Ankylosaurs battled each other using their tail clubs for social dominance in intraspecific combat. A recently published scientific paper on the ankylosaur Zuul crurivastator suggests that these armoured dinosaurs used their tail clubs to bash each other as well as to fend off tyrannosaurs.

In the study, published in “Biology Letters” the research team, examined the osteoderms of the remarkably well preserved Zuul crurivastator, an armoured dinosaur described from fossils found in the Coal Ridge Member of the Judith River Formation (Montana). Several of osteoderms along the flanks show signs of damage and healing which led the scientists to postulate that these dinosaurs battled each other with their tail clubs. These fights would have been for social or territorial dominance, perhaps even a result of a “rutting” season fighting for mates – behaviour associated with many mammals today.

Zuul crurivastator

Named and formally described in 2017, Zuul crurivastator (pronounced Zoo-ul cruh-uh-vass-tate-or) roamed the northern part of Laramidia approximately 76 million years ago (Campanian faunal stage of the Late Cretaceous).

To read Everything Dinosaur’s 2017 blog post about the fossil discovery: Zuul – The Destroyer of Shins.

Zuul’s body was covered in bony plates (osteoderms) of different shapes and sizes and the ones along its flanks were particularly large and spiky. Interestingly, the scientists which included lead author and renowned ankylosaur expert Dr Victoria Arbour (Royal British Columbia Museum, Canada), noted that dermal armour near the hips on both sides of the body showed damage that had subsequently healed. This localised, bilaterally symmetrical pathology is speculated to have been caused by ritualised combat rather than wounds inflicted by an attacking theropod dinosaur.

An Exciting Piece of the Ankylosaur Puzzle

Dr Arbour commented:

“I’ve been interested in how ankylosaurs used their tail clubs for years and this is a really exciting new
piece of the puzzle. We know that ankylosaurs could use their tail clubs to deliver very strong blows to an opponent, but most people thought they were using their tail clubs to fight predators. Instead, ankylosaurs like Zuul may have been fighting each other.”

The genus name honours a fictional monster from the 1984 film “Ghostbusters”, whilst the trivial part of the binomial name translates as “the destroyer of shins”, a nod to the idea that tail clubs were used as defensive weapons to deter attacks from predatory theropod dinosaurs. The substantial club on the end of the three-metre-long tail being used to bash into the lower legs of tyrannosaurs. This new research does not refute the idea that these tail clubs had a role in defence, but based on the pathology seen in the Zuul holotype (specimen number ROM 75860) the scientists propose that sexual selection and intraspecific combat drove their evolution. Many mammals today such as deer, antelope, cattle and sheep have horns and antlers that have evolved for use in battles between members of the same species.

It had been suggested previously that ankylosaurs may have clubbed each other, and that broken and healed ribs could provide evidence to support this idea. Unfortunately, ankylosaurid skeletons are extremely rare in the fossil record, these animals were not common, even in the Late Cretaceous of North America, where the ecosystem was dominated by other ornithischian dinosaurs such as duck-billed dinosaurs and ceratopsians.

Implications for Ankylosaur Behaviour

The remarkable Zuul fossil skeleton provides palaeontologists with an opportunity to study pathology recorded on the bones and dermal armour.

Co-author Dr David Evans (Curator of Vertebrate Palaeontology at the Royal Ontario Museum) explained:

“The fact that the skin and armour are preserved in place is like a snapshot of how Zuul looked when it
was alive. And the injuries Zuul sustained during its lifetime tell us about how it may have behaved and
interacted with other animals in its ancient environment.”

Tail Clubs for Social Dominance

The researchers conclude that the imposing tail club of Zuul could have been used in defence when needed, but the analysis suggest that sexual selection drove the evolution of this weapon. This finding has consequences for how palaeontologists perceive ankylosaurs. It suggests that these dinosaurs were capable of complex behaviours and that they likely engaged in ritualised combat over mates or for social dominance as inferred in other types of dinosaurs and observed in living mammals and birds.

