Quantcast
ZME Science
  • News
  • Environment
  • Health
  • Future
  • Space
  • Features
    Menu
    Natural Sciences
    Health
    History & Humanities
    Space & Astronomy
    Technology
    Culture
    Resources
    Natural Sciences

    Physics

    • Matter and Energy
    • Quantum Mechanics
    • Thermodynamics

    Chemistry

    • Periodic Table
    • Applied Chemistry
    • Materials
    • Physical Chemistry

    Biology

    • Anatomy
    • Biochemistry
    • Ecology
    • Genetics
    • Microbiology
    • Plants and Fungi

    Geology and Paleontology

    • Planet Earth
    • Earth Dynamics
    • Rocks and Minerals
    • Volcanoes
    • Dinosaurs
    • Fossils

    Animals

    • Mammals
    • Birds
    • Fish
    • Reptiles
    • Amphibians
    • Invertebrates
    • Pets
    • Conservation
    • Animals Facts

    Climate and Weather

    • Climate Change
    • Weather and Atmosphere

    Geography

    Mathematics

    Health
    • Drugs
    • Diseases and Conditions
    • Human Body
    • Mind and Brain
    • Food and Nutrition
    • Wellness
    History & Humanities
    • Anthropology
    • Archaeology
    • Economics
    • History
    • People
    • Sociology
    Space & Astronomy
    • The Solar System
    • The Sun
    • The Moon
    • Planets
    • Asteroids, Meteors and Comets
    • Astronomy
    • Astrophysics
    • Cosmology
    • Exoplanets and Alien Life
    • Spaceflight and Exploration
    Technology
    • Computer Science & IT
    • Engineering
    • Inventions
    • Sustainability
    • Renewable Energy
    • Green Living
    Culture
    • Culture and Society
    • Bizarre Stories
    • Lifestyle
    • Art and Music
    • Gaming
    • Books
    • Movies and Shows
    Resources
    • How To
    • Science Careers
    • Metascience
    • Fringe Science
    • Science Experiments
    • School and Study
    • Natural Sciences
    • Health
    • History and Humanities
    • Space & Astronomy
    • Culture
    • Technology
    • Resources
  • Reviews
  • More
    • Agriculture
    • Anthropology
    • Biology
    • Chemistry
    • Electronics
    • Geology
    • History
    • Mathematics
    • Nanotechnology
    • Economics
    • Paleontology
    • Physics
    • Psychology
    • Robotics
  • About Us
    • About
    • The Team
    • Advertise
    • Contribute
    • Privacy Policy
    • Contact
No Result
View All Result
ZME Science

No Result
View All Result
ZME Science

Home → Science

Strange creature with mouth but no anus isn’t earliest human ancestor — and we’re a little bit relieved

It lived around 500 million years ago and was thought to be a common ancestor of deuterostomes

Fermin Koop by Fermin Koop
August 19, 2022
in Animals, Environment, News, Science

Scientists have solved an evolutionary conundrum involving a 500-million-year-old microscopic creature that intriguingly, has no anus. When discovered in 2017, it was reported the fossil of this marine beast could be humans’ earliest-known ancestor. Now, new evidence suggests it was probably an early ancestor of crabs and spiders — so you’re probably not really related to this guy.

Image credit: The researchers.

The animal, Saccorhytus coronarius, was first placed into a group called the deuterostomes. These are primitive ancestors of vertebrates, including humans. But curiously, deuterostomes animals typically characterized by their anus forming before their mouth during embryonic development — and this creature doesn’t have an anus at all. Now, researchers in China and the UK are claiming it actually belongs to a group called the ecdysozoans, ancestors of spiders and insects, based on an X-ray analysis of the creature.

“The paper suggested that Saccorhytus was an early member of our own evolutionary lineage, a group of animals known as the deuterostomes. But we had specimens that were better preserved, so we knew immediately that the authors had got it flat-out wrong,” Philip Donoghue, UK researcher and study co-author, told The Guardian.

A strange-looking creature

When discovered in 2017, Simon Conway Morris at the University of Cambridge and his colleagues analyzed 45 poorly preserved Saccorhytus specimens and suggested that a set of small openings near its mouth were the evolutionary precursors to gills now seen in fish. This led them to place the creature under the deuterostomes group.

However, Donoghue and his colleagues now have evidence to say this isn’t the case. The researchers collected several hundred more Saccorhytus specimens, much well preserved than the ones from the previous study. They used a weak acid to dissolve hundreds of kilograms of rock from the same site in China, revealing the fossils.

A closer look at the newly uncovered specimens using scanning electron microscopy and X-ray generated by a particle accelerator revealed three-pointed spikes not seen in the previous fossils. This suggested that the supposed gill-precursors around the Saccorhytus’ mouth were likely holes left over from spikes broken off at their bases.

“There was another layer of tissue preserved that extended up through these holes and created spines,” Donoghue told New Scientist. “Since the interpretation of those holes was the key evidence for interpreting the animal as a deuterostome, the lack of these openings basically pulls the rug from under that interpretation completely.”

Instead, the strangely-looking creature likely belonged to a big group of animals known as the ecdysozoans, which includes insects, crustaceans, and roundworms. The spikes helped it to catch prey, although it’s not clear what it would have eaten. Living animals such as penis worms have the same spines and use them to capture prey, Donoghue added.

The finding suggests that Saccorhytus can’t fill a gap in the fossil record that exists before the sudden appearance of a big diversity of animals. However, the hunt for other early deuterostomes – and perhaps our earliest ancestor – isn’t over, the researchers said, as there are many more enigmatic fossils left to be studied.

The study was published in the journal Nature.

Was this helpful?
Thanks for your feedback!
Related posts:
  1. This rat-like creature is the earliest ancestor of mankind
  2. Bizarre, ancient, bag-like creature in China is all mouth and spikes
  3. New magnetic brain stimulation technique relieved depression in 90% of the participants in a small-scale study
  4. Mysterious vomiting condition tied to marijuana can be relieved by hot showers, doctors say
  5. Strange Spherical Fossils may be Among World’s Earliest Multicellular Animals
Tags: fossilshuman ancestor

ADVERTISEMENT
  • News
  • Environment
  • Health
  • Future
  • Space
  • Features
  • Reviews
  • More
  • About Us

© 2007-2021 ZME Science - Not exactly rocket science. All Rights Reserved.

No Result
View All Result
  • News
  • Environment
  • Health
  • Future
  • Space
  • Features
    • Natural Sciences
    • Health
    • History and Humanities
    • Space & Astronomy
    • Culture
    • Technology
    • Resources
  • Reviews
  • More
    • Agriculture
    • Anthropology
    • Biology
    • Chemistry
    • Electronics
    • Geology
    • History
    • Mathematics
    • Nanotechnology
    • Economics
    • Paleontology
    • Physics
    • Psychology
    • Robotics
  • About Us
    • About
    • The Team
    • Advertise
    • Contribute
    • Privacy Policy
    • Contact

© 2007-2021 ZME Science - Not exactly rocket science. All Rights Reserved.

Don’t you want to get smarter every day?

YES, sign me up!

Over 35,000 subscribers can’t be wrong. Don’t worry, we never spam. By signing up you agree to our privacy policy.

✕
ZME Science News

FREE
VIEW