Hidden deep in the uninhabited mountains of western Nevada are secrets of evolution that have lain buried for 250 million years, drawing scientists from as close as Reno and as far away as Germany. They travel in four-wheel drives over open range and potholed roads hauling the tools of their trade, ranging from gas-powered jackhammers to dental picks and artist brushes, just to dig under a blazing sun, often in triple-digit temperatures.
Some became obsessed in elementary school or junior high; among recent generations, their fate was sealed with the release of the book and movie, Jurassic Park. UNR’s Paula Noble and Martin Sander of the University of Bonn, Germany, were already card-carrying paleontologists before “Life finds a way” was on everyone’s lips. They — and others like them — were annoyed by scientific errors in the movie.
They’re here to find evidence of the life and disappearance of some of the first giant animals to inhabit the globe: ichthyosaurs. Studying extinct life forms of any kind or era is the point of paleontology. What’s so attractive about ichthyosaurs in particular? “Today’s whales evolved from land-living mammals along the same line as the ichthyosaurs from land-living reptiles much earlier,” Sanders says. “By comparing the two groups, we find out what is specific about us mammals compared to other animals and what is the effect of adapting to a special lifestyle.”
And adaptation is on scientists’ minds. Fossils tell the stories of not only the animals that came before us, but the causes of Earth’s past five mass extinctions. As the globe heats up and species begin to disappear at an accelerated rate, the race is on to understand where we might be headed. Perhaps the ichthyosaur can help.
AT THE END OF THE PERMIAN PERIOD, there was only a supercontinent named Pangaea surrounded by one ocean, Panthalassa. California and most of Nevada were completely submerged, Sander says. As the future continents began to separate, plate movements pulled Earth’s crust apart, opening gigantic fissures that spewed lava up to 9,000 feet thick in some places. Thus began the world’s worst disaster movie, which lasted several hundred thousand years. The eruptions released four greenhouse gases — carbon dioxide, sulfur dioxide, chlorine, methane — that combined to produce hellish global warming, clouds of acid rain, and dust that colored the skies a perpetual gray or orange, blotting out the sun. Most plants, insects, and arachnids simply perished, as did the amphibians, proto-reptiles, and proto-mammals that fed on them. As carbon dioxide permeated the oceans, it formed carbonic acid, known to corrode coral reefs and prevent calcification by shellfish and other marine organisms. Oceans overheated and were starved of oxygen, decimating whole food chains and ecosystems. By the beginning of the next period, the Triassic, an estimated 90 percent of life on Earth had disappeared. It was the worst of the planet’s five mass extinctions, easily surpassing the effects of the cataclysmic asteroid or comet impact off the Yucatan Peninsula that wiped out non-avian dinosaurs some 66 million years ago.
What happened next, beginning about 251 million years ago, points to that famous Jurassic Park line uttered by character Ian Malcolm (played by Jeff Goldblum). As lava flows slowly ceased and the environment became more amenable to life, the few surviving plants and animals began to flourish and evolve. The oceans cooled. Oxygen levels increased. The first mammals, crocodiles, lizards, and dinosaurs appeared. It was as if Earth had been reborn.
Over the next few million years, proto-reptiles that had found safety near shorelines returned to the sea, much like the mammalian ancestors of whales, filling the niches in the food web left by extinct sharks and other marine organisms. The identity of those proto-reptiles is largely unknown, according to Sander. One of the earliest, from China, was named Chaohusaurus, which Professor Ryosuke Motani of UC Davis likened to a “lizard with flippers.” Limbs evolved into paddles, first used for propulsion but later only for steering. Ancestral ichthyosaurs had evolved.
THE ICHTHYOSAUR RESEMBLED a cross between a shark and a dolphin. It had a long snout, dinner plate-sized eyes, nostrils below the eyes on the snout, a pair of fins at both front and rear, and a long, streamlined body. Some species also had dorsal fins, although it’s difficult to determine, because they were not composed of bone and therefore rarely fossilized. A few species were either toothless or nearly so and sucked up their prey, but most had either conical, pointed teeth for eating fish and squid or cutting teeth to prey on smaller marine reptiles. Some even had grinding teeth to crush spiral-shelled cephalopods, called ammonites, which looked like chambered nautiluses but were more closely related to squids and octopuses.
As the Triassic marched on, for the next 50 million years, so did the size and diversity of ichthyosaurs around the world, fueled by a plentiful food supply. They were the apex predators, much like Tyrannosaurus rex and its relatives in the Cretaceous Period. The earliest large one discovered was Cymbospondylus, up to 40 feet long, in Nevada’s Humboldt Range. University of Bonn’s Sander later found one that stretched to 55 feet in the Augusta Mountains of Nevada. It lacked a dorsal fin and wriggled side to side like a sea snake or eel, propelled by its tail fin. Chinese scientists discovered two specimens of Himalayasaurus, 67 feet long with formidable, pointed teeth, not far from a base camp on Mt. Everest in Tibet. Two jawbones of the aptly named Ichthyotitan were discovered on the beaches of Somerset, England, in 2016 and 2020. It was massive, an estimated 82 feet long, as big as the average blue whale.
