One of the world’s most unusual dinosaurs is even stranger than first thought.  Newly published research in the journal “Nature” confirms that the Moroccan armoured dinosaur Spicomellus afer is definitely an ankylosaur.  In addition, to the extremely spiky appearance, it probably had a tail weapon.  The evolution of a tail weapon predates this feature in any other known ankylosaur by more than thirty million years.  Furthermore, Spicomellus had a unique bony collar ringed with metre-long spikes sticking out from either side of its neck.

It has been nicknamed the “punk rock dinosaur”.

A Spicomellus life reconstruction in anterior view. Picture credit: Matthew Dempsey.

Picture credit: Matthew Dempsey

This dinosaur was formally named and described in 2021 (Maidment et al).  The initial description was made based on a single rib bone. The rib had spikes fused to it, a unique feature, not seen in any other animal.  However, the “T-shaped” cross section of the rib permitted the scientists to confidently assign this fossil to an ankylosaur.  Named Spicomellus afer, it represents Africa’s first known ankylosaur and the earliest representative of this iconic dinosaur clade (Ankylosauria).

To read Everything Dinosaur’s blog post from 2021 announcing the discovery of Africa’s first ankylosaur: The Earliest Ankylosaur and Africa’s First – Spicomellus.

The Remarkable Early Ankylosaur Spicomellus afer

The fossils are more than 165 million years old. This armoured dinosaur lived during the Middle Jurassic, near what is now the Moroccan town of Boulemane.  Further fossil discoveries have enabled the research team to learn more about this remarkable armoured dinosaur.  For example, they now know that Spicomellus had bony spikes fused onto and projecting from all of its ribs, a feature not seen in any other vertebrate species living or extinct. It had long spikes, measuring eighty-seven centimetres in length, which the researchers believe would have been even longer in real life.  These spikes emerged from a bony collar that sat around the reptile’s neck.

A fossil rib showing the spikes fused to it, a unique feature not seen in any other animal. Picture credit: The Trustees of the Natural History Museum, London.

Picture credit: The Trustees of the Natural History Museum, London

Professor Susannah Maidment of Natural History Museum, London, and the University of Birmingham, who co-led the team of researchers commented:

“To find such elaborate armour in an early ankylosaur changes our understanding of how these dinosaurs evolved. It shows just how significant Africa’s dinosaurs are, and how important it is to improve our understanding of them.”

Elaborate Dermal Armour

Ankylosaurs are best known from Late Cretaceous Northern Hemisphere ecosystems.  For instance, Ankylosaurus and Euoplocephalus are known from Upper Cretaceous rocks in the northern United States and Canada.  Ziapelta is known from fossils found in New Mexico, whereas Saichania, Pinacosaurus and Tarchia are known from Upper Cretaceous rocks in Asia.

“Sede” the Ankylosaurus dinosaur model.  The authors of the Spicomellus study postulate that with the emergence of larger predators this could have resulted in ankylosaur armour becoming simpler and more defensive.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The picture (above) shows a model of the Late Cretaceous ankylosaur Ankylosaurus magniventris.  The figure is from the Chinese manufacturer PNSO.

To view the range of PNSO models and figures in stock: PNSO Age of Dinosaurs Models.

The researchers postulate that the unique, elaborate spines and spikes of Spicomellus may have functioned for display as well as defence.  Later ankylosaurs had simpler armour with less extravagant osteoderms.  This might indicate a shift towards a primarily defensive function, perhaps in response to increased predation pressures or a switch to combative courtship displays.

Professor Maidment added:

“Spicomellus had a diversity of plates and spikes extending from all over its body, including metre-long neck spikes, huge upwards-projecting spikes over the hips, and a whole range of long, blade-like spikes, pieces of armour made up of two long spikes, and plates down the shoulder. We’ve never seen anything like this in any animal before. It’s particularly strange as this is the oldest known ankylosaur, so we might expect that a later species might have inherited similar features, but they haven’t.”

Professor Susannah Maidment of the Natural History Museum holding a rib with fused spikes. Picture credit: The Trustees of the Natural History Museum, London.

Picture credit: The Trustees of the Natural History Museum, London

Was There a Large Theropod in the Ecosystem?

There is another potential explanation for the remarkable armour associated with Spicomellus afer.  Could it have shared its environment with a large predator such as a theropod dinosaur?  There is certainly evidence to suggest that by the Middle Jurassic formidable tetanuran theropods were present in many ecosystems.

