Timimus: A Small Yet Agile Predator from Australia’s Early Cretaceous

Timimus was a theropod dinosaur that roamed the ancient landscapes of what is now southern Australia during the Early Cretaceous. Though smaller in size compared to its more famous relatives like Tyrannosaurus rex, this nimble dinosaur holds an important place in paleontological studies. Its discovery helped shed light on the diversity of predators in the southern hemisphere. Particularly during a period when many parts of the world were ruled by massive carnivores. Timimus lived at a time when Australia was very close to Antarctica. Providing a fascinating glimpse into a time when polar dinosaurs existed.

Timimus Key Facts

KeywordFact
PronunciationTIE-muh-mus
Meaning of nameTim’s Mimic
GroupTheropoda (Coelurosauria)
Type SpeciesTimimus hermani
DietCarnivore
When it Lived112.03 to 109.0 MYA
PeriodEarly Cretaceous
EpochAlbian
Length14.0 feet
HeightApproximately 4.0 feet at the hips
Weight441.0 pounds
MobilityMoved on two legs
First Discovery1991, by Dr. Thomas Rich and Patricia Vickers-Rich
Described by1993/1994, by Dr. Thomas Rich and Patricia Vickers-Rich
HolotypeNMV P186303
Location of first findDinosaur Cove East, Otway Ranges, Victoria, Australia

Timimus Origins, Taxonomy, and Timeline

The generic name Timimus, as mentioned earlier, translates to “Tim’s mimic.” As is so often the case in taxonomy, this name acts as a homage – in this case to the discoverer’s son, Timothy Rich, and the famous Australian paleontologist Timothy Flannery, who has made significant contributions to the study of early mammals. The specific name, “mimus,” follows a convention found in ornithomimosaurs, meaning “mimic” in Greek. While this may initially suggest that Timimus was a typical member of the “bird-mimicking” group, later examination suggested a place among the tyrannosauroids, a family of theropod dinosaurs that also includes the famous T. rex.

Timimus, a Nimble Tyrannosauroid from the Early Cretaceous, Roamed the Ancient Landscapes of Southern Australia as a Skilled Predator.

Within Theropoda,Timimus can be confidently placed within the Coelurosauria, a broad clade of dinosaurs that includes a staggering variety of forms – ranging from lumbering mega-predators to modern-day birds. With Timimus provisionally assigned to the smaller clade Tyrannosauroidea, it’s easy to associate it with the massive, fearsome predators the name evokes. However, this smaller member of the group offers a different picture.

The holotype specimen that defines this species, NMV P186303, while represented by a single leg bone, provides paleontologists with key anatomical details that have helped distinguish it from other theropods in the region. Timimus lived during the Early Cretaceous Period, specifically in the Lower Albian Epoch, which dates to between 112.03 and 109 million years ago. This era was marked by significant geological changes, as the ancient landmass that included Australia was still in the process of splitting from Antarctica. This time frame provides valuable context for understanding the dinosaur’s adaptability to a cooler, polar environment.

Discovery & Fossil Evidence

In 1991, two femora—one from an adult and one from a juvenile—were discovered at Dinosaur Cove East in the Otway Ranges of Victoria, Australia, by a team led by Dr. Thomas Rich and Patricia Vickers-Rich. These fossils were found within a meter of each other in a small quarry called “Lake Copco.” The discovery was part of a broader excavation in a region known for its Early Cretaceous fossil deposits. Timimus, a species initially classified as an ornithomimosaur, was formally named Timimus hermani in 1993/1994 by the Riches, honoring both their son, Timothy Rich, and paleontologist Tim Flannery.

