The ion thyosaur fossil site in Nevada, the birthing ground of an endangered marine species, chronicles the life and death of a huge marine predator

Geological evidence showed that the bones of the ionthyosaurs were buried at the bottom of the sea and that they ended up covering a large part of Nevada.

Now, though, scientists say that they have ruled out these hypotheses and have a much better understanding of why 37 of the ancient creatures died at the same location. The researchers believe their findings illuminate a fascinating aspect of the reptile species reproductive behavior, which is shared by some of today’s marine mammals.

Neil Kelley, a research assistant professor in Earth, and his team started to consider whether this might have been a birthing ground once it became clear that there was nothing for them to eat here.

The arms race started after the Triassic. Prey evolved harder shells and hunted fish better than ever before. The pressure was partly caused by Ichthyosaurs, which evolved into new species of different sizes and quickly dominated the ocean. The Shonisaurus genus, in particular, grew to be some of the largest marine predators around. “They achieved whale sizes before anything else,” says Pyenson.

Between the Permian and Triassic periods, an extinction event wiped out 95 percent of all marine species. There were many different creatures in the ocean. Some of the animals that grew back in their place turned out to be weirder and larger than ever before.

There has been debate among paleontologists as to why the ichthyosaurs died in large numbers at this particular fossil site 230 million years ago. The species looked much like a dolphin and was 50 feet long.

Blue and Humpback whales regularly migrate across the ocean to breed and give birth in waters where there is little to no other mammals in the area. The same stretches of coastline host many whales year after year.

Grouping or starvation? A study of a Berlin-Ichthyosaur fossil site at the Natural History Museum of Utah

“There are other examples of ichthyosaur embryos and newborns, but this is the first time we have strong evidence for reproductive grouping behavior,” said study coauthor Randy Irmis, chief curator and curator of paleontology at the Natural History Museum of Utah in Salt Lake City.

The researchers from the United States, United Kingdom and Belgium used new techniques, such as 3D modeling, to investigate the fossil site, which is part of Berlin-Ichthyosaur State Park.

The team examined the chemical makeup of rocks surrounding the fossils and found no evidence of any sudden increases in organic matter, such as algae, that might have starved the creatures of oxygen.