A number of researchers in China managed to find fossils of the oldest marine animals in the world. it is Yunnanozoan which is the ancestor of the strange water creatures that have inhabited Earth more than 500 million years ago.
These Yunnanozoans are the oldest relatives of all vertebrates on Earth. Researchers in China have analyzed the fossils of Yunnanozoans, extinct soft-bodied organisms that lived during the Cambrian Period.
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Fossils found in Yunnan Province, China, show that the creature is the oldest known ‘stem vertebrate’ on Earth, closely related to living vertebrates.
Yunnanozoans are very simple fish-like organisms that live underwater. But they had a ‘basket-like’ skeleton similar to that of today’s vertebrates.
They are also considered to be deuterostomes, which means that their anus is formed in front of their mouth during embryonic development, as reported by the Daily Mail, Sunday (10/7/2022).
The new study has been carried out by experts at the Nanjing Institute of Geology and Paleontology and Nanjing University in China’s Jiangsu province. It was revealed Yunnanozoa were Cambrian animals with a long-debated taxonomic position.
Scientists have long been puzzled about gaps in the fossil record that would explain the evolution of invertebrates into vertebrates. The evolutionary process of developing the backbone has been a mystery for centuries.
When scientists have studied how vertebrates evolved, the main focus has been on the pharyngeal arch, a paired structure that grows on either side of the future head and neck of the developing embryo and fuses in the middle.
Mammalian embryos have five pairs of these pharyngeal arches. As the mammalian embryo grows, the pharyngeal arch produces parts of the face and neck, such as muscles, bones, and connective tissue.
The authors say this pharyngeal curvature is a ‘key innovation’ that may have contributed to the evolution of the vertebrate jaw and braincase.
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