Scientists found 46 specimens from four different species of extinct ichthyosaurs.
These creatures, whose Greek name means "fish lizards," were a group of
large, fast-swimming marine reptiles that lived during the Mesozoic
Era, about 245 million to 90 million years ago.
The newly discovered skeletons are from both embryos and adults. The
creatures, likely killed during a series of catastrophic mudslides, were
preserved in deep-sea sediments that were later exposed by the melting
glacier, the researchers said in the study, published May 22 in the
journal Geological Society of America Bulletin
Ichthyosaurs had torpedo-shaped bodies with vertical flippers, and long snouts with teeth.
"They look a lot like dolphins today," said Wolfgang Stinnesbeck, a
paleontologist at the University of Heidelberg in Germany and the leader
of the study.
Stinnesbeck
and his team found the Early Cretaceous (150 million to 100 million
years old) specimens near the Tyndall Glacier in the Torres del Paine
National Park in Chile. As the glacier melted, the rock containing the
fossils became exposed, Stinnesbeck told Live Science.
Very few of the ancient
reptiles have been found in South America before; only a few remnants of
rib cages and vertebrae had been found.
The largest ichthyosaur skeleton unearthed in Chile measures more than
16 feet (5 meters) long. The skeletons were extremely well preserved —
some even retained soft tissues. The researchers also found fossil embryos inside a female specimen. They assigned the fossils to the family Ophthalmosauridae.
These "fish lizards" probably hunted in an underwater canyon near the
coastline, pursuing a diet of squidlike animals and fish, the
researchers said. Occasionally, there would have been mudflows that
cascaded into the water like an avalanche, and the researchers think
these mudflows killed the ichthyosaurs. The animals likely became
disoriented and drowned, getting sucked into the deep sea, where their
bodies were entombed in the sediment, the researchers said.
Ichthyosaurs
swam the seas at the same time as dinosaurs roamed the Earth and
pterosaurs reigned the skies, but they may have died out before their
land- and air-dwelling brethren, Stinnesbeck said. A global depletion of
oxygen in the oceans, possibly due to volcanism, may have caused the
extinction of these seagoing reptiles, he said.
The discovery of these creatures establishes the Chilean glacier as one
of the prime sites for Early Cretaceous marine reptiles worldwide, the
researchers said. But getting to the fossil site is half the battle. To
reach it, the team had to drive for five hours, hike for 10 to 12 hours
to camp and then hike another two hours, sometimes in heavy rain, hail
or snow.
"This has been one of the toughest field camps I ever had," Stinnesbeck said.
