Ancient Fossils of 380-Million-Year-Old Placoderm Show Evolution of 'Six Pack'

Scientists have found the 380-million-year-old fossils of a pre-historic fish that may help explain how strong abdominals evolved.

The placoderm fish from north west Australia may be responsible for these well-developed powerful abdominal muscles that Swedish researchers note are "not unlike the human equivalents displayed on the beaches of the world every summer." 

According to the Environmental News Network, this discovery will help scientists better understand how neck and, as mentioned before, abdominal muscles, evolved during the transition from jawless to jawed vertebrates.

The team of scientists who studied this fossilized fish was jointly directed by Professor Kate Trinajstic of Curtin University of Perth, Australia and Professor Per Erik Ahlberg of Uppsala University Sweden.

The fish were found in the Gogo Formation, according to background information from the study, a north-western region of Kimberly in Australia.

Geographical researchers note that this area is famous as a home to a variety of preserved fossil fishes, including the placoderms.

History notes that these guys were hugely successful in the Devonian period, which is sometimes called the "Age of Fish."  

Researchers from Uppsala University in Sweden made this latest discovery and found that the muscle and soft tissue were well preserved.

Though the word "fossil" might make readers envision rattling skeletons and bones, the rarity of a soft tissue fossil shows traces of the animals remains, which give actual glimpses into the biology of the extinct organism. Further to the point, such tissues rarely fossilize and give scientists the chance to extrapolate skin coverings and musculature from the knowledge of modern organism and from the fossilized skeletons.

Researchers note that though living fish usually have a rather simple body musculature without specializations, the placoderm showed a well-developed neck musculature and powerful abdominal muscles.

"It also cautions against thinking that we can interpret fossil organisms simply by metaphorically draping their skeletons in the soft tissues of living relatives," the researchers said, via the study.

The findings for the study can be found in the journal Science.