The discovery of what may be the earliest known creature with what can be discerned as a face has been reported in Nature. Entelognathus primordialis is an exceptionally well-preserved 419-million-year-old fish from China that is the most primitive vertebrate to have a modern type of jaw.
This fish is a placoderm, one of a member of an extinct group of gnathostomes (jawed vertebrates), but its jaw is much more like that of a modern bony fish: its discovery may offer a new perspective on the early evolution of these creatures.
The evolution of jaws is one of the key episodes in the evolution of vertebrates, but the gap between jawed and jawless vertebrates is so large that it is hard to work out the individual evolutionary steps in the transition. Min Zhu and colleagues illuminate a step near the end of the process, where modern jawed vertebrates, such as sharks and bony fishes, emerge from a collection of jawed, armored fishes known as placoderms.
Linked from USA Today because the version we received had the head chopped off, which defeats the point. Credit: Brian Choo
Entelognathus primordialis has jaw bone features previously restricted to bony fishes (osteichthyans) as well as full body armor seen in placoderms, and it would have been around 20 cm long. This is the first stem gnathostome with dermal marginal jaw bones (premaxilla, maxilla and dentary), features previously restricted to Osteichthyes.
It was thought that the most recent common ancestor of jawed vertebrates resembled modern sharks, but the new fossil turns this view on its head, according to Matt Friedman and Martin Brazeau. They suggest that the finding provides compelling evidence for the evolutionary link between placoderms and osteichthyans, and adjusts our understanding of early gnathostome evolution.
In USA Today, University of Chicago paleontologist Michael Coates said, "It's important … because it's unexpected. It does present something we had no hint of before."
That's not really true. This is a bombshell because it was absolutely expected. And predicted. It was just a matter of time and luck finding it.
Citation: Min Zhu, Xiaobo Yu, Per Erik Ahlberg, Brian Choo, Jing Lu, Tuo Qiao, Qingming Qu, Wenjin Zhao, Liantao Jia, Henning Blom&You’an Zhu, 'A Silurian placoderm with osteichthyan-like marginal jaw bones', Nature 25 September 2013 doi:10.1038/nature12617
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Thank You Guido
- Replacing Exercise With A Pill
- Public Health vs. EU's Tobacco Product Directive: The Battle is Joined
- VB-111 Gene Therapy Doubles Survival In Recurrent Glioblastoma
- Celiac Disease Diagnosis Gets Simplified
- Online Market For Invasive Plants Is Booming
- September 24th, 2015 - Just Another Day In Space - Asteroid Flybys, "Blood Moons" And Armageddon Demystified
- "Oh, are you talking about the numbers? The 24 hours with a set tilt of 23.44 degrees (which..."
- "Robert,'WHAT embitters the world is not excess of criticism, but absence of self-criticism.'and'So..."
- "Thanks Robert. I very much appreciate your reply. I read it carefully. It certainly would be classified..."
- "Hi Joe, I've been traveling and limited access because I left my keyboard behind and had to buy..."
- "Well Robert, To put it another way, show me in a compelling manner how this precise system came..."