Space and Science

Snakes had back legs for 70 million years before losing them, new fossil shows

Ashley Strickland
By Ashley Strickland, CNN
Published 2:02 PM EST, Wed November 20, 2019
This artist's illustration shows a young Purussaurus attacking a ground sloth in Amazonia 13 million years ago.
This artist's illustration shows a young Purussaurus attacking a ground sloth in Amazonia 13 million years ago.
Jorge A. González
This bundle of bones is the torso of another marine reptile inside the stomach of a fossilized ichthyosaur from 240 million years ago.
This bundle of bones is the torso of another marine reptile inside the stomach of a fossilized ichthyosaur from 240 million years ago.
Jiang et al.
Researchers uncovered the fossilized fragments of 200,000-year-old grass bedding in South Africa's Border Cave.
Researchers uncovered the fossilized fragments of 200,000-year-old grass bedding in South Africa's Border Cave.
Lyn Wadley/Wits University
Meet Sasha, the preserved and reconstructed remains of a baby woolly rhinoceros named that was discovered in Siberia.
Meet Sasha, the preserved and reconstructed remains of a baby woolly rhinoceros named that was discovered in Siberia.
Albert Protopopov
Stone tools made from limestone have helped researchers to suggest that humans arrived in North America as early as 30,000 years ago.
Stone tools made from limestone have helped researchers to suggest that humans arrived in North America as early as 30,000 years ago.
Ciprian Ardelean
This image shows both sides of the 1.4 million-year-old bone handaxe made from the femur of a hippopotamus. It was most likely crafted by ancient human ancestors like Homo erectus.
This image shows both sides of the 1.4 million-year-old bone handaxe made from the femur of a hippopotamus. It was most likely crafted by ancient human ancestors like Homo erectus.
Berhane Asfaw
This illustration shows Kongonaphon kely, a newly described reptile that was an early ancestor of dinosaurs and pterosaurs. The fossil was found in Madagascar. It lived about 237 million years ago.
This illustration shows Kongonaphon kely, a newly described reptile that was an early ancestor of dinosaurs and pterosaurs. The fossil was found in Madagascar. It lived about 237 million years ago.
Courtesy Alex Boersma
The Okavango Delta in Botswana showcases a patchy landscape where the ability to plan results in a huge survival payoff.
The Okavango Delta in Botswana showcases a patchy landscape where the ability to plan results in a huge survival payoff.
Tim Copeland
This is a clutch of fossilized Protoceratops eggs and embryos, discovered in the Gobi Desert of Mongolia. They provide evidence that dinosaurs laid soft-shell eggs.
This is a clutch of fossilized Protoceratops eggs and embryos, discovered in the Gobi Desert of Mongolia. They provide evidence that dinosaurs laid soft-shell eggs.
M. Ellison/AMNH
These tools, made from the bones and teeth of monkeys and smaller mammals, were recovered from Fa-Hien Lena cave in Sri Lanka. The sharp tips served as arrow points.
These tools, made from the bones and teeth of monkeys and smaller mammals, were recovered from Fa-Hien Lena cave in Sri Lanka. The sharp tips served as arrow points.
M.C. Langley
This labeled map shows the complete ancient Roman city of Falerii Novi as it currently exists underground.
This labeled map shows the complete ancient Roman city of Falerii Novi as it currently exists underground.
L. Verdonck
Fragments of the Dead Sea Scrolls found in the 1950s are seen here.
Fragments of the Dead Sea Scrolls found in the 1950s are seen here.
Najib Albina/Courtesy Israel Antiquities Authority
This is one of the 408 human footprints preserved at the Engare Sero site in Tanzania. The fossilized footprints reveal a group of 17 people that traveled together, likely including 14 women, two men and one juvenile male.
This is one of the 408 human footprints preserved at the Engare Sero site in Tanzania. The fossilized footprints reveal a group of 17 people that traveled together, likely including 14 women, two men and one juvenile male.
William Harcourt-Smith
Blade-like stone tools and beads found in Bulgaria's Bacho Kiro cave provide the earliest evidence for modern humans in Europe 47,000 years ago.
Blade-like stone tools and beads found in Bulgaria's Bacho Kiro cave provide the earliest evidence for modern humans in Europe 47,000 years ago.
