Paleontologists Unearth 139 Million-Year-Old Pregnant Dinosaur Fossil in Chile

The fossilized remains of a 13ft-long pregnant ichthyosaur have been uncovered in Chile – marking the first time a complete ichthyosaur has been found in the country.
The remains of the creature, named Fiona, were unearthed by researchers from the University of Manchester from a melting glacier deep in Patagonia. Fiona was pregnant at the time of her death 139 million years ago, with several embryos still in her belly.

paleontologists-unearth-139-million-year-old-pregnant-dinosaur-fossil-in-chileDr Dean Lomax, a paleontologist working on the study, said: ‘The fact that these incredible ichthyosaurs are so well preserved in an extreme environment, revealed by a retreating glacier, is unlike anywhere else in the world. ‘The considerable number of ichthyosaurs found in the area, including complete skeletons of adults, juveniles, and newborns provides a unique window into the past.’

Ichtyhosaurs were marine reptiles that lived in the age of the dinosaurs, and are famous for their fish-like shape, resembling today’s dolphins. Fiona’s remains were uncovered during an expedition to the Tyndall Glacier during March and April 2022.The glacier is a 10-hour-hike or horse ride away, making collecting the specimen particularly difficult.
The expedition lasted 31 days and was described by the researchers as an ‘almost titanic challenge.’ The ichthyosaur is the only pregnant female of Valanginian-Hauterivian age (between 129 and 139 million years old from the Early Cretaceous) recorded and extracted on the planet. ‘At four metres long, complete, and with embryos in gestation, the excavation will help to provide information on its species, on the palaeobiology of embryonic development, and on a disease that affected it during its lifetime,’ said Dr Judith Pardo-Perez from the University of Magallanes, who led the study.

paleontologists-unearth-139-million-year-old-pregnant-dinosaur-fossil-in-chileAlongside Fiona, 23 other new specimens were discovered during the expedition, making the Tyndall Glacier the most abundant ichthyosaur graveyard in the world, according to the team. ‘The results of the expedition met all expectations, and even more than expected,’ Dr Pardo-Perez added. ‘We hope to obtain results on the diversity, disparity and palaeobiology of the ichthyosaurs of the Tyndall Glacier locality, establish degrees of bone maturity and ecological niches to evaluate possible dietary transitions that occurred throughout their evolution and that could help to establish palaeobiogeographical connections with ichthyosaurs from other latitudes.


To excavate Fiona, the researchers constructed a hangar over her remains and had to contend with heavy winds, rain and snow. They also needed specialist equipment to break through the hard rock. ‘The rock of the outcrop is so hard that it cannot be excavated with a lump hammer, chisel and brush, and we had to cut, drill and break blocks with diamond and high calibre tools,’ said Hector Ortiz, one of the excavators.

‘We were only two people who made glacier camp and, in a month of field work, we managed to get the most complete ichthyosaur from the southern tip of America to the world in two helicopter flights.’ Once they had managed to excavate Fiona, they then had to transport her remains from high in the Tyndall Glacier to the Rio Seco Museum of Natural History in Punta Arenas, around 250 miles away.

The ichthyosaur will now be prepared in the palaeontology laboratory at the museum, where it will be temporarily stored for later exhibition. The other ichthyosaurs found at the site will not be excavated. ‘We have almost a hundred ichthyosaurs in the Tyndall Glacier fossil deposit and many of them, unfortunately, will never be excavated, due to the difficulty of access, being in risk areas (cliff edge), and lack of funds etc,’ Dr Pardo-Perez explained. ‘The ichthyosaurs that will not be excavated need protection and consolidation in situ, as the erosion to which they are being subjected on a daily basis is destroying them.’

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