<h1 class= "pgc-h-arrow-right" > rebel echinos: "rebels" in the Triassic ocean</h1>
Keywords: Coelacanth Permian mass extinction event Triassic Ocean rebellion
The order Coelacanth is an ancient and mysterious family whose members are extinct except for the Ratima (also known as speartail fish), which is hidden in the depths of the ocean today. Coelacanths are slow-moving fish, but there are exceptions, with paleontologists discovering that this family had a "traitor" 250 million years ago!
Picture note: The Ratimai fish, known as a living fossil, is from the Internet
Lake Wapiti Provincial Park is located in british Columbia, western Canada, and attracts many tourists because of its magnificent natural scenery. In addition to tourists, many paleontologists come to Lake Wapiti Provincial Park because the Sulphur Mountain formation here preserves a large number of fossils of Triassic marine life.
Photo note: Magnificent Lake Wapiti Provincial Park, picture from the Internet
At the end of the 20th century, paleontologists collected many paleontological fossils in the Sulphur Mountain Formation formation, which were preserved at the Royal Taylor Paleontology Museum and the Peaceful Regional Paleontology Research Center. The fossils appeared to have been forgotten until 2009, when Andrew Wendruff, a paleontologist at the University of Alberta, examined the fossils and saw a complete fish fossil and some fragments. Although this fish clearly belongs to the order Coelacanth, it is very different from the traditional sense of the order Coelacanth.
Photo note: Paleontologists hike in Lake Wapiti Provincial Park in search of fossils, image from the Internet
Image note: Fossils found in the Iwo Shan Formation formation, image from the network
In 2012, after research, paleontologists named this new prehistoric echinoscete fish rebellatrix, and its genus name comes from "rebel" + "coelacanth.". The model species name of the rebellious coelacanth is rebellatrix divaricerca, and the model species name comes from its distinctively large tail.
The rebellious coelacanth is also seen today as a large fish, with a body length of up to 1.3 meters. The body of the rebellious coelacanth is significantly more slender than today's Ratimai, a streamlined body designed to reduce resistance in the water. The rebellious spiny fish has a pointed head, a pair of large round eyes, a broad mouth, and sharp teeth in its mouth. The rebellious coelacanth, like today's fish, had fins, two dorsal fins on its back, and a pair of pectoral fins, a pair of ventral fins, and an fin underneath its body. Although all fins, the fins of the rebellious coelacanth are different from those of common fins, because they have fleshy fins wrapped around bones in their fins, which is why they are called meat fin fish.
Illustration: A restoration of the rebellious coelacanth, picture from the network
Illustration: Skeletal line diagram of the rebellious coelacanth, picture from the network
The biggest feature of the appearance of the rebellious coelacanth is the large tail fin that develops well behind it, and there are a large number of powerful muscles at the base of the tail fin, which can make the rebellious coelacanth reach a high swimming speed, which is also unique in the order of coelacanth, and it is also its "rebellious" place.
Image note: Fossil tail fin of the rebellious coelacanth, picture from the internet
Illustration: The big tail in the rebellious coelacanth restoration figure, picture from the network
Why the rebellious coelacanth has such a unique appearance is closely related to the era in which it lived. The rebellious coelacanth lived in the early Triassic period, 250 million years ago, when life on Earth had just experienced a great catastrophe, the famous extinction event of the late Permian. In this extinction event, 90% of species went extinct, and 96% of marine life disappeared, and ecosystems were devastated.
Image note: Oceans during the Permian mass extinction event, image from the web
When the Permian mass extinction ended, a large number of blank niches appeared in the oceans, including the absence of large predators. The coelacanth, which escaped the mass extinction, took the opportunity to evolve in a rapidly positive direction and occupied a position similar to that of sharks in the ocean today, and the rebellious coelacanth was one of them. As John Long, an expert at the Natural History Museum of Natural History in Los Angeles, California, said: "In general, this discovery reflects the natural shaping and flexible evolutionary process, a certain species of coelacanth that lived 200 million years ago suddenly deviated from the original way of life and hunting habits, evolved different characteristics from other coelacanths, and completely entered another state of life." ”
The rebellious coelacanth completed the jump from the traditional coelacanth hunting method to the active fast predator, but this jump did not bring ultimate success, and when sharks and marine reptiles, including ichthyosaurs, rose strongly, the rebellious coelacanth was doomed to the end, and the Mesozoic coelacanth continued to evolve in the opposite direction.
Evolution will also be capricious, and even if it rises strongly, it is likely that it will eventually be eliminated beyond its own ecological niche.
Picture note: Marine life in the early Triassic Period, where to find the rebellious coelacanth? Image from the web
Resources:
Wendruff, A. J.; Wilson, M. V. H. (2012). "A fork-tailed coelacanth, Rebellatrix divaricerca, gen. et sp. nov. (Actinistia, Rebellatricidae, fam. nov.), from the Lower Triassic of Western Canada". Journal of Vertebrate Paleontology. 32 (3): 499–511.
Image / Network (Intrusion and Deletion)
Text / Paleontological Exploration (Jiang Hong)
Typography / Paleontological exploration