Tag: Dinosaurs

Europe’s very own dinosaurs – the enigmatic Late Cretaceous rhabdodontids

Despite being widespread and abundant, these gregarious herbivores vanished in Western Europe around 69 million years ago due to environmental changes, while surviving longer in Eastern Europe.

When you think of dinosaurs, you might automatically imagine iconic dinosaurs as Tyrannosaurus and Triceratops. But at the same time when these were stomping on the ancient coastal plains of North America, some of their very distant cousins were reigning over Europe’s lands.

Life reconstructions and size comparison of three rhabdodontids. From left to right: Mochlodon suessi from eastern Austria (the smallest member of the group), Rhabdodon priscus from southern France (the largest member of the group), and Transylvanosaurus platycephalus from western Romania (the most recently named member of the group). Also shown is the silhoutte of a human (1.8 m tall) for scale. Reconstruction by Peter Nickolaus

During the Late Cretaceous (between 100 and 66 million years ago), Europe was an extensive archipelago with numerous small and large islands situated in a shallow tropical sea, the so-called Late Cretaceous European Archipelago. The dinosaur groups that lived on these islands were very different from those of other continents, often being much smaller than their mainland relatives. These European dinosaurs include small and medium-sized carnivorous theropods, armoured ankylosaurs, long-necked sauropods, duck-billed hadrosaurs, and rhabdodontids.

Skeletal reconstruction of Zalmoxes robustus. Scale bar: 20 cm

Arguably one of the most important of these European dinosaur groups is the family Rhabdodontidae, which groups together the most common medium-sized herbivores of the Late Cretaceous European Archipelago. A joint research team from the Universities of Tübingen (Germany), Budapest (Hungary) and Bucharest (Romania) recently reviewed what we know about these peculiar dinosaurs in a new paper published in the journal Fossil Record.

Generally, rhabdodontid dinosaurs were small to medium-sized animals with an overall body length of approximately 2–6 m. “They were probably habitually bipedal herbivores, characterised by a rather stocky build, with strong hind limbs, short forelimbs, a long tail, and a comparatively large, triangular skull that tapers anteriorly and ends in a narrow snout,” explains Felix Augustin, lead author of the study in Fossil Record.

“They had a relatively robust skull with strong jaws, large teeth and a pointy beak that was covered in keratin, demonstrating that these dinosaurs were well-adapted to eating tough plants.”

In some instances, fossil remains of several individuals of different ages have been found together, indicating that they were gregarious.

Although they died out well before the mass extinction in Western Europe (about 69 million years ago), potentially due to environmental changes that affected the plants they fed on, they survived much longer in Eastern Europe and were among the last non-avian dinosaurs still present before the end of the Cretaceous (66 million years ago).

Interestingly, fossils of rhabdodontids have only been found in Europe and only in rocks ranging in age from 86–66 million years ago, so they were endemic to the Late Cretaceous European Archipelago.

The group currently comprises nine different species from five European countries (France, Spain, Austria, Hungary, and Romania).

Palaeogeographic map of Europe during the latest Cretaceous (late Campanian), with the location of the most important rhabdodontid-bearing assemblages. 1 Transylvania, western Romania. 2 Iharkút, western Hungary. 3 Muthmannsdorf, eastern Austria. 4 Eastern southern France. 5 Western southern France. 6 Northern Spain. 7 Central Spain.

“The first rhabdodontid species was scientifically named more than 150 years ago and the last one as recently as November 2022, so, although the group looks back to a long research history, we still have much to learn about it,” says Felix Augustin.

“Generally, our portraying of the world of dinosaurs is heavily biased towards the well-known North-American and Asian dinosaur faunas,” he adds.

Type specimens of some rhabdodontid species. A. The original drawing of the lectotype of Rhabdodon priscus, MPLM 30, a partial left dentary. The specimen has since deteriorated (Pincemaille-Quillevere 2002). Modified after Matheron (1869). B. Holotype of Rhabdodon septimanicus, MDE D-30, an incomplete right dentary. Photo kindly provided by Eric Buffetaut. C. Lectotype of Mochlodon suessi, PIUW 2349/2, a right dentary. D. Holotype of Mochlodon vorosi, MTM V 2010.105.1, a left dentary. E. Holotype of Zalmoxes robustus, NHMUK R.3392, a right dentary. Photo kindly provided by János Magyar. F. Holotype right dentary of Zalmoxes shqiperorum, NHMUK R.4900. Note that the holotype of Z. shqiperorum also comprises several postcranial elements that presumably belong to the same individual as the dentary. Photo kindly provided by János Magyar.

Dinosaur fossils from the Late Cretaceous are much rarer in Europe than in North America or Asia, and thus far no complete skeleton of a rhabdodontid has been described. Even though they were so abundant and common in the Upper Cretaceous of Europe, several key aspects about them remain poorly known, including their detailed body proportions, their posture and locomotion, as well as their feeding behaviour.