Co-author of the study, Professor Richard Butler (University of Birmingham) stated:

“Seeing and studying the Spicomellus fossils for the first time was spine-tingling. We just couldn’t believe how weird it was and how unlike any other dinosaur, or indeed any other animal we know of alive or extinct. It turns much of what we thought we knew about ankylosaurs and their evolution on its head and demonstrates just how much there still is to learn about dinosaurs”.

Professor Susannah Maidment of the London Natural History Museum and Professor Richard Butler (University of Birmingham) examine the fossil remains along with fellow researchers. Picture credit: The Trustees of the Natural History Museum, London.

Picture credit: The Trustees of the Natural History Museum, London

Did Spicomellus afer Have a Tail Club?

One feature of early ankylosaurs that may have survived, however, is their tail weaponry. While the end of Spicomellus’ tail has not be found, the caudal vertebrae that do survive suggest that it had a club or a similar tail weapon. Some of these tail vertebrae are fused together.  They form a structure referred to as a “handle”.  This feature has only been found in ankylosaurs that possessed a tail club.  If Spicomellus did have a tail club, it overturns current understanding regarding tail club evolution in the Ankylosauria.  These structures were previously thought to have first evolved in the Early Cretaceous.

The authors believe that the combination of a tail weapon and an armoured shield that protected the hips suggest that many of the ankylosaurs’ key adaptations already existed by the time of Spicomellus.

Spicomellus fossil material. This dinosaur was originally described in 2021, however, more fossils were excavated in 2023 providing the research team with further information about the bizarre anatomy of Spicomellus. Picture credit: The Trustees of the Natural History Museum, London.

Picture credit: The Trustees of the Natural History Museum, London

Improving Our Understanding of the Geographic Distribution of Armoured Dinosaurs

Finding more fossils of Spicomellus confirms its ankylosaurian affinities.  In addition, it helps to deepen our understanding of the geographic distribution of armoured dinosaurs. It also helps to spark public imagination in the Dinosauria as we learn more about the baffling characteristics of species like Spicomellus.

Professor Driss Ouarhache, lead of the Moroccan team from the Université Sidi Mohamed Ben Abdellah who co-developed the research, commented:

“This study is helping to drive forward Moroccan science. We’ve never seen dinosaurs like this before, and there’s still a lot more this region has to offer.”

The Spicomellus afer fossils that form the basis of this study were cleaned and prepared at the Department of Geology of the Dhar El Mahraz Faculty of Sciences in Fez, Morocco, using scientific equipment provided by the University of Birmingham’s Research England International Strategy and Partnership Fund. The fossils are now catalogued and stored on this site.  Perhaps, they will be put on display so that the public will have the opportunity to view these amazing fossils.

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

In addition, Everything Dinosaur acknowledges the assistance of the London Natural History Museum for the use of their images.

The scientific paper: “Extreme armour in the world’s oldest ankylosaur” by Susannah C. R. Maidment, Driss Ouarhache, Kawtar Ech-charay, Ahmed Oussou, Khadija Boumir, Abdessalam El Khanchoufi, Alison Park, Luke E. Meade, D. Cary Woodruff, Simon Wills, Mike Smith, Paul M. Barrett and Richard J. Butler published in the journal Nature.

The award-winning Everything Dinosaur website: Everything Dinosaur.

The Queensland-based Age of Dinosaurs Natural History Museum has announced a remarkable Australian ichthyosaur discovery. The specimen, probably representing Platypterygius australis is perhaps the most complete ichthyosaur ever found “Down Under”.  It was unearthed some sixty miles south of McKinlay (Queensland).  Preparation will soon commence at the Australian Age of Dinosaurs Museum of Natural History.  The fossil find highlights the rich palaeontological heritage of this part of western Queensland.

An aerial view of the ichthyosaur quarry. Picture credit: Australian Age of Dinosaurs Museum.

Picture credit: Australian Age of Dinosaurs Museum of Natural History

A Remarkable Australian Ichthyosaur Discovery

The skeleton measures an impressive 7.1 metres in length.  It was discovered on Toolebuc Station by neighbouring property owner and fossil enthusiast Cassandra Prince two years ago.  The specimen was carefully excavated the following year by Cassandra and her family. Remarkably well-preserved, the skeleton includes a complete vertebral column, intact left flipper, partial right flipper, rare hind flippers, partial caudal vertebrae and a nearly complete skull and torso.  Palaeontologists have described this find as one of the most scientifically valuable marine reptile fossils from Australia.

