Nature

The Oldest Complete Fish Fossil was Discovered

It’s been more than 65 million years since the dinosaurs have been extinct from the earth, but their fossils still exist today under the sediments, rocks, soil, and rivers. Their fossils prove that the species of dinosaurs were real and also defined the climate change of that time, what was responsible for the extinction of dinosaurs, what had happened in the past, and how the climatic condition has changed. Not just only dinosaurs, scientists and researchers have found millions of years old fossil than dinosaurs which have extinct before the dinosaurs meanwhile the oldest fossils in the world.

Let’s back to 2019, when three Chinese researchers revealed a discovery in the world. They have found a fossil that was inside a rock face, undisturbed, and has been preserved for millions of years. After researching the fossil, they got to know that the fossil was of a jawed fish around 439 million years old found at the Chongqing site.

And this discovery shocked the world and opened a new page in history after founding the world’s oldest fossil. Along with this, they have also found some other fossils nearby, as they are 11 million years older than any fish fossils ever found before. This was a significant discovery in the world, the jaws are suspected to be evolved some 450 million years ago in all aquatic species. The oldest fossils were found 439 million years old with articulated jaws.

Articulated jaw means, the joint of the bones forming the skeleton surrounding the mouth of vertebrates, between the upper jaw and lower jaw. However, in this discovery, there were new species of shark have found that was also 439-million-year-old, with a fully articulated jaw.

Well, some of the world’s most significant fossil discoveries have come from China. Whether it is amazing feathered dinosaurs, the earliest modern mammals, and some of the oldest-known animals on the planet that have been discovered in China. Their researchers have revealed the world’s oldest well-preserved jawed fish long back 436 million years old, which was the start of the Silurian period.

In short, the Silurian period was a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, 443.8 million years ago. The Silurian (443.7 to 416.0 million years ago) was a time when the Earth underwent some changes that had an important effect on the environment and life within it. And the result of these changes was the melting of large glacial formations. Also, Silurian was the time when the evolution of fishes evolved. In this period, the wide and rapid spread of jawless fish, the first known freshwater fish as well as the first fish with jaws have evolved. 

The Chongqing site had over 1000 specimens of this species and the species was named Fanjingshania renovata. The Chinese researchers have published even four papers on the discoveries. And said, they are staring at complete early Silurian fishes around 11 million years earlier than the previous oldest finds. 

Even the researchers said that some of the fish that was discovered was Placoderms, an extinct species of fish that has hard plates that formed a shield around the head and trunk, while others were an ancestral type of shark or shark-like fishes called acanthodians. Even scientists have discovered the oldest complete shark-like fish, called Shenacanthus. It has a body shape that is similar to the acanthodians but just has thick plates from Armor around it like placoderms. 

The scientists found the oldest-known teeth of any vertebrate, 14 million years older than any previously discovered that has ever happened, as well as two other shark descendants called Shenacanthus

What kinds of fish were they? Most of the fishes fall into two main groups today-

  1. Chondrichthyans (which include sharks, rays, and chimaerids) have cartilaginous skeletons
  2. Osteichthyans (bony fishes such as trout) have bone forming the skeleton.

The origins of these living fish groups are now much clearer because of the new findings of the oldest complete fishes from China.

Chondrichthyans (which include sharks, rays, and chimaerids) have cartilaginous skeletons
Chondrichthyans (which include sharks, rays, and chimaerids) have cartilaginous skeletons
Osteichthyans (bony fishes such as trout) have bone forming the skeleton
Osteichthyans (bony fishes such as trout) have bone forming the skeleton

Well finally after all these discoveries that have revealed the first radiation of the jewed vertebrate that has evolved much earlier than any of us could imagine. These discoveries appeared and clearly define that jawed and jawless fishes coexisted for longer than ever thought. Hence, there is evidence now of earlier sharks and other jawed fish in the Ordovician period. 

The Oldest Complete Fish Fossil was Discovered
The Oldest Complete Fish Fossil was Discovered

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