Bag-like sea creature was humans' oldest known ancestor

Source: Phys.org

Bag-like sea creature was humans' oldest known ancestor

January 30, 2017

Researchers have identified traces of what they believe is the earliest known prehistoric ancestor of humans—a microscopic, bag-like sea creature, which lived about 540 million years ago.

Named Saccorhytus, after the sack-like features created by its elliptical body and large mouth, the species is new to science and was identified from microfossils found in China. It is thought to be the most primitive example of a so-called "deuterostome"—a broad biological category that encompasses a number of sub-groups, including the vertebrates.

If the conclusions of the study, published in the journal Nature, are correct, then Saccorhytus was the common ancestor of a huge range of species, and the earliest step yet discovered on the evolutionary path that eventually led to humans, hundreds of millions of years later.

Modern humans are, however, unlikely to perceive much by way of a family resemblance. Saccorhytus was about a millimetre in size, and probably lived between grains of sand on the seabed. Its features were spectacularly preserved in the fossil record—and intriguingly, the researchers were unable to find any evidence that the animal had an anus.

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Read more: https://phys.org/news/2017-01-bag-like-sea-creature-humans-oldest.html


[font size=1]Artist's reconstruction of Saccorhytus coronarius, based on the original fossil finds. The actual creature was probably no more than a millimeter in size. Credit: S Conway Morris / Jian Han[/font]

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Related: Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China) (Nature)


[font size=1]Saccorhytus was also covered with a thin, relatively flexible skin and muscles. It probably moved around by wriggling[/font]

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Source: BBC

Scientists find 'oldest human ancestor'

By Pallab Ghosh
Science correspondent, BBC News

30 January 2017 Science & Environment

Researchers have discovered the earliest known ancestor of humans - along with a vast range of other species.

They say that fossilised traces of the 540-million-year-old creature are "exquisitely well preserved".

The microscopic sea animal is the earliest known step on the evolutionary path that led to fish and - eventually - to humans.

Details of the discovery from central China appear in Nature journal.

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Read more: http://www.bbc.com/news/science-environment-38800987