Tsenka Tsanova
This artist's illustration shows what an early, small ichthyosaur that lived 248 million years ago may have looked like. It resembled a cross between a tadpole and a seal, grew to be one foot long and had pebble-like teeth that it likely used to eat invertebrates like snails and bivalves.
This artist's illustration shows what an early, small ichthyosaur that lived 248 million years ago may have looked like. It resembled a cross between a tadpole and a seal, grew to be one foot long and had pebble-like teeth that it likely used to eat invertebrates like snails and bivalves.
Stefano Broccoli
This is an artist's illustration of Adalatherium hui, an early mammal that lived on Madagascar 66 million years ago.
This is an artist's illustration of Adalatherium hui, an early mammal that lived on Madagascar 66 million years ago.
Andrey Atuchin
This is an artist's illustration showing a cross-section of Earth's forming crust approximately 3 to 4 billion years ago.
This is an artist's illustration showing a cross-section of Earth's forming crust approximately 3 to 4 billion years ago.
Alec Brenner/Harvard University
Illuminated medieval manuscripts are full of intricate decorations, illustrations and colors, including "endangered colors" that can no longer be recreated today.
Illuminated medieval manuscripts are full of intricate decorations, illustrations and colors, including "endangered colors" that can no longer be recreated today.
Duarte Belo
These monkeys can be found in ancient Grecian frescoes. And the details are so accurate that researchers were able to identify them as vervet monkeys and baboons.
These monkeys can be found in ancient Grecian frescoes. And the details are so accurate that researchers were able to identify them as vervet monkeys and baboons.
Bernardo Urbani/Antiquity Journal
Archeologists have found the oldest string of yarn at a prehistoric site in southern France. This photograph, taken by digital microscopy, shows that of the cord fragment, which is approximately 6.2 mm long and 0.5 mm wide.
Archeologists have found the oldest string of yarn at a prehistoric site in southern France. This photograph, taken by digital microscopy, shows that of the cord fragment, which is approximately 6.2 mm long and 0.5 mm wide.
C2RMF
This illustration shows Elessaurus gondwanoccidens, a long-legged reptile that lived in South America during the Early Triassic Period. It's a cousin to other mysterious early reptiles that arose after the Permian mass extinction event 250 million years ago.
This illustration shows Elessaurus gondwanoccidens, a long-legged reptile that lived in South America during the Early Triassic Period. It's a cousin to other mysterious early reptiles that arose after the Permian mass extinction event 250 million years ago.
Márcio L. Castro
The skeletal remains of Homo antecessor are on display in this image. A recent study suggests antecessor is a sister lineage to Homo erectus, a common ancestor of modern humans, Neanderthals and Denisovans.
The skeletal remains of Homo antecessor are on display in this image. A recent study suggests antecessor is a sister lineage to Homo erectus, a common ancestor of modern humans, Neanderthals and Denisovans.
Prof. José María Bermúdez de Castro
A nearly two-million-year-old Homo erectus skullcap was found in South Africa. This is the first fossil of erectus to be found in southern Africa, which places it in the area at the same time as other ancient human ancestors.
A nearly two-million-year-old Homo erectus skullcap was found in South Africa. This is the first fossil of erectus to be found in southern Africa, which places it in the area at the same time as other ancient human ancestors.
Therese van Wyk/University of Johannesburg
This painting shows what Antarctica may have looked like 90 million years ago. It had a temperate swampy rainforest.
This painting shows what Antarctica may have looked like 90 million years ago. It had a temperate swampy rainforest.
Alfred-Wegener-Institut/James McKay
This artist's illustration of Dineobellator notohesperus shows them in an open landscape, across what is now New Mexico, along with Ojoceratops and Alamosaurus in the background.
This artist's illustration of Dineobellator notohesperus shows them in an open landscape, across what is now New Mexico, along with Ojoceratops and Alamosaurus in the background.
Courtesy Sergey Krasovskiy
Ikaria wariootia was a worm-like creature that lived 555 million years ago. It represents the oldest ancestor on the family tree for most animals.
Ikaria wariootia was a worm-like creature that lived 555 million years ago. It represents the oldest ancestor on the family tree for most animals.
Sohail Wasif/University of California-Riverside
This is the 3.67-million-year-old 'Little Foot' skull. The view from the bottom (right) shows the original position of the first cervical vertebra, which tells us about her head movements and blood flow to the brain.
