Pachyrhinosaurus: The Thick-Nosed Lizard of the Late Cretaceous

The Pachyrhinosaurus, whose name translates to “thick-nosed lizard,” was a resident of what is now North America during the Late Cretaceous period. Its story is one of discovery, evolution, and survival, offering us a glimpse into a world long past.

With its distinctive thick, bony nasal boss, this dinosaur is a testament to the diversity and adaptability of life on Earth millions of years ago. As we journey back in time, we’ll explore the world of this fascinating dinosaur, from its origins and taxonomy to its discovery and the environment it thrived in.

Pachyrhinosaurus Key Facts

KeywordFact
Pachyrhinosaurus pronunciationpack-ee-RINE-oh-sore-us
Meaning of nameThick-nosed lizard
GroupCeratopsia
Type SpeciesPachyrhinosaurus canadensis
DietHerbivore
When it Lived72.1 to 66.0 MYA
PeriodLate Cretaceous
EpochMaastrichtian to Early/Lower Maastrichtian
Length19.7 to 26.2 ft
Height7.5 ft
Weight3.3 to 4.0 tons
MobilityMoved on four legs
First Discovery1946 by Charles Mortram Sternberg
Location of first findAlberta, Canada
First Described by1950 by Charles Mortram Sternberg
HolotypeNMC 8867

Pachyrhinosaurus Origins, Taxonomy and Timeline

A digital illustration of a Pachyrhinosaurus, a large ceratopsid dinosaur known for its unique, broad nasal boss instead of horns. The dinosaur is depicted in a side view, showcasing its robust body, textured skin, and distinctive frill adorned with small horn-like projections.

The Pachyrhinosaurus (thick-nosed lizard) is a testament to the descriptive nature of scientific nomenclature. Its name is derived from the Greek words ‘pachy’ (thick), ‘rino’ (nose), and ‘sauros’ (reptile/lizard). This perfectly encapsulates one of its most distinctive features–its thick, bony nasal boss.

Belonging to the group Ceratopsia, its part of the Ceratopsidae family–a group of herbivorous dinosaurs known for their distinctive frills and horns. These features, combined with their large size and typically quadrupedal stance, make them some of the most recognizable dinosaurs. The genus includes the type species Pachyrhinosaurus canadensis, named in reference to its discovery in Canada. Other species in this genus include P. lakustai and P. prerotum. 

The Cretaceous period, during which the Pachyrhinosaurus lived, was a time of significant geological and environmental changes. The continents were slowly drifting apart, creating the familiar shapes and positions we recognize today. The climate was generally warmer and more humid than today, with active volcanism contributing to these conditions. This warm, humid climate would have created a lush, verdant environment for the Pachyrhinosaurus, teeming with a variety of plant life for this herbivore to feast on.

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Discovery & Fossil Evidence

The story of this discovery begins in 1946 in the rugged landscapes of Alberta, Canada. It was here that Charles M. Sternberg, a renowned fossil collector and paleontologist, unearthed the first known remains of this dinosaur. Sternberg’s discovery was significant and he went on to describe the dinosaur in 1950. 

A photograph of a Pachyrhinosaurus perotorum skeleton exhibit in a museum. The skeletal structure displays the dinosaur's robust frame, including its distinct nasal boss and frill. The skeleton is mounted in a dynamic pose, with its head slightly tilted and legs positioned as if in mid-stride.
Bryan from Taipei, Taiwan, CC BY-SA 2.0, via Wikimedia Commons

Sternberg’s discovery was just the beginning of our understanding of the Pachyrhinosaurus. Since his initial find, additional fossils have been discovered, notably in Alaska. These later finds have expanded our understanding of this dinosaur by providing further insight into its physical characteristics and lifestyle. Each new discovery adds another piece to the puzzle and helps us to paint a more complete picture of this fascinating creature and the world it inhabited.

Pachyrhinosaurus Size and Description

This is a dinosaur that captures the imagination with its distinctive features and size. Let’s delve into a more detailed description of this fascinating creature.

Short description of Pachyrhinosaurus

This was a ceratopsian dinosaur, a group known for their horned faces and frilled neck shields. Its most distinctive feature was its thick, bony nasal boss, a feature that sets it apart from other ceratopsians. This nasal boss, its large body, and its quadrupedal stance would have made it a formidable presence in its environment.

Size and Weight of Type Species

A size comparison chart featuring a silhouette of Pachyrhinosaurus canadensis alongside a human figure for scale. The Pachyrhinosaurus silhouette is shown to be approximately 5 meters in length. The chart highlights the dinosaur's robust build and distinctive nasal boss.
Slate Weasel, Public domain, via Wikimedia Commons

The size of the Pachyrhinosaurus is a topic of ongoing research, with different sources providing different estimates. Based on the fossil evidence we have, we can make some educated guesses. This was likely a large dinosaur with a body length of 19.7 to 26.2 feet and a weight of several tons. This size would have made it one of the larger ceratopsians, a group known for their large body sizes.