To view a replica of the armoured dinosaur Zuul and other prehistoric animal models (whilst stocks last): Armoured Dinosaurs and Prehistoric Animal Figures (Wild Safari).

Everything Dinosaur acknowledges the assistance of a media release from the Royal Ontario Museum in the compilation of this article.

The scientific paper: “Palaeopathological evidence for intraspecific combat in ankylosaurid dinosaurs” by Victoria M. Arbour, Lindsay E. Zanno and David C. Evans published in Biology Letters.

A new species of Chinese dromaeosaurid dinosaur has been described based on superbly preserved remains found in Inner Mongolia. The new dromaeosaurid species has been named Daurlong wangi and a phylogenetic assessment suggests that this dinosaur was closely related to Tianyuraptor and Zhenyuanlong.

Daurlong wangi

Described by the scientists, which include researchers from Chinese Academy of Geological Sciences and the Inner Mongolia Museum of Natural History, as a mid-sized dromaeosaurid, Daurlong is estimated to have been around 1.5 metres long. The nearly complete specimen comes from Lower Cretaceous exposures of the Longjiang Formation in the Morin Dawa Daur Autonomous Banner (Inner Mongolia). The fossilised remains were excavated from Pigeon Hill, apt as this feathered dinosaur was related to modern birds (Aves). Both birds and the Dromaeosauridae are members of the Eumaniraptora clade.

New Dromaeosaurid Species

The binomial scientific name for this new dromaeosaurid is derived from the indigenous Daur Nation and from the Chinese word for dragon. The species name honours the director of the Inner Mongolia Museum of Natural History, Mr Wang Junyou.

Finding a Frog

Some evidence of plumage is preserved along the top of the back of the skull, around the trunk and along the edges of the tail. The scientists writing in the academic journal “Scientific Reports” found no evidence of preserved melanosomes in association with the feather filaments.

A bluish layer located towards the back of the rib cage has been putatively described as remnants of the intestines. Such a soft tissue discovery would be exceptionally rare within the Dinosauria, and could help inform palaeontologists over the origins and evolution of the digestive tract of birds and other closely related genera.

The fossilised remains of a small frog were found in the same slab as the Daurlong specimen. Everything Dinosaur is not aware of any gut contents indicating that this small, meat-eater ate frogs, but it is very likely that Daurlong would have consumed amphibians such as frogs as well as lizards and small mammals.

The Beasts of the Mesozoic range of articulated prehistoric animal figures contains several examples of Cretaceous dromaeosaurids.

To view the Beasts of the Mesozoic range of models: Beasts of the Mesozoic Model Range.

The scientific paper: “Intestinal preservation in a birdlike dinosaur supports conservatism in digestive canal evolution among theropods” by Xuri Wang, Andrea Cau, Bin Guo, Feimin Ma, Gele Qing and Yichuan Liu published in Scientific Reports.

A world’s first complete fossil skeleton of a prehistoric reptile studied by scientists that was thought lost forever, has been re-discovered as researchers uncovered marine reptile casts. These casts, although replica copies of the actual fossils, can still provide palaeontologists with valuable information.

“Proteosaurus” Resurfaces

The fossilised remains of an ichthyosaur that was probably excavated by Mary Anning and named “Proteosaurus”, was destroyed in a German bombing raid in World War II. It had been assumed that this historically significant fossil had been lost to science, however, palaeontologists have identified two plaster casts held in collections outside of the UK, which reveal important new data. The casts were discovered by Dr Dean Lomax, a palaeontologist and Visiting Scientist at the University of Manchester, and Professor Judy Massare, from the State University of New York, Brockport, USA.

Dr Lomax in collaboration with renowned palaeoartist Bob Nicholls recently produced a book which looks at the astonishing direct evidence indicating the lives and behaviours of long-extinct animals that can be found in the fossil record. The book entitled “Locked in Time” can be found here (search on the website for author Dean Lomax): Columbia University Press.

