Stegouros elengassen.
Credit: Luis Enrique Pérez López (licensed under CC BY-SA 4.0)

Looking at plant-eating dinosaurs is like browsing a Medieval armory. Helmets (dome-headed pachycephalosaurs), whips (sauropods), shields (Stegosaurus and ceratopsians—though those of the latter probably weren’t used for defense), spears (Stegosaurus, Triceratops), clubs, and thick armor (both ankylosaurs). Now, paleontologists (scientists who study ancient life) have added a sword to the list of prehistoric weaponry. 

A team led by Sergio Soto-Acuña, a paleontology student at the University of Chile, discovered a dinosaur they named Stegouroselengassen. The dinosaur lived between 75 and 72 million years ago in what is now Patagonia. The team published their findings in the scientific journal Nature. 

The new dinosaur is an ankylosaur, a member of the group that includes Ankylosaurus and other armored plant-eating dinosaurs. Stegouros was lightly-armored for an ankylosaur, possessing several rows of knobby plates—called scutes—that ran down its back and sides. It was relatively small, only about 6 feet (2 meters) long. It also had thin limbs and an unusually short tail. 

The tail of Stegouros has attracted the most attention. Some ankylosaurs possessed tail clubs to defend themselves against predators. But Stegouros had a different tail weapon. Its scutes became larger and sharper down the tail, fusing into a large, bladelike weapon at the tip. 

Stegouros’s tail resembles a macuahuitl, a weapon used in the Aztec empire. The macuahuitl was a heavy wooden club lined with several sharp obsidian blades. As with the macuahuitl and the European broadsword, the sheer weight of the swinging tail made it dangerous, more so than the sharpness of the blade. A well-placed swing would have dealt a slicing, shattering blow to the legs of any predator that was trying to catch it. 

In paleontology, as in other sciences, one discovery often sheds light on others. The ankylosaur Antarctopelta was discovered in 1986 on James Ross Island, just off the coast of Antarctica. It had unusual vertebrae at the base of its tail, but the rest of the tail was not found. These basal tail vertebrae closely resemble those of Stegouros, so scientists now think Antarctopelta had a similar tail sword.  

Soto-Acuña and his colleagues suggest that these two strange dinosaurs, along with another named Kunbarrasaurus from Australia, formed a part of a separate group of ankylosaurs. This group diverged from the main ankylosaur lineage early in its history and lived for tens of millions of years in relative isolation near the South Pole. 

March 30, 2020

Some 15 million years ago, long after the non-bird dinosaurs and the beasts they lived alongside had gone extinct, giant creatures still walked (or swam) the Earth. Recently, the discoveries of a team of scientists led by Edwin Cadena of Del Rosario University in Colombia have been putting more of a face—or a shell, in this case—on one of these ancient giants. And, not only did the giant have a shell, but the shell had spikes! Meet Stupendemys, the titanic turtle.

Stupendemys lived during the Miocene Epoch, around 23 million to 5.3 million years ago. credit: © Jaime Chirinos

The giant aquatic (water-dwelling) Stupendemys had a big head with a sharp beak. It had four paddlelike limbs and a short tail. It probably could not withdraw its head or limbs into its large shell, as can many turtles. Its shell alone measured about 8 feet (2.4 meters) long. Stupendemys weighed about 2,500 pounds (1,150 kilograms). It and the prehistoric marine turtle Archelon were the largest turtles known to have ever lived.

Stupendemys had been known since the 1970’s from huge pieces of shells and limb bones, but no cranial (skull) material had been positively identified. Cadena’s new trove of Stupendemys fossils included skull fragments, however. Found in Colombia and neighboring Venezuela, the skull pieces matched those of previously unidentified ancient turtle remains discovered in other parts of South America, showing that Stupendemys was fairly widespread.

