Scientists have analysed the soft tissue preserved in a nearly complete Jurassic plesiosaur fossil. This is the first in-depth study of plesiosaur soft tissues to be published.  The study has been published in the journal “Current Biology”.  The research was led by scientists from Lund University (Sweden).  The results show that some plesiosaurs had smooth skin on the body and small scales on the flippers.  This integumentary covering permitted maximum swimming efficiency by reducing drag.  The scales on the flippers are reminiscent of modern reptile scales.  They may have played a role in flipper hydrodynamics and/or provided protection and traction as these marine reptiles moved across rough seabeds in search of food (benthic feeding).

Reconstruction of the new plesiosaur with scales on the flipper and smooth scale-less skin along the body as informed by this new plesiosaur fossil. This is a significant update to how we reconstruct plesiosaurs which has otherwise not change substantially since their initial discovery more than 200 years ago. Picture credit: Joschua Knüppe.

Picture credit: Joschua Knüppe

Studying a Remarkable Jurassic Plesiosaur

Plesiosaurs are an iconic group of Mesozoic marine reptiles with an evolutionary history spanning over 140 million years Their skeletal remains have been discovered worldwide. However, accompanying fossilised soft tissues are exceptionally rare. Only eight instances of plesiosaur soft tissue preservation have been reported to date. The research team examined a beautifully preserved fossil specimen from the Lower Jurassic Posidonia Shale (Posidonienschiefer Formation) of southern Germany.  The fossil is estimated to be around 183 million years old.  It dates from the Toarcian faunal stage of the Early Jurassic.

Skeleton of the new plesiosaur at the Urwelt-Museum Hauff in Holzmaden, Germany. Picture credit: Klaus Nilkens/Urwelt-Museum Hauff.

Picture credit: Klaus Nilkens/Urwelt-Museum Hauff

Until now, little was known about the external anatomy of plesiosaurs.  For example, considerable debate has occurred in regards to whether plesiosaurs had tail flukes, and if they did, what shape they were.  In 2021, CollectA introduced a replica of the Late Cretaceous derived plesiosaur Elasmosaurus.  This model had a diamond-shaped tail fluke.  In Everything Dinosaur’s video review of this figure, the controversy over the tail fluke was highlighted.

To read more about this and to view Everything Dinosaur’s video review: New for 2021 CollectA Figures Including a New Interpretation of Elasmosaurus.

The specimen (MH 7) was excavated from a quarry near the town of Holzmaden in 1940. More complete preparation undertaken in 2020 revealed traces of soft tissue preservation. The soft tissue was associated with the tail and the trailing edge of the right forelimb.

Skin from the bottom half of the tail in the new plesiosaur. The skin as preserved is beige in colour with some parts showing a pitted surface. This pitted surface represents the underside of the skin, with the outer surface facing into the rock matrix. Picture credit: Klaus Nilkens/Urwelt-Museum Hauff.

Picture credit: Klaus Nilkens/Urwelt-Museum Hauff

What Does Specimen MH 7 Reveal?

The scientists utilised a variety of techniques, including transmitted light microscopy (TLM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), examining specimen MH 7 in unprecedented detail. In addition, the researchers used electron backscatter diffraction (EBSD), infrared (IR) microspectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to reveal details of the integumentary covering including the identification of potential melanosomes.

Their research indicates that plesiosaurs had both smooth and scaly skin.

The tip of the right flipper with two scales along the trailing edge. Picture credit: Klaus Nilkens/Urwelt-Museum Hauff.

Picture credit: Klaus Nilkens/Urwelt-Museum Hauff

Lead author of the study into this remarkable Jurassic plesiosaur fossil, Miguel Marx, a PhD student in geology at Lund University commented:

“Fossilised soft tissue, such as skin and internal organs, is exceptionally rare. We used a broad range of techniques to identify smooth skin in the tail region as well as scales along the rear edge of the flippers. This provided us with unparalleled insights into the appearance and biology of these long-extinct reptiles.”

Smooth and Scaly Skin

An unusual combination of smooth and scaly skin on different parts of the body was revealed.  The scientists conclude that this variation related to different functions.  For example, the plesiosaur needed to be streamlined so that it could swim efficiently.  Moreover, the smooth and hydrodynamic skin would have reduced drag and helped the animal to use less energy as it swam after prey.  However, it also needed to move across rough seafloors, the scaly flippers would have likely allowed it to do so with maximum efficiency and without damaging its skin.

Miguel Marx added:

“Our findings help us create more accurate life reconstructions of plesiosaurs, something that has been extremely difficult since they were first studied over 200 years ago. Also, the well-preserved German fossil really highlights the potential for soft tissue in providing valuable insights into the biology of these long-extinct animals.”

A close-up image of the two scales from the right flipper. Note the triangular shape of the scale remnants that are distinct from the skin found on the tail of this plesiosaur.
Picture credit: Klaus Nilkens/Urwelt-Museum Hauff.

Picture credit: Klaus Nilkens/Urwelt-Museum Hauff

Reconstructing the Appearance of an Ancient Marine Reptile

With a better understanding of the anatomy and adaptations of extinct creatures palaeontologists can develop an improved understanding of macroevolution.  Furthermore, in recreating the past, scientists can make better predictions about future events.

Summarising the importance of this study, Miguel Marx stated:

“Apart from the mosaic of smooth skin and scales, it was an incredible moment to visualize the cells in thin sections of the fossilized plesiosaur’s skin. I was shocked when I saw skin cells that had been preserved for 183 million years. It was almost like looking at modern skin.”

In addition to Lund University, collaborators from Uppsala University, RISE (Research Institutes of Sweden), Naturkunde-Museum Bielefeld, and Urwelt-Museum Hauff took part in this research.

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

The scientific paper: “Skin, scales, and cells in a Jurassic plesiosaur” by Miguel Marx, Peter Sjövall, Benjamin P. Kear, Martin Jarenmark, Mats E. Eriksson, Sven Sachs, Klaus Nilkens, Michiel Op De Beeck and Johan Lindgren published in Current Biology.

The award-winning Everything Dinosaur website: Models of Prehistoric Animals.

A newly published scientific paper demonstrates that an Edmontosaurus fossil contains collagen. The study confirms fossils can retain original organic materials.  The discovery of hydroxyproline, a unique collagen-indicator amino acid, in acid-digested samples resolves a long-standing debate amongst palaeontologists.  Identifying organic materials in dinosaur bones could provide a new perspective on the Dinosauria.

Reports of proteins in fossilised bones have been a subject of controversy in the scientific literature.  It is assumed that fossilisation results in the destruction of all organic components.  However, this new research adds weight to the theory that in exceptional circumstances traces of organic materials can persist for tens of millions of years.  Research led by scientists from the University of Liverpool suggests that Mesozoic fossils could still preserve remnants of original organic materials.

A view of the inside of the Edmontosaurus fossil bone. An exceptionally well-preserved Edmontosaurus sacrum excavated from the Upper Cretaceous strata of the South Dakota Hell Creek Formation is demonstrated to preserve evidence of hydroxyproline. Hydroxyproline is a unique collagen-indicator amino acid. Picture credit: University of Liverpool.

Picture credit: University of Liverpool

Edmontosaurus Fossil Contains Collagen

The research team used mass spectrometry and other advanced techniques to tease out traces of preserved collagen within the sacrum of an Edmontosaurus.  Edmontosaurus is a duck-billed dinosaur (family Hadrosauridae).  Fossils of these taxon come from Upper Cretaceous deposits of North America. It was a large, herbivorous dinosaur. Some specimens indicate a body length in excess of thirteen metres.

The CollectA Deluxe 1:40 scale Edmontosaurus dinosaur model. A detailed analysis of Edmontosaurus hip bone fossils (sacrum) reveals evidence of collagen.

The picture (above) shows a model of Edmontosaurus.  This figure is from the CollectA Deluxe series.

To view the range of CollectA Deluxe prehistoric animal models: CollectA Deluxe Prehistoric Animal Figures.

Writing in the journal “Analytical Chemistry” the researchers outline several techniques, including protein sequencing that led to the detection of collagen in the fossilised bone. The specimen (a sacrum), was excavated from Hell Creek Formation deposits located in South Dakota. It is part of the University of Liverpool’s collections and offered a unique opportunity for cutting-edge analyses.

The Implications of this Research

Commenting on the significance of this study, co-author Professor Steve Taylor (chair of the Mass Spectrometry Research Group at the University of Liverpool), stated:

“This research shows beyond doubt that organic biomolecules, such as proteins like collagen, appear to be present in some fossils. Our results have far-reaching implications. Firstly, it refutes the hypothesis that any organics found in fossils must result from contamination. Secondly, it suggests that cross-polarised light microscopy images of fossil bones, collected for a century, should be revisited. These images may reveal intact patches of bone collagen, potentially offering a ready-made trove of fossil candidates for further protein analysis. This could unlock new insights into dinosaurs. For example, revealing connections between dinosaur species that remain unknown. Lastly, the findings inform the intriguing mystery of how these proteins have managed to persist in fossils for so long.”

Researchers from the University of California were also involved in this study.  Mass spectrometry was used to detect and quantify, for the first time, the amino acid hydroxyproline, which is specific to collagen when found in bone, thus confirming the presence of decayed collagen.

Edmontosaurus fossil specimen used in collagen study. Picture credit: University of Liverpool.

Picture credit: University of Liverpool

The researchers conclude that their study demonstrated the presence of identical collagen peptide sequences previously discovered in another hadrosaur and a T. rex sample.

Links to Other Blog Posts

To read an article from 2017 about a study that identified fragments of collagen in the femur of a hadrosaur (Brachylophosaurus):Researchers Confirm the Presence of Dinosaur Collagen.

Traces of organic material discovered in a juvenile hadrosaur fossil: Has Dinosaur DNA Been Found?

Research from 2008 outlining the search for organic materials in a femur of Tyrannosaurus rex: Are You Going to Call the “Tyrant Lizard King” Chicken?

This newly published research opens further avenues for studying ancient life, offering a glimpse into the biochemical preservation of fossils of extinct creatures.

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

The scientific paper: “Evidence for Endogenous Collagen in Edmontosaurus Fossil Bone” by Lucien Tuinstra, Brian Thomas, Steven Robinson, Krzysztof Pawlak, Gazmend Elezi, Kym Francis Faull, and Stephen Taylor published in Analytical Chemistry.

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