Shell-cracking turtles defied mass extinction at the end of the Cretaceous period
Staatliche Naturwissenschaftliche Sammlungen Bayerns
image:
Reconstruction of a snail-eating turtle of the group Baenidae. It is sitting on a land turtle of the genus Basilemys, which became extinct at the end of the Cretaceous period. In the background is a skull of Tyrannosaurus rex.
view moreCredit: Joschua Knüppe, Palaeoartist
The mass extinction at the boundary between the Cretaceous and Paleogene periods was catastrophic, wiping out much of Life on Earth. Vertebrate groups that dominated at the time, such as dinosaurs and many large marine reptiles, fell victim to the effects of the asteroid impact around 66 million years ago. However, the catastrophe did not affect all organisms to the same extent: turtles, for example, survived with only minimal losses.
A new study by the research group led by Serjoscha Evers, paleontologist at the Bavarian State Collection of Natural History (SNSB), now shows that turtles that fed on hard-shelled organisms such as gastropods and bivalves survived the mass extinction largely unscathed. And they were more than five times more likely to survive than turtles that hunted fish or were purely herbivorous.
Apparently, this ecological adaptation in turtles had an impact on their probability of survival. “We are observing an ecological filter. Specializing in hard-shelled food gave these turtle species an evolutionary advantage,” explains author Serjoscha Evers. "This is probably due to the resilience of these food sources themselves – mainly gastropods and bivalves – to the catastrophic effects of the impact. Herbivores had difficulty surviving in the nuclear winter following the impact, with effects on the entire food chain, including carnivores. Mollusks and other opportunists, on the other hand, were able to survive well. Turtles that specialized in such prey were therefore under less pressure."
The diet of turtles is revealed by special anatomical features of their jaws. On this basis, Serjoscha Evers and his doctoral student Guilherme Hermanson from the University of Fribourg in Switzerland constructed a large data set that includes all turtle lineages at the Cretaceous-Paleogene boundary. This enabled the paleontologists to use statistical models to assess how diet as an ecological factor influenced the probability of extinction in turtles.
Senior author Serjoscha Evers is director of the Urwelt-Museum Oberfranken, one of ten museums belonging to the Bavarian State Collection of Natural History (SNSB). Guilherme Hermanson is a doctoral student at the University of Fribourg in Switzerland.
Jurassic turtle (Solnhofia parsonsi) with broadened jaw ridges adapted for crushing hard-shelled food (permanent exhibition Jura Museum Eichstätt / Collection of the Bischöfliches Seminar Eichstätt)
Credit
Photo: Serjoscha Knüppe
Photo: Serjoscha Knüppe
Journal
Biology Letters
Subject of Research
Animals
Article Title
Ecological selectivity of diet on turtle K/Pg survivorship
Article Publication Date
25-Mar-2026
Prehistoric fish: coelacanths heard underwater using their lungs
A study by UNIGE and MHNG shows that 240-million-year-old coelacanths could hear underwater using an ossified lung
image:
3D rendering of the skeleton of Graulia branchiodonta. The auditory organ includes the bony wings (red) on the ossified lung (white) which transmitted sound vibrations to the inner ear (not shown) located in the prootic bone in the skull (pink)
view moreCredit: © L. Manuelli–MHNG
How did ancient fish perceive their environment in the deep-sea? An international team led by scientists from the Natural History Museum of Geneva (MHNG) and the University of Geneva (UNIGE) reveals that some coelacanths – fish living 240 million years ago – used their lung to detect sounds underwater. These findings, published in the journal Communications Biology, were obtained using synchrotron imaging, an especially powerful X-ray technique. They shed new light on the evolution of sensory systems in vertebrates.
Coelacanths have fascinated biologists since their rediscovery in the 20th century. These fish, now represented by two species of the genus Latimeria, are more closely related to terrestrial vertebrates than to other fishes. While modern species live at great depths and breathe exclusively through gills, their ancestors from around 240 million years ago displayed a much wider diversity of forms and habitats. Some had a well-developed lung covered with bony plates arranged like roof tiles. Until now, this organ has mainly been interpreted as an adaptation for air breathing.
To explore its potential additional functions, a research team led by Lionel Cavin, curator at the Natural History Museum of Geneva and adjunct professor in the Department of Genetics and Evolution at the Faculty of Science of the University of Geneva, analyzed Triassic coelacanth fossils discovered in Lorraine (France). The fossils were examined using the European Synchrotron Radiation Facility (ESRF) in Grenoble. This particle accelerator made it possible to investigate the internal structure of the fossils with micrometric precision.
A new auditory system revealed by imaging
The images revealed an exceptionally well-preserved ossified lung, featuring wing-like bony structures at its extremity. At the same time, the study of embryos of modern coelacanths highlighted a canal connecting the organs of hearing and balance located on either side of the skull.
By combining these observations, the scientists suggest that these two structures formed a complete sensory system. Sound waves captured by the ossified lung would have been transmitted to the inner ears via this canal, enabling the animal to perceive sounds underwater. “Our hypothesis is based on analogies with modern freshwater fish such as carp or catfish. In these species, a structure known as the Weberian apparatus connects the swim bladder to the inner ear. This system allows them to detect underwater waves and therefore hear underwater. The air bubble contained in the swim bladder is essential for detecting these waves, which would otherwise pass through the fish’s body undetected,” explains Luigi Manuelli, a doctoral student in Lionel Cavin’s group and first author of the study.
A capacity lost over the course of evolution
For now, this anatomical feature has only been observed in two species of Triassic coelacanths. However, it may have been more widespread among ancient coelacanths possessing an ossified lung. “This auditory ability was likely gradually lost as the ancestors of modern coelacanths adapted to deep marine environments. Their lung regressed, making this system unnecessary,” suggests Lionel Cavin.
Remarkably, some structures associated with the inner ear have nonetheless been preserved. “These anatomical remnants now provide valuable insight into the evolutionary history of these fish – and perhaps also into that of our own aquatic ancestors,” the researcher concludes.
Reconstruction of a Triassic coelacanth (Graulia branchiodonta or Loreleia eucingulata) schematically showing the otophysic connection linking the ossified lung to the inner ear and enabling underwater hearing
Credit
© A. Beneteau (reconstruction), L. Cavin (diagram) – MHNG
Journal
Communications Biology
Method of Research
News article
Subject of Research
Not applicable
Article Title
A dual respiratory and auditory function for the coelacanth lung
Article Publication Date
19-Mar-2026
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