Tylocephale: The Swelling Head Dinosaur from the Late Cretaceous

Imagine stepping back in time to the Late Cretaceous period. You’re in what is now known as Mongolia and you encounter a dinosaur with a peculiarly swollen head. This is the Tylocephale, a dinosaur that stands out in the annals of paleontology for its unique cranial structure.

The Tylocephale, whose name accurately translates to ‘swelling head’, is a member of the Pachycephalosauridae family. As we delve into the world of this fascinating creature, we’ll explore its origins, its discovery, and the environment it once called home.

Key Facts

Tylocephale pronunciationtie-loh-keff-ah-lee
Meaning of nameSwelling head
Type SpeciesTylocephale gilmorei
When it Lived83.5 to 70.6 MYA
PeriodLate Cretaceous
EpochMiddle Campanian to Late/Upper Campanian
Length6.6 ft
Height1.5 ft
Weight0.04 ton
MobilityMoved on two legs
First Discovery1965 by Teresa Maryańska and Halszka Osmólska
Location of first findBarun Goyot Formation, Mongolia
First Described by1974 by Teresa Maryańska and Halszka Osmólska
HolotypeZPAL MgD-I/105

Tylocephale Origins, Taxonomy and Timeline

An illustration of two Tylocephale dinosaurs, small pachycephalosaurids from the Late Cretaceous period, depicted in a forested environment. These bipedal herbivores are shown with distinctive dome-shaped skulls and agile builds.

The name of this dinosaur is a fascinating blend of the Greek words ‘tyli’ meaning callus or hard swelling, and ‘kefale’ meaning head. This name perfectly encapsulates the unique physical characteristic that sets this dinosaur apart–its swollen head.

Belonging to the Ornithopoda group, it is a part of the Pachycephalosauridae family. The type species of this genus is Tylocephale gilmorei. As of now, no subspecies or sister taxa have been identified.

The timeline is set in the Late Cretaceous period, specifically from the Middle Campanian to Late Campanian epoch. This places our dino friend near the end of the time of dinosaurs, yet still a period teeming with a diverse array of dinosaur species.

To hear how ‘Tylocephale’ is pronounced, you can check out this video:

Discovery & Fossil Evidence

The first discovery of these fossils dates back to 1965. The location of this significant find was the Barun Goyot Formation in Mongolia, a site known for its rich fossil deposits. The holotype, designated as ZPAL MgD-I/105, was first described by Teresa Maryańska and Halszka Osmólska in 1974.

The fossil evidence is primarily cranial, reflecting its distinctive swollen head. The degree of preservation of these fossils has allowed paleontologists to gain valuable insights into the physical characteristics and probable behaviors of this dinosaur. While there have been other finds since the initial discovery, each new find adds a piece to the puzzle that helps us understand this unique creature better.

Tylocephale Size and Description

Let’s take a moment to visualize our unique dinosaur friend. As a proud member of the Pachycephalosauridae family, it shares a lineage with some truly remarkable creatures. Yet, even among its impressive relatives it stands out thanks to its distinctive swollen head.

Short description of Tylocephale

Much like its Pachycephalosauridae kin, it likely adopted a bipedal stance, moving with agility and grace on its two hind legs. Its body would have been perfectly balanced by a long, stiff tail. 

Each fossil that we uncover adds to our understanding of this fascinating creature. These remnants of a time long past allow us to piece together the story of a dinosaur that once roamed the earth, leaving its mark in the form of its distinctive, swollen-headed fossils. Through these fossils, we can glimpse the world of the Tylocephale–a world of ancient forests, vast plains, and fierce competition for survival. Each fossil is a testament to the Tylocephale’s resilience and adaptability, qualities that allowed it to thrive in the challenging environment of the Late Cretaceous period.

Size and Weight of Type Species

A size comparison chart featuring Tylocephale, a small pachycephalosaurid dinosaur from the Late Cretaceous period, at approximately 2 meters in length. The chart includes a human figure for scale, highlighting the dinosaur's small size and agile build.
Slate Weasel, Public domain, via Wikimedia Commons

While specific size and weight estimates are currently unavailable, we can make some educated guesses based on its family characteristics and the size of its cranial fossils. It’s reasonable to assume that this was a medium-sized dinosaur, fitting comfortably within the size range of its Pachycephalosauridae relatives.

