8 Oldest Fossils in the World

Fossils are largely responsible for all the knowledge we have about Earth and the organisms living here. Studying fossils (paleontology) has helped scientists piece together our planet’s history and has provided insight into the origins of life. A specimen must be about 10,000 years old to be considered a fossil and many of them on the fossil record are millions of years old.

The oldest fossils are over 3.5 billion years old, which may mean that life emerged relatively early in the Earth’s history (Earth is 4.543 billion years old).

8. Rhyniognatha hirsti

Age: 400 million years
Location:  Aberdeen, Scotland
Species:  Ryniognatha hirsti

Rhyniognatha Hirstiphoto source: Wikimedia Commons

A tiny fossil containing the remains of the world’s oldest insect was initially found in 1920s, but not studied until recently. The fossil contains the jaw remains of Rhyniognatha hirsti and is about 400 million years old. Scientists say that the findings push back the origins of winged insects by 80 million years.

Rhyniognatha is not only the oldest-known insect, it was most likely one of the first animals to arrive on land.

Although Rhyniognatha‘s mandible structure is only ever found in winged insects, scientists cannot say with absolute certainty whether or not it had wings as no wing remains have been found. Scientists suggest that Rhyniognatha provides clues into why insects started to develop wings — shortly before Rhyniognatha lived, plants became massive and tall. Early insects fed on these plants and needed to develop a way to reach the plant tops.


7. Tortotubus

Age: about 440 million – 445 million years
Location:  Gotland, Sweden
Species:  Tortotubus protuberans

Tortotubusphoto source: sci-news.com

Fossils of the earliest-known fungus, Tortotubus, were discovered by paleontologists in Scotland in 2016. Paleontologists estimate that the fossil is about 440 million years old. Not only is the Tortotubus fossil the oldest fungus, it is the oldest fossil of any strictly land-based organism ever found.

Tortotubus has cord-like structures that are similar to modern fungi. These structures are also seen in other land-based organisms and scientists believe that they helped Tortotubus spread out and colonize land surfaces. Tortotubus and other early fungi played an important role in forming the soil and nutrients that were needed for plants and animals to transition onto land.


6. Metaspriggina

Age: about 505 million years
Location:  Burgess Shale, British Columbia, Canada
Species:  Metaspriggina walcotti

Metaspriggina
photo source: Slate

The Metaspriggina fossil found in the Burgess Shale is one of the oldest and best-preserved fossils of a primitive fish. In 2014, scientists released a study on Metaspriggina and announced that it played a key role in the development of jaws. Unlike other early fish, Metaspriggina had seven pairs of gill arches rather than the individual gill arches of the other fish.

Scientists believe that the pair of gill arches closest to Metaspriggina’s head evolved into the upper and lower jaw bones. For several decades, paleontologists believed that a creature like this existed, but the discovery of Metaspriggina provides the first fossil evidence of early jaw development.


5. Redlichiida

Age: 525 million – 500 million
Location:  Southern Australia and China
Species:  Redlichiida

Redlichiida

photo source: Slate

The oldest trilobite (ancient marine arthropods) fossils are about 525 million – 500 million years old. They are known as Redlichiida and they first appear in the fossil record in the Lower Cambrian period. The earliest Redlichiida are considered the ancestors of all other trilobite species.

Redlichiidas were flat and had an oval-shaped exoskeleton. Very few fossil specimens have any appendages, but scientists do know that Redlichiidas follow typical trilobite patterns in terms of the number, placement, and types of legs, antennae, and gills. Most Redlichiida fossils have been found in the Emu Bay shales of Southern Australia and the Maotianshan shales near Chengjiang in China.


4. Pikaia

Age: 523 million years
Location:  Alberta, Canada
Species:  Pikaia gracilens

Pikaia photo source: Wikimedia Commons

Pikaia fossils were first discovered by Charles Walcott in 1911. He found them in a mountain called Pika Peak (for which they are named) in Alberta, Canada. The fossils are about 523 million years old and Pikaia are the oldest known ancestor of modern vertebrates. However, there is some debate over whether or not Pikaia actually was a vertebrate ancestor even though it does have early vertebrate characteristics.

Recreations of what Pikaia looked like suggest it was similar to modern-day lancelets and swam like an eel. It also had a pair of large antennas on its head and short appendages on both sides of it head. There are 114 known fossils of Pikaia, which has allowed scientists to paint an accurate picture of what Pikaia may have looked like.


3. “Seaweed-Like” Fossils

Age: about 1.56 billion years
Location:  near Beijing, China
Species:  Eukaryotes

Seaweed Fossils photo source: The Washington Post

Researchers from China uncovered “seaweed-like” fossils in 2016. The find was a surprise because the organisms trapped in the fossils were visible to the naked eye, which is unusual for such ancient multi-cellular lifeforms known as eukaryotes. About 167 fossils were found and dated to about 1.56 billion years ago.

Before the new discovery, the earliest known examples of multi-cellular life of this size weren’t seen in the fossil record until about 600 million years ago.

The time period before this in the fossil record is known as the “boring billions” because researchers had previously only found microfossils from this far back. Additionally, the shape of the fossils suggest that these organisms may have been photosynthetic.


2. Stromatolites

Age: about 3.5 billion
Location:  Archaen Rocks, Western Australia
Species:  Cyanobacteria

Stromatolitesphoto source: Wikimedia Commons

Although a claim in 2017 says that the oldest fossils come from rocks found in Canada, the stromatolites from Archaean rocks in Western Australia are widely accepted as the oldest-known fossils with strong evidence. Stromatolite fossils are distinctive and look like layered rock formation. They were formed by ancient blue-green algae known as cyanobacteria and the oldest stromatolites are estimated to be about 3.5 billion years old.

Most of the stromatolites found so far are old and dead, but in 1956 living stromatolites — which are extremely rare — were found in Hamelin Pool in Western Australia. Hamelin Pool has the most abundant and diverse living stromatolites found anywhere in the world. The water in the area is twice the salinity of regular seawater, which allows cyanobacteria to thrive.


1. Hematite Tubes

Age: 3.77 billion – 4.2 billion years
Location:  Quebec, Canada
Species:  Unknown microscopic bacteria

Hematite Tubesphoto source: The New York Times

In early 2017, scientists found tubelike microscopic bacteria on hematite ore that are currently believed to be the oldest fossils in the world. The fossils are similar to those found at hydrothermal vents, where thriving biological communities exist. Though other scientists are skeptical about their claims, the scientists who found the fossils say they are at least 3.7 billion years old and may even be older than 4 billion years.

These scientists are hopeful that the new fossils will shed some insights into early life on Earth. If the fossils really are 4.2 billion years old this will provide evidence that life began quickly after the Earth’s oceans were formed.

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