Some­ of the Stupendemys shells found by Cadena and his team had large forward-pointing horns at the shoulders. The scientists believe this is a case of sexual dimorphism. Sexual dimorphism is a difference in body size or shape between males and females of the same species. Males probably used these horns in combat over mates and territory. Deep gouges were often found near the Stupendemys shell horns, suggesting that males literally locked horns when fighting.

Stupendemys was not the top boss of South American waterways during the Miocene Epoch, a time in Earth’s history that lasted from 23 million to 5.3 million years ago. The turtle was likely a gentle giant, surviving on a diet of hard-shelled mollusks, fruits, and seeds. And its huge size did not grant it complete protection from predators. Giant crocodilians prowled the region at that time, including the 40-foot (12.5-meter) giant caiman Purussaurus. One Stupendemys shell found by Cadena’s team contained an embedded crocodilian tooth! It’s hard to say who came out on top in that encounter, but it was likely an epic struggle.

October 18, 2019

Recent excavations in central Thailand have led to the discovery of a new type of predatory dinosaur, Siamraptor suwati. The ancient creature belonged to a group of giant meat-eaters called carcharodontosaurs, which means shark-toothed reptiles. Siamraptor dates from the Cretaceous Period, a time in Earth’s history from about 145 million years ago to 66 million years ago. The Cretaceous was the last of the three periods that make up the Mesozoic Era, the time when the dinosaurs lived.

Fossils found in Thailand helped scientists reconstruct the skull of the newly identified Siamraptor suwati dinosaur. Credit: Duangsuda Chokchaloemwong, et al/Nakhon Ratchasima Rajabhat University

Siamraptor (Siam is the previous name for Thailand; raptors were carnivorous, bipedal dinosaurs) is the first example of a carcharodontosaur to be found in Southeast Asia. Previous examples came from northern Africa and Europe, and close cousins have been found in Argentina (Giganotosaurus) and the United States (Acrocanthosaurus).

The fossilized bones of Siamraptor were found in 115-million-year-old rocks in the central Thai district of Ban Saphan between 2008 and 2013. Paleontologists from Thailand’s Nakhon Ratchasima Rajabhat University found the fossils—22 in all—while working on a project with Japan’s Fukui Prefectural Dinosaur Museum. The announcement that the fossils belonged to a new type of carcharodontosaur came in October 2019 after years of study. Siamraptor was not the first find for the Japan-Thailand Dinosaur Project. The team earlier identified two new types of plant-eating dinosaurs and an ancient relative of the alligator and crocodile.

Twenty-two fossils aided in the skeletal reconstruction of Siamraptor suwati. Credit: Duangsuda Chokchaloemwong, et al/Nakhon Ratchasima Rajabhat University

The Siamraptor fossils include parts of a single animal’s feet, hands, hips, spine, and skull. The animals’s bones were somewhat porous, containing air sacs that would have made the creature a lighter and more agile hunter. Nearby were also many Siamraptor teeth, suggesting that this animal had not been alone. Like sharks, dinosaurs shed teeth throughout their lives, particularly when they ate, and the Ban Saphan site (a floodplain during the Cretaceous Period) may have been a common feeding ground. Siamraptor probably preyed on plant-eating dinosaurs in the area, using its bladelike serrated teeth—measuring up to 6 inches (15 centimeters) long—to slice through tough dinosaur flesh.

Scientists classify Carcharodontosaurus with other meat-eating dinosaurs in a large group known as theropods. These animals make up one of two main groups of saurischian (lizard-hipped) dinosaurs. Saurischians include such famous dinosaurs as Tyrannosaurus and Velociraptor. Although Carcharodontosaurus is classified in the same main group as Tyrannosaurus and Velociraptor, it was not closely related to them.

Tyrannosaurus and Carcharodontosaurus shared such traits as big heads, long bodies, and short arms, but the animals’ snouts were quite different. Tyrannosaurus had a broad head and a wide mouth with teeth made for crushing bone and pulling away flesh. Carcharodontosaurus had a much narrower head and a more precise bite with sharper teeth meant for slicing flesh. The two apex predators (at the top of the food chain) appear to have coexisted in several areas, which probably made for some rather interesting confrontations.

August 26, 2019

In New Zealand, a newly identified species of ancient giant penguin—or “monster” penguin as dubbed by the Canterbury Museum in Christchurch—has added to the southwest Pacific island nation’s roster of extinct oversized animals. The leg and foot bones of Crossvallia waiparensis, a 5-foot, 3-inch (1.6-meter) tall, 180-pound (80-kilogram) penguin, were found in Waipara, North Canterbury, on New Zealand’s South Island.

This illustration shows the ancient giant penguin Crossvallia waiparensis alongside a modern human. Credit: © Canterbury Museum

The ancient “monster” penguin bones were discovered in 2018 at Waipara Greensand, a geological formation that has produced significant penguin fossils before. Researchers from the nearby Canterbury Museum and the Senckenberg Natural History Museum in Frankfurt, Germany, studied the penguin fossils, and they named C. waiparensis as a new species in the Aug. 12, 2019, issue of Alcheringa: An Australasian Journal of Palaeontology.

C. waiparensis, which lived during the Paleocene Epoch between 66 million and 56 million years ago, was roughly four times larger than the emperor penguin, the largest of all modern penguins. During the time of C. waiparensis, New Zealand was still attached to Australia, which was once connected to Antarctica. A related prehistoric giant penguin, Crossvallia unienwillia, was discovered in Antarctica’s Cross Valley in 2000. The leg bones of both giant penguins suggest their feet were more adapted for swimming than those of modern penguins, and they may not have stood upright as modern penguins do.

Emperor penguins, seen here in Antarctica, are the largest living penguins. They stand about 3 feet (1 meter) tall and weigh as much as 100 pounds (45 kilograms). (Credit: © Shutterstock)

Prior to the discovery of C. waiparensis, New Zealand’s legacy of ancient giant critters already included the world’s largest parrot (Heracles inexpectatus), a massive eagle (Hieraaetus moorei), a dog-sized burrowing bat (Vulcanops jennyworthyae), the more than 6-foot (2-meter) tall moa, and other giant penguins.

April 13, 2017

For thousands of years, indigenous (native) people of Western Australia knew about giant ancient footprints along the shore of the Indian Ocean. But only recently have scientists learned about, and been able to study, the tracks, which were made by dinosaurs some 100 million years ago. A team of scientists led by Steven W. Salisbury of the University of Queensland studied the collection of fossilized footprints—which includes the largest ever discovered—for five years. Salisbury and his team recently published their findings as a memoir in the Journal of Vertebrate Paleontology.

Richard Hunter, an elder of the Goolarabooloo community, lies alongside a massive sauropod track in the Walmadany area of Dampier Peninsula in Western Australia. Credit: © Steve Salisbury, University of Queensland

A fossil is the mark or remains of an organism that lived thousands or millions of years ago. Most people think of bones or shells when they hear the word fossil. But tracks, trails, and burrows left by ancient organisms are also extremely important in paleontology (the study of prehistoric life). These marks, called trace fossils, give paleontologists a rare glimpse into the lives of prehistoric animals. The scientists can use trace fossils to answer many questions about an animal’s behavior, such as how it moved or how many animals moved together at a time. Scientists cannot usually pair a trace fossil to an exact species (kind) of animal, but they can often determine broadly what type of animal left the mark.

The fossilized tracks in question are on the northern shores of Western Australia. About 130 million years ago, the region was a sandy floodplain covered with braided rivers. Braided rivers have numerous channels separated by small temporary islands. After the tracks were made, floods rapidly covered them in sediment, preserving them from destruction. Thousands of tracks are scattered over several dozen sites in the area, and about 150 are in excellent condition. The findings give scientists a valuable snapshot into life during the early Cretaceous Period in Australia.