This is the 3.67-million-year-old 'Little Foot' skull. The view from the bottom (right) shows the original position of the first cervical vertebra, which tells us about her head movements and blood flow to the brain.
courtesy R.J. Clarke
This is an artist's illustration of the world's oldest modern bird, Asteriornis maastrichtensis, in its original environment. Parts of Belgium were covered by a shallow sea, and conditions were similar to modern tropical beaches like The Bahamas 66.7 million years ago.
This is an artist's illustration of the world's oldest modern bird, Asteriornis maastrichtensis, in its original environment. Parts of Belgium were covered by a shallow sea, and conditions were similar to modern tropical beaches like The Bahamas 66.7 million years ago.
Phillip Krzeminski
This donkey skull was recovered in a Tang Dynasty noblewoman's tomb. The researchers determined that she played donkey polo and was buried with her donkeys so that she may continue her favorite sport in the afterlife.
This donkey skull was recovered in a Tang Dynasty noblewoman's tomb. The researchers determined that she played donkey polo and was buried with her donkeys so that she may continue her favorite sport in the afterlife.
T. Wang, Junkai Yang and Songmei Hu
Hundreds of mammoth bones found at a site in Russia were once used by hunter-gatherers to build a massive structure 25,000 years ago.
Hundreds of mammoth bones found at a site in Russia were once used by hunter-gatherers to build a massive structure 25,000 years ago.
Alex Pryor
A fossil of an ancient rudist clam called Torreites sanchezi revealed that Earth's days lasted 23.5 hours 70 million years ago.
A fossil of an ancient rudist clam called Torreites sanchezi revealed that Earth's days lasted 23.5 hours 70 million years ago.
Wilson44691/Wikipedia
This is an artist's impression of dinosaurs on prehistoric mudflat in Scotland, based on varied dinosaur footprints recovered on the Isle of Skye.
This is an artist's impression of dinosaurs on prehistoric mudflat in Scotland, based on varied dinosaur footprints recovered on the Isle of Skye.
Jon Hoad
A new study suggests that ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years.
A new study suggests that ostrich eggshell beads have been used to cement relationships in Africa for more than 30,000 years.
John Klausmeyer/Yuchao Zhao/Brian Stewart
This rock lined the seafloor roughly 3.2 billion years ago, providing evidence that Earth may have been a 'waterworld' in its ancient past.
This rock lined the seafloor roughly 3.2 billion years ago, providing evidence that Earth may have been a 'waterworld' in its ancient past.
Benjamin Johnson
These stone tools were found at the Dhaba site in India, showing that Homo sapiens survived a massive volcanic eruption 74,000 years ago.
These stone tools were found at the Dhaba site in India, showing that Homo sapiens survived a massive volcanic eruption 74,000 years ago.
Chris Clarkson
The remains of 48 people who were buried in a 14th century Black Death mass grave were found in England's Lincolnshire countryside.
The remains of 48 people who were buried in a 14th century Black Death mass grave were found in England's Lincolnshire countryside.
Antiquity Publications Ltd
The articulated remains of a Neanderthal have been found in Shanidar Cave, representing the first discovery of its kind in 20 years.
The articulated remains of a Neanderthal have been found in Shanidar Cave, representing the first discovery of its kind in 20 years.
Graeme Barker/Cambridge University
A rare disease that still affects humans today has been found in the fossilized vertabra of a duck-billed dinosaur that roamed the Earth at least 66 million years ago.
A rare disease that still affects humans today has been found in the fossilized vertabra of a duck-billed dinosaur that roamed the Earth at least 66 million years ago.
Assaf Ehrenreic
Venezuelan Palaeontologist Rodolfo Sánchez is shown next to a male carapace of the giant turtle Stupendemys geographicus, for scale.
Venezuelan Palaeontologist Rodolfo Sánchez is shown next to a male carapace of the giant turtle Stupendemys geographicus, for scale.
Edwin Cadena
This artist's illustration shows the newly discovered Tyrannosaurus rex relative, Thanatotheristes degrootorum.
This artist's illustration shows the newly discovered Tyrannosaurus rex relative, Thanatotheristes degrootorum.
Julius Csotonyi
The newly discovered species Allosaurus jimmadseni represents the earliest Allosaurus known. It was a fearsome predator that lived during the Late Jurassic Period millions of years before Tyrannosaurus rex.