The size of this herbivore would have had significant implications for its lifestyle and behavior. As a large herbivore, it would have needed to consume large amounts of plant matter to sustain its size. Its large size would have also offered some protection against predators, as few carnivorous dinosaurs would have been able to take on a full-grown Pachyrhinosaurus.

The Dinosaur in Detail

The Pachyrhinosaurus is a dinosaur that stands out not just for its size, but also for its unique features. Its thick, bony nasal boss for which it is named is unlike anything seen in modern reptiles. It also had smaller flattened bosses above its eyes in place of horns. These bosses have been used to distinguish between species of the Pachyrhinosaurus.

Its body was built for an herbivorous lifestyle. Strong limbs would have supported its large body as it moved through its environment to forage for plant matter. Its long tail would have provided balance while its frilled neck shield could have served a variety of purposes, from defense against predators to a display feature for attracting mates.

The Pachyrhinosaurus’s skull is particularly interesting. Despite having bosses instead of horns on its face, it still had a pair of horns growing upwards from the top of its frill. These features would have made its head a formidable weapon, potentially used in combat with other Pachyrhinosaurus or against predators.

The Pachyrhinosaurus in its Natural Habitat

A dynamic scene in a dense forest depicting a confrontation between a group of Pachyrhinosaurus and an Albertosaurus. The Pachyrhinosaurus are in the foreground, displaying their distinctive nasal bosses and frills, while the Albertosaurus, with its sharp teeth and agile build, approaches from the right.
ABelov2014, CC BY 3.0, via Wikimedia Commons

This herbivorous dinosaur lived during the Late Cretaceous period during a time of significant geological and environmental changes. The continents were slowly drifting apart, creating the familiar shapes and positions we recognize today. North America was still split into two paleocontinents. The climate was generally warmer and more humid than today, with active volcanism contributing to these conditions. The polar regions were free of ice, covered instead by lush forests.

The warm, humid climate of Laramidia would have created a lush, verdant environment for this herbivore, teeming with a variety of plant life for it to feast on. With its large size and herbivorous diet, it would have played a significant role in shaping its environment. By feeding on plants, it would have helped to control plant populations and contribute to the cycling of nutrients in the ecosystem.

Its lifestyle would have been shaped by its environment. As a large herbivore, it would have needed to consume large amounts of plant matter to sustain its size. This size alone would help to deter predators. Its thick nasal boss and frilled neck shield could have served as defensive weapons, helping to deter potential predators even further.

Interesting Points about Pachyrhinosaurus

  1. Its thick nasal boss is a unique feature among ceratopsians, which typically have large horns on their noses.
  2. It lived during the Late Cretaceous period, a time of significant geological and environmental changes, with the continents slowly taking on their modern forms.
  3. This dinosaur was first discovered in Alberta, Canada in 1946 by Charles M. Sternberg. Since then, additional fossils have been found in Alaska.
  4. It was a large dinosaur, with a body length of around 20 feet and a weight of several tons. This size would have made it one of the larger ceratopsians.
  5. As an herbivore, it fed on the abundant plant life in its environment. Its large size would have required it to consume large amounts of plant matter.

Contemporary Dinosaurs

The Pachyrhinosaurus was a creature of notable resilience that shared its world with a captivating ensemble of contemporaries. Among them were the Edmontosaurus, Ankylosaurus, and Albertosaurus, each of their lives woven together in a complex web of survival and competition.

The Edmontosaurus was an herbivore like our main dinosaur that may have been a companion in the quest for sustenance. Their shared dietary preferences could have led to a friendly rivalry in a competition for the most lush and nutritious vegetation. Yet despite their potential rivalry, these two species coexisted and each found their niche in the ecosystem. The Ankylosaurus, with its armored body and club-like tail, presents a stark contrast to the Pachyrhinosaurus. This dinosaur was built like a living tank and might have been an intimidating presence. Yet it was another herbivore–a testament to the diverse forms that plant-eating dinosaurs could take.

The Albertosaurus, on the other hand, was a carnivore. This predator’s sharp teeth and claws might have posed a threat to these herbivores. The presence of such a predator would have added an element of danger to the Pachyrhinosaurus’ existence as a constant reminder of the survival of the fittest. Yet, it’s also possible that the Pachyrhinosaurus–with its strong build and protective frill–could have held its own against such threats. This dynamic interplay of species, each with their unique traits and roles, paints a vivid picture of a world where survival was a communal effort.

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 “thick-nosed lizard,” a reference to its distinctive thick, bony nasal boss. It comes from Greek roots.

When did it live?

The Pachyrhinosaurus lived during the Late Cretaceous period, specifically the Maastrichtian to Early/Lower Maastrichtian epoch, between 72.1 and 66 million years ago.

What did it eat?

This was an herbivore, feeding on the abundant plant life in its environment.

How big was this dinosaur?

It was a large dinosaur with a body length of 19.7 to 26.2 ft and a weight of several tons.

What made the Pachyrhinosaurus unique?

It is unique for its thick, bony nasal boss–a feature that sets it apart from other ceratopsians, which typically have large horns on their noses.

Sources

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 Pachyrhinosaurus. However, 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: Nobu Tamura, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons