Nodosaurus: The Knobbed Lizard from the Late Cretaceous

In this article, our focus will be on the Nodosaurus, a dinosaur whose name literally translates to “Knobbed Lizard”. This dinosaur, with its unique physical characteristics and intriguing history, is sure to captivate your imagination.

In the next few paragraphs, we’ll dive deep into the world of the Nodosaurus to explore its key facts, origins, taxonomy, timeline, and much more. We’ll also discuss the discovery and fossil evidence of this dinosaur, its size and description, and its natural habitat and environment.

Key Facts

Nodosaurus pronunciationno-doh-SORE-us
Meaning of nameKnobbed lizard
Type SpeciesNodosaurus textilis
When it Lived99.6 to 66.0 MYA
PeriodLate Cretaceous
EpochMiddle Cenomanian to Late/Upper Maastrichtian
Length13.0 to 20.0 ft
Height6.2 ft
Weight3.85 tons
MobilityMoved on all four
First Discovery1881 by William Harlow Reed
Location of first findAlberta, Canada
First Described by1889 by Othneil Charles Marsh
HolotypeYPM VP 1815

Nodosaurus Origins, Taxonomy and Timeline

Illustration of Nodosaurus, a heavily armored dinosaur with a broad, low body covered in bony plates and spikes. It is depicted walking on all fours with a tail extending straight out behind.

Let’s start by understanding the name of our dinosaur. The Nodosaurus, or the “Knobbed Lizard”, gets its name from the Latin word for knob or swelling, and the Greek word ‘sauros’, which means reptile or lizard. This name is a nod to the unique physical characteristics of this dinosaur–which we’ll delve into a bit later.

In terms of taxonomy, it belongs to the Ornithopoda group, specifically the Nodosauridae family. The type species of this genus is Nodosaurus textilis. It’s interesting to note that this is the only known species of this dinosaur.

It lived during the Late Cretaceous period, specifically from the Middle Cenomanian to Late Campanian epoch. It’s fascinating to think about the world as it was during this time, with these incredible creatures roaming the earth.

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Discovery & Fossil Evidence

The first discovery was made in 1881 by William Harlow Reed in Alberta, Canada. This find was significant as it marked the first time any Nodosaurus fossil had been identified. The holotype, or the specimen used to describe the species, is known as YPM VP 1815.

Photograph of a Nodosaurus fossil, showing the pelvis and rib structure. The fossil is well-preserved, displaying the intricate details of the bones and their connections.
Internet Archive Book Images, No restrictions, via Wikimedia Commons

Since that initial discovery, more fossils have also been found in Wyoming, USA. These finds have helped to expand our understanding of this dinosaur and its place in history. The fossils found include vertebrae and armor, both providing valuable insights into the physical characteristics and defensive mechanisms of this dinosaur.

The discovery of these fossils has been instrumental in shaping our understanding of this herbivorous dinosaur. Each find adds a new piece to the puzzle and helps us to build a more complete picture of this fascinating creature. It’s a testament to the power of paleontology and the enduring mystery of the world’s prehistoric past.

Nodosaurus Size and Description

This was a unique creature with physical characteristics that set it apart from other dinosaurs. Let’s take a closer look at what made this dinosaur so special.

Short description of Nodosaurus

This herbivore was not just another dinosaur. It had unique features that set it apart from others. For instance, its bony dermal plates were not just for show. They served as a form of protection against predators and made this dinosaur a tough target for any would-be attacker.

Its four short legs ended in five-toed feet. In contrast to its short neck it had a long, stiff, clubless tail. The head was narrow with a pointed snout, powerful jaws, and small teeth. The Nodosaurus was likely an herbivore that fed on soft plants.

Size and Weight of Type Species

It was a medium-sized dinosaur with estimates suggesting that it grew up to roughly 13 to 20 feet long. In terms of weight, it’s estimated that it could have weighed up to 3.5 tonnes (or 3.85 short tons). These estimates give us a sense of the sheer size and scale of this dinosaur.

