preview.tinyurl.com/yw3thm -> news.nationalgeographic.com/news/2007/02/070212-fossil-tissue.html
National Geographic News February 12, 2007 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.
Sea Monsters Interactive: Giant Prehistoric Swimmers * T Rex Soft Tissue Found Preserved (March 24, 2005) 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.
"On the evolutionary tree, they're the first jawed animal, and we're the last. So they're our first jawed ancestors," said lead study author Kate Trinajstic, a paleontologist at the University of Western Australia. "Gothic Monsters" The fossil fish's muscle tissue grew in W-shaped blocks--a trait also seen in lampreys, a modern-day remnant of other primitive fish--the scans revealed.
"These muscles show us that placoderms were the most primitive fishes and the most primitive jawed fishes." Ranging in length from 6 inches to 6 feet (15 to 180 centimeters), placoderms lacked bony, internal skeletons and were put together a bit like lobsters. The fish had thick plates that interlocked like suits of armor over their heads and bodies, while sharklike tails sprouted from their backs.
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