Found in 1818

The ichthyosaur fossil was discovered in 1818 at Lyme Regis, Dorset, and almost certainly found by the famous pioneering palaeontologist Mary Anning. Named “Proteosaurus” the specimen was acquired by a prolific collector, Lt-Col. Thomas James Birch, who sold it to the Royal College of Surgeons, London in 1820, to raise funds for Mary Anning and her family who were struggling to pay their rent.

The fossil discovery came at a time when academics were beginning to scientifically study prehistoric animal remains, the sciences of geology and palaeontology were developing. Ichthyosaur fossils had been found earlier, but there was disagreement as to what the specimens represented. Each new fossil find was adding important information to the debate and the 1818 specimen was the most complete ichthyosaur skeleton found to date. It was examined by Sir Everard Home, a highly respected British surgeon, who published his findings in the journal of The Royal Society in 1819.

Unfortunately, the fossil was completely destroyed by a German air raid in May 1941, when the Royal College of Surgeons in London was bombed.

An Important Role in Establishing Palaeontology as a Scientific Discipline

Dr Dean Lomax commented:

“When research on this fossil was published, it was still more than twenty years before the word “dinosaur” would be invented. This and other early ichthyosaur finds sparked a major interest in collecting more of these curious, enigmatic creatures. The discoveries and research on ichthyosaurs played an important role in establishing palaeontology as a scientific discipline.”

Dr Lomax and Professor Massare have collaborated on numerous projects and have made several important discoveries whilst studying historic fossil collections. For example, in 2015, their research led to the naming of Ichthyosaurus anningae, the first, new Ichthyosaurus species to be named in nearly 130 years.

To read more about I. anningae: New Ichthyosaurus Species Named Honouring Mary Anning.

Discovery at the Peabody Museum

In 2016, whilst examining the marine reptile collection housed at the Peabody Museum (Yale University), Massare and Lomax found an extremely old replica cast of an ichthyosaur, which was subsequently identified as the first-known cast of the fossil studied by Sir Everard Home. Up until this point, there was no record of any casts of this significant ichthyosaur fossil.

The Museum Assistant in vertebrate palaeontology at the Peabody Museum, Daniel Brinkman explained:

“Peabody curatorial staff assumed that the specimen was a real ichthyosaur fossil and not a plaster cast painted to look like the original fossil from which it was moulded.”

The Yale University cast was purchased by Yale Professor Charles Schuchert, as part of a substantial collection of fossils from the estate of Frederick A. Braun, a professional fossil dealer, however, very little else is known about the cast. It is not known when Braun acquired it, or who made the cast.

The Berlin Discovery

In 2019, Dean Lomax visited the Natural History Museum in Berlin (Germany) to study their fossil collection and was surprised to find a second cast of the 1818 ichthyosaur. This replica was in much better condition than the Yale cast.

The scientific head of collections at the Natural History Museum (Berlin), Dr Daniela Schwarz commented:

“When Dr Lomax visited our collections, he kept asking me for information about this cast and I couldn’t help him very much because of missing records and labelling of the specimen. So, when I learned about the outcome of his detective work and that this important specimen’s cast now rested in our collections for more than a century, I was really stunned! This discovery once more demonstrates the necessity to carefully preserve also undetermined and casted material in a natural history collection for centuries, because in the end, there will always be someone who discovers its scientific value!”

Studying the Ichthyosaur Fossil Replicas

Studies of both casts have shown that they were made at two different times. The Yale cast might even be a very old cast made when the ichthyosaur was still in the possession of Lt-Col. Thomas James Birch.

Professor Massare said:

“In Home’s 1819 article, he illustrated the original skeleton. This drawing by William Clift was the only visual evidence we had of the ichthyosaur. Now, having two casts, we can verify the reliability of the original illustration by comparison with the casts. We have identified a couple of bones that Home missed, and found a few discrepancies between the drawing and the casts.”

This new study has been published today in the journal, Royal Society Open Science, one of the journals of The Royal Society, which ironically published the original paper on the discovery of the ichthyosaur fossil back in 1819.

Explaining the decision to publish in Royal Society Open Science, Dr Lomax stated:

“When we discovered the casts, we felt compelled to submit our research to The Royal Society, especially because they had played a major role in publishing the first accounts of ichthyosaurs in the scientific literature over two hundred years ago.”

