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– It swam slowly through the seas with a caudal fin similar to that of modern sharks and lateral fins that extended outward like the wings of modern birds. It’s no wonder, then, that this bizarre creature, who died about 93 million years ago in what is now Mexico, is called the eagle shark. It is especially fitting because the pectoral fins on this specimen – the first of its kind found – gave it a “wingspan” of about 2 meters, overshadowing its length of 1.40 meters, lead researcher Romain Vullo of the French National Center for Scientific Research and the University of Rennes tells Live Science. In 2012, a quarry worker discovered the fossilized shark skeleton and soft tissue imprints in a slab of limestone in Mexico’s Nuevo León state, which was once part of a vast inland sea. The species is mentioned Aquilolamna milarcae, or eagle shark from the Milarca Museum, where the fossil will be on display.
It would have had “a uniquely chimeric look,” says Vullo. But although it is classified as a shark, the eagle shark looked more like a stingray than a great white. The fossil shows no signs of pelvic or dorsal fins – or teeth. “This previously unknown body plan represents an unexpected evolutionary experiment of underwater flight among sharks more than 30 million years before the emergence of mantas and devil rays,” reads the study published Thursday in ScienceAccording to Live Science, modern plankton-eating cartilaginous fish (fish with skeletons made of cartilage) form two groups: those with traditional shark bodies and those with flatter bodies, like rays. The eagle shark is not an ancestor of rays, but was likely a wide-mouthed filter feeder that ate plankton, as rays do today. Vullo tells AFP that rays replaced eagle sharks after most species went extinct about 66 million years ago. (Read more discovery stories.)