The first, definitive proof of a dinosaur eating a mammal has been found. A foot of a tiny, mouse-sized mammal has been discovered inside the body cavity of the feathered theropod Microraptor (M. zhaoianus). Previously, other Microraptor specimens from Lower Cretaceous rocks of northern China had revealed the fossilised remains of a fish, a primitive bird and a lizard associated with the body cavity. Palaeontologists now know that this crow-sized predator also ate mammals. This is the first record of a dinosaur consuming a mammal.

Mammal Foot Found Inside Ribcage

A new study led by Dr David Hone (Queen Mary University of London), published in the academic “Journal of Vertebrate Paleontology”, documents the first known incident of a dinosaur having eaten a mammal.

Microraptor is a genus of small, dromaeosaurid which lived in the forests of northern China around 120 million years ago (Early Cretaceous). The remarkable fossils found in Liaoning Province have enabled palaeontologists to build up a detailed picture of life in these ancient, dinosaur-dominated forests.

Researchers have also identified a wide variety of mammals and mammaliamorphs that co-existed with the dinosaurs and pterosaurs. Together these creatures make up a diverse ecosystem known as the Jehol biota

To read Everything Dinosaur’s blog post from 2021 describing the remarkable diversity of vertebrates associated with the Jehol biota: The Jehol Biota.

Microraptor had long feathers on its arms and legs and was, very probably arboreal, gliding from tree to tree, hunting out small animals to eat.

Spotting the Fossilised Foot

The Microraptor specimen was first described twenty-two years ago, but the preserved remains of the tiny foot had been overlooked. Professor Hans Larsson of McGill University in Montreal spotted what others had missed – the remains of another animal inside the Microraptor’s rib cage. In collaboration with Dr Hone, and colleagues from Canada, China and the USA, a paper describing this remarkable discovery has now been published.

Dinosaur Eating a Mammal

The mammal foot is almost complete and belonged to a very small animal, approximately the size of a modern house mouse. Examination of the bones suggest that it was one that predominantly lived on the ground and was not well adapted for climbing trees, making it an interesting prey choice for the mainly arboreal Microraptor.

Previous studies have revealed other Microraptor specimens containing the remains of a bird, a lizard and a fish. This specimen of the species Microraptor zhaoianus demonstrates that Microraptor also consumed small mammals. This little feathered dinosaur was a generalist, consuming a wide variety of prey.

It is not certain if the dromaeosaurids in question had directly preyed upon and eaten these animals or found them already dead and had scavenged them (or a mixture of both) but the mammal at least falls into the range of typical prey size predicated for a predator the size of Microraptor.

Dr Hone’s co-authors on the paper include Dr Alex Dececchi, Mount Marty College (USA), Dr Corwin Sullivan at the Department of Biological Sciences, University of Alberta, and Professor Xu Xing at the Institute of Vertebrate Palaeontology and Palaeoanthropology, Beijing.

A Significant Fossil Discovery

Commenting on the significance of this fossil discovery, Dr David Hone stated:

“It’s so rare to find examples of food inside dinosaurs so every example is really important as it gives direct evidence of what they were eating.“

Dr Hone from the University’s School of Biological and Behavioural Sciences added:

“While this mammal would absolutely not have been a human ancestor, we can look back at some of our ancient relatives being a meal for hungry dinosaurs. This study paints a picture of a fascinating moment in time – the first record of a dinosaur eating a mammal – even if it isn’t quite as frightening as anything in Jurassic Park.”

Co-author of the study, Dr Alex Dececchi, from Mount Marty College, commented:

“The great thing is that, like your housecat which was about the same size, Microraptor would have been an easy animal to live with but a terror if it got out as it would hunt everything from the birds at your feeder to the mice in your hedge or the fish in your pond.”

Everything Dinosaur acknowledges the assistance of a media release supplied by Dr David Hone in the compilation of this article.

The scientific paper: “Generalist diet of Microraptor zhaoianus included mammals” by Hone, D.W.E., Dececchi, T.A., Sullivan, C., Xu, X. and Larsson, H.C.E. published in the Journal of Vertebrate Paleontology.

Correction

This is not the first recorded incidence of a dinosaur consuming a mammal. The press release, although provided by the appropriate authorities, had failed to recognise evidence cited in an earlier scientific paper.

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.