A new species of Late Jurassic iguanodontian has been described from fossils discovered in western Portugal. The dinosaur has been named Hesperonyx martinhotomasorum. The discovery of this dinosaur adds to the diversity of relatively small ornithopods known from the Lourinhã Formation.  The fossil material consisting of a partial left hindlimb and isolated forelimb bones were excavated from the cliffs at the picturesque Porto Dinheiro beach (Lourinhã, Portugal). The fossils probably represent a single, individual dinosaur.

Hesperonyx martinhotomasorum life reconstruction. Picture credit: Victor Carvalho.

Hesperonyx martinhotomasorum

The researchers conclude that this dinosaur had a body length of between 3-4 metres. It was rather small when compared to Early Cretaceous iguanodontians such as Iguanodon bernissartensis which had an estimated length of approximately 10 metres and weighed around 5 tonnes. The forelimb bones lack modifications for quadrupedal locomotion. Hesperonyx probably was a biped and considerably more agile than later, much larger iguanodontians.

Hesperonyx roamed western Portugal approximately 150 million years ago (Late Jurassic). The research project was a collaboration between scientists from the NOVA School of Science and Technology, University of Zaragoza and University of Bonn, supported by the local Museu da Lourinhã and Sociedade de História Natural de Torres Vedras.

Co-author of the study Bruno Camilo, head of Sociedade of História Natural of Torres Vedras (Universidade NOVA de Lisboa). Picture credit: Universidade NOVA de Lisboa.

A New Dinosaur Taxon

The almost complete and semi-articulated left hindlimb was discovered in the summer of 2021. The fossil material was cleaned and prepared in the Museu da Lourinhã laboratory. The morphology of the bones puzzled the researchers. 

Student and co-author of the scientific paper Lucrezia Ferrari who worked on the fossilised material commented:

“It simply did not match anything we have seen before.”

The team were quietly confident that these fossils represented a new dinosaur taxon.

Student Lucrezia Ferrari who worked on the fossil preparation and presented a thesis on this new ornithopod dinosaur as part of her Master’s degree. Picture credit: Universidade NOVA de Lisboa.

Filippo Maria Rotatori, lead author of the paper published in the Journal of Vertebrate Palaeontology added:

“It was something familiar, but it has several features that just looked unusual.  It was some kind of bipedal herbivorous dinosaur, but such animal was never recorded in Portugal before.   It’s a new species. One more in the highly diverse ecosystem of the Portuguese Jurassic.”

What’s in a Name?

The genus name is derived from “Hesperus” the Greek God, whose name is associated with the planet Venus and it being seen in the western sky. This is a nod to the fact that the fossils come from the western region of Portugal. The genus name also contains the Greek “onyx” meaning claw. The specific name honours Micael Martinho and Carla Alexandra Tomás for their dedicated work as fossil preparators at the Museu da Lourinhã.

Lead author of the scientific paper, Filippo Maria Rotatori with the preparators Micael Martinho and Carla Tomás (Museu da Lourinhã) with the toe bones. The trivial name of this new dinosaur honours Micael and Carlo and recognises their dedication to the work of fossil preparation. Picture credit: Universidade NOVA de Lisboa.

Hesperonyx martinhotomasorum – A Small Iguanodontian Dinosaur

The Iguanodontia is an extensive and specious clade of ornithischian dinosaurs. These herbivores were abundant during the Jurassic and Cretaceous. Their early origins are not well understood. This is due to the lack of fossil material representing basal members of this clade. The fossil record of early iguanodontians is particularly poor in Europe. Only a handful of European species are currently recognised. For example, Cumnoria prestwichii and the geologically older Callovosaurus leedsi, both these dinosaurs are associated with English Jurassic deposits (Oxfordshire and Cambridgeshire respectively).

The discovery of Hesperonyx adds to the diversity of small ornithopod dinosaurs already recognised in the fossil record of the Lourinhã Formation.  It was an unexpected fossil find. Hesperonyx demonstrates that there are probably many more types of dinosaur awaiting discovery in the Upper Jurassic strata of western Portugal.

The partial left hindlimb of Hesperonyx martinhotomasorum assembled to reflect the position within the skeleton. Picture credit: Inês Marques.

Miguel Moreno-Azanza, the main advisor of Filippo, noted:

“This is a wonderful discovery, and also a great example of how scientific collaborations in palaeontology can help to reach great results.”