Salisbury and his team identified several types of prints coming from ornithopods (plant-eating dinosaurs that could walk on two or four legs), sauropods (large plant-eating dinosaurs with long necks and tails), stegosaurs (relatives of Stegasaurus), and theropods (meat-eating dinosaurs) of different sizes. One of the tracks measures a whopping 5 ½ feet (1.7 meters) long. This print was made by the hind foot of a huge sauropod some 18 feet (5.5 meters) tall at the hip.

The indigenous people of the Western Australia coast had known of the tracks for thousands of years and had incorporated them into their belief system. In one story, the Dreamtime figure Marala, also known as the Emu Man, makes the three-toed footprints that today are believed to have been made by theropods. (The emu is an Australian bird that has three toes on each foot.) The Dreamtime is a fundamental spiritual concept that connects traditional beliefs and practices among the Aboriginal people of Australia.

In 2008, the state government of Western Australia—unaware of the ancient tracks—proposed that a natural gas processing facility be located near the site. Fearing that the tracks would be damaged or destroyed, the Aboriginal people contacted Salisbury to assess the tracks’ scientific importance. As word spread of the natural gas plant and the damage it could cause to the tracks, environmental groups, paleontologists, and local citizens campaigned for the area to be preserved. The company planning to build the processing plant eventually withdrew its application. Now the tracks, with their important connections to prehistory and the Dreamtime will remain protected.

December 27, 2016

Lida Xing, a paleontologist (scientist who studies fossils) from the China University of Geosciences in Beijing, made a spectacular find just by going to the market. There, he found part of a tiny dinosaur—complete with feathers—perfectly preserved in amber.

A lump of amber has preserved this feathered dinosaur tail (along with ants, a beetle, and bits of foliage) for 99 million years. Credit: © Ryan C. McKellar, Royal Saskatchewan Museum

Amber is a hard, yellowish-brown fossilized resin. It comes chiefly from the resins of pine trees that grew millions of years ago. These resins were gummy materials mixed with oils in the trees. When the oils oxidized (combined with oxygen), hard resins were left. These pine trees were then buried underground or underwater, and the resins slowly changed into lumps of amber. These lumps often contain insects trapped as the resins flowed from the trees. But finding larger animals such as small vertebrates (animals with backbones) is incredibly rare.

Xing found the remarkable fossil at an amber market in the Southeast Asian nation of Myanmar (also called Burma). The seller thought the bushy object in the amber was part of a plant and had polished the piece to be made into jewelry. But it was in fact part of the feathery tail of a small dinosaur. Xing promptly brought the specimen to fellow paleontologist Ryan McKellar of the Royal Saskatchewan Museum in Regina, Canada, where they studied it with other scientists using computed tomography (CT). Computed tomography involves taking many X-ray images of an object from a number of directions. A computer combines the set of X-ray “slices” of the object to create a three-dimensional image called a volumetric model. The scientists recently wrote about what they found in the journal Current Biology.

Paleontologists have discovered feathered dinosaur fossils in the past, but the heavy weight of the sediments and rocks deposited above them had flattened the carcasses during the fossilization process. Because this tail was trapped in amber, however, it was preserved in three dimensions, allowing scientists to see the exact layout of the feathers. Even traces of the pigments that colored the feathers have been preserved, showing that the animal would have been light brown with a whitish underside.

The tail likely belonged to a juvenile (young) bipedal dinosaur related to Tyrannosaurus rex. Despite the specimen’s prominent plumage, paleontologists know that the tail belonged to a nonbird dinosaur (all birds are technically dinosaurs). The fossil dates back 99 million years, some 50 million years after the appearance of early birds such as Archaeopteryx. A tail from Archaeopteryx would have been short and stiff. The tail from this new fossil, however, is long and flexible. It is bent a great deal in the amber, and scientists estimate that only a third of the tail was preserved. Furthermore, the beautifully preserved feathers trapped in amber would have been useless for flight. The feathers possess simple barbs and barbules that would hold strands of the feathers together, but they have much thinner central shafts than modern flight-worthy feathers. These ancient feathers would have been soft and downy, and they probably kept the young animal warm.

