The fossil shark flew under the water like a ray
Early in the Cretaceous period, some wide-winged sharks flew underwater, like large rays today. This was surprising to experts who previously suspected that this type of underwater excursion did not occur until much later, when the ancestors of the day’s rays specialized in it. However, a team of European and Mexican paleontologists have now discovered the “eagle shark” fossil that was able to sail underwater with fins that were more than 93 million years long.
The Aquilamna Melark The baptized animal was provided from the Cretaceous period by Roman Follo’s team from the University of Rennes In the magazine “Science”. The research team also included scientists from the Jura Eichstätt Museum, the universities of Heidelberg and Bonn, the Karlsruhe Museum of Natural History, and from France and Mexico. They excavated a fossil specimen of a 1.7-meter-long eagle shark in a limestone quarry near Vallecilo, in northeastern Mexico. According to reconstructions, the shark was wider than its length and had pectoral fins with a wingspan of 1.9 meters.
Plate gills, which include all sharks and rays, appeared with their first specimens about 380 million years ago, and today they fill many ecological niches. In addition to the classic carnivorous sharks, there are also many forms that feed on plankton. A distinction is made between large shapes with structures typical of sharks such as whale sharks and shapes such as predatory eagle rays and devil rays, which tend to float above the sea floor and mainly filter plankton from the water. The eagle shark that has now been discovered has a wide mouth, possibly with small teeth, at the end of a blunt head. So experts assume it was also a plankton eater.
© Vullo, R. et al: Late Cretaceous Manta Sharks. Science 371, 2021, fig. 1 A (Oceannet)
Eagle Shark Fossil | The fossil of an eagle shark lived about 93 million years ago. The animal was 1.7 meters long and had pectoral fins 1.9 meters long, with which it could glide underwater in a similar – but not quite – manner like a ray.
The combination of body structure, wing-like pectoral fins and filtering of food, typical of devil rays, existed as early as the Cretaceous – and thus long before the existence of the Devil’s rays. Accordingly, it is clear that underwater flight of sharks and rays occurred twice and in different ways during evolution, the researchers write in Science. It is possible that the eagle shark of the Cretaceous period did not swim like a manta today, so instead of wavy pectoral fin movements, the forked caudal fin may have pushed the extinct shark forward.
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