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Image: Tentative existence reconstruction of the hybodontiform shark Asteracanthus for scale see silhouettes at the suitable reduced corner
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Credit score: © Sebastian Stumpf/Fabrizio De Rossi

In a new study, an international research team led by Sebastian Stumpf from the University of Vienna describes an extremely properly-preserved skeleton of the historical shark Asteracanthus. This particularly rare fossil come across comes from the well known Solnhofen limestones in Bavaria, which was shaped in a tropical-subtropical lagoon landscape in the course of the Late Jurassic, about 150 million a long time in the past. The practically full skeleton shows that Asteracanthus was two-and-a-half meters extensive in existence, which can make this historical shark 1 of the largest of its time. The examine is published in the journal Papers in Palaeontology.

Cartilaginous fishes, which consist of sharks and rays, are a single of the most profitable vertebrate groups nonetheless alive currently. Due to their life-extensive tooth substitution, teeth of cartilaginous fishes are between the most common fossil vertebrate finds. Nevertheless, the lower preservation possible of their cartilaginous skeletons helps prevent fossilization of entirely preserved specimens in most situations. The exceptionally unusual preservation of fossil cartilaginous fish skeletons is as a result connected to exclusive conditions in the course of fossilization and restricted to a couple fossil-bearing localities only.

The Solnhofen limestones in Bavaria, Germany, which had been shaped during the Late Jurassic, about 150 million a long time back, is these kinds of a rare occurrence. They are environment-renowned for owning developed skeletons of the modest feathered dinosaur Archaeopteryx and have yielded numerous shark and ray skeletons, recovered for the duration of excavations over the earlier 150 years. A new analyze released in the journal Papers in Palaeontology and led by the paleontologist Sebastian Stumpf from the College of Vienna provides the major fossil shark skeleton that has ever been uncovered in the Solnhofen limestones. The specimen is represented by an just about absolutely preserved skeleton of the extinct hybodontiform shark Asteracanthus, the complete size of which was two-and-a-fifty percent meters in everyday living, which produced it a huge between Jurassic sharks.

Hybodontiform sharks, which are the closest kin of modern-day sharks and rays, 1st appeared during the most current Devonian, about 361 million decades back, and went extinct with each other with dinosaurs at the conclude of the Cretaceous, about 66 million several years ago. They experienced two dorsal fins, every supported by a prominent fin spine. The human body dimensions of hybodontiform sharks ranged from a number of centimeters to somewhere around a few meters in greatest size, which therefore would make Asteracanthus a single of the greatest reps of the two its group and its time. In distinction, present day sharks and rays, which were being previously various through the Jurassic, only achieved a physique size of up to two meters in greatest size in really rare situations.

Asteracanthus was scientifically explained additional than 180 many years in the past by the Swiss-American naturalist Louis Agassiz on the foundation of isolated fossil dorsal fin spines. Nonetheless, articulated skeletal stays have never ever been observed – until now. The dentition of the skeleton is exceptionally very well-preserved and consists of far more than 150 teeth, every with a properly-developed central cusp that is accompanied on equally sides by quite a few lesser cusplets. “This specialised sort of dentition indicates that Asteracanthus was an energetic predator feeding on a broad assortment of prey animals. Asteracanthus was definitely not only one particular of the largest cartilaginous fishes of its time, but also a single of the most remarkable.” claims Sebastian Stumpf.

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Publication in Papers in Palaeontology:&#13
Stumpf, S., López-Romero, F.A., Kindlimann, R., Lacombat, F., Pohl, B. & Kriwet, J. 2020. A distinctive hybodontiform skeleton provides novel insights into Mesozoic chondrichthyan daily life. Papers in Palaeontology.

DOI: https://doi.org/10.1002/spp2.1350&#13

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