The loss of the dinosaur’s tail in amber probably cost it its life. Dinosaurs could not detach their tails the way some lizards can. A dinosaur could likely survive without the tip of its tail, but this fossil is from the mid-section of a dinosaur’s tail. Once the hapless youngster got stuck in resin, it probably either starved to death or became an easy snack for a predator—except for the part stuck in resin, of course.

Lida Xing has a knack for making spectacular finds of amber-entrapped animals. Earlier this year, he announced the discovery of a pair of 100-million-year-old bird wings. His remarkable discoveries are shining a new light on the evolution of feathers in birds and dinosaurs.

November 23, 2016

At a recent convention of paleontologists (scientists who study animals and plants that lived in prehistoric times), things got a bit venomous. A group of researchers claimed that a fossil recently identified as an early snake was not a snake at all. Furthermore, they stated that the specimen should not have been studied in the first place. The presentation was the most recent shot fired in the battle over the evolution (a process of change over time) of snakes.

This artist’s impression shows the four-footed tetrapodophis amplectus snatching its prey, an unlucky salamander. Credit: © James Brown, University of Portsmouth

In 2015, Dave Martill and his colleagues at the University of Portsmouth in England reported that they had discovered a new type of primitive snake. They found the ancient animal’s fossilized imprint (which came from Brazil) among the collections of a German museum. The British researchers named their discovery Tetrapodophis amplectus and published their findings in the journal Science. Tetrapodophis means “four-footed snake.” The animal was about 6 inches (15 centimeters) long and possessed four tiny limbs. It lived in an ocean environment some 110 million years ago.

This month, however, at the annual Society of Vertebrate Paleontology conference in Salt Lake City, Utah, Michael Caldwell of the University of Alberta in Edmonton, Canada, gave a presentation refuting Martill’s “four-footed snake” diagnosis. In the creature’s skull, for instance, Caldwell noted “every single character that was identified in the original manuscript as being diagnostic of a snake was either not the case or not observable.” Instead, Caldwell’s group contended that Tetrapodophis is not a snake at all, but rather a member of a group of unrelated marine reptiles.

The fossilized imprint of Tetrapodophis reveals small, specialized feet—or perhaps flippers. Credit: © Dave Martill, University of Portsmouth

This dispute is merely the latest spat among paleontologists on snake origins. Paleontologists agree that snakes likely evolved in the Jurassic Period some 150 million years ago. Some people (like Martill) think that snakes evolved from aquatic reptiles. Over million of years, four-legged reptiles would have spent more and more time in the water, eventually losing their limbs in favor of a long body good for swimming. Later, snakes made their way onto land, with some (sea snakes) remaining in their ancestral habitat. Martill’s group contends that snakes were closely related to mosasaurs, giant marine reptiles that prowled the oceans some 100 million years ago. Most paleontologists, however, think that snakes evolved from burrowing, terrestrial reptiles. As these aimals dug deeper and more complex burrows with their strong heads, their limbs vanished over millions of years. Later, snakes moved into different habitats, including the sea. In this scenario, snakes’ closest relatives would be monitor lizards such as the Komodo dragon. So far, a lack of ancient snake fossils has prevented either hypothesis from being proven.

Further muddying the water, Caldwell—of the “land snake” faction—reported that when he went to study the fossil in the German museum, the fossil was no longer there. Apparently, it had been a loan to the museum from a private collector. The collector had retrieved it from the museum because it had been damaged during an earlier study. Most paleontologists will not study privately owned fossils for this exact reason: an owner may take back the fossil at any time. Science must be repeatable, so a description of a specimen that is no longer available for study is not science at all. Since Tetrapodophis was revealed to be a privately owned specimen, many experts have vowed to ignore it while conducting future studies on snake evolution. We will have to wait for more fossils—in the permanent collections of museums and universities—to determine if snakes started out on land or in the water—with four legs or, perhaps, four flippers.

