Approximately 93 million years ago, a peculiar plankton-consuming shark with a shape never seen before glided through the sea in what is nowadays’ Mexico with the help of a pair of spectacular wing-like fins that made its body wider than it was long.
The discovery of the nearly complete fossil of the shark, known as Aquilolamna milarcae that thrived during the Cretaceous Period, was announced on Thursday.
Its curious proportions – the fin span of approximately 1.9 meters and a length between the head to its tail of 1.65 meters left multiple scientists puzzled.
The creature’s name translates to “eagle shark,” a reference to its pectoral fins, which worked like an effective stabilizer, Romain Vullo, a palaeontologist and lead author of the study that was recently published in the journal Science says.
“Many adjectives can be used to describe this shark: unusual, unique, extraordinary, bizarre, weird. Yes, it is the only shark that is wider than long. Aquilolamna is indeed a perfect example of an extinct creature revealing an unexpected new morphology. This strongly suggests that other outstanding body shapes and morphological adaptations may have existed through the evolutionary history of sharks,” Vullo said.
Like all sharks and their relatives, rays and skates, Aquilolamna presented a cartilaginous skeleton. It had the typical torpedo-shaped body and tail of a shark, but it had huge, unique pectoral fins.
The researchers claimed that the specimens seem to have been a slow-swimming species fed on plankton via filter-feeding, as many whale sharks and basking sharks do today.
The fossil was discovered in Mexico’s state of Nuevo Leon, and it did not reveal the shark’s filter mechanism for feeding.