The most important fossils in the world

A team of scientists presented the world’s oldest fossils: ruins of colonies of ancient bacteria known as stromatolites in rocks 3.7 billion years old in Greenland, being 200 million years older than the 3.48 billion-year-old fossil stromatolites discovered in the Pilbara region of northwestern Australia.

Molecular clocks, the mutation rate of genetic material, suggest that life on Earth began about 4 billion years ago, So having fossils as old as the stromatolites of Greenland indicates that life on Earth may have started quite quickly: these would be the first organisms on Earth.

These fossils from 505 million years ago discovered in Canada represent the oldest known fossil record of fish and, fortunately, contains incredible details of the animal’s facial features. The discovery of Metaspriggina, published in Nature in 2014, was remarkable, as the first fish fossils of the Cambrian period are very rare and poorly preserved. However, these fossils have well-defined eyes and nasal structures, and a number of exceptionally well-preserved arches near the front of your body, which are early evidence of the jaws.

These algae-like fossils found in rocks 1.56 million years old in China are the first known examples of organisms formed by many cells, multicellular life: the beginning of a complex life.

The discovery was made public in 2016 in Nature Communications magazine. Until this discovery, we had not seen large multicellular life forms in the fossil record until 600 million years ago, so it was an incredibly important finding leaving us this headline: Complex multicellular life emerged 600 million years ago.

In 2017, however, we rewrote history. The results of an exhaustive genetic analysis of current organisms by scientists at MIT suggested that eukaryotes, the group that includes animals, plants and protists, were present on Earth for at least 2.330 million years, just at the time when oxygen began to be a frequent and permanent element in the atmosphere. These tests place eukaryotes on Earth for 2,330 million years. This new estimate precedes the earliest fossil evidence by 800 million years.

When the partial femur of Megalosaurus was unearthed in England in 1676, a professor at Oxford University identified it as belonging to a human giant. It wasn’t until 1824 that William Buckland gave this genus its distinctive name, and it would be almost 20 years before the Megalosaurus was definitely identified as a dinosaur by the famous paleontologist Richard Owen. So, the megalosaurus femur was the first dinosaur described and baptized.

For hundreds of years before the eighteenth century, the inhabitants of Central and Western Europe had been digging up strange-looking bones along the beds of lakes and river banks. What made the spectacular skeleton of the marine reptile Mosasaurus important was that it was the first fossil to be positively identified by the naturalist Georges Cuvier as belonging to an extinct species. From this moment on, scientists realized that they were dealing with creatures that lived and died millions of years before humans appeared on earth. The fossil of Mosasaurus, a species that lived during Maastrichtian in the Cretaceous period between 70-66 million years ago, was discovered in 1764.

We got to the dinosaur that looks like a duck. 2017 was a great year for paleontologists; one of those that stood out was the fossil of a theropod dinosaur, studied non-invasively with high-tech 3D scanning, which showed surprising characteristics similar to those of birds.

The theory that birds descend from dinosaurs is now commonly accepted among vertebrate paleontologists. However, no one could have predicted Halszkaraptor escuilliei, a new species of non-avian theropod dinosaur from Mongolia described in 2017 and published in the journal Nature. Its long neck, which constitutes 50% of the total length of the snout to tail and the longest for any mesozoic theropod dinosaur, is a reminiscence that we can observe in some birds, such as swans. The morphology of Halszkaraptor suggested a semi-aquatic lifestyle and appears to be the first non-avian dinosaur to move both on land and in water. He lived 71 and 75 million years ago.

Lucy, a 3.2 million year old Australopithecus afarensis named after the Beatles' song "Lucy in the Sky with Diamonds", is perhaps the most famous fossil in the world. It was discovered in the Afar region of Ethiopia in 1974 and remains one of the most complete skeletons of a walking human ancestor, with approximately 40% of its bones intact. Its discovery allowed scientists to determine for the first time that the ability to walk upright predates the large brains of modern humans. Lucy’s brain is the size of a chimpanzee and is the most obvious proof of the mono-man link. 