Professor Massare added:

“We hope that our discovery of these two casts might encourage curators and researchers to take a closer look at old casts in museum collections.”

Everything Dinosaur acknowledges the assistance of a media release from the University of Manchester.

The scientific paper: “Rediscovery of two casts of the historically important ‘Proteo-saurus’, the first complete ichthyosaur skeleton” by D. R. Lomax and J. A. Massare published in Royal Society Open Science.

Sometimes serendipity and palaeontology combine, for example, a sharp-eyed field team member spotting a hadrosaur fossil specimen eroding out of a small hill in the Dinosaur Provincial Park (Alberta, Canada). The fossils could represent a rare skeleton of a juvenile and there is evidence that skin impressions have been preserved.

Whilst hadrosaur fossils are relatively common in this part of southern Alberta, the animal’s tail and right hind foot are orientated in the hillside to suggest that the entire skeleton may still be preserved within the rapidly eroding mudstone.

Potentially a Very Significant Fossil Discovery

Whole dinosaur skeletons are extremely rare, this specimen tentatively referred to as a “dinosaur mummy” could provide important new information on juvenile hadrosaurs and the ontogeny of duck-billed dinosaurs.

Spotting a Hadrosaur

The exposed caudal vertebrae (tail bones) show preserved skin impressions as does the exposed right ankle. The size of the bones and the distance between the tail and the astragalus (ankle) suggest that these are the fossilised remains of a young hadrosaur.

Discovering a Duck-billed Dinosaur

During a field school scouting visit in 2021 to look for possible excavation sites, Dr Brian Pickles (University of Reading) was leading a small team examining one location when volunteer crew member Teri Kaskie spotted the fossil skeleton protruding from the hillside.

The first international palaeontology field school is taking place, involving academics and students from the University of Reading and the University of New England in Australia. In collaboration with researchers from the Royal Tyrrell Museum (Drumheller, Alberta), the team are working together to excavate the skeleton and ensure the material that remains in the hill is protected from the elements.

The first part of the conservation work involves coating the fossil site in a thick layer of mud, to help conserve the delicate fossils and to prevent erosion.

An Exciting Fossil Discovery

Commenting on the significance of this hadrosaur fossil find, Dr Pickles stated:

“This is a very exciting discovery, and we hope to complete the excavation over the next two field seasons. Based on the small size of the tail and foot, this is likely to be a juvenile. Although adult duck-billed dinosaurs are well represented in the fossil record, younger animals are far less common. This means the find could help palaeontologists to understand how hadrosaurs grew and developed.”

Vertebrate palaeontologist from the Royal Tyrrell Museum, Dr Caleb Brown added:

“Hadrosaur fossils are relatively common in this part of the world but another thing that makes this find unique is the fact that large areas of the exposed skeleton are covered in fossilised skin. This suggests that there may be even more preserved skin within the rock, which can give us further insight into what the hadrosaur looked like.”

A Substantial Project

Collecting the entire skeleton is going to take many months and the site will have to be closed down and secured as the weather worsens towards winter. It may take several field seasons to complete this work. Once the specimen has been removed from the field, it will be delivered to the Royal Tyrrell Museum’s Preparation Laboratory, where skilled technicians will work to uncover and conserve the fossilised bones.

At this time, the scientists are unsure as to how complete the specimen is and which genus the fossils represent. Species identification will only be possible if a substantial proportion of the skeleton, including skull material can be recovered.

Which Hadrosaur?

Several different types of hadrosaur are known from the Dinosaur Provincial Park Formation (Campanian faunal stage). Lambeosaurines are represented by Corythosaurus, Parasaurolophus and Lambeosaurus whilst members of the Saurolophinae subfamily represented include Gryposaurus and Prosaurolophus. As more of the skeleton is prepared, the researchers are hopeful that they will be able to confirm the species.

Everything Dinosaur acknowledges the assistance of a media release from Reading University in the compilation of this article.