By the time ichthyosaurs went extinct about 90 million years ago, at least 150 described species had prowled the waters of Panthalassa, says Neil Kelley, a professor of earth and environmental sciences at Vanderbilt University. One of those was Nevada’s state fossil, Shonisaurus popularis, which, along with other species, has made Nevada a global hot spot for ichthyosaur research since the mid-1800s.
BRITISH-BORN MARY ANNING was the first to discover the bones of ichthyosaurs while walking along the coast of Dorset in southwest England when she was 12 years old. Some 50 years later, in 1863, prospectors across the Atlantic discovered silver in the Shoshone Mountains of Nye and Lander counties, Nevada. It spurred an influx of miners and the establishment of Berlin, a town named by German miners. At its peak in 1898, Berlin numbered 250-300 residents, including “miners, woodcutters, charcoal makers, a doctor, nurse, forest ranger, and a prostitute,” Nevada State Parks says on its website. By 1911, when it became a ghost town, three miles of tunnels had been excavated in nearby Union Canyon.
Among the silver and gold ore that miners in the area chiseled out were bones that they used for dog bowls and ashtrays, says Jeff Morris, a ranger at present-day Berlin-Ichthyosaur State Park. It wasn’t until 1928 that Stanford University professor Siemon Muller recognized that these Berlin fossils were the vertebrae of giant ichthyosaurs. Meanwhile, specimens from the Humboldt and New Pass Ranges had been sent to professor Joseph Leidy, a University of Pennsylvania paleontologist who named a new genus based on them, Cymbospondylus, in 1868. They would later inspire the Alexander-Merriam expeditions.
Annie Alexander was the Hawaii-born heiress of a sugar cane plantation who developed a passion for paleontology in her early 30s. In 1901, she was riveted by a lecture of John Merriam, a University of California paleontologist famous for his fossil work at the La Brea Tar Pits in present day Los Angeles. Alexander decided to organize, fund, and participate in Merriam’s fossil-hunting expeditions in Oregon, California, and Nevada. Their work in the Humboldt Range in Nevada’s Pershing and Churchill counties yielded 25 superb specimens of Triassic ichthyosaurs in 1905.
Alexander later founded the University of California Museum of Paleontology and Museum of Vertebrate Zoology, for which she hand picked Charles Camp, chair of UC Berkeley’s paleontology department, as her successor. In the mid-1950s, Camp and Merriam excavated between 37 and 40 giant ichthyosaurs up to 50 feet long from the Luning Formation of the Shoshone Mountains, dating from 237-227 million years ago. Vanderbilt’s Kelley says the exact number of individuals is hard to pin down because “most of the fossils we find are isolated bones and not complete skeletons.”
Camp named the species Shonisaurus popularis in work published posthumously in 1976 with a more detailed description in 1980.The generic name refers to the Shoshone Mountains where they were discovered, and the species epithet means “of the people," in reference to the many who helped excavate the bones.
The Nevada Legislature designated ichthyosaurs as the state fossil in 1977, a designation it amended in 1989 to specify the Shonisaurus popularis. It was a “smart move,” Sander says. “There are now so many more new and exciting ichthyosaur fossils, since the state proclamation, that Nevada is well on its way to be one of the top sites for ichthyosaurs globally.”
In 1957, Camp and Fallon anthropologist-paleontologist Margaret Wheat successfully lobbied the state government to designate 1,245 (now 1,520) acres around Berlin as the Berlin-Ichthyosaur State Park. Since then, excavations have continued in the Luning Formation of the Shoshone Mountains, the Augusta Mountains, and the New Pass, Pilot, and Humboldt ranges, bringing new species of ichthyosaurs to light. Some sites are extremely remote. Sander says he spent three seasons just locating access routes to canyons in the Augustas, where “almost anything we find is something new!”
PALEONTOLOGISTS ARE DRIVEN by the mysteries of the species they study — how and why did they become extinct? One mystery of Nevada’s ichthyosaurs is why so many of their skeletons in the Luning Formation are grouped together. The Visitor’s Quarry at Berlin-Ichthyosaur State Park contains bones of at least seven Shonisaurus individuals, but bones from dozens of other ichthyosaurs are in two other quarries.
Camp argued that these groupings resulted from mass stranding and death on mud flats as waters receded. Another theory is that local ammonites were infected with blooms of red-tide algae, and when the ichthyosaurs ate the ammonites they were poisoned. A third theory was proposed by an international team of researchers led by Kelley, which included Noble, chair of UNR’s Department of Geological Sciences and Engineering. Their scans and tests of the sites over eight years ruled out the other two theories, for which there was no evidence. They wondered: Could this have been a site where ichthyosaurs migrated as a group to give birth and avoid predators? There were precedents; bones of embryos had been discovered elsewhere in the world under similar circumstances. An analog today is humpback and gray whales’ annual, instinctive migration from their feeding grounds to calmer, safer, and warmer waters at mid-latitudes to calve. And soon, there would be evidence.