As we continue to discover and study more fossils, our understanding of its physical dimensions will become more precise. Each new find brings us one step closer to painting a complete picture of this fascinating creature.

The Dinosaur in Detail

This is a shining example of the incredible diversity of dinosaur life during the Late Cretaceous period. Its swollen head–the feature that gives it its name–is not just a physical characteristic, but a window into its behavior and lifestyle. This unique cranial structure suggests that it might have used its head for display or even combat, much like modern-day animals with similar features. This could indicate a complex social structure within Tylocephale populations, where individuals competed for dominance or mates.

At the other end of this large head would have been a long, stiff tail providing counterbalance. This tail would have served not only as a counterbalance but also as a crucial tool for communication and possibly defense. But the pièce de résistance of the Tylocephale is, without a doubt, its swollen head. This unique feature likely played a significant role in its behavior and interactions with other dinosaurs. It’s this swollen head that gives this dinosaur its name and its place in the annals of paleontology.

The Tylocephale in its Natural Habitat

This herbivorous dinosaur lived during the Late Cretaceous period during a time when the earth was warm and sea levels were high. The environment of what is now Mongolia, where Tylocephale fossils have been found, would have been quite different from what it is today.

As an herbivore, it would have fed on the diverse plant life that thrived during this period. Its mobility–likely bipedal–would have allowed it to navigate its environment effectively, whether it was foraging for food or evading predators.

With its unique swollen head, it would have been a notable presence in its environment. Its interactions with other dinosaurs, whether as a competitor or a prey species, would have played a role in shaping the ecosystem of its time.

Interesting Points about Tylocephale

  1. The name, which translates to ‘swelling head’, is a direct reference to its most distinctive feature–its swollen cranial structure.
  2. It lived during the Late Cretaceous period, a time of great dinosaur diversity.
  3. The first fossils were discovered in Mongolia in a region known for its rich fossil deposits.
  4. It is a member of the Pachycephalosauridae family, a group of dinosaurs known for their domed skulls.
  5. The unique cranial structure suggests that it might have used its head for display or combat, indicating a complex social structure.

Contemporary Dinosaurs

This Asian dinosaur shared this world with a fascinating cast of dinosaurs. Among them were the Protoceratops, Velociraptor, Oviraptor, and Pinacosaurus, each contributing to the intricate dynamics of their shared environment. 

Consider the Protoceratops, a creature considerably smaller than the Tylocephale. Despite its smaller size, the Protoceratops was no less significant in the ecosystem. Its presence might have influenced the behavior of the Tylocephale, perhaps even shaping its feeding habits or territorial instincts. The herbivorous Protoceratops could have been a competitor for resources or perhaps even a prey item for larger predators, thereby indirectly affecting the survival strategies of the Tylocephale. Another potential competitor would have been the armored Pinacosaurus. These two herbivores would have had very different survival strategies, and yet they both fought to survive off the same resources in the same environment.

Then there was the Velociraptor–a dinosaur known for its agility and cunning. The Velociraptor’s coexistence with the Tylocephale paints a picture of a dynamic environment where speed and intelligence often trumped size and strength. The domed skull and robust body of the Tylocephale might have been an imposing figure to the smaller Velociraptor. Yet, these two dinosaurs shared the same world despite being so different in form and habit, each influencing the other in ways we can only begin to understand.

The Oviraptor too, was part of this fascinating prehistoric tableau. With its toothless beak and nimble fingers, the Oviraptor added further complexity to the Tylocephale’s world by providing a contrast to its own way of life. Through this exploration of these dinosaurs, we gain a deeper understanding of the Tylocephale’s existence–not as an isolated entity, but as a key player in a vibrant and dynamic prehistoric world.

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 ‘swelling head’ and is a reference to its distinctive cranial structure.

What did this dinosaur eat?

It was an herbivore, feeding on the diverse plant life of the Late Cretaceous period.

When did it live?

It lived during the Late Cretaceous period, specifically from the Middle Campanian to Late Campanian epoch, around 83.5 to 70.6 million years ago.

Where were the fossils found?

The first fossils were discovered in the Barun Goyot Formation in Mongolia.

What group does it belong to?

This dinosaur is a member of the Ornithopod group and the Pachycephalosaurid family.

Who first described this species?

It was first described by Teresa Maryańska and Halszka Osmólska  in 1974.


Article last fact checked: Joey Arboleda,06-14-2023

Featured Image Credit: ABelov2014, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons