Scientists have discovered a vast graveyard of ancient marine reptiles, hidden under a glacier in Chile, that could change our understanding of how the species lived, died – and ultimately became extinct altogether.

Palaeontologists at the remote site in the southern Torres del Paine National Park said rocks containing nearly 50 complete ichthyosaur fossils were exposed as the vast Tyndall Glacier melted.

The specimens, from four different species of the ancient reptiles whose Greek name means “fish lizard”, lived between the Triassic and Cretaceous periods, which extended from 250 million to 66 million years ago.

Download the new Independent Premium app Sharing the full story, not just the headlines

Christian Salazar, a palaeontologist and natural history museum curator, said the way the remains had been deposited at the ichthyosaur cemetery was “unique”.

“It's the most recent great find in their history,” he said. “That's going to answer a lot of questions about how they became extinct, where they migrated to and how they lived.”

Shape Created with Sketch. In pictures: 12 amazing archaeological discoveries Show all 12 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. In pictures: 12 amazing archaeological discoveries 1/12 Ancient forest, discovered in February 2014 Ancient forest revealed by storms. The recent huge storms and gale force winds that have battered the coast of West Wales have stripped away much of the sand from stretches of the beach between Borth and Ynyslas. The disappearing sands have revealed ancients forests, with the remains of oak trees dating back to the Bronze Age, 6,000 years ago. The ancient remains are said by some to be the origins of the legend of ‚Cantre‚r Gwealod‚ , a mythical kingdom now submerged under the waters pif Cardigan Bay 2/12 Medieval royal palaces, discovered in November 2014 Archaeologists in southern England have discovered what may be one of the largest medieval royal palaces ever found – buried under the ground inside a vast prehistoric fortress at Old Sarum. The probable 12th century palace was discovered by archaeologists, using geophysical ground-penetrating ‘x-ray’ technology to map a long-vanished medieval city which has lain under grass on the site for more than 700 years 3/12 The Dead Sea Scrolls, discovered ca. 1950 The Dead Sea Scrolls are almost 1,000 biblical manuscripts discovered in the decade after the Second World War in what is now the West Bank. The texts, mostly written on parchment but also on papyrus and bronze, are the earliest surviving copies of biblical and extra-biblical documents known to be in existence, dating over a 700-year period around the birth of Jesus. The ancient Jewish sect the Essenes is supposed to have authored the scrolls, written in Hebrew, Aramaic and Greek, although no conclusive proof has been found to this effect 4/12 Diamond, discovered in March 2014 This rare diamond that survived a trip from deep within the Earth's interior confirmed that there is an ocean’s worth of water beneath the planet’s crust 5/12 Whale skeletons, discovered in February 2014 Chilean and Smithsonian paleontologists study several fossil whale skeletons at Cerro Ballena, next to the Pan-American Highway in the Atacama Region of Chile 6/12 Complete mammoth skeleton, discovered in November 2012 The first complete mammoth skeleton to be found in France for more than a century was uncovered in a gravel pit on the banks of the Marne, 30 miles north-east of Paris. Picture shows experts at work making a silicon cast of the mammoth's tusk 7/12 Million-year-old human footprints, discovered in February 2014 Photograph of the footprint hollows in situ on the beach as Happisburgh, Norfolk 8/12 Terracotta warrior, discovered in June 2010 Chinese archaeologists unearthed around 120 more clay figures in June 2010 excavations at the terracotta army site that surrounds the tomb of the nation's first emperor in the northwestern Shaanxi Province © Jason Lee / Reuters 9/12 Neolithic 'lost avenue' - prehistoric stone circle, discovered in September 1999 The discovery of a Neolithic 'lost avenue' was described as one of the most important finds of the last century. Since the 1700s, archeologists and historians have argued over the existence of the huge sarsen stones, which were unearthed at the site of the world's biggest prehistoric stone circle at Avebury in Wiltshire 10/12 Byzantine mosaic, discovered in February 2007 Plans for a walkway at the centre of the furious dispute over Jerusalem's holiest site were delayed by the discovery of a Byzantine mosaic 11/12 Ancient gold, discovered in March 2014 Gold fitting for a dagger sheath (around 1900 BC.) found near Stonehenge 12/12 Rosetta Stone, discovered in 1799 The Rosetta Stone is a basalt slab inscribed with a decree of pharaoh Ptolemy Epiphanes (205-180 BC) in three languages, Greek, Hieroglyphic and Demotic script. Discovered near Rosetta in Egypt 1/12 Ancient forest, discovered in February 2014 Ancient forest revealed by storms. The recent huge storms and gale force winds that have battered the coast of West Wales have stripped away much of the sand from stretches of the beach between Borth and Ynyslas. The disappearing sands have revealed ancients forests, with the remains of oak trees dating back to the Bronze Age, 6,000 years ago. The ancient remains are said by some to be the origins of the legend of ‚Cantre‚r Gwealod‚ , a mythical kingdom now submerged under the waters pif Cardigan Bay 2/12 Medieval royal palaces, discovered in November 2014 Archaeologists in southern England have discovered what may be one of the largest medieval royal palaces ever found – buried under the ground inside a vast prehistoric fortress at Old Sarum. The probable 12th century palace was discovered by archaeologists, using geophysical ground-penetrating ‘x-ray’ technology to map a long-vanished medieval city which has lain under grass on the site for more than 700 years 3/12 The Dead Sea Scrolls, discovered ca. 1950 The Dead Sea Scrolls are almost 1,000 biblical manuscripts discovered in the decade after the Second World War in what is now the West Bank. The texts, mostly written on parchment but also on papyrus and bronze, are the earliest surviving copies of biblical and extra-biblical documents known to be in existence, dating over a 700-year period around the birth of Jesus. The ancient Jewish sect the Essenes is supposed to have authored the scrolls, written in Hebrew, Aramaic and Greek, although no conclusive proof has been found to this effect 4/12 Diamond, discovered in March 2014 This rare diamond that survived a trip from deep within the Earth's interior confirmed that there is an ocean’s worth of water beneath the planet’s crust 5/12 Whale skeletons, discovered in February 2014 Chilean and Smithsonian paleontologists study several fossil whale skeletons at Cerro Ballena, next to the Pan-American Highway in the Atacama Region of Chile 6/12 Complete mammoth skeleton, discovered in November 2012 The first complete mammoth skeleton to be found in France for more than a century was uncovered in a gravel pit on the banks of the Marne, 30 miles north-east of Paris. Picture shows experts at work making a silicon cast of the mammoth's tusk 7/12 Million-year-old human footprints, discovered in February 2014 Photograph of the footprint hollows in situ on the beach as Happisburgh, Norfolk 8/12 Terracotta warrior, discovered in June 2010 Chinese archaeologists unearthed around 120 more clay figures in June 2010 excavations at the terracotta army site that surrounds the tomb of the nation's first emperor in the northwestern Shaanxi Province © Jason Lee / Reuters 9/12 Neolithic 'lost avenue' - prehistoric stone circle, discovered in September 1999 The discovery of a Neolithic 'lost avenue' was described as one of the most important finds of the last century. Since the 1700s, archeologists and historians have argued over the existence of the huge sarsen stones, which were unearthed at the site of the world's biggest prehistoric stone circle at Avebury in Wiltshire 10/12 Byzantine mosaic, discovered in February 2007 Plans for a walkway at the centre of the furious dispute over Jerusalem's holiest site were delayed by the discovery of a Byzantine mosaic 11/12 Ancient gold, discovered in March 2014 Gold fitting for a dagger sheath (around 1900 BC.) found near Stonehenge 12/12 Rosetta Stone, discovered in 1799 The Rosetta Stone is a basalt slab inscribed with a decree of pharaoh Ptolemy Epiphanes (205-180 BC) in three languages, Greek, Hieroglyphic and Demotic script. Discovered near Rosetta in Egypt

Wolfgang Stinnesbech, a palaeontologist from the University of Heidelberg in Germany who led the study, told Live Science that the ichthyosaurs, which “look a lot like dolphins today”, were extraordinarily well-preserved.

Only a small number of partial remnants from the ancient reptiles have ever been found in South America before, making this find all the more unusual.

Stinnesbech said these ichthyosaurs hunted for fish and squid-like creatures in flooded caves and canyons near the coastline, and were probably killed by a sudden mudslide to be preserved so well.

Such mudflows due to global warming have been described as one possible cause for the species to become extinct. Stinnesbeck said ichthyosaurs ruled the Earth’s seas at the same time as the dinosaurs and pterosaurs, but that they may well have died out before their land- and air-dwelling counterparts.