Timimus hermani (NMV P186303; holotype) left femur in posterior view.
Timimus hermani (NMV P186303; holotype) left femur in posterior view.
Stephen F. Poropat, Phil R. Bell, Lachlan J. Hart, Steven W. Salisbury, & Benjamin P. Kear, CC BY-SA 4.0, via Wikimedia Commons

Holotype

The holotype, NMV P186303, consists of the left femur of an adult individual and was found in the Eumeralla Formation, dating to the Albian Stage of the Early Cretaceous, approximately 106.0 million years ago. Though a partial fossil, this femur provided enough material for a provisional classification and has been pivotal in studying theropod diversity in Gondwana. Additionally, the second femur found, belonging to a juvenile, was assigned as the paratype (NMV P186323), though later studies suggest that it might represent a different dinosaur species, possibly an indeterminate maniraptoran, based on observed differences between the two bones.

Despite initial classification as an ornithomimosaur, later examination suggested a tyrannosauroid affinity for Timimus: still coelurosaurian, but a significant shift in understanding its evolutionary position nonetheless. Other fragments, such as vertebrae found at the site, have been tentatively linked to Timimus, though no major discoveries have been reported since. In 1994, Dr. Thomas Rich remarked that future findings of Timimus fossils were unlikely, given the limited excavation opportunities in the area, and emphasized the importance of coherent naming for clarity in paleontological records. His comments underscore how names serve as “handles” for better communication about fossil material, even when dealing with incomplete specimens.

Timimus Size and Description

Timimus, like many theropods, was built for agility and speed. Its body was relatively lightweight, with long legs that suggest it was a fast runner. The head of this dinosaur was likely modest in proportion to its body, much like other early tyrannosauroids, with a mouthful of sharp teeth suited for a carnivorous diet. Its neck would have been somewhat flexible, and the overall body shape was streamlined, enabling swift movement. Though we lack direct fossil evidence of its skin or external features, it’s possible that Timimus, like many theropods, had a partial covering of feathers or proto-feathers.

The long, powerful hindlimbs of Timimus were adapted for quick movement. Like other, more primitive tyrannosaurids, its forelimbs probably had not undergone the extreme reduction seen in larger, more derived members of the group, likely retaining some functionality in grasping prey once it got in close. Its tail would have been used as a counterbalance, enabling swift turns and changes in direction while running.

Size and Weight of Type Species

Skeletal reconstruction of Timimus hermani, an enigmatic Australian coelurosaur.
Slate Weasel, CC BY 4.0, via Wikimedia Commons

Based on the fossil evidence available, it is estimated that Timimus hermani stood about 4.0 feet at the hips. Measuring approximately 14.0 feet in length from head to tail. In terms of weight, this dinosaur likely weighed around 440.0 pounds. Making it a fairly modest size compared to some of its larger theropod relatives. 

Comparatively, Timimus would have been larger than some of its contemporaries, such as the herbivorous Atlascopcosaurus, but much smaller than the long-necked Austrosaurus, a sauropod that roamed the same region. Its body structure indicates that it was a capable predator, though it likely relied on speed rather than brute strength to catch its prey.

The Dinosaur in Detail

Timimus stands out for its adaptation to a relatively cold climate, a rarity among dinosaurs. During the Early Cretaceous, southern Australia experienced long winters with extended periods of darkness, as it was located much closer to Antarctica. This suggests that Timimus had to adapt to cooler temperatures and possibly a more seasonal availability of prey. The possibility of it having a feathered body covering aligns with theories that many theropods were at least partially covered in feathers for insulation. Particularly those living in colder environments. There is also the suggestion – based on the stop-start nature of its bone histology – that it may have hibernated over the cooler months, conserving energy during the cooler months.   

Another interesting aspect of Timimus is its place within the tyrannosauroid family. While unlikely to be a direct ancestor of the infamous Tyrannosaurus rex, Timimus shares certain features that hint at its evolutionary path. The long, slender legs, for example, are a trait seen in some of the more primitive members of this group. As opposed to the massive, powerfully built hind legs of later tyrannosaurids.

Finally, the discovery of Timimus in Australia adds to the growing evidence that the southern continents, which formed part of Gondwana during the Cretaceous, hosted a diverse range of theropods. Timimus represents a significant piece of this puzzle. Offering insights into how theropods diversified and adapted to different environments across the globe.

