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 → Research → Discoveries

Ancient 420-million-year-old fossil hints of bony fish and cartilaginous fish common ancestor

Based on fossil evidence and genome analysis, scientists know that the two groups diverged from a common ancestor around 420 million years ago, but we've yet to find actual fossil of it. Things are shaping up though after paleontologists have identified an Early Devonian fish from Siberia, approximately 415 million years old, which bears features of both classes.

Tibi Puiu by Tibi Puiu
January 13, 2015
in Discoveries, News, Science

As far as charting the tree of life goes, a basic indicator used to distinguished between classes of animals is the skeleton. Fish, for instance, can have a cartilaginous skeleton and here were remind sharks, rays and skates, or a bony skeleton like the sturgeon or ocean sunfish. In fact, bony fish or Osteichthyes as they’re also known represent the largest class of vertebrates in existence today. Based on fossil evidence and genome analysis, scientists know that the two groups diverged from a common ancestor around 420 million years ago, but we’ve yet to find actual fossil of it. Things are shaping up though after paleontologists have identified  an Early Devonian fish from Siberia, approximately 415 million years old, which bears features of both classes.

In search of the common fish ancestor

The 415-million-year-old fish Janusiscus provides evidence of a common bony and cartilaginous fish. Credit: SAM GILES, MATT FRIEDMAN, AND MARTIN BRAZEAU
The 415-million-year-old fish Janusiscus provides evidence of a common bony and cartilaginous fish. Credit: SAM GILES, MATT FRIEDMAN, AND MARTIN BRAZEAU

Initially, the specimen was classified in a 1992 paper as a bony fish belonging to the genus Dialipina, based on the scales and the head bones’ similarity to those of bony fish called Dialipina from the New Siberian Islands. Martin Brazeau at Imperial College London found it odd, however, that a bony fish was this old, so he requested more details. Eventually, him and his team were convinced that this was worth a thorough investigation.

[ALSO SEE] Ancient 385-million-year-old fish pioneered sex

The scientists performed micro CT scans to peek inside the delicate structure of the bones that encase the fragile head of the fish, whose fossil was only one centimeter long.  Because of the shape of the skull roof and the enamel on the scales, the fish was naturally classified as a bony one. Inside, however, things are a bit different. The CT scans showed how the skull is traversed by  nerves and blood vessels around the brain more closely resembled those of cartilaginous fish. As such, the fish has features of both classes. The fossil was eventually named Janusiscus schultzei, in honor to  the two-faced Roman god Janus.

The feeds previous speculations that suggested that both classes of jawed fish  had features of bony fish, but the cartilaginous ones eventually lost these. It also supports a 2014 study that showed that a 325-million-year-old fossil shark had a surprising number of bony fish features, suggesting that the ancestor also had these features and that sharks may be more specialized than originally believed.

“[…] Both groups evolved different adaptations, and they’ve also retained different primitive features from their ancestor,” Giles explains. “Each group has found a different way of approaching the problem of living in the sea.”

“Janusiscus is a fascinating discovery,” says John Long, a paleontologist at Flinders University in Adelaide, Australia. It’s also one that couldn’t have been made without the use of a detailed CT scan, he notes. “Such use of modern technology is transforming the way we do paleontology by revealing new layers of information in these critical transitional fossils.”

Findings appeared in Nature // via Science

Was this helpful?


Thanks for your feedback!

Related posts:
  1. Fossil Friday: private collector wanted a dinosaur skull, but got a huge, fossilized bony fish lung
  2. Ancient bony fish that was larger than a whale shark and a fast swimmer
  3. Origins of alcohol consumption traced back to 10-million-year-old common ancestor
  4. Small Somalian cavefish hints at mammals’ nocturnal ancestor
  5. Ancient 150-million-year-old ancestor could explain how turtles evolved to retreat their necks
Tags: bony fishcartilaginous fishfishpaleontology

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