Cassandra Prince with her ichthyosaur discovery. Picture credit: Australian Age of Dinosaurs Museum.

Picture credit: Australian Age of Dinosaurs Museum of Natural History

Platypterygius australis

The Platypterygius genus is a geographically and temporally widespread genus.  Numerous species have been named.  Although, their taxonomic affinity is controversial all the specimens assigned to this genus are robust, macropredators with robust teeth.  It is likely that Platypterygius australis was a formidable predator in the inland sea (Eromanga Sea) that covered much of Australian in the late Early Cretaceous.

Museum Founders David and Judy Elliott assisted Cassandra and her family with collecting the specimen, which was subsequently transported to the Museum so that its preparation can start.  The fossil specimen has been generously donated to the Museum by the Toolebuc Station owners.  Once cleaned and prepared, the ichthyosaur specimen will be mounted in a special exhibition at the Museum.

David Elliott stated:

“This find is a huge win for science and public exhibitions in Australia. Its discovery is testament to the dedication and expertise of Cassandra and her fossil-hunting family and the unique geological heritage of the region. We look forward to sharing this incredible piece of Australia’s prehistory with visitors for generations to come.”

The Toolebuc fossil ichthyosaur specimen uncovered. This 7.1 metre specimen represents a remarkable Australian ichthyosaur discovery. Picture credit: Australian Age of Dinosaurs Museum.

Picture credit: Australian Age of Dinosaurs Museum of Natural History

Everything Dinosaur acknowledges the assistance of a media release from the Australian Age of Dinosaurs Museum in the compilation of this article.

The award-winning Everything Dinosaur website: Prehistoric Animal Models and Toys.

Researchers have described a new dinosaur species from the Wessex Formation of the Isle of Wight.  The dinosaur, an iguanodontian, has been named Istiorachis macarthurae.  The extended neural spines associated with the dorsal and caudal vertebrae suggest that it possessed a sail structure.

Possible explanations for neural spine elongation in the Ankylopollexia include biomechanical advantage, perhaps related to increasing body size and a move towards quadrupedalism. In addition, such structures could have evolved as aids to visual signalling or to deter rivals. Perhaps these changes in body shape were driven by sexual selection, species recognition or both

Hyperelongation of neural spines is known in a number of dinosaur taxa. Most recorded incidences occur during the Barremian and early Aptian faunal stages of the Early Cretaceous. The evolution of elongated neural spines probably took place due to a variety of evolutionary pressures. The drivers for this body shape probably differed in different taxa. Furthermore, it is likely that no single explanation fully supports the variation seen throughout the Cretaceous.

A life reconstruction of Istiorachis macarthurae. Picture credit: James Brown (University of Portsmouth).

Picture credit: James Brown (University of Portsmouth)

Istiorachis macarthurae

This new iguanodontian dinosaur was identified by Jeremy Lockwood, a retired GP, as part of his PhD studies at the University of Portsmouth and the Natural History Museum, London.  Detailed analysis of fossil bones held in the collection of the Dinosaur Isle museum, Isle of Wight led to the identification of several autapomorphies which resulted in the establishment of this new taxon.

The genus name is derived from the Ancient Greek words ἱστίον (istion), meaning a sail, and ῥάχις (rachis), the spine or backbone. It refers to the probable sail-back appearance of the dinosaur.

Pronounced Is-tree-oh-rak-is mack-ar-four-eye, the species name honours the Isle of Wight resident Dame Ellen MacArthur. Dame Ellen MacArthur is a famous sailor.  Therefore, it seemed appropriate to honour her by naming a possible sail-backed dinosaur after her. In 2005, she set a world record for the fastest solo non-stop voyage around the world on her first attempt and Dame Ellen MacArthur has also founded the Ellen MacArthur Cancer Trust for young people on the Isle of Wight.

Dr Jeremy Lockwood with the spinal column of Istiorachis macarthurae with some of the pelvic elements (pubis and head of the ischium). Note the elongated neural spines. Picture credit: University of Portsmouth.

Picture credit: University of Portsmouth

Smaller Iguanodontians Including Istiorachis macarthurae

Dr Lockwood has played a significant role in helping palaeontologists to better understand the smaller iguanodontians from the Isle of Wight.  This is the third iguanodontian named from fossils found on the island in recent years.  For example, last year (2024), Comptonatus chasei was described.  Moreover, in 2021, an iguanodontian with an unusual bulbous snout was described (Brighstoneus simmondsi).

