SaccorhytusAnd the A microscopic creature, considered the first known step on the evolutionary path leading to man, However, analysis of the new fossils contradicts this theory as experts now estimate that it is part of a different family tree.
Discovery of the first fossils of Saccorhytus, dAbout 535 million years ago, in China and the analysis that led to him being considered the first possible ancestor of man It was published in 2017 in Nature, the same journal that now includes the new study.
In light of the new analyzes, an international team believes that Saccorhytus is not the oldest representative of animals with an anus.an evolutionary lineage we’re a part of, but it will be protozoan, only with a basic mouth.
This new knowledge provides important adjustments in the primitive phylogenetic tree and in understanding how life evolved.
It means removing this little creature from the place it was thought to occupy “That there is a huge gap in the fossil record of diodes, that is, our side of the animal tree. “So we will continue to dig and look for the first true fossils of the binary,” said Shuhai Xiao of Virginia State University, one of the authors of the research.
Similar to Saccorhytus “Angry Minion”, As described by the University of Bristol (UK). “a spiny and wrinkled sac, with a large mouth surrounded by thorns and holes.”
It is precisely these holes that, in the first analysis published in 2017, were interpreted as gill pores, a primitive characteristic of the group of deuterostomes, but which the new study refutes.
The team recently discovered hundreds of fossilized specimens of Saccorhytus, some of them “It’s so perfectly preserved that it looks almost alive,” It highlights Yunhuan Liu, from Chang’an University (China), who has provided new insights into anatomy and the convergence of evolution.
Various types of analysis and recreation on a supercomputer to create 3D digital models have revealed the internal and external structures of this microscopic creature.
Numerical models have shown that the pores previously interpreted as gills are in fact the spibroken hands, “Destroy the only evidence supporting the deuterostome explanation,” said Zhag Huaqiao of the Chinese Academy of Sciences.
Saccorhytus could be related to several lines of the great evolutionary tree, and researchers have conducted an extensive morphology-based phylogenetic analysis along with other experiments to test different possibilities.
In all tests, the results supported the hypothesis that Saccorhytus belongs to the group ecdysozoa, which includes, among others, arthropods – insects, crabs and earthworms, explained Philip Donoghue of the University of Bristol.
This marine creature would thus be one of the oldest known exozoans, although its exact location is unclear, plus its sack-shaped body defies the traditional worm shape of this group, but”It might reflect the ancestral condition from which all of its members have grown up.”
There is still much to discover about this tiny animal and among the questions that await an answer, Michael Steiner, of the Free University of Berlin, highlights the need to determine whether it lives floating in the sea or among grains of sand or whether its thorns act to deter predators or to stabilize The organism on the sea floor.