September 28, 2016

When you see models or illustrations of dinosaurs, have you ever wondered how accurate they are? Bones, skin impressions, and tracks can tell scientists and artists a great deal about the shape, size, and movements of these animals, but how do people know what color patterns the beasts adopted? Most of the time, artists make educated guesses based on what is known about each dinosaur and its habitat. But researchers led by Jakob Vinther of the University of Bristol in the United Kingdom recently collaborated with artist Bob Nicholls to create what may be the most accurate representation of a dinosaur to date. What’s more, the finished model provided clues about the animal’s habitat (rather than the other way around).

The recently created Psittacosaurus model shows the dinosaur with countershading camouflage (darker on top, lighter on bottom). Many modern-day animals exhibit countershading. Credit: © Jakob Vinther, Robert Nicholls, Stephan Lautenschlager, Michael Pittman, Thomas G. Kaye, Emily Rayfield, Gerald Mayr, Innes C. Cuthill/Univerity of Bristol

Psittacosaurus was a small plant-eating dinosaur that lived 130 million to 100 million years ago in what is now Asia. Its name, which means parrot lizard, comes from its large, sharp, parrotlike beak. The dinosaur measured up to about 2 feet (60 centimeters) tall at the hips and 6 1/2 feet (2 meters) long.

Vinther’s team examined an exquisitely preserved Psittacosaurus from China that included much of its skin. They found that darker areas of skin were full of melanosomes, tiny structures that produce pigments, but the lighter areas were not. This discovery showed that the color pattern seen in the fossil was real, and not the result of discoloration during fossilization.

With that knowledge, the researchers turned to Bob Nicholls, a Bristol-based paleoartist (an artist who specializes in depicting prehistoric life). He carefully examined the specimen, taking into account every minute pattern on the animal’s skin. He then created two sculptures of the animal, painting one a uniform shade of gray, and decorating the other with the intricate patterns seen in the fossil.

From the sculpture, it became clear that Psittacosaurus exhibited countershading. Countershading is a type of camouflage in which the parts of an animal exposed to sunlight are darker colored and the animal’s underside is lighter colored. In sunlight, the exposed, darker-colored sections appear brighter and the lighter-colored sections are shaded by the rest of the body. This effect flattens the appearance of the animal and makes it more difficult to see. Many kinds of animals, from sharks to antelope, exhibit countershading. In the case of Psittacosaurus, this small herbivore (plant eater) was countershaded to try to escape the sight of large meat-eating dinosaurs—relatives of the infamous Tyrannosaurus rex—that lived in the area at the time.

Vinther and his team then took the two sculptures to ecosystems with different lighting characteristics and observed how well camouflaged the countershaded model was in relation to the gray one. They found that the countershaded sculpture was best camouflaged in areas with moderate tree cover, suggesting that this species of Psittacosaurus lived in woodland environments. This evidence also jibes with other fossils that have been found along with the Psittacosaurus, such as petrified tree trunks and remains of shade-loving plants. This is the first time that a dinosaur’s color pattern was used to infer the type of environment in which it lived.

This study showed that determining the colors and color patterns of dinosaurs isn’t just a goal in and of itself, but it can also help define a dinosaur’s ancient environment. It’s not just good for art; it’s good for science!

August 17, 2016

Eons ago, a monstrous beast stalked an ancient South American floodplain. One of its enormous footprints in the soft clay was covered with layers of silt and was preserved for some 70 million years. Last month, the track was discovered, revealing that huge predatory dinosaurs lived in South America up until the extinction of the group about 65 million years ago.

