Australian scientists say they have found morsels of fossilized muscle?the oldest vertebrate tissue ever known?in the remains of two fish that lived 380 to 384 million years ago.
Unearthed in western Australia 20 years ago, the specimens belong to two species of an extinct group of primitive, armored fish known as placoderms (map of Australia).
The fish's remarkably well-preserved soft tissues include bundles of muscle cells, blood vessels, and nerve cells. They were found during recent electron microscope scans, the research team reported last week in the British journal Biology Letters.
Fossilized muscle is quite rare, and the new finds are even more exceptional, because they weren't flattened but rather preserved with their three-dimensional shape intact, the researchers say. (Related: "Fossils Yield 10-Million-Year-Old Bone Marrow -- A First" [July 25, 2006].)
http://news.nationalgeographic.com/news/2007/02/070212-fossil-tissue.html
The remains shed light on the evolution of placoderms, which ruled the world's oceans, rivers, and lakes for 70 million years until they died out about 360 million years ago.
"On the evolutionary tree, they're the first jawed animal, and we're the last. So they're our first jawed ancestors,"
Unearthed in western Australia 20 years ago, the specimens belong to two species of an extinct group of primitive, armored fish known as placoderms (map of Australia).
The fish's remarkably well-preserved soft tissues include bundles of muscle cells, blood vessels, and nerve cells. They were found during recent electron microscope scans, the research team reported last week in the British journal Biology Letters.
Fossilized muscle is quite rare, and the new finds are even more exceptional, because they weren't flattened but rather preserved with their three-dimensional shape intact, the researchers say. (Related: "Fossils Yield 10-Million-Year-Old Bone Marrow -- A First" [July 25, 2006].)
http://news.nationalgeographic.com/news/2007/02/070212-fossil-tissue.html
The remains shed light on the evolution of placoderms, which ruled the world's oceans, rivers, and lakes for 70 million years until they died out about 360 million years ago.
"On the evolutionary tree, they're the first jawed animal, and we're the last. So they're our first jawed ancestors,"
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