“In the past decades, a wealth of new, and often well-preserved, rhabdodontid fossils has been discovered throughout Europe, the majority of which still remains to be studied,” says Felix Augustin. “A joint research project is currently underway to study the available fossil material in order to gain new insights into the evolution and lifestyle of these fascinating yet still poorly known dinosaurs.”

Original source:

Augustin FJ, Ősi A, Csiki-Sava Z (2023) The Rhabdodontidae (Dinosauria, Ornithischia), an enigmatic dinosaur group endemic to the Late Cretaceous European Archipelago. Fossil Record 26(2): 171-189. https://doi.org/10.3897/fr.26.108967

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Oldest Pterodactylus fossil found in Germany

The fossil, just described in a study in the journal Fossil Record, is about one million years older than other Pterodactylus specimens.

Pterosaurs, the flying reptiles of the dinosaur era, originated in the Late Triassic (227 million years ago) and became extinct at the end-Cretaceous extinction event (66 million years ago). With wing spans ranging from 1 to 12 meters, they dominated the world’s skies for more than 160 million years.

The first described and named pterosaur – and namesake of the whole group – is Pterodactylus from the famous Solnhofen Limestone of Bavaria, southern Germany. Originally described in 1784 by the Italian naturalist Cosimo Alessandro Collini, the fossil was considered to be an aquatic animal for 25 years, before Georges Cuvier found out it was a flying reptile belonging to a new, previously unrecognized group.

The oldest specimen of this iconic pterosaur was recently found near Painten, a small town in the southern part of the Franconian Alb in central Bavaria. The fossil, described in a study in the journal Fossil Record, is about one million years older than other Pterodactylus specimens.

The specimen was unearthed in 2014 during excavations in an active limestone quarry. It took more than 120 hours of meticulous mechanical work using pneumatic tools and needles before the researchers could study it. The research team behind the discovery are Felix Augustin, Andreas Matzke, Panagiotis Kampouridis and Josephina Hartung from the University of Tübingen (Germany) and Raimund Albersdörfer from the Dinosaurier Museum Altmühltal (Germany).

“The rocks of the quarry, which yielded the new Pterodactylus specimen, consist of silicified limestone that has been dated to the upper Kimmeridgian stage (around 152 million years ago)”, explains Felix Augustin of the University of Tübingen, who is the lead author of the study. “Previously, Pterodactylus had only been found in younger rocks of southern Germany belonging to the Tithonian stage that follows after the Kimmeridgian”.

The specimen is a complete, well-preserved skeleton of a small-sized individual. “Only a very small portion of the left mandible as well as of the left and right tibia is missing. Otherwise, the skeleton is nearly perfectly preserved with every bone present and in its roughly correct anatomical position”, the researchers write in their study.

With a 5-cm-long skull, the Painten Pterodactylus represents a rare “sub-adult” individual. “Generally, the Pterodactylus specimens are not evenly distributed across the full size range but predominantly fall into distinct size-classes that are separated by marked gaps. The specimen from Painten is a rare representative of the first gap between the small and large sizes,” explains Augustin. “The Painten Pterodactylus was of an intermediate, and rarely found, ontogenetic age at the time of its death, between two consecutive year-classes.”

The Painten quarry has yielded many other “exquisitely preserved fossils”, including ichthyosaurs, turtles, marine and terrestrial crocodile-relatives, and dinosaurs.  Many of them, like this new pterosaur specimen, are on display in the new Dinosaurier Museum Altmühltal in Denkendorf (Bavaria, Germany).

Research article:

Augustin FJ, Kampouridis P, Hartung J, Albersdörfer R, Matzke AT (2022) The geologically oldest specimen of Pterodactylus: a new exquisitely preserved skeleton from the Upper Jurassic (Kimmeridgian) Plattenkalk deposits of Painten (Bavaria, Germany). Fossil Record 25(2): 331-343. https://doi.org/10.3897/fr.25.90692

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Jurassic Park in Eastern Morocco: Paleontology of the Kem Kem Group

The Kem Kem beds in Morocco are famous for the spectacular fossils found there, including at least four large-bodied non-avian theropods, several large-bodied pterosaurs and crocodilians. In their study, published in the open-access journal Zookeys, an international group of scientists, led by Dr. Nizar Ibrahim and Prof. Paul Sereno, evaluate the geological and paleontological significance of the study area.

The Kem Kem beds in Morocco are famous for the spectacular fossils found there, including at least four large-bodied non-avian theropods, several large-bodied pterosaurs and crocodilians.

Now, in a new geology and paleontology monograph, that reveals much more about the famous Kem Kem beds in Morocco, Dr. Nizar Ibrahim from the University of Detroit Mercy, Prof. Paul Sereno from the University of Chicago, and a team of international scholars from the United States, Europe and Morocco, have put together a comprehensive story that is published in the open-access journal Zookeys.

The aim of the new research is to provide the international community with an in-depth review of the rocks and fossils of the region. It reviews the geology and paleontology of this famous but surprisingly understudied area, describing and formally naming the strata and summarizing all of the preserved life forms, from fragile plants and insects to massive dinosaurs. The monograph also paints a picture of life as it once was some 95 million years ago by describing the paleoenvironments of the region, and the unusual predator-dominated fauna.

