Researchers have identified a new species of early tetrapod from the Lower Permian of Germany. It is a plant-eater, and it has been named Diadectes dreigleichenensis.  The fossils originate from the Bromacker locality in central Germany.  The ancient creatures from the Bromacker locality lived approximately 290 million years ago.  The site is helping palaeontologists to better understand the evolution of herbivory in early vertebrate ecosystems.

Fossil skull material showing the teeth in the jaws and palatal teeth rows. A new species of advanced reptiliomorph has been named (Diadectes dreigleichenensis). Picture credit: Carola Radke, Museum für Naturkunde Berlin.

Picture credit: Carola Radke, Museum für Naturkunde Berlin

Diadectes dreigleichenensis

The lower Permian Bromacker locality, situated in the UNESCO Global Geopark Thüringen Inselsberg – Drei Gleichen, central Germany, represents a unique inland fossil ecosystem that preserves a diverse early tetrapod fauna.  This palaeoenvironment is dominated by advanced reptiliomorphs, land animals that show a variety of amphibian as well as reptilian traits.  Lead author of the study, PhD student Jasper Ponstein (Museum für Naturkunde and the Humboldt-Universität zu Berlin) explained that the research team examined skull and jaw material representing the Diadectomorpha.  The research has been published in the Royal Society Open Science.

The researchers used traditional examination techniques that involved carefully measuring the bones in the skull and jaws and comparing them to specimens in other collections.  In addition, CT scans were undertaken to reveal fine details obscured by matrix.  This research supports the identification of a third species of the group, representing a second species of the genus Diadectes, from Bromacker. This adds to the already diverse fauna of this herbivore-dominated ecosystem.

Since the 1990s palaeontologists have described fossil specimens belonging to the Diadectes genus from the Bromacker site. These specimens had all been assigned to a single species – Diadectes absitus.  Diadectes is a member of the Diadectidae family.  This family of reptilomorphs show both amphibian and amniote characteristics.  They evolved during the Early Carboniferous (Mississippian subperiod), and their fossils are known from America, Asia and Europe. These animals are typically, robust, heavily-built tetrapods.  They had strong, deep jawbones and molar-like teeth adapted to a diet of plants.

Diadectes dreigleichenensis fossil jawbone shown in lateral view. The jaw is robust, and the molar-like teeth are adapted for the efficient grinding of plant material. Picture credit: Carola Radke, Museum für Naturkunde Berlin.

Picture credit: Carola Radke, Museum für Naturkunde Berlin

The Diadectomorpha include the earliest known herbivorous tetrapods, which evolved 305 million years ago in North America during the Late Carboniferous. Through the Late Carboniferous and much of the early Permian, herbivores remained a rare component of their respective ecosystem.

Abundant Early Herbivores

The Bromacker quarry is extremely significant.  It preserves evidence of the earliest ecosystem known in which herbivores were highly abundant.  Palaeontologists consider the Bromacker locality as the first modern ecosystem with a food chain that is recognisable today.  Herbivores make up the greatest proportion of vertebrates present.  In comparison, there are few secondary and apex predators.  The herbivore fossil record at this location includes numerous and exquisitely preserved skeletons of the diadectomorphs Diadectes absitus and Orobates pabsti, the pot-bellied caseid Martensius bromackerensis and the small agile lizard-like bolosaurid Eudibamus cursoris.

Jasper Ponstein outlined how the study was undertaken.  He stated:

“These skulls are preserved with the jaws firmly attached to the rest of the skull. Key features related to feeding, like the tooth row and the shape of the jaw joint, are obscured by the skull.  Through the CT-scans, we could actually reconstruct what these regions look like and compare the different specimens”.

The detailed study of the skull fossils revealed that diadectomorphs have a sinuous row of teeth on their lower jaws.  In addition, there are two rows of conical teeth located on the palate and a long blade-like process connected to the jaw joint.  The teeth in the lower jaw are widely spaced to maximise the available plant grinding surface. The blade-like process of the jaw joint probably played a role in helping to support the jaw whilst plant material was masticated. These adaptations allowed diadectomorphs to more effectively grind vegetation. Furthermore, the powerful CT images revealed a few replacement teeth within the palate. This suggests that diadectomorphs occasionally replaced their palatal teeth as well.

