So what would it look like if a Manta Ray and a shark produced offspring? Probably something sort of like this Aquilolamna milarcae, nicknamed "eagle shark," was likely a slow moving planktivorous filter-feeder (like modern whale sharks and basking sharks) that more glided through the water than actively swam where the elongated pectoral fins, according to vertebrate paleontologist Romain Vullo from France's National Centre for Scientific Research and the University of Rennes (who lead the team of researchers who described the creature), "mainly acted as an effective stabilizer."
"You could make the analogy of a glider... it wasn't at all adapted to swimming fast and following prey," Vullo observed.
And while the body is similar to the torpedo-shaped one commonly seen on sharks, its head was broad (necessary to gather sufficient plankton through filter feeding). The tail, while distinctly shark-like as well, is typical of those found on sharks that don't rely on speed to eat.
Aquilolamna lived in the open ocean at a time when it was populated with marine reptiles, squid relatives with large shells called ammonites, various bony fishes, and large sharks like the 6 meter long Cretoxyrhina.
I should note that actual manta rays don't appear in the fossil record until the Oligocene, a geologic epoch of the Paleogene Period, which ran from 33.9 to 23 mya. Sharks and rays are completely different groups -- neither evolved from the other.
Here is the abstract from the paper, Manta-like planktivorous sharks in Late Cretaceous oceans:
"You could make the analogy of a glider... it wasn't at all adapted to swimming fast and following prey," Vullo observed.
And while the body is similar to the torpedo-shaped one commonly seen on sharks, its head was broad (necessary to gather sufficient plankton through filter feeding). The tail, while distinctly shark-like as well, is typical of those found on sharks that don't rely on speed to eat.
Aquilolamna lived in the open ocean at a time when it was populated with marine reptiles, squid relatives with large shells called ammonites, various bony fishes, and large sharks like the 6 meter long Cretoxyrhina.
I should note that actual manta rays don't appear in the fossil record until the Oligocene, a geologic epoch of the Paleogene Period, which ran from 33.9 to 23 mya. Sharks and rays are completely different groups -- neither evolved from the other.
Here is the abstract from the paper, Manta-like planktivorous sharks in Late Cretaceous oceans:
Abstract
The ecomorphological diversity of extinct elasmobranchs is incompletely known. Here, we describe Aquilolamna milarcae, a bizarre probable planktivorous shark from early Late Cretaceous open marine deposits in Mexico. Aquilolamna, tentatively assigned to Lamniformes, is characterized by hypertrophied, slender pectoral fins. This previously unknown body plan represents an unexpected evolutionary experimentation with underwater flight among sharks, more than 30 million years before the rise of manta and devil rays (Mobulidae), and shows that winglike pectoral fins have evolved independently in two distantly related clades of filter-feeding elasmobranchs. This newly described group of highly specialized long-winged sharks (Aquilolamnidae) displays an aquilopelagic-like ecomorphotype and may have occupied, in late Mesozoic seas, the ecological niche filled by mobulids and other batoids after the Cretaceous–Paleogene boundary.
The ecomorphological diversity of extinct elasmobranchs is incompletely known. Here, we describe Aquilolamna milarcae, a bizarre probable planktivorous shark from early Late Cretaceous open marine deposits in Mexico. Aquilolamna, tentatively assigned to Lamniformes, is characterized by hypertrophied, slender pectoral fins. This previously unknown body plan represents an unexpected evolutionary experimentation with underwater flight among sharks, more than 30 million years before the rise of manta and devil rays (Mobulidae), and shows that winglike pectoral fins have evolved independently in two distantly related clades of filter-feeding elasmobranchs. This newly described group of highly specialized long-winged sharks (Aquilolamnidae) displays an aquilopelagic-like ecomorphotype and may have occupied, in late Mesozoic seas, the ecological niche filled by mobulids and other batoids after the Cretaceous–Paleogene boundary.
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