380-million-year-old fish sheds light on evolution of abs

The incredibly preserved musculature of a 380-million-year-old armoured fish could help explain how the modern-day 'six pack abs' - sported by movie stars such as Salman Khan and Arnold Schwarzenegger - evolved.
Swedish, Australian and French researchers have for the first time presented the preserved musculature of 380 million year old armoured fish discovered in north-west Australia.
This research will help scientists to better understand how neck and abdominal muscles evolved during the transition from jawless to jawed vertebrates.
The Gogo Formation, a sedimentary rock formation in north-western Australia, has long been famous for yielding exquisitely preserved fossil fish. Among other things it contains placoderms, an extinct group that includes some of the earliest jawed fish.

A few years ago, an Australian research team work led by Professor Kate Trinajstic made the remarkable discovery that these fossils also contained soft tissues including nerve and muscle cells.
Now they have collaborated with the research group of Professor Per Erik Ahlberg, Uppsala University, and with the European Synchrotron (ESRF) in Grenoble, France, to document and reconstruct the musculature of the placoderms.

"High contrast X-ray images were produced thanks to a powerful beam and a protocol developed for fossil imaging at the ESRF," said Sophie Sanchez, one of the authors, from the ESRF and Uppsala University.
"This is unique in the world and has enabled us to "reconstruct" some fossilised muscles and document the muscles of neck and abdomen in these early jawed fish, without damaging or affecting the fossilised remains," Sanchez said.

These early vertebrates prove to have a well-developed neck musculature as well as powerful abdominal muscles - not unlike some human equivalents displayed on the beaches of the world every summer, researchers said.
Living fish, by contrast, usually have a rather simple body musculature without such specialisations.
"This shows that vertebrates developed a sophisticated musculature much earlier than we had thought," said Per Ahlberg, co-author of the project.
The study was published in the journal Science.