After Camp died, blocks of bones from Berlin-Ichthyosaur State Park eventually ended up at the Nevada State Museum in Las Vegas. Staff shortages and curatorial lack of familiarity with ichthyosaurs had prevented rigorous study of those fossils until 2018. That’s when Noble’s former undergraduate student, Paige dePolo, took time out from her master’s degree at the University of Edinburgh to visit the museum and catalog the bones. The next-to-last block she examined was labeled “ammonites.” Among those nautilus-like shells of the ammonites was a tiny vertebra of an embryo Shonisaurus. The birthing theory to explain the bone groupings in the Berlin-Ichthyosaur quarries had found some support at last!
But that still didn’t explain why they’d died out. The Triassic period had been one of rebirth and introduction of ancestors of modern mammals, reptiles, and birds. By its end about 201 million years ago, ichthyosaurs were the largest predators in the ocean. But just as the Triassic began, so would it end. Pangaea continued to fracture, with magma upwellings and volcanic activity releasing unimaginable amounts of carbon dioxide and toxic gas to produce a runaway greenhouse effect. Once again, the ocean became acidic and depleted of oxygen, this time killing off most ichthyosaurs and all of the giant ones.
This mass extinction was not as annihilating as the end-Permian 50 million years earlier; still, 75 percent of life was wiped out on the doorstep of the Jurassic period. Coral reefs completely disappeared. Temperatures soared to 140 degrees on land and 104 degrees in the ocean, according to a 2012 article in Science. It took millions of years for life to recover. For comparison, the hottest land temperature recorded in modern times was 134 degrees at Death Valley in 1913; early this year it reached 126 near New Delhi, India. Last year, the ocean temperature hit 101.1 degrees near Key Largo, Florida.
Organisms that somehow survived the Permian period included turtles, crocodiles, and smaller mammals. Giant ichthyosaurs such as Shonisaurus died out, but smaller species survived and remained smaller, a phenomenon that biologists call the Lilliput Effect. Ichthyosaurs never regained their huge sizes through the Jurassic and Cretaceous periods, when dinosaurs such as T. rex ruled the land and giant mosasaurs and sharks replaced ichthyosaurs as the apex predators.
Most paleontologists agree that ichthyosaurs as a group became extinct about 90 million years ago in the middle of the Cretaceous, some 36 million years before the asteroid struck. The reasons why aren’t as clear. UNR’s Noble mentions predation by larger marine animals, competition for resources, and climate change. University of Utah geology professor Randy Irmis believes possible causes were, once again, oxygen-depleted waters, shallow oceans, volcanic eruptions, or a combination of them. He says, “The rate of carbon dioxide release now is double what it was 200 million years ago, even if the volume isn’t as large. So, we study the Triassic in part because it helps us better understand how ecosystems recover from one mass extinction, their lead up to the next mass extinction, what adapts and survives versus what goes extinct.”
This information can be useful to the bigger picture today. Asked if we have already entered the sixth mass extinction, the University of Bonn’s Sander replies somberly, “That is the consensus among biologists and paleontologists. Life will survive, but we will not.”
Far be it from scientists to give up, however. An exhibit opening in September at the Nevada State Museum — with elements specifically targeting children — is designed to deepen visitors’ understanding of Earth’s history and its marine animals. It’s also meant to make us more aware of climate change and what we can do to reverse current trends.
From Earth’s mass extinctions over the last 440-plus million years, scientists have learned how fragile terrestrial and ocean life are, because of global cooling and warming. But we humans don’t have to end up like ichthyosaurs. If there is anything positive about the current threats, it is that they are almost all caused by us, and we have the technology to reverse course — given the willpower.
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Fun fact: Cymbospondylus youngorum was the first giant animal to inhabit the globe and is named after Tom and Bonda Young, inventors of Icky (for “ichthyosaur”) IPA beer at their Great Basin Brewing Company in Reno and Sparks. The species is named after the Youngs in recognition both of fundraisers they held at the brewery to support Sander’s expedition and their transporting the whole skeleton encased in plaster from the Augustas to Los Angeles County’s Natural History Museum in the company’s beer truck.
Also at the exhibition, two new ichthyosaur species will make their debut. There will be exhibits dedicated to fossil hunters Mary Anning and Annie Alexander, in conjunction with a children’s book about Alexander and her discoveries. Children will also be able to enjoy the collection of vintage toy dinosaurs and other prehistoric animals, as well as depictions of extinct marine creatures created by artists in collaboration with scientists.
Through Jan. 11