These observations enabled the research team to conclude that there was sufficient variation between the skulls to erect a new species – Diadectes dreigleichenensis.

Ponstein remarked:

“We named the species after UNESCO Global Geopark Thüringen Inselsberg – Drei Gleichen, which also contains the world-famous Bromacker locality. The species name is after Drei Gleichen, which means three of the same, in reference to the seemingly similar looking three diadectids from Bromacker, just like three iconic castles from the Middle Ages, each situated on a hilltop between Gotha and Erfurt within the Geopark.”

Co-author Professor Jörg Fröbisch (Humboldt-Universität zu Berlin) added:

“The ongoing Bromacker project is a prime example of an innovative and interdisciplinary research and science communication program, building on a multiple-decade-long international collaboration.”

Everything Dinosaur acknowledges the assistance of a media release from the Museum für Naturkunde, Berlin in the compilation of this article.

The scientific paper: “A comprehensive phylogeny and revised taxonomy of Diadectomorpha with a discussion on the origin of tetrapod herbivory” by Ponstein, J., MacDougall, M.J., and Fröbisch, J. 2024 published in the Royal Society Open Science.

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

Researchers have named a new species of iguanodontian dinosaur from fossils found on the Isle of Wight.  The dinosaur has been named Comptonatus chasei.  The fossil material represents the most complete iguanodontian skeleton discovered in the Wealden Group for over a hundred years.  This new taxon has been erected based on numerous unique characteristics (autapomorphies) related to the skull, the straight dentary bone and a markedly expanded pubic hip bone described as being “the size of a dinner plate”.

A view of the head of the newly described iguanodontian Comptonatus chasei. Picture credit: John Sibbick.

Comptonatus chasei

The fossil material is around 125 million years old (Barremian faunal stage). The dinosaur fossils was found in the cliffs of Compton Bay on the Isle of Wight in 2013 by fossil collector Nick Chase, before he tragically died of cancer.  Dr Jeremy Lockwood, helped with the excavation of the bones and teeth. He then spent years carefully comparing these fossils to other Wealden Group iguanodontians before he was confident that these fossils represented a new species.

Dr Jeremy Lockwood walking on the beach in front of the cliffs that mark the excavation site. Picture credit: University of Portsmouth.

Dr Lockwood has become synonymous with Isle of Wight ornithopods along with Professor David Martill (University of Portsmouth) and Professor Susannah Maidment (London Natural History Museum).  These three scientists described Brighstoneus simmondsi, another Isle of Wight ornithopod in 2021.  The discovery of Comptonatus chasei demonstrates that these dinosaurs were particularly diverse during the Barremian to early Aptian faunal stages.

Lateral views of the skulls of three taxa of Isle of Wight iguanodontian dinosaurs. Comptonatus chasei (A), Brighstoneus simmondsi (B) and Mantellisaurus atherfieldensis (C). Picture credit: University of Portsmouth.

Honouring the Late Nick Chase

A total of 149 fossil bones were collected.  The genus name translates as “Compton thunderer”.  This dinosaur was named after Compton Bay where the fossils were found and the “thunderer” element of the genus name relates to the large size of this dinosaur.   Bone histology indicates that the animal was around five or six years old when it died. It is estimated to have weighed around nine hundred kilograms.

The species name honours Nick Chase, winner of the Palaeontological Association’s Mary Anning Award in 2018, who made the initial discovery and through his lifetime contributed enormously to the collections at the Dinosaur Isle Museum on the Isle of Wight, and the Natural History Museum, London.

The late Nick Chase who found the fossil remains in 2013. The species name honours him, a winner of the Palaeontological Association’s Mary Anning Award in 2018, Nick Chase made the initial discovery. During his lifetime he contributed enormously to the study of the dinosaur biota of the Wessex Formation. Picture credit: University of Portsmouth.

Dr Lockwood commented:

“Nick had a phenomenal nose for finding dinosaur bones – he really was a modern-day Mary Anning. He collected fossils daily in all weathers and donated them to museums. I was hoping we’d spend our dotage collecting together as we were of similar ages, but sadly that wasn’t to be the case. Despite his many wonderful discoveries over the years, including the most complete Iguanodon skull ever found in Britain, this is the first dinosaur to be named after him.”

