Wannanosaurus was a quite small pachycephalosaur dinosaur that roamed the lush landscape of modern day China during the tail end of the Late Cretaceous Period. The first and only specimen was discovered in the seventies so this dinosaur was possibly quite rare. Another possibility is that we have so far just been unlucky with regsrds to finding its fossilized remains.

Wannanosaurus Key Facts

Wannanosaurus Taxonomy and Timeline

Wannanosaurus got its name from the location of its discovery–Wannan in China.  

Belonging to the Ornithopoda group and the Pachycephalosauridae family, its type species is Wannanosaurus yansiensis. W. yansiensi is a unique dinosaur, the only species of the genus, and the based on only a single find ( so far).

This classification places the Wannanosaurus in a group of dinosaurs known for their bipedal stance and (mostly) herbivorous diet. However, some pachycephalosaurs are believed to have been omnivore, which might have been the case whit W. yansiensis as well.

This timeline is set in the Late Cretaceous period, specifically the Early/Lower Maastrichtian epoch, some 70.6 to 66 million years ago. This places its existence around a time when the Earth was teeming with diverse life forms and dinosaurs were a dominant presence.

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Discovery & Fossil Evidence

Wannanosaurus was first discovered in 1972 by Hou Lian-Hai in Anhui, China. This has so far been the only discovery of any remains identified with this species.

The first described specimen, known as the holotype IVPP V 4447, was a partial skeleton that included a partial skull roof, lower jaw, a femur, a tibia, part of a rib, and other fragments. The fused bones in its skull suggest that, despite its small size, it was indeed an adult at death.

The discovery has provided valuable insights into the diversity of dinosaur species during the Late Cretaceous period. The fossils found have been instrumental in understanding the physical characteristics and lifestyle of this dinosaur.

The degree of preservation of the fossils has allowed for a detailed study of its physical characteristics. The flat skull roof with large openings, for instance, has led to it being considered primitive among pachycephalosaurs. This unique feature, along with the other fossil evidence, has contributed significantly to our understanding of this fascinating dinosaur and its relatives.

Wannanosaurus Size and Description

It is known for its flat skull roof with large openings, a feature that is considered primitive among pachycephalosaurs. It moved on two legs and most likely had an herbivorous diet, possibly it was an omnivore.

Despite its small size, this dinosaur was able to thrive in a diverse ecosystem and feed on a variety of plant matter and possibly insects. Its bipedal stance allowed it to move swiftly, aiding in its survival.

The partial skeleton discovered includes a femur and tibia that suggest a bipedal stance. The physical characteristics, including its body shape, head, neck, vertebrae, limbs, and tail, provide insights into its lifestyle and survival strategies.

Size and Weight of Type Species

This is one of the smaller dinosaurs with an overall length of about 2 feet and a height likely less than half that. The femur length of the discovered specimen is approx. 3.1 inches. American paleontologist Thomas Holtz have estimated the weight as similar to that of a turkey, so likely around 8 to 12 lbs.

Wannanosaurus in its Natural Habitat

This dinosaur thrived in the diverse ecosystems of modern day Chinas’ Late Cretaceous period. The environment during this time was characterized by lush vegetation and a variety of other life forms. With its herbivorous diet, it would have fed on the abundant plant life in its environment.

The bipedal stance suggests that it was a swift mover capable of navigating its environment with ease. This would have been crucial for its survival by allowing it to evade predators and access food sources. Its diet likely consisted of a variety of plant matter and possibly insects, reflecting the biodiversity of its environment.

Despite its small size, this was a resilient creature. Its survival in a diverse ecosystem during the Late Cretaceous period is a testament to its adaptability. Its lifestyle and survival strategies, as inferred from its physical characteristics and fossil evidence, provide fascinating insights into life during this period.

Interesting Points about Wannanosaurus

Contemporary Dinosaurs

This tiny dinosaur shared its world with a diverse array of contemporaries. Among them were Psittacosaurus, Shantungosaurus, and Troodon, each occupying different parts of the environment to work with and against the Wannanosaurus.

Psittacosaurus was a dinosaur considerably larger than Wannanosaurus that may have been a potential competitor for resources. Yet, with its compact size and agility, Wannanosaurus might have navigated the dense vegetation of their shared environment with greater ease to access food sources out of reach for its larger contemporary. Shantungosaurus was a true titan among dinosaurs that towered over Wannanosaurus. Despite their size difference, these two herbivores likely coexisted peacefully, their diets likely consisting of different plant types–thus reducing competition.

Troodon, with its keen intellect and sharp claws, presents an interesting contrast to Wannanosaurus. As a potential predator, Troodon might have viewed the small Wannanosaurus as prey. However, Wannanosaurus may have been able to use its small size and agility to slip away from this predator. This dynamic interplay between hunter and potential prey adds a layer of complexity to our understanding of Wannanosaurus’s existence, painting a vivid picture of life in the 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

Sources

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

Article last fact checked:Joey Arboleda, 01-15-2025

Featured Image Credit: Jack Mayer Wood, CC BY-SA 4.0, via Wikimedia Commons