Miguel Moreno-Azanza, from Zaragoza University, co-author of the Hesperonyx scientific paper with a titanosaur egg fossil and an Ampelosaurus model. Picture credit: Universidade NOVA de Lisboa.

Everything Dinosaur recognises the assistance of a media release and personal email correspondence with the lead author in the compilation of this article.

The scientific paper: “An unexpected early-diverging iguanodontian dinosaur (Ornithischia, Ornithopoda) from the Upper Jurassic of Portugal” by Filippo Maria Rotatori, Lucrezia Ferrari, Cristina Sequero, Bruno Camilo, Octávio Mateus and Miguel Moreno-Azanza published in the Journal of Vertebrate Palaeontology.

Evidence of a Devonian fossil forest has been found in the high sandstone cliffs located near Minehead in Devon. Researchers from the University of Cambridge and the University of Cardiff have discovered the oldest fossilised trees ever found in the UK. The fossil remains of the trees, known as Calamophyton represent the oldest known fossil forest on Earth.

Fossilised tree stumps near the town of Gilboa (New York, USA) and a quarry at nearby Cairo, New York are thought to be 380 and 385 million years old respectively. The Gilboa site is dominated by remains of Wattieza trees. These trees are related to the Calamophyton trees identified at the Devon site. They are both members of the Pseudosporochnales Order and are distantly related to modern ferns.

Devonian Fossil Forest

The Devonian fossil forest is thought to be around four million years older than the tree fossils discovered in New York. The forest is approximately 390 million years old (Eifelian faunal stage of the Middle Devonian).

The fossils were found near the town of Minehead. The site is located on the south bank of the Bristol Channel, near a Butlin’s holiday camp. The fossilised trees, known as Calamophyton, at first glance resemble palm trees, but they are not related to modern angiosperms. Rather than solid wood, their trunks were thin and hollow in the centre. They also lacked leaves, and their branches were covered in hundreds of twig-like structures.

Evidence of Arthropods Found

The trees were much shorter than extant trees. The largest specimens were between two and four metres high. As the trees grew, they shed their branches. The floor of the forest was covered in a dense mat of decaying vegetation. This was home to an array of invertebrates and arthropod tracks have been discovered at this site.

A Devonian Ecosystem

It had been thought that these sandstone cliffs were largely devoid of fossils. This remarkable discovery demonstrates how early trees helped to stabilise riverbanks and coastlines hundreds of millions of years ago. It was during the Devonian that the first extensive terrestrial forests formed.

The Devonian lasted between 419 million and 359 million years ago. During this geological period the first complex terrestrial ecosystems evolved. By the end of the Devonian, the first seed-bearing plants (pteridosperms) appeared and the earliest land animals, mostly arthropods, were well-established.

Fundamentally Changing Life on Earth

Commenting on the significance of the fossil forest discovery, one of the paper’s co-authors, Professor Neil Davies (Cambridge University), stated:

“The Devonian period fundamentally changed life on Earth. It also changed how water and land interacted with each other, since trees and other plants helped stabilise sediment through their root systems, but little is known about the very earliest forests.”

The Devonian fossil forest identified by the researchers was found in the Hangman Sandstone Formation, along the north Devon and west Somerset coasts. During the Devonian period, this region was not attached to the rest of England, but instead lay further south, connected to parts of Germany and Belgium, where similar Devonian fossils have been found.

Studying the Ecology of the Earliest Forests on Earth

Co-author Dr Christopher Berry (Cardiff University) commented:

“When I first saw pictures of the tree trunks I immediately knew what they were, based on 30 years of studying this type of tree worldwide. It was amazing to see them so near to home. But the most revealing insight comes from seeing, for the first time, these trees in the positions where they grew. It is our first opportunity to look directly at the ecology of this earliest type of forest, to interpret the environment in which Calamophyton trees were growing, and to evaluate their impact on the sedimentary system.”

During the Devonian, this location was a semi-arid plain, criss-crossed by small river channels spilling out from mountains to the northwest. The fieldwork was undertaken along the highest sea-cliffs in England, some of which are only accessible by boat. The sandstone formation is in fact rich with plant fossil material. The researchers identified fossilised plants and plant debris, fossilised tree logs, traces of roots and sedimentary structures, preserved within the sandstone.

A Weird Forest

Professor Davies explained:

“This was a pretty weird forest – not like any forest you would see today. There wasn’t any undergrowth to speak of and grass hadn’t yet appeared, but there were lots of twigs dropped by these densely-packed trees, which had a big effect on the landscape.”