Contemporary Dinosaurs

In the ancient landscapes of southern Australia, Timimus wasn’t alone in its Cretaceous world. One of its contemporaries was Atlascopcosaurus, a nimble herbivore that likely shared the same forests and plains. Named in honor of the Atlas Copco company that supported its excavation. Atlascopcosaurus was a small, bipedal ornithopod that thrived on the lush vegetation of the time. While Timimus roamed as a swift predator, Atlascopcosaurus may have had to rely on its agility to escape its larger, meat-eating neighbors. This small dinosaur, though modest in size, was a quick runner. A skill that probably served it well when faced with predators like Timimus.

Sharing this same habitat was the giant Austrosaurus, a towering sauropod that dwarfed all other dinosaurs in its vicinity. With its massive frame and long neck, Austrosaurus was a herbivore on a grand scale. Grazing on the treetops that other dinosaurs couldn’t reach. Though Timimus was far too small to challenge this colossus when fully grown, its hatchlings and juveniles would surely have been fair game. Timimus’ relationship with larger Austrosaurus was likely of a more opportunistic variety. When one of these behemoths fell due to illness or old age, its carcass would have provided a feast for scavengers like Timimus.

Not all dinosaurs in this region were giants. Diluvicursor, another contemporary of Timimus, was a small, swift herbivore. Similar in size to Atlascopcosaurus but with a more specialized diet. Where Timimus might have been chasing after prey or scouring the forest for smaller creatures, Diluvicursor would have been darting through the underbrush, foraging for low-lying plants. Both species shared an aptitude for speed. However, their purposes were quite different—Timimus hunted, while Diluvicursor focused on survival through evasion. Despite occupying different roles in the food chain, these dinosaurs would have shared the same spaces.

Interesting Points about Timimus

Timimus in Its Natural Habitat

Timimus roamed southern Australia during the Early Cretaceous Period, a time when this region was much closer to Antarctica. The climate was cooler than most dinosaur environments, marked by long, harsh winters with extended periods of darkness. Forests of conifers, ferns, and cycads likely dominated the landscape. Creating a dense, green environment that provided shelter and hunting grounds for Timimus. The rivers and lakes scattered across the area would have been vital sources of water for the various dinosaurs that called this region home.

As a carnivore, Timimus would have preyed on smaller herbivorous dinosaurs, as well as possibly scavenging from the carcasses of larger animals. Its lightweight build and long legs indicate that it was well-suited to chase down fast-moving prey like small ornithopods. Its agility and speed would have been essential for survival in this predator-prey dynamic. Larger theropods could certainly have posed a threat to Timimus. The harsh, seasonal climate may have required Timimus to adapt its hunting patterns throughout the year,. Likley focusing on different prey sources as availability shifted.

In terms of social behavior, it is unclear whether Timimus was a solitary hunter or lived in small groups. However, given its size and predatory nature, it may have hunted alone, relying on stealth and speed. Its senses, especially vision and smell, were likely highly developed. Aiding it in hunting, particularly in the dim winter months when daylight was scarce. Timimus would have played a crucial role in controlling the populations of smaller dinosaurs and other prey animals. Subsequently helping to shape the balance of its ecosystem.

Frequently Asked Questions

What did this dinosaur eat?

Timimus was a carnivore, likely preying on smaller dinosaurs, small vertebrates, and possibly scavenging carcasses in its habitat.

How big was this dinosaur?

The adult, holotypic specimen of Timimus was about 14.0 feet long and approximately 4.0 feet tall at the hips.

Where did this dinosaur live?

Timimus lived in southern Australia during the Early Cretaceous Period. At that time the region was cooler and closer to Antarctica, experiencing long winters.

Was this dinosaur fast?

Yes, Timimus had long, slender legs that suggest it was a swift runner. Probably relying on its speed to chase prey or escape larger predators.

Did this dinosaur live in groups?

It is unclear if Timimus lived in groups. However, given its predatory nature and size, it may have been a solitary hunter.

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 Timimus.

Article last fact checked: Joey Arboleda, 09–22–2024

Featured Image Credit: Jurassic Park Institute

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