In 1996 Prof. Sereno and colleagues introduced the informal term “Kem Kem beds” for this fossil-rich escarpment. In this monograph, the authors review the original tri-level proposal for the region by French geologist Choubert (his informal “trilogie mésocretacée”) and propose the Kem Kem Group for the entire package of rock with two new names for the dinosaur-bearing layers based on the richest fossil sites, the Gara Sbaa and Douira formations.

The region is famous for the prodigious fossils found in all of these units, many derived from commercial fossil collecting, which obscures the precise location and level of the specimens. The monograph is the first work to pinpoint where many of the most important finds were made. Over the last 25 years in particular, paleontologists have brought to light a diverse array of new vertebrate fossils including at least four large-bodied non-avian theropods, several large-bodied pterosaurs, crocodilians, turtles and an array of sharks and bony fish.  

To put a comprehensive story together on the Kem Kem, the authors of the monograph visited collections of Kem Kem fossils around the world and led many expeditions to the region. Fossil and geological data reviewed in the monograph is derived from a number of different sources. A University of Chicago-led major expedition in 1995 generated a wealth of geological and paleontological data, as did later expeditions involving teams from the University College Dublin, the University of Portsmouth, the Faculté des Sciences Aïn Chock, the Muséum national d’Histoire naturelle, the University Cadi Ayyad, the Museo Civico di Storia Naturale (Milan), and the University of Detroit Mercy.

One of the key features of the Kem Kem assemblage is the presence of several large-bodied theropods, a group of dinosaurs that includes all of the meat-eaters. Most famous among these from the Kem Kem include the sail-backed Spinosaurus and the sabre-toothed Carcharodontosaurus.

Most fossils in the Kem Kem region are discovered as isolated fragmentary pieces weathered from sandstones. Only four partial dinosaur skeletons or skulls have been recovered, which include the long-necked sauropod Rebbachisaurus garasbae and the theropods Deltadromeus agilis, Carcharodontosaurus saharicus and Spinosaurus aegyptiacus. These Kem Kem theropods are among the largest known dinosaurian predators on record reaching adult body lengths in excess of 12 meters. 

“Given the continued input of new specimens and the continuing expansion of paleontological research, we predict that diversity in the Kem Kem Group will increase substantially in the coming decades. Based on our review of existing collections, this increase will include scores of taxa from the pond locality Oum Tkout including nonvertebrates, such as plants, insects, and ostracods, as well as an array of actinopterygian fish. We also anticipate a continuing trickle of new terrestrial vertebrates that will be named on better preserved specimens that are diagnostic at present only at the familial level, including turtles and various kinds of archosaurs. As nearly half of the reptilian families listed are indeterminate, better preserved specimens will offer future opportunities to recognize new reptilian genera” ,

share the authors.
Predators abound on land, in the air and in water some 95 million years on the shores of northern Africa —as shown by the abundant fossils in the Kem Kem region.
Large herbivores, such as the long-necked sauropod Rebbachisaurus, could have been hunted or scavenged by several large predators.
Credit: Artwork by Davide Bonadonna
License: CC-BY 4.0

“In summary, the Kem Kem assemblage of non-vertebrates and vertebrates is likely to continue to show dramatic increase in diversity in the coming decades. Nonetheless, the array of taxa currently known, which extends from plants across a range of aquatic and terrestrial vertebrates, is sufficiently mature to allow a summary of the vertebrate assemblage and a discussion of its paleoecological contex”,

conclude the researchers.

In his earlier research, a famous paleontologist from the University of Chicago Prof. Paul Sereno has described many outstanding dinosaur discoveries, including new Cretaceous crocodilians from the Sahara and two new fanged vegetarian dinosaur dwarfs (called heterodontosaurids). 


The most famous of Kem Kem dinosaurs, the semi-aquatic giant Spinosaurus, and the most common of Kem Kem fossils, the giant sawfish Onchopristis, tangle in the shallow coastal waters on a warm Late Cretaceous day.
Credit: Artwork by Davide Bonadonna
License: CC-BY 4.0

The wealth of aquatic life, including shrimp, bony fish, lungfish and giant lobe-finned coelacanths, supported a remarkable array of predators, including the fish-eating sail-backed Spinosaurus and toothless pterosaur Alanqa soaring overhead.
Credit: Artwork by Davide Bonadonna
License: CC-BY 4.0

Original source:

Ibrahim N, Sereno PC, Varricchio DJ, Martill DM, Dutheil DB, Unwin DM, Baidder L, Larsson HCE, Zouhri S, Kaoukaya A (2020) Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco. ZooKeys 928: 1-216. https://doi.org/10.3897/zookeys.928.47517

Contacts:

Prof. Paul Sereno
Email: dinosaur@uchicago.edu 

Dr. Nizar Ibrahim
Email: ibrahini@udmercy.edu