To read Everything Dinosaur’s blog post about the discovery of Comptonatus chasei: A New Dinosaur From the Isle of Wight.

To learn more about B. simmondsi: A New Iguanodontid from the Isle of Wight.

A Highly Diverse Early Cretaceous Ecosystem

The fossil material is estimated to be around 125 million years old.  It came from Wessex Formation exposures from the southwestern part of the island.  This discovery further demonstrates the remarkable dinosaur diversity during the Early Cretaceous.  In addition, it helps to cement the Isle of Wight as a globally significant location for dinosaur fossils.

Commenting on how the new taxon was established, Dr Lockwood explained:

“While the skeleton wasn’t as complete as some of the others that have been found, no one had really taken a close look at these bones before. It was thought to be just another specimen of one of the existing species, but this one had particularly long neural spines, which was very unusual.”

The findings have been published this week in the academic journal “Papers in Palaeontology”.

Dr Lockwood holding the single cervical vertebra (neck bone) known from Istiorachis macarthurae. Picture credit: University of Portsmouth.

Picture credit: University of Portsmouth

Dr Lockwood added:

“Evolution sometimes seems to favour the extravagant over the practical. While the exact purpose of such features has long been debated – with theories ranging from body heat regulation to fat storage – researchers believe that the most likely explanation in this case is visual signalling, possibly as part of a sexual display and this usually is because of sexual selection. In modern reptiles, sail structures often show up more prominently in males, suggesting that these attributes evolved to impress mates or intimidate rivals. We think Istiorachis may have been doing much the same.”

A Detailed Analysis of Neural Spines in Iguanodontids and Their Relatives

A large database was constructed consisting of data on the neural spines of iguanodontids and their close relatives.  The database was created using observations, photographs, scientific illustrations and reconstructions of vertebrae.  The data enabled the researchers to trace the evolutionary history of elongated neural spines within the Iguanodontia.  This analysis permitted the team to identify broad trends in the evolution of sail-like structures.

Dr Lockwood stated:

“These methods let us move beyond simply describing the fossil and actually test hypotheses about its function. We showed that Istiorachis’s spines weren’t just tall – they were more exaggerated than is usual in Iguanodon-like dinosaurs, which is exactly the kind of trait you’d expect to evolve through sexual selection.”

Co-author of the study, Professor Susannah Maidment (London Natural History Museum), added:

“Jeremy’s careful study of fossils that have been in museum collections for several years has brought to life the iguanodontian dinosaurs of the Isle of Wight. His work highlights the importance of collections like those at Dinosaur Isle, where fossil specimens are preserved in perpetuity and can be studied and revised in the light of new data and new ideas about evolution. Over the past five years, Jeremy has single-handedly quadrupled the known diversity of the smaller iguanodontians on the Isle of Wight, and Istiorachis demonstrates we still have much to learn about Early Cretaceous ecosystems in the UK.”

A silhouette of Istiorachis macarthurae showing known fossil material and providing a size estimate. Note scale bar = 50 cm. Picture credit: James Brown (University of Portsmouth) with additional annotation by Everything Dinosaur.

Picture credit: James Brown (University of Portsmouth) with additional annotation by Everything Dinosaur

Highlighting a Broader Evolutionary Trend

Importantly, Istiorachis macarthurae appears to highlight a broader evolutionary trend.  The database suggests that elongation of neural spines in iguanodontians began in the Late Jurassic.  It becomes an increasingly common feature during the Early Cretaceous. However, true hyper-elongation, where neural spines reach heights in excess of four times the height of the vertebral body remain rare.

Similar elongated spines are seen in living reptiles.  For example, many species of extant lizards sport elaborate crests and sail-like structures.  These play a role in visual communication as well as signalling the health and vitality of the animal.

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

The scientific paper: “The origins of neural spine elongation in iguanodontian dinosaurs and the osteology of a new sail-back styracosternan (Dinosauria, Ornithischia) from the Lower Cretaceous Wealden Group of England” by Jeremy A. F. Lockwood, David M. Martill, Susannah C. R. Maidment published in Papers in Palaeontology.

The award-winning Everything Dinosaur website: Prehistoric Animal Models and Toys.