The record-setting dinosaur footprint was found at Maragua Crater near Sucre, Bolivia, a site already known for other, smaller dinosaur tracks. Credit: WORLD BOOK map

Dinosaurs are a group of prehistoric reptiles that ruled Earth for about 160 million years. Most of these animals died millions of years ago, but their direct descendants—birds—continue to flourish today. Dinosaurs have fascinated people ever since they were first described in the early 1800′s as having strange appearances and huge sizes. Scientists now know that not all dinosaurs were large. Many, such as the microraptor and compsognathus, were, in fact, quite small.

The South American footprint, however, belonged to something gigantic with really big feet. It was found about 45 miles (60 kilometers) outside of Sucre, the official capital city of Bolivia, by a local tour guide. At some 45 inches (115 centimeters) wide, it is the largest carnivorous (meat-eating) dinosaur footprint ever discovered. The previous record was nothing to sneeze at either: a 40-inch (110-centimeter) wide track from New Mexico, a state in the southwestern United States.

The animal that made the South American print probably belonged to a group of dinosaurs called abelisaurids, large meat-eaters with short skulls and tiny arms that lived in South America, Africa, and India. Based on the enormous size of the footprint, scientists think the dinosaur could have been up to 40 feet (12 meters) long.

The discovery of this footprint helps paleontologists fill in the history of large meat-eating dinosaurs in South America. Giganotosaurus, one of the largest meat-eating dinosaurs known, stalked the continent some 95 million years ago. But Giganotosaurus probably died out after 5 million years or so, and paleontologists had not found fossil evidence of any large carnivores taking its place. The print was dated at 70 million years old, showing that abelisaurids took over after the demise of Giganotosaurus. With any luck, paleontologists will soon find the bones of these giant hunters and better understand the ecology of South America at the end of the age of dinosaurs.

July 19, 2016

Late last month, paleontologists (scientists who study fossils) announced an amazing discovery. Researchers led by Lida Xing at the China University of Geosciences in Beijing had discovered two bird wings preserved in amber. They published their findings in the journal Nature Communications.

Amber preserved this 100 million-year-old wing tip featuring bones, feathers, and soft tissue.
Credit: © Ryan C. McKellar, Royal Saskatchewan Museum

Amber is a hard, yellowish-brown fossilized resin. It comes chiefly from the resins of pine trees that grew millions of years ago. These resins were gummy materials mixed with oils in the trees. When the oils oxidized (combined with oxygen), hard resins were left. These pine trees were then buried underground or underwater, and the resins slowly changed into lumps of amber. These lumps often contain insects trapped as the resins flowed from the trees. But finding larger animals such as small vertebrates (animals with backbones) is incredibly rare. In the 1993 science fiction film Jurassic Park, dinosaur DNA (deoxyriboneucleic acid) is discovered in the blood of an ancient mosquito fossilized in amber. Movie scientists then used the DNA to recreate dinosaurs—an improbable, yet intriguing, plot line.

The wing fossil subjects of last month’s report were formed about 100 million years ago, in the Cretaceous Period, in what is now Myanmar (also called Burma). Two birds apparently became stuck in the sticky resin of a tree and died. The amber preserved the three-dimensional structure of the birds’ wings, as well as the wings’ feathers, skin, and bones—even the color patterns!

Xing and his team think the wings came from a group of birds called enantiornithines, which means opposite birds in Greek. These birds had claws and teeth, and they went extinct along with the nonflying dinosaurs about 65 million years ago. The fossils showed that the wings were from young birds and that the birds hatched as miniature adults, ready to fly. This is different from modern birds, which must develop for weeks or months before they can leave the nest.

The structure of the wings and the arrangement of feathers are similar to modern bird wings. Birds evolved (developed over time) about 150 million years ago from meat-eating dinosaurs, so they must have quickly developed modern-looking wings, before enantiornithines and the ancestors of modern birds split.

Unlike science fiction, these fossils won’t resurrect the extinct enantiornithines, even if they do contain DNA. The technology to create entire animals from bits of ancient DNA does not yet—and might never—exist. The fossils do, however, offer paleontologists a treasure trove of information that will help us better understand early birds and their world.