This was the first time in the history of our planet that large plants could grow together on land. The sheer abundance of debris shed by the Calamophyton trees built up within layers of sediment. The sediment affected the way that the rivers flowed across the landscape, the first time that the course of rivers could be affected in this way.

Professor Davies added:

“The evidence contained in these fossils preserves a key stage in Earth’s development, when rivers started to operate in a fundamentally different way than they had before, becoming the great erosive force they are today. People sometimes think that British rocks have been looked at enough, but this shows that revisiting them can yield important new discoveries.”

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

The scientific paper: “Earth’s earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England” by Neil S. Davies, William J. McMahon and Christopher M. Berry published in Journal of the Geological Society.

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A new mosasaur taxon from the Late Cretaceous of Morocco has been scientifically described. Khinjaria acuta was as long as an Orca (Orcinus orca). It had a robust skull, strong jaws and dagger-like teeth. The researchers contrast today’s marine ecosystems with few apex predators, with the Late Cretaceous marine environment. Writing in the journal “Cretaceous Research” the researchers portray an ancient marine ecosystem teeming with predators.

Khinjaria acuta

The study is based on a skull and parts of the postcranial skeleton collected from a phosphate mine southeast of Casablanca (Morocco). Researchers from the University of Bath, the Marrakech Museum of Natural History, the Museum National d’ Histoire Naturelle (NMNH) in Paris (France), Southern Methodist University in Texas (USA), and the University of the Basque Country (Bilbao) were involved.

Measuring around eight metres in length, Khinjaria used its long, dagger-like teeth to seize prey. It was part of an extraordinarily diverse fauna of predators that inhabited the Atlantic Ocean off the coast of Morocco during the Maastrichtian faunal stage of the Late Cretaceous.

The Sheer Diversity of Top Predators in the Marine Ecosystem

One of the authors of the scientific paper, Dr Nick Longrich (University of Bath), stated:

“What’s remarkable here is the sheer diversity of top predators. We have multiple species growing larger than a great white shark, and they’re top predators, but they all have different teeth, suggesting they’re hunting in different ways.”

Dr Longrich added:

“Some mosasaurs had teeth to pierce prey, others to cut, tear, or crush. Now we have Khinjaria, with a short face full of huge, dagger-shaped teeth. This is one of the most diverse marine faunas seen anywhere, at any time in history, and it existed just before the marine reptiles and the dinosaurs went extinct.”

A Diversity of Moroccan Marine Reptiles

Fossil discoveries have highlighted the astonishing diversity of large marine reptiles in the environment. Their different dentition suggests that many were not directly competing, that niche partitioning was occurring. For example, the researchers conducted a phylogenetic analysis and placed Khinjaria in a mosasaur clade which they named the Selmasaurini. Also placed in this clade was the Moroccan plioplatecarpine mosasaur Gavialimimus almaghribensis. This mosasaur was a specialised fish hunter.

To read Everything Dinosaur’s article about Gavialimimus almaghribensis: A New Species of Mosasaur from Morocco.

Mosasaurs, plesiosaurs and giant sea turtles disappeared, along with entire families of fish at the end of the Cretaceous. This led to the evolution of modern marine ecosystems with whales and seals as apex predators along with teleost fish such as swordfish and tuna.

Dr Longrich commented:

“There seems to have been a huge change in the ecosystem structure in the past 66 million years. This incredible diversity of top predators in the Late Cretaceous is unusual, and we don’t see that in modern marine communities.”

An Ecosystem Different from a Modern Marine Ecosystem

Modern marine food chains have just a few large apex predators, animals like orcas, white sharks, and leopard seals. The Late Cretaceous had many more types of marine predators.

Dr Longrich continued:

“Modern ecosystems have predators like baleen whales and dolphins that eat small prey, and not many things eating large prey. The Cretaceous has a huge number of marine reptile species that take large prey. Whether there’s something about marine reptiles that caused the ecosystem to be different, or the prey, or perhaps the environment, we don’t know. But this was an incredibly dangerous time to be a fish, a sea turtle, or even a marine reptile.”

Professor Nathalie Bardet, (Natural History Museum of Paris), explained:

“The Phosphates of Morocco deposit in a shallow and warm epicontinental sea, under a system of upwellings; these zones are caused by currents of deep, cold, nutrient-rich waters rising towards the surface, providing food for large numbers of sea creatures and, as a result, supporting a lot of predators. This is probably one of the explanations for this extraordinary paleobiodiversity observed in Morocco at the end of the Cretaceous.”.

