Elmisaurus: The Foot Sole Lizard of the Late Cretaceous

Elmisaurus: The Foot Sole Lizard of the Late Cretaceous

In this post, we will be covering a dinosaur known as the Elmisaurus. While it is a name that may not be as familiar as the T-Rex or the Diplodocus, however it is no less intriguing. This journey is not just about exploring the past; it’s about understanding the intricate web of life that existed millions of years ago. 

The Elmisaurus, with its unique foot structure and place in the Theropoda group, offers a glimpse into the diversity and complexity of life during the age of dinosaurs. So, let’s step back in time and discover the story of the ‘foot sole lizard’.

Key Facts

Elmisaurus pronunciationelm-ee-saw-ruhs
Meaning of nameFoot sole lizard
Type SpeciesElmisaurus rarus
When it Lived72.1 to 66.0 MYA
PeriodLate Cretaceous
Length6.6 ft
Height2.6 ft
Weight0.02 tons
MobilityMoved on two legs
First Discovery1970 by Polish-Mongolian Palaeontological Expedition
Location of first findOmnogov, Mongolia
First Described by1981 by Halszka Osmólska
HolotypeZPAL MgD-I/172

Elmisaurus Origins, Taxonomy and Timeline

"Illustration of Elmisaurus, a Late Cretaceous theropod dinosaur known for its bird-like appearance. This omnivorous dinosaur, characterized by its long neck, beak-like mouth, and feather-like structures, is shown in a dynamic bipedal stance.

The Elmisaurus, whose name interestingly translates to “foot sole lizard,” is a captivating creature from the annals of prehistoric life. The name is derived from the Mongol word ‘elmyi’ or ‘ölmyi,’ which means “foot sole,” and the Greek word ‘sauros,’ meaning “lizard.” This unique nomenclature was chosen due to the dinosaur’s distinctive foot structure, which was among the first of its remains to be discovered.

In the grand scheme of dinosaur taxonomy, it falls under the Theropoda group–specifically the Caenagnathidae family. The genus is represented by a single type species, Elmisaurus rarus. This classification places it among the bipedal dinosaurs known for their bird-like features and carnivorous or omnivorous diets.

It lived during the Late Cretaceous period, specifically the Maastrichtian epoch. This places its existence in a time when dinosaurs were the dominant terrestrial vertebrates. The Late Cretaceous period was the last segment of the Age of Dinosaurs, ending with the mass extinction event that wiped out about three-quarters of the earth’s species.

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Discovery & Fossil Evidence

This dinosaur first came to light during a Polish-Mongolian Palaeontological Expedition in 1970, in the Omnogov region of Mongolia. This expedition unearthed two fragmentary specimens of a small theropod, which were later identified as belonging to this genus. The type species, Elmisaurus rarus, was named and described by Polish paleontologist Halszka Osmólska in 1981. The specific name ‘rarus’ translates to “rare” in Latin, perhaps indicating the scarcity of its fossils.

Fossilized claws of Elmisaurus, a theropod dinosaur from the Late Cretaceous period. These sharp, curved claws are indicative of the dinosaur's predatory lifestyle, likely used for hunting and gripping prey. The image provides a close-up view of the fossilized remains, showcasing the distinct shape and texture of the claws.
Ghedoghedo, CC BY-SA 3.0, via Wikimedia Commons

The holotype consists of a left metatarsus fused with the tarsalia. Two paratypes were also identified: one consisting of a right hand and foot and another of the upper part of the left metatarsus of a larger individual. These specimens provided the first insights into the physical characteristics of this dinosaur, particularly its unique foot structure.

Further studies have been conducted on these fossils, including a 2001 study by Bruce Rothschild and other paleontologists. They examined 23 foot bones referred to Elmisaurus for signs of stress fracture, but none were found. This lack of stress fractures could suggest certain lifestyle aspects of the Elmisaurus, such as its movement patterns and hunting behavior.

Elmisaurus Size and Description

Before we delve into the physical characteristics of this dinosaur, it’s important to note that our understanding of this dinosaur is primarily based on the limited fossil evidence available. As such, some aspects of its appearance and size are subject to interpretation and ongoing research.

Short Description of Elmisaurus

This was a small theropod–a group of dinosaurs known for their bipedal stance and often carnivorous or omnivorous diets. Its unique foot structure, as indicated by its name, is one of its most distinguishing features. It moved on two legs as is typical for theropods. Unfortunately, due to the limited fossil evidence, detailed descriptions of its body shape, head, neck, vertebrae, limbs, tail, and skin remain largely speculative.

Size and Weight of Type Species

Estimating the size and weight is a challenging task due to the limited fossil evidence. The available fossils primarily consist of foot and hand bones, which provide limited information about the overall size of the dinosaur. As such, any size and weight estimates would be largely speculative and subject to change as new discoveries are made. However, as a small theropod, it’s likely that this was not among the larger dinosaurs of its time.