The newly discovered species Allosaurus jimmadseni represents the earliest Allosaurus known. It was a fearsome predator that lived during the Late Jurassic Period millions of years before Tyrannosaurus rex.
Andrey Atuchin
Remains found in ancient Herculaneum boat houses revealed that people trying to flee the eruption of Mount Vesuvius slowly suffocated as volcanic clouds overtook the town.
Remains found in ancient Herculaneum boat houses revealed that people trying to flee the eruption of Mount Vesuvius slowly suffocated as volcanic clouds overtook the town.
Antiquity Publications Ltd
The Wulong bohaiensis fossil found in China's Jehol Province shows some early, intriguing aspects that relate to both birds and dinosaurs.
The Wulong bohaiensis fossil found in China's Jehol Province shows some early, intriguing aspects that relate to both birds and dinosaurs.
Ashley Poust
Shell tools were recovered from an Italian cave that show Neanderthals combed beaches and dove in the ocean to retrieve a specific type of clam shell to use as tools.
Shell tools were recovered from an Italian cave that show Neanderthals combed beaches and dove in the ocean to retrieve a specific type of clam shell to use as tools.
Villa et al., 2020
A closer look at the Heslington brain, which is considered to be Britain's oldest brain and belonged to a man who lived 2,600 years ago. Amazingly, the soft tissue was not artificially preserved.
A closer look at the Heslington brain, which is considered to be Britain's oldest brain and belonged to a man who lived 2,600 years ago. Amazingly, the soft tissue was not artificially preserved.
Courtesy Dr. Axel Petzold/University College London
Researchers from Russia's RAS Institute of Archeology excavated the burial sites of four women, who were buried with battle equipment in southwestern Russia and believed to be Amazon warrior women. The oldest woman found in the graves bore a unique, rare ceremonial headdress.
Researchers from Russia's RAS Institute of Archeology excavated the burial sites of four women, who were buried with battle equipment in southwestern Russia and believed to be Amazon warrior women. The oldest woman found in the graves bore a unique, rare ceremonial headdress.
Institute of Archaeology RAS
Teen Tyrannosaurus rex were fleet-footed with knife-like teeth, serving as mid-sized carnivores before they grew into giant bone-crushing adults.
Teen Tyrannosaurus rex were fleet-footed with knife-like teeth, serving as mid-sized carnivores before they grew into giant bone-crushing adults.
Julius T. Csotonyi
A Homo erectus skull cap discovered in Central Java, Indonesia reveals how long they lived and when the first human species to walk upright died out.
A Homo erectus skull cap discovered in Central Java, Indonesia reveals how long they lived and when the first human species to walk upright died out.
Rizal et al
This is an artistic reconstruction of Lola, a young girl who lived 5,700 years ago.
This is an artistic reconstruction of Lola, a young girl who lived 5,700 years ago.
Tom Björklund
Part of the scene depicted in the world's oldest cave art, which shows half-animal, half-human hybrids hunting pigs and buffalo.
Part of the scene depicted in the world's oldest cave art, which shows half-animal, half-human hybrids hunting pigs and buffalo.
Endra
An ancient Egyptian head cone was first found with the remains of a young woman buried in one of Amarna's graves.
An ancient Egyptian head cone was first found with the remains of a young woman buried in one of Amarna's graves.
courtesy Amarna Project
A lice-like insect was trapped in amber crawling and munching on a dinosaur feather.
A lice-like insect was trapped in amber crawling and munching on a dinosaur feather.
Taiping Ga
Newly discovered penguin species Kupoupou stilwelli lived after the dinosaurs went extinct and acts as a missing link between giant extinct penguins and the modern penguins in Antarctica today.
Newly discovered penguin species Kupoupou stilwelli lived after the dinosaurs went extinct and acts as a missing link between giant extinct penguins and the modern penguins in Antarctica today.
Jacob Blokland, Flinders University
This illustration compares the jaws and teeth of two predatory dinosaurs, Allosaurus (left) and Majungasaurus (right).
This illustration compares the jaws and teeth of two predatory dinosaurs, Allosaurus (left) and Majungasaurus (right).
Sae Bom Ra/Adelphi University
This is an artist's illustration of Najash rionegrina in the dunes of the Kokorkom desert that extended across Northern Patagonia during the Late Cretaceous period. The snake is coiled around with its hindlimbs on top of the remains of a jaw bone from a small charcharodontosaurid dinosaur.