The phosphate mines of Morocco have provided a wealth of marine fossil material. The specimens collected include the “saw-toothed” mosasaur Xenodens, Stelladens which had teeth with additional cutting edges and Thalassotitan whose teeth were conical in shape and massive.

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

The scientific paper: “A bizarre new plioplatecarpine mosasaurid from the Maastrichtian of Morocco” by Nicholas R. Longrich, Michael J. Polcyn, Nour-Eddine Jalil, Xabier Pereda-Suberbiola and Nathalie Bardet published in Cretaceous Research.

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A team of scientists have described new specimens of Dinocephalosaurus orientalis a bizarre, Triassic marine reptile. First scientifically described in 2003 (Li Chun), this new study has permitted scientists to construct the enormous neck of this animal in detail.

Measuring up to five metres in length, Dinocephalosaurus orientalis had an extremely long and flexible neck. The neck contains a total of thirty-two vertebrae. Tanystropheus in contrast, had thirteen cervical vertebrae. In some specimens the neck is 1.7 metres in length. It is much longer than the animal’s torso. The researchers compare D. orientalis to the Tanystropheus taxon. Tanystropheus is known from the Middle Triassic of Europe and China. Whilst Tanystropheus and Dinocephalosaurus had similar body shapes, these reptiles were not closely related. The long necks seen in these two taxa are an example of convergent evolution.

Dinocephalosaurus orientalis A Remarkable Marine Reptile

The scientific paper describing the animal is published in full in the academic journal Earth and Environmental Science: Transactions of the Royal Society of Edinburgh – forming the entirety of the latest volume.

Fellow of the Royal Society of Edinburgh and Editor-in-Chief of the RSE’s academic journal Transactions, Professor Robert Ellam FRSE commented:

“This remarkable marine reptile is another example of the stunning fossils that continue to be discovered in China”.

Comparisons with Tanystropheus

Both reptiles were of similar size and have several features of the skull in common, including a fish-trap type of dentition. However, Dinocephalosaurus is unique in possessing several more vertebrae both in the neck and in the torso, giving the animal a much more snake-like appearance. The neck of Dinocephalosaurus was more flexible than the neck of Tanystropheus. The fossils analysed in the newly published paper come from the Guizhou Province of China.

Dr Nick Fraser FRSE, Keeper of Natural Sciences at National Museums Scotland stated:

“This discovery allows us to see this remarkable long-necked animal in full for the very first time. It is yet one more example of the weird and wonderful world of the Triassic that continues to baffle palaeontologists. We are certain that it will capture imaginations across the globe due to its striking appearance, reminiscent of the long and snake-like, mythical Chinese Dragon.”

Appropriate for the “Year of the Dragon”

As we have now entered the Chinese “Year of the Dragon”, a new scientific paper on a Chinese reptile that superficially resembled a mythical dragon is highly appropriate. The fossils were studied over a period of ten years by researchers from Scotland, China, America and Germany.

Professor Li Chun from the Institute of Vertebrate Palaeontology and Palaeoanthropology in China, the scientist who originally described Dinocephalosaurus orientalis said:

“This has been an international effort. Working together with colleagues from the United States of America, the United Kingdom and Europe, we used newly discovered specimens housed at the Chinese Academy of Sciences to build on our existing knowledge of this animal. Among all of the extraordinary finds we have made in the Triassic of Guizhou Province, Dinocephalosaurus probably stands out as the most remarkable.”

Scientists propose that Dinocephalosaurus was superbly adapted to its marine environment. Given the length of its neck, moving on land would have been difficult. A remarkable fossil described in 2017 revealed that Dinocephalosaurus was viviparous (live birth). This remains the only record of viviparity associated with the Archosauromorpha.

To read Everything Dinosaur’s blog post about this discovery: First Evidence of Live Birth in Ancient Dinosaur Relative.

Dinocephalosaurus orientalis – Significant Fossil Discoveries

Dr Stephan Spiekman, a postdoctoral researcher based at the Stuttgart State Museum of Natural History, commented:

“As an early-career researcher, it has been an incredible experience to contribute to these significant findings. We hope that our future research will help us understand more about the evolution of this group of animals, and particularly how the elongate neck functioned.”

The paper describing the animal is published in full in the academic journal Earth and Environmental Science: Transactions of the Royal Society of Edinburgh – forming the entirety of the latest volume. The journal was first published in 1788.

Everything Dinosaur acknowledges the assistance of media releases from the Royal Society of Edinburgh and National Museums Scotland in the compilation of this article.

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