Imagine stepping back in time, about 150 million years ago, to the Late Jurassic period. The landscape is teeming with unusual life and among the diverse array of creatures, a particular dinosaur stands out: the Aviatyrannis. This intriguing dinosaur has an even more intriguing name that translates to ‘Grandmother Tyrant’, and is a captivating subject for anyone interested in paleontology.

Aviatyrannis Key Facts

Aviatyrannis Origins: Taxonomy, Timeline, and Discovery

The name Aviatyrannis, which translates to ‘Tyrant’s grandmother’, is derived from Latin. The term ‘avia’ means ‘grandmother’, and ‘tyrannus’ translates to ‘the tyrant’. This dinosaur belongs to the theropod group, specifically the Tyrannosauridae family. The type species of this genus is Aviatyrannis jurassic.

This carnivore lived during the Late Jurassic period, specifically the Kimmeridgian epoch, a time when the Earth was a vastly different place than it is today.

The first discovery of Aviatyrannis was made in the year 2000 by the paleontologists Oliver Walter and Mischa Rauhut. The find was made in Leiria, Portugal, and Walter and Rauhut also described the dinosaur for the first time in 2003.

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Fossil Evidence

The first fossils were discovered in the lignite coal mine of Guimarota, near Leiria, Portugal. The discovery included tyrannosauroid material that was initially referred to as Stokesosaurus. However, the distinctiveness of the material justified a separate genus, leading to the name Aviatyrannis jurassic.

The holotype, IPFUB Gui Th 1, was found in a layer of the Alcobaça Formation dating from the early Kimmeridgian, about 155 million years old. It consists of a right ilium. Rauhut in 2003 referred two other bones to Aviatyrannis: IPFUB Gui Th 2, a partial right ilium, and IPFUB Gui Th 3, a right ischium. The referred elements represent slightly larger individuals. Additionally, sixteen isolated teeth were referred: IPFUB GUI D 89–91: three teeth of the premaxilla, and IPFUB GUI D 174–186: thirteen teeth of the maxilla and dentary.

Aviatyrannis Size and Description

Aviatyrannis was a small, bipedal predator—a characteristic feature of early tyrannosauroids. Its body was likely streamlined for efficient movement, with a long tail for balance. The dinosaur’s head would have been home to sharp, elongated teeth, perfect for gripping prey. Its discovery has also led to some interesting hypotheses. For instance, some of the specimens initially referred to as Stokesosaurus might belong to Aviatyrannis. This highlights the complex and often overlapping nature of dinosaur taxonomy, reminding us that our understanding of these prehistoric creatures is constantly evolving.

Short description of Aviatyrannis

Aviatyrannis is a fascinating dinosaur, not just because of its small size but also due to its unique features. As an early tyrannosauroid, it provides valuable insights into the evolution of this group of dinosaurs. The holotype specimen, for example, is an ilium only ninety millimeters long. In 2016, Gregory S. Paul estimated size based on this specimen and suggested that the holotype possibly belongs to a juvenile. The ilium is elongated and low, with the typical tyrannosauroid vertical ridge on the outer blade surface above the hip joint. This is not the only fossil evidence that hints at its lifestyle, however. Its teeth were built for a predatory lifestyle of tearing through prey and have their own unique shape and build.

Size and Weight of Type Species

As per the estimates of Gregory S. Paul in 2016, Aviatyrannis was approximately 3.3 ft long and weighed around 8-10 lbs. This estimation is based on the holotype specimen, which is an ilium only ninety millimeters long. However, it’s worth noting that this specimen possibly belongs to a juvenile, suggesting that adult Aviatyrannis could have been slightly larger. Despite this, it was still a rather small dinosaur, especially when compared to its later tyrannosaurid relatives.

The Dinosaur in Detail

While the size of this dinosaur may be typical for its relatives, it has several traits that make it distinct as well. Its teeth, for instance, are particularly interesting. The premaxilla teeth have a D-shaped cross-section, a feature not commonly seen in other dinosaurs. This unique dental structure might have given Aviatyrannis an edge when it came to hunting and feeding. The maxillary and dentary teeth, found in the main body of the upper jaw and the lower jaw, respectively, were elongated and recurved near the top. They also had perpendicular denticles on both edges, which would have made them effective tools for tearing flesh.

The ilium is another feature that sets it apart. It’s elongated and low, with a vertical ridge on the outer blade surface above the hip joint. This is a typical tyrannosauroid feature and is indicative of the dinosaur’s bipedal locomotion. The ilium’s structure would have allowed for the attachment of strong muscles, aiding in the dinosaur’s movement.

The Aviatyrannis in its Natural Habitat and Environment

This dinosaur lived in Europe during the Late Jurassic period, a time when the Earth was an unrecognizable place compared to today. The climate was likely warm and humid with lush vegetation covering the landscape. As a carnivore, Aviatyrannis would have been a predator, hunting smaller animals for food. Its sharp, elongated teeth would have been perfect for gripping prey and tearing flesh.

The dinosaur’s bipedal locomotion and smaller size suggest that it was a fast and agile hunter. It would have moved on two legs and used its long tail for balance. This would have allowed it to navigate the dense vegetation of its environment and chase after prey.

While not much is known about the social behavior of Aviatyrannis, it’s possible that it was a solitary hunter, like many other theropods. However, this is purely speculative, and more research is needed to confirm it.

Interesting Points about Aviatyrannis

Contemporary Dinosaurs

This predator could be found both hunting and prey and competing with other predators. These European dinosaurs, each with their own unique traits, were part of a complex ecosystem that intertwined their lives in a delicate balance of survival and competition.

The Allosaurus, a larger carnivorous dinosaur, was a formidable presence. Its size and predatory nature might suggest a potential threat to Aviatyrannis. Yet, the Aviatyrannis could have used its smaller size and agility to navigate the landscape with a nimbleness that allowed it to coexist and possibly even evade this larger predator. The Ceratosaurus, another carnivorous contemporary, adds another layer to this back-and-forth between predator and prey. Its distinctive horn and large body size set it apart, yet it shared the same world as the Aviatyrannis and Allosaurus.

The Stegosaurus and Hylaeosaurus, both herbivores, present an interesting contrast to the Aviatyrannis. While they would not have been direct competitors for food, their presence would have contributed to the overall dynamics of the environment. The Aviatyrannis might have observed these larger dinosaurs from a distance, their interactions providing valuable insights into the behaviors and habits of different species. This coexistence paints a picture of a diverse and vibrant ecosystem where each creature, from the smallest Aviatyrannis to the largest Ceratosaurus, played a crucial role. Through this lens, we can begin to appreciate the complex and fascinating world in which the Aviatyrannis lived.

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Article last fact checked: Joey Arboleda, 06-08-2023

Featured Image Credit: IJReid, CC BY 4.0, via Wikimedia Commons