This is an artist's illustration of Najash rionegrina in the dunes of the Kokorkom desert that extended across Northern Patagonia during the Late Cretaceous period. The snake is coiled around with its hindlimbs on top of the remains of a jaw bone from a small charcharodontosaurid dinosaur.
Courtesy Ral Orencio Gomez
University of South Carolina archaelogist Christopher Moore (second from right) and colleagues collect core samples from White Pond near Elgin, South Carolina, to look for evidence of an impact from an asteroid or comet that may have caused the extinction of large ice-age animals such as sabre-tooth cats and giant sloths and mastodons.
University of South Carolina archaelogist Christopher Moore (second from right) and colleagues collect core samples from White Pond near Elgin, South Carolina, to look for evidence of an impact from an asteroid or comet that may have caused the extinction of large ice-age animals such as sabre-tooth cats and giant sloths and mastodons.
University of South Carolina
Core samples from White Pond near Elgin, South Carolina, show evidence of platinum spikes and soot indicative of an impact from an asteroid or comet.
Core samples from White Pond near Elgin, South Carolina, show evidence of platinum spikes and soot indicative of an impact from an asteroid or comet.
University of South Carolina
The Sosnogorsk lagoon as it likely appeared 372 million years ago just before a deadly storm, according to an artist's rendering. The newly discovered tetrapod can be seen in the left side of the image below the surface.
The Sosnogorsk lagoon as it likely appeared 372 million years ago just before a deadly storm, according to an artist's rendering. The newly discovered tetrapod can be seen in the left side of the image below the surface.
Mikhail Shekhanov for the Ukhta Local Museum
Bronze goods recovered from a river in northern Germany indicate an ancient toolkit of a Bronze Age warrior.
Bronze goods recovered from a river in northern Germany indicate an ancient toolkit of a Bronze Age warrior.
Volker Minkus
Mold pigs are a newly discovered family, genus and species of microinvertebrates that lived 30 million years ago.
Mold pigs are a newly discovered family, genus and species of microinvertebrates that lived 30 million years ago.
Courtesy George Poinar Jr.
Ferrodraco lentoni was a pterosaur, or "flying lizard," that lived among dinosaurs 96 million years ago. The fossil was found in Australia.
Ferrodraco lentoni was a pterosaur, or "flying lizard," that lived among dinosaurs 96 million years ago. The fossil was found in Australia.
Scientific Reports
These Late Bronze Age feeding vessels were likely used for infants drinking animal milk.
These Late Bronze Age feeding vessels were likely used for infants drinking animal milk.
courtesy Katharina Rebay-Salisbury/Nature
This is the first depiction of what mysterious ancient humans called Denisovans, a sister group to Neanderthals, looked like. This image shows a young female Denisovan, reconstructed based on DNA methylation maps. The art was created by Maayan Harel.
This is the first depiction of what mysterious ancient humans called Denisovans, a sister group to Neanderthals, looked like. This image shows a young female Denisovan, reconstructed based on DNA methylation maps. The art was created by Maayan Harel.
courtesy Maayan Harel
Researchers found a fossil of one of the oldest bird species in New Zealand. While its descendants were giant seafaring birds, this smaller ancestor likely flew over shorter ranges.
Researchers found a fossil of one of the oldest bird species in New Zealand. While its descendants were giant seafaring birds, this smaller ancestor likely flew over shorter ranges.
Canterbury Museum
A painting shows the new species of giant salamander called Andrias sligoi, the largest amphibian in the world.
A painting shows the new species of giant salamander called Andrias sligoi, the largest amphibian in the world.
ZSL
After her discovery in 2013, Victoria's 66-million-year-old, fossilized skeleton was restored bone by bone. She's the second most complete T. rex fossil on record.
After her discovery in 2013, Victoria's 66-million-year-old, fossilized skeleton was restored bone by bone. She's the second most complete T. rex fossil on record.
Courtesy IMG
An artist's illustration shows how different an ancient "short-faced" kangaroo called Simosthenurus occidentalis looked, as opposed to modern kangaroos. Its skull more closely resembles a koala.
An artist's illustration shows how different an ancient "short-faced" kangaroo called Simosthenurus occidentalis looked, as opposed to modern kangaroos. Its skull more closely resembles a koala.
Nobu Tamura