The remains of this hominid are currently stored in a safe in Addis Ababa, the capital of Ethiopia.

The Iguanodon was the second dinosaur after the Megalosaurus to receive formal name of its genus; more importantly, its numerous fossils (first researched by Gideon Mantell in 1820) precipitated a heated debate among naturalists as to whether or not these ancient reptiles existed. Georges Cuvier and William Buckland, for example, claimed that these bones belonged to a rhino but, English biologist and paleontologist Richard Owen imposed himself with reality by identifying the Iguanodon as a true dinosaur.

The Iguanodon lived at the beginning of the Cretaceous period, approximately 130 to 120 million years ago, in what is now Europe.

The Hadrosaurus is very important, more for historical reasons than paleontological: it was the first almost complete dinosaur fossil excavated in the United States, and one of the few that was discovered on the east coast (found in the Woodbury Formation of New Jersey) instead of in the west. Named after the American paleontologist Joseph Leidy in 1858, Hadrosaurus lent its nickname to a large family of duck-billed dinosaurs, the hadrosaurs, a species that lived about 80 million years ago, in Campania, in what is now North America.

In 1860, Charles Darwin published his fantastic treatise on evolution, 'On the Origin of Species'. Luckily, in the following years there were a series of spectacular discoveries in the limestone deposits of Solnhofen, Germany: complete and exquisitely preserved fossils of an ancient creature, Archaeopteryx, which seemed to be the perfect "missing link" between dinosaurs and birds. Since then, other fossils have been unearthed, but none have had as deep an impact as this dove-sized dinosaur. The Archaeopteryx, which lived in the Upper Jurassic period about 150 million years ago, in what is now southern Germany, represents the dinosaur-bird link.

Borealopelta mark mitchell is a type of battleship herbivore that lived about 110 million years ago in present-day Alberta, Canada. This pineapple-like dinosaur was 5.5 meters long and had to weigh 1.2 tons. It’s one of the best fossils of its kind ever found, and it gave us an unprecedented picture of the anatomy and life of armored dinosaurs. This armored dinosaur (relative of the famous ankylosaur) represents a rarity; this terrestrial animal floated for many miles offshore before sinking, intact, buried and finally recovered millions of years later. 

It’s the most complete skeleton ever discovered. The child of Turkana, an almost complete fossil - just missing hands and feet- 1.6 million years old, from what some scientists call Homo ergaster, an early African population of Homo erectus, is considered the most complete skeleton of a prehistoric human ever found. The boy, discovered in 1984 in the Turkana region of Kenya, measures 160 cms, indicating that hominids had become considerably taller since Lucy’s days 3.2 million years ago. It is believed that the cause of the child’s death was generalized septicemia from the infection of a tooth.

For a historical peculiarity, most dinosaur fossils unearthed in the late eighteenth and early nineteenth centuries belonged to relatively small ornithopods or slightly larger theropods. The discovery of Diplodocus in the Morrison formation of western North America in 1877 marked the beginning of the era of giant sauropods, that have since captured the public’s imagination to a greater extent than dinosaurs like the Megalosaurus or the Iguanodon. The Diplodocus lived at the end of the Jurassic period, about 155.7-150.8 million years ago, in the Kimmeridgien and the Titoniense, in what is today North America.

Coelophysis was appointed in 1889 (by the famous paleontologist Edward Drinker Cope). However, this primitive dinosaur that lived at the end of the Triassic period and at the beginning of the Jurassic, about 203 to 196 million years ago, did not cause popular sensation until 1947, when the American paleontologist Edwin H. Colbert discovered innumerable Coelophysis skeletons entangled in the fossil site of Ghost Ranch in New Mexico. This discovery showed that at least some genera of small theropods traveled in vast herds, and that large populations of dinosaurs, carnivores and herbivores were often drowned by sudden floods.

