Mysterious Microscopic Creature Without Anus Discovered

An international research team had recently found that a mysterious microscopic creature from which humans were believed to descend came from a different family tree.

Described in a EurekAlert! report as "resembling an angry Minion," the so-called "Saccorhytus" is a spikey, wrinkly sack with a large mouth surrounded by holes and spines described as pores for gills, a primitive trait of the deuterostome group, from which humans' deep ancestors appeared.

Nonetheless, extensive analysis of 500-million-year-old fossils from China has revealed that the holes surrounding the mouth are bases of spines that broke away during the fossils' preservation, finally showing the microfossil Saccorhytus's evolutionary affinity.

According to a professor in Paleobiology, Yunhuan Liu, from Chang'an University, Xi'an, China, some of the fossils are perfectly preserved and look nearly alive.

Essentially, Saccorhytus was a curious beast that had a mouth but without an anus and rings of complex spines around its mouth.

The Ancestry of 'Saccorhytus'

Study findings published recently in the Nature journal have made essential amendments to the early phylogenetic tree and the insight into how life developed.

The true story of the ancestry of the Saccorhytus lies in the microscopic internal and external traits of this small fossil.

Nonetheless, with the help of powerful computers, the fossils' detailed 3D digital model could be rebuilt by taking hundreds of X-ray images at little different angles.

Emily Carlisle, a researcher from the University of Bristol's School of Eart Sciences, said fossils could be extremely difficult to describe, and Saccorhytus is not an exemption.

Supercomputer Used

As this fossil analysis's basis, there's a need to use a synchrotron, a type of particle accelerator. Such a synchrotron offers extensively intense X-Rays that can be employed to take detailed images of the fossils.

Carlisle explained that they took hundreds of X-Ray images at slightly different angles and employed a supercomputer to develop a 3D digital prototype of the fossils, showing the small features of its internal and external constructions.

The digital models revealed that pores surrounding the mouth were closed by another layer of the body that extends through, producing spines around the mouth.

The Nanjing Institute of Geology and Paleontology's Huaquiao Zhang suggested that they believe these would have helped Saccorhytus capture and process its prey.

Nematodes and Arthropods

The study authors believe that Saccorhytus is an "ecdysoszoan," a group containing nematodes and arthropods, a related ScienceDaily report said.

According to Professor Philip Donoghue, from the University of Bristol's School of Earth Sciences, who co-led the research, they considered many of the alternative groups that Saccorhytus might be associated with, which include the corals, jellyfish, and anemones, which have mouths but without an anus.

To readdress the problem, the team's computational analysis compared the anatomy of Saccorhytus with all other living groups of animals, which concluded a link to the arthropods and their kin, the group to which crabs, roundworms, and insects belong.

The lack of anus of Saccorhytus is an interesting feature of the microscopic ancient organism. Even though the question that's springing to mind is the substitute route of digestive waste out of the mouth, rather undesirably, such a trait is essential for a fundamental reason for evolutionary biology.

Saccorhytus's membership of the group specifies that it has relapsed in terms of evolution, dispensing "with the anus its ancestors would have inherited," explained Shuhai Xiao, from Virginia Tech, United States, who co-led the project.

Xiao added that they still do not know the exact position of Saccorhytus within the tree of life, although it may reflect the ancestral occurrence from which all members of these diverse group's members evolved.

Related information about the discovery of the earliest human ancestor is shown on Timeline's YouTube video below:

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