movement to access its food sources. These creatures may have grown between 26 and 36 feet long and weighed about 6,000 pounds to 8,400 pounds! Several other unique members of this genus exist as well.
Members of the Hadrosauridae family were around when the mass extinction event ended the lives of terrestrial dinosaurs about 66 million years ago. These commonly known reptiles were the “duckbilled” dinosaurs, named for their flat, duck-like snouts. The type species, Hadrosaurus foulkii, was found in the Woodbury Formation. They measured about 23 to 26 feet long and weighed between 4,000 and 8,800 pounds!
Shantungosaurus is the genus with the largest ornithopods. The species Shantungosaurus giganteus was simply massive compared to the smaller members of the clade. This creature measured about 49 to 54 feet long and weighed between 30,000 and 36,000 pounds! Researchers originally found the creature in Shandong China.
Ornithopods are very diverse. Some of them were about three feet long and weighed less than 50 pounds, and others were massive, like Shantungosaurus giganteus. The defining features of these creatures are found by exploring their hips, feet, form of locomotion, and diet.
Generally, ornithopods were bipedal herbivores with bird-like hips as well as bird-like feet. Studies frequently find exceptions to some of those traits, though. Also, the organization of dinosaurs continues to undergo development. As mentioned, scientists generally support a two-clade or three-clade model for dinosaur classification. That could change in the future as new, better ways to organize the creatures emerge.
The photo featured at the top of this post is © Daniel Eskridge/Shutterstock.com
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