The American paleontologist and dinosaurologist Jack Horner is known to be the inspiration for the character of Sam Neill in the movie Jurassic Park, but in paleontology circles, this expert is famous for discovering the extensive nesting grounds of Maiasaura, a medium-sized hadrosaur that roamed the American west in vast herds that lived at the end of the Upper Cretaceous period, approximately 80 to 70 million years ago, in Campania, in present-day North America. Taken together, the fossilized nests and fairly well-preserved skeletons of Maiasaura -baby, juvenile and adult- show that at least some dinosaurs had an active family life and did not necessarily abandon their offspring after they were born.

We make a mandatory stop at the site of Atapuerca in Burgos (Spain). More than 400,000 years old, the Sima de los Huesos is the largest deposit of human fossils in history. In 1976 the first human fossils were found, but it was hard to imagine the great amount of paleontological material that lay buried in their sediments. The site is full of human bones attributed to Homo heidelbergensis (considered the ancestor of Homo neanderthalensis), with an antiquity of about 300,000 years. It houses 2,000 bones belonging to at least 32 individuals. " All the human species that lived in Europe are represented in Atapuerca which, after more than 40 years of excavations, 99% of the fossils are still buried. There are still several decades of work left in this magical place and it will take much longer to extract all the information enclosed in such fossils.

It’s called Sue and it’s the largest, most complete, best-preserved Tyrannosaurus Rex ever discovered. Named after paleontologist Susan Hendrickson, who discovered the remains in South Dakota in 1990, Sue is one of the largest carnivores to have walked the Earth 67-65 million years ago.

The Chicago Field Museum, which exhibits the fossils (which it bought at an auction for $8.4 million) announced that it will dismantle the tyrannosaurus of 12,3 meters and will reassemble it according to the latest knowledge about the ferocious predator of the Cretaceous period. It will be exposed again in 2019.

Nyasasaurus, the oldest known dinosaur. Dinosaur fossils -found in the 1930s in Tanzania- the size of a Labrador dog, with a foot-and-a-half tail, belong to a reptile that lived in the Middle Triassic, between 10 and 15 million years before the eoraptor and blacksmith, the most primitive dinosaurs of the late Triassic period (between 230 and 225 million years ago). It is believed to be between six and ten feet long, weighing between 20 and 60 kilos.

The fossils discovered in the north-central province of Chubut (Argentinian Patagonia) of the Patagonian mayorum, which lived in the middle of the Cretaceous period, approximately 101 million years ago, in what is now South America, show us the biggest dinosaur ever. The size of the femurs found indicates that an adult could measure up to 40 meters from head to tail. It could reach 80 tons of weight, as if we were weighing 14 African elephants together. Without a doubt, the largest terrestrial animal in the history of planet Earth.

Montsecchia Vidalii is the oldest example of a flowering plant. It grew in swamps 130 million years ago, scattering abundantly in freshwater lakes in what are now mountainous regions of Spain. The fossil surpassed in five million years another aquatic plant, Archaefructus sinensis, which lived in what is today China, as its remains are dated in the Barremiense age of the lower Cretaceous.

The Sinosauropteryx was the first in a spectacular series of dinosaur discoveries at the Liaoning quarry in China. The fossil reveals the unmistakable impression of primitive hair-like feathers; it was the first time that paleontologists directly identified this characteristic in a dinosaur. Unexpectedly, an analysis of the remains of Sinosauropteryx showed that it only related in isolation to another famous feathered dinosaur, Archaeopteryx, which led paleontologists to revise their theories on how and when dinosaurs became birds. This dinosaur lived in the middle of the Cretaceous period, approximately 120 million years ago.

We bid farewell to the first known mammal: the Rugosodon eurasiaticus. This species of mammal, already extinct, measured 17 centimeters and weighed 80 grams. Its appearance was to be similar to that of a contemporary rat or squirrel and it lived 160 million years ago in the territory that today is China. Despite its small size, it had a series of anatomical characteristics that allowed it to move with agility through different lands and to have an omnivorous diet (it could feed on both plants and animals). His discovery was published in 2013 in the magazine Science.