Flying dinos

How do you retell a 65-million-year-old story? No one thought ‘real’ dinosaur tissue could ever be found, as it would have degraded aeons ago, writes Prakash Chandra.

How do you retell a 65-million-year-old story? No one thought ‘real’ dinosaur tissue could ever be found, as it would have degraded aeons ago. But in 2005, North Carolina State University paleontologist Mary Schweitzer discovered soft tissue in the femur of a Tyrannosaurus rex at an excavation site in Montana, where dinosaurs were entombed by mudflows. Although plenty of dino bones were unearthed before, this was the first time that actual blood cells were identified. The clay-rich mud had sealed the ancient bone, preventing chemical changes and, amazingly, preserving the blood cells. These could provide important clues about the big creatures that once roamed Earth.

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Dinosaurs lived during the Mesozoic Era, from late in the Triassic period (225 million years ago) until the end of the Cretaceous (about 65 million years ago), evolving into many sizes, with diverse modes of living. After British biologist Sir Richard Owen coined Dinosauria (Greek deinos for ‘fearfully great’, and sauros meaning ‘lizard’), in 1842, mammoths, mastodons, pterosaurs, ichthyosaurs, and the sail-backed Dimetrodons all captured popular imagination. But these animals were actually very different from how books and movies often portray them. For instance, the T. Rex could never run so fast as shown in the Jurassic Park, just as the velociraptor (with a brain inferior to those of most mammals) couldn’t open doors or tap its toes impatiently!

Curiously, outside of movies and museums, there are plenty of dinosaurs all around us. Although most died out when an asteroid hit Earth 65 million years ago, some did survive and are still with us — as birds. Every new discovery adds to the evidence that dinosaurs are most closely related to birds. Birds and reptiles have skeletal resemblances and soft anatomy. Like reptiles, birds also lay eggs and have scales (produced by tissues similar to those that produce feathers) on their feet. And insulation indicates they were warm-blooded, like birds. The latest proof of the dino-bird link comes from Prof. Schweitzer: she sequenced collagen proteins in the T rex fossil — the oldest sequences ever — and found they were similar to chicken collagen.