In the shadow of a massive Patagonian glacier, paleontologists have made a rare fossil find: an ancient marine reptile that died during pregnancy. This dolphin-like creature, called an ichthyosaur, is the first of its kind to be discovered in Chile, recovered from a drill site near the Tyndale Glacier in a southern Patagonian glacier field.
“This site is really unique, because it records a time period in Earth history where we don’t have a very good fossil record of marine reptiles,” Erin Maxwell, an ichthyosaur specialist and curator of marine reptiles at the State Museum of Natural History in Stuttgart, Germany who helped excavate the fossil, told Live Science.
Ichthyosaurs (which translate to “fish lizards”) dominated the seas beginning in the early Triassic period, about 251 million years ago, and lived along with the dinosaurs until about 95 million years ago, according to University of California, Berkeley. These enormous marine reptiles mostly fed on ancient relatives of the hard-shelled squid, as well as some species of fish and smaller ichthyosaurs. The The smallest species of ichthyosaur It grew to be about 1.3 feet (0.4 m) long, while the largest reached nearly 69 feet (21 m) from snout to tail, according to National Geographic.
The ichthyosaur Tyndall was 13 feet (4 m) long, a medium-sized specimen dating from about 129 to 139 million years ago, in the early part of the Cretaceous period (about 145 million to 66 million years ago).
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This fossil came to Maxwell’s attention when it was first discovered in 2009 by paleontologist Judith Pardo Perez, who joined Maxwell’s research group in Stuttgart shortly after the fossil was discovered. Pardo Perez – now a researcher at the GAIA Research Center in Antarctica at the University of Magallanes (UMAG) in Punta Arenas, Chile – and her colleagues who found the ichthyosaur specimen they named “Fiona” after the ghoul character of Cameron Diaz in the movie “Shrek” (Dreamworks, 2001) , because the fossil’s preservative oxide coating turned it green, like its namesake ghoul.
But it took 13 years for scientists to finally excavate and study Fiona’s remains, which Maxwell said isn’t rare.
“There is often a very large gap between the discovery of a fossil and the study of a fossil,” Maxwell explains. In this case, the delay was partly due to the site: the Tyndale Glacier is very remote, so every fossil from the site – including 23 other ichthyosaurs discovered along with Fiona – had to be carefully airlifted by helicopter after the excavation. Unfortunately, many fossils have been left behind. “We have close to a hundred ichthyosaurs in the fossil deposits of the Tyndale Glacier and many of them, unfortunately, will never be excavated, due to inaccessibility, being in danger zones (cliff edge), and lack of funds,” Pardo Perez said in statment.
Specimens like Fiona, which were fossilized during pregnancy, are especially useful to paleontologists because they offer a glimpse into multiple stages in the species’ life cycle. “We can say, for example, how many fetuses this species might have, and how large they were at birth,” Maxwell said. She added that the first known pregnant ichthyosaur fossil, discovered in 1749 and described scientifically in 1842, confirmed that ichthyosaurs produce live young instead of laying eggs as most modern reptiles do.
Maxwell hopes the discovery will help spark enthusiasm for South American paleontology, which has historically been neglected in favor of North American, Russian, Chinese and Western European sites. “We only really have a picture of what is happening in the Mesozoic hemisphere [252 million to 66 million years ago]”,” So these discoveries are very, very important to help provide a global perspective to our understanding of the Cretaceous oceans.
Originally published on Live Science.