The Comptonatus chasei excavation in 2013. Nick Chase (in the foreground sketching), Steve Hutt (blue jumper), Jeremy Lockwood (wearing gloves), and Penny Newberry examining the exposed fossil material. Picture credit: University of Portsmouth.

Unique Autapomorphies

During the collection and initial preparation it was thought that these fossils represented a Mantellisaurus atherfieldensis. However, a detailed study identified several autapomorphies (unique characteristics) that led to the erection of a new taxon.

Dr Lockwood explained:

“I’ve been able to show this dinosaur is different because of certain unique features in its skull, teeth and other parts of its body. For example its lower jaw has a straight bottom edge, whereas most iguanodontians have a jaw that curves downwards. It also has a very large pubic hip bone, which is much bigger than other similar dinosaurs. It’s like a dinner plate!”

The large pubis bone of Comptonatus pubis. The enlarged blade-like feature of the pubis is a unique characteristic that helped to define this new taxon. Picture credit: University of Portsmouth.

The scientists are uncertain as to why the pubic hip bone is so large. It could have been for muscle attachments indicating that this ornithopod had a different mode of locomotion. Perhaps it could have helped support the large stomach, or played a role in respiration.

The Geological Setting of Comptonatus chasei

Comptonatus chasei and Brighstoneus simmondsi fossils are associated with the Wessex Formation of the Wealden Group.  However, the deposits where Brighstoneous fossils have been found might be two million years older than the strata associated with C. chasei.  Conversely, Mantellisaurus atherfieldensis is geologically younger than Comptonatus.  Mantellisaurus fossils seem confined to the overlying Vectis Formation (Wealden Group).  This means that Comptonatus and Brighstoneus lived during the early Barremian faunal stage of the Cretaceous.  Mantellisaurus lived several million years later (late Barremian).

The scientists state that the Wessex Formation may have supported a greater diversity than previously realised, or that evolutionary and or migratory pressures resulted in faunal turnover. Comptonatus provides further evidence for a greater iguanodontian diversity and it is now unclear as to which iguanodontian taxon or taxa dominated the Wessex sub-basin during the Barremian.  In addition, the researchers postulate that a reassessment of ornithopod fossil material may be required, as with our improved understanding of the differences between these taxa, more new species might be identified.

Isle of Wight Dinosaur Taxa

Despite only four new dinosaur species being described on the Isle of Wight in the whole of the 20th century, there have been eight new species named in the last five years.  A remarkable number of new dinosaur taxa have been described from fossils found on the Isle of Wight. Ornithischians such as Vectidromeus insularis, Brighstoneus simmondsi and Vectipelta barretti have been named.

To read more about Vectidromeus insularis: Vectidromeus – A New Hypsilophodontid.

An article on Brighstoneus simmondsi: A New Iguanodontid from the Isle of Wight.

A scale drawing of the recently described Isle of Wight iguanodontian Brighstoneus.  CollectA added a model of Brighstoneus simmondsi to their CollectA Age of Dinosaur Popular range of figures.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

A new, armoured dinosaur from the Isle of Wight described in 2023 (Vectipelta barretti): New Armoured Dinosaur Honours Natural History Museum Professor.

In addition, several theropod dinosaurs have been described including Vectiraptor greeni, Ceratosuchops inferodios and Riparovenator milnerae. Furthermore, there is evidence of a gigantic spinosaurid (the “white rock spinosaurid”). These discoveries suggest that the Wessex Formation supported a greater diversity of dinosaurs than previously realised. It could also indicate a substantial faunal turnover during the deposition of the Wessex Formation deposits.

Ancient relative of Velociraptor from “Dinosaur Isle”: Early Cretaceous Dromaeosaurid from the Isle of Wight.

To read about Ceratosuchops inferodios and Riparovenator milnerae: Two New Spinosaurids from the Isle of Wight.

News about the enormous “white rock spinosaurid”: Super-sized Carnivorous Dinosaur from the Isle of Wight.

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

The scientific paper: “Comptonatus chasei, a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England” by Jeremy A. F. Lockwood, David M. Martill and Susannah C. R. Maidment published in the Journal of Systematic Palaeontology.

The Everything Dinosaur website: Dinosaur Models.