Fish fossils uncovered in China have the earliest development of jaws seen in the ancient remains; they contrast with filter feeders before their evolution. They found the remains in a layer called the Rongxi Formation, with fish species supposed to be evolved about 15 million years earlier.
Evolution of Jaws Leads to New Ways of Eating
Ivan Sansom, a paleobiologist at the University of Birmingham, claims that fish previously lost their ability to suction to develop a mandible packed with teeth. Spiny fins or fossilized teeth were the previous options, according to Science Alert.
According to theory, the first fish existed 423 million years ago and had jaws, noted Nature.
One group of 20 teeth was extracted from a rock bed that was assumed to be 439 million years old. They had the jaw structure and teeth previously observed and belonged to the extinct fish species Qianodus duplicities.
Gaining mandibles is a crucial adaptation of vertebrates that gave options to get more prey instead of relying on a suction-type mouth like a lamprey made a difference. Developing a jawed head will give more options for a wider prey selection than an earlier filter feeder.
The earliest development of jaws is obviously one of the great achievements of the animal kingdom. They still account for more than 99 percent of all vertebrate species and are primarily highly modified fish gills, per WIREs.
From the first jawed precursor from which two classes of modern fish developed, one group is made up of sharks and rays that are cartilage fishes. Another is the osteichthyans, from which the seahorse, tuna, and lungfish came; one main ancestor several million years back.
Mammals would come from the second group, which enabled the rise of tetrapods, where warm-blooded animals came from.
Paleontologist Qiang Li of Qujing Normal University continued, "Qianodus provides us the first solid evidence of teeth, and subsequently of jaws, from such a vital preliminary phase of vertebrate development.
Evidence of Evolutionary Journey From Fish to Humans
Skeletal remains were recovered from the Rongxi Formation. This time, researchers were able to meticulously assemble them back together and expose a portion of the body of an antiquated shark forebear named Fanjingshania renovata.
According to vertebrate paleontologist Min Zhu of the Chinese Academy of Sciences, it is the oldest known jawed fish.
The details supplied allowed Fanjingshania to be situated inside the phylogenetic tree of early vertebrates, and insight was provided into the evolutionary processes which occurred in the progression of crucial vertebrate adaptive responses such as jaws, sensory systems, and partnered appendages.
Shenacanthus vermiformi, a distinct shark ancestor, and Xiushanosteus mirabilis, a much more ancient fish species, were also found in South China's Huixingshao Formation, which is dated in the same time frame.
These observations quite precisely approximate the fish fossil evidence with molecular clock results extracted from the genetic makeup of extant and extinct species. That also suggests that jawed animals initially popped up approximately 450 million years ago.
Early fins create lift from forwarding motion as a paper plane is pushed through the air. This supports the hypothesis that animals developed with a single pair of limbs which ultimately divided into pectoral (arm) and pelvic (leg) fins over evolutionary history.
The earliest development of jaws in fish was a game changer over the older filter feeders and the gaining of limbs from segmented fins. It was a turning point mover complex body shapes later on.
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