99.8% of the vertebrates that exist on Earth have jaws (upper jaw and chin), collectively referred to as jawed vertebrates or jaws. The emergence and rise of jawed animals is one of the most critical leaps in the evolutionary history of vertebrates from fish to man. But when, where, and how exactly did this jump occur? These questions require paleontological evidence to answer. Let's first take a look at the following world's top ten jaw fish fossils:
1. Megalodon
This is a giant shark that lived during the Miocene period between about 23 million and 16 million years ago. It is classified as an extinct odontodontidae, which diverged from great white sharks in the Early Cretaceous. Megalodon is considered the largest large predatory shark ever made. Megalodons are found all over the world; Its fossils have been unearthed in many parts of the world, including Europe, Africa, the Americas and Australia. Megalodon has appeared in many works of fiction, including films and novels, and remains a popular subject in novels involving sea monsters.
2, Dunkleosteus
Dun's fish is a pelagic fish that inhabited open waters, living between 380 million and 350 million years ago during the Devonian period. It is a large predatory fish with a powerful jaw and sharp teeth. It is also the apex predator of its ecosystem. Dunkle's fish fossils were first discovered in 1867 by paleontologist Jay Terrell, and the world's largest collection of Dun's fish fossils is housed at the Natural History Museum in Cleveland.
3, Coelacanth
Coelacanth is a rare ancient fish that lived 410 million years ago. It became extinct in the Late Cretaceous about 66 million years ago, and the extant coelacanth belongs to its descendants. The earliest coelacanth fossils were discovered in the 19th century and are thought to be a transitional species between fish and quadrupeds. According to the analysis of growth markers in the previous year of body weight, it is estimated that their lifespan is similar to that of humans up to 100 years and reach maturity around 55 years; The oldest known specimen was 84 years old in 1960. Coelacanth fossils are on display at the Senckenberg Museum for Nature in Frankfurt, Germany.
4, sword ray (Xiphactinus)
Sword rays lived between 83 million and 66 million years ago during the Cretaceous period. It is also a giant predatory fish with sharp teeth and powerful jaws. Also voracious predatory fish, at least a dozen specimens have been collected, and their stomachs contain the remains of large, undigested or partially digested prey. The fossil is on display at the Sternberg Museum of Natural History in Hayes, Kansas.
5, spiral tooth shark (Helicoprion)
It lived during the Permian period between 320 million and 270 million years ago. It has a row of curved serrated teeth and is considered a carnivore. Almost all fossil specimens are spirally arranged clusters of individual teeth, called "tooth wheels," that are embedded in the lower jaw in life. Like most extinct cartilaginous fish, the bones are mostly unknown. Fossils of spiral-toothed sharks have been found all over the world.
6, Leedsichthys
Fossilized tail fin from the Natural History Museum, London
It lived during the Jurassic period between 150 million and 130 million years ago. It is a huge fish that is believed to be up to 27 meters long, making it one of the largest known fish. Leeds fish appeared in the 2003 British production of the "Bottom Overlord" movie, a Leeds fish was hunted by ground lizard crocodiles, bow mackerel, and finally killed by a troodontosaurus, becoming a group of troodontosaurs feast. Above, a tail fin fossil from the Natural History Museum in London.
7, dorsal fin shark (Stethacanthus)
It lived during the Devonian and Permian periods between 340 million and 280 million years ago. It has peculiar flipper appendages that may have been used to adsorb to other animals. It has a shark-like appearance. However, it is best known for its unusually shaped dorsal fin, similar to an anvil or ironing board. Small spikes (enlarged versions of the dermal fine teeth that usually cover shark skin) cover this crest, as well as the head of the ratfish.
8, Arandaspis
It lived during the Ordovician period between 430 million and 420 million years ago. It is a primitive fish with a relatively simple body size and skull structure. The streamlined body is covered with rows of knobby armor scales. The front and head of the body are protected by hard plates with openings for the eyes, nostrils and gills. It may be a filter feeder. It has no fins; Its only way to advance is to use a vertically flat tail. Therefore, it may swim in a way similar to modern tadpoles. Fossils of Arandaspis at the Natural History Museum in London.
9, leaf-finned fish (Eusthenopteron)
It lived during the Devonian period between 370 million and 350 million years ago. It is a famous ancient fish and is considered one of the ancestors of modern vertebrates. The earliest known evidence of bone marrow fossils was found in euptera, which may be the origin of the four-legged bone marrow.
10, the odd shrimp (Anomalocaris)
Odd shrimp lived between 515 million and 485 million years ago during the Cambrian period. It is an early arthropod with a strong jaw structure and sharp teeth, and the odd shrimp is nearly 40 cm long, making it one of the largest animals of the Cambrian period and is considered one of the earliest apex predators. It propels itself through the water by swinging the flexible flaps on the sides of its body. Each flap slopes below the flap farther back than it is, and this overlap allows the lobes on either side of the body to act as individual "fins" that maximize swimming efficiency.