The Dinosaur in Detail

Diagram of the Nodosaurus textilis skeleton, highlighting the known fossil elements in black. The illustration depicts the dinosaur's robust body structure, armored back, and bony plates along its tail.
R. Lull, Public domain, via Wikimedia Commons

This was an ankylosaurian dinosaur characterized by bony dermal plates covering the top of its body. It’s believed that it may have also had spikes along its sides. These dermal plates were arranged in bands along its body, with narrow bands over the ribs alternating with wider plates in between. These wider plates were covered in regularly arranged bony nodules, which give the animal its scientific name.

In addition to its defensive armor, it also had a unique feeding strategy. Its skull suggests that it fed on soft plants. However, it’s also possible that it used gastroliths–stones in the stomach that help with digestion–and its enormous intestinal apparatus to process tougher, fibrous plants.

The Nodosaurus in its Natural Habitat and Environment

This dinosaur lived during a time when the earth was a vastly different place than it is today. The Late Cretaceous period was characterized by warm temperatures and high sea levels, resulting in a landscape that was dominated by shallow inland seas. North America was no exception, as it was split in two by one of these inland seas. The Nodosaurus made its home on Laramidia, the western half of North America. It likely inhabited areas that were close to these seas, feeding on the lush vegetation that thrived in these environments.

As an herbivore, it would have had a diet that consisted primarily of plants. It’s possible that it fed on a variety of vegetation–including ferns, cycads, and conifers. This dinosaur was a quadruped, meaning it moved on all four legs. This mode of locomotion would have made it a slow-moving creature when combined with its size and weight. However, its heavy bony armor would have provided it with a necessary degree of protection against predators. It’s also possible that it lived in herds, as many herbivorous dinosaurs did, which would have provided additional protection against predators.

Interesting Points about Nodosaurus

  1. This was one of the first armored dinosaurs to be discovered in North America.
  2. The name translates to “Knobbed Lizard”, a nod to the bony nodules on its dermal plates.
  3. It is the type genus for the family Nodosauridae.
  4. It likely used its bony dermal plates and possibly spikes as a form of protection against predators.
  5. This herbivore may have used gastroliths (swallowed rocks) to process tough, fibrous plants.

Contemporary Dinosaurs

This creature of notable stature shared its world with a fascinating ensemble of contemporaries. Among them were the Edmontia, Anodontosaurus, and Euoplocephalus, each playing a part in the intricate dance of existence. Their lives were intertwined in the complex web of survival and competition of their shared environment.

The Edmontia was a relative of the Nodosaurus and also belonged to the family Nodosauridae. It is easy to imagine these two heavily armored beasts lumbering side-by-side in their daily foraging. These two dinosaurs likely existed in a tense balance of cooperation and competition.

Ankylosaurians from other families could be found in this landscape as well. The Anodontosaurus, while smaller in size, was no less formidable. Its robust armor and club-like tail hinted at a life where defense was paramount. The Euoplocephalus was larger and more heavily armored, and might have been a formidable competitor for resources. Yet despite their subtle differences, these creatures coexisted. Their interactions–whether as competitors or indifferent cohabitants–shaped the landscape of their time and now paint a vivid picture of a world long past.

List Of All Dinosaurs

We have created a list of all dinosaurs we have covered here, sorted across the seven main groups of dinosaurs. We also include information about their type of diet, (omnivore, herbivore or carnivore) and the time they lived.

Frequently Asked Questions

What does the name mean?

The name translates to “Knobbed Lizard”, a reference to the bony nodules on its dermal plates. It comes from Latin and Greek roots.

When did the Nodosaurus live?

It lived during the Late Cretaceous period, specifically from the Middle Cenomanian to Late Campanian epoch. This places its age range between 99.6 to 66.0 million years ago.

What did it eat?

This dinosaur was an herbivore, meaning it ate plants. It’s possible that it fed on a variety of vegetation such as ferns, cycads, and conifers.

How did this dinosaur move?

It was a quadruped, meaning it moved on all four legs. This would have made it a slow-moving creature due to its size and weight.

Where were the fossils first discovered?

The first discovery was made in 1881 by William Harlow Reed in Alberta, Canada.

What made this dinosaur unique?

It had unique physical characteristics that set it apart from other dinosaurs, including bony dermal plates and possibly spikes that served as a form of protection against predators.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of the Nodosaurus. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

Article last fact-checked: Joey Arboleda, 06-12-2023

Featured Image Credit: Conty, CC BY 3.0, via Wikimedia Commons