The Dinosaur in Detail

Silhouette of Elmisaurus rarus, the type species of Elmisaurus, showcasing its distinct theropod anatomy. This image highlights the dinosaur's bipedal stance, long tail, and notable limb proportions.
Jaime A. Headden, CC BY 3.0, via Wikimedia Commons

The Elmisaurus, despite its relatively obscure status in the dinosaur world, holds a unique place in the annals of paleontology. Its distinctive foot structure sets it apart from many other dinosaurs and offers intriguing insights into its lifestyle and behavior. The fused metatarsus and tarsalia in the holotype specimen suggest a highly specialized foot design. This foot was possibly adapted for a specific type of movement or hunting strategy.

Notable specimens include the paratypes which consist of a right hand and foot and the upper part of a left metatarsus, respectively. A paratype is an additional specimen that helps define a species alongside a holotype. These specimens have contributed significantly to our understanding of the Elmisaurus by providing valuable information about its physical characteristics and potential behavior.

This dinosaur, like all dinosaurs, was a product of its environment. It adapted and evolved to survive in the Late Cretaceous period. Its unique features reflect its adaptability and survival instincts. Its unique foot structure may have been an adaptation for a highly specialized hunter that was adept at capturing specific types of prey.

The Elmisaurus in its Natural Habitat and Environment

This dinosaur lived during the Late Cretaceous period in a time when the Earth was undergoing significant changes. The climate during this period was warm with high sea levels and a lack of polar ice caps. This would have resulted in a variety of lush, green environments for the Elmisaurus to inhabit.

As a theropod, this dinosaur was likely a carnivore or omnivore that hunted smaller animals and possibly scavenged for food. Its unique foot structure may have been an adaptation for a specific type of hunting or movement, allowing it to navigate its environment with ease.

These unique features reflect its adaptability and survival instincts, providing us with a glimpse into the life of this fascinating dinosaur.

Interesting Points about Elmisaurus

  1. This is one of the few dinosaurs known primarily from its feet. This unique circumstance has led to a greater understanding of dinosaur foot structure and its implications for behavior and lifestyle.
  2. It belongs to the Caenagnathidae family, which is part of the larger group known as Oviraptorosauria. This group is known for its bird-like features, including beaked mouths and likely feathered bodies.
  3. Despite the limited fossil evidence, it has contributed significantly to our understanding of small theropods and their adaptations.
  4. It lived during the Late Cretaceous period, a time of significant change and diversification in the dinosaur world just before their extinction.
  5. The name translates to ‘foot sole lizard’, highlighting the unique foot structure that sets this dinosaur apart from others.

Contemporary Dinosaurs

The Elmisaurus shared its world with a captivating array of contemporaries. These fellow dinosaurs were each unique in their own right, their lives intertwined in a delicate balance of survival and competition.

Imagine, if you will, the Elmisaurus navigating its world alongside the Conchoraptor. This smaller contemporary, while not as physically imposing, was no less a part of this intricate ecosystem. Despite their size difference, they may have competed for similar resources with their survival hinging on their ability to adapt and thrive in a shared environment.

Now, consider the Oviraptor and Protoceratops, two other contemporaries of the Elmisaurus. The Oviraptor was known for its bird-like features and the Protoceratops was a smaller relative of the Triceratops. Each brought their own unique traits to this prehistoric landscape. The distinctive characteristics of the Elmisaurus may have allowed it to interact with these dinosaurs in a myriad of ways, from competition for food to evasion of predators.

Finally, the Velociraptor–a dinosaur known for its speed and agility–shared this ancient world with the Elmisaurus. The Velociraptor was a predator that may have posed a threat to the Elmisaurus, adding another layer of complexity to the Elmisaurus’s existence. This dynamic paints a vivid picture of the Elmisaurus’s life, a testament to the intricate web of relationships that defined its existence in 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 ‘foot sole lizard’, highlighting the unique foot structure of this dinosaur.

When did the Elmisaurus live?

It lived during the Late Cretaceous period, approximately 70 million years ago.

What did it eat?

As a theropod, it was likely a carnivore or omnivore that hunted smaller animals and possibly scavenged for food.

How big was this dinosaur?

The exact size is unknown due to the limited fossil evidence. However, as a small theropod, it’s likely that it was not among the larger dinosaurs of its time.

What makes the Elmisaurus unique?

It is unique due to its distinctive foot structure, which sets it apart from many other dinosaurs.


Please note that 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 Elmisaurus, but please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

This article was last fact-checked: Joey Arboleda, 06-11-2023

Featured Image Credit: FunkMonk (Michael B. H.), CC BY-SA 3.0, via Wikimedia Commons