Feathered dinosaurs

March 2, 2009 • 10:01 pm

by Greg Mayer

One of the most exciting developments in paleontology in the past ten years or so has been the discovery that many species of theropod dinosaurs had feathers.  The earliest discoveries were quite controversial.  At the 1997 meetings of the Society of Vertebrate Paleontology in Chicago, a paper was read criticizing the interpretation of the skin structures on these fossils as feathers. In response, Phil Currie, one of the team working on the fossils,  presented an impromptu rebuttal paper later the same day, a rather unusual development for a normally tightly scheduled scientific meeting.  I was not convinced they were feathers myself until a while later, when a number of fossils of the new forms were brought to the Field Museum, and I was able to see them for myself– they had feathers!  One of the strangest of these feathered dinosaurs was Microraptor gui, which had both its forelimbs and hindlimbs modified into feathered wings.  It seems to exemplify the remark of J.B.S Haldane, the British geneticist who was one of the founders of the modern synthesis, “that the universe is not only queerer than we suppose, but queerer than we can suppose.”  Jerry highlights Microraptor in chap. 2 of WEIT, and notes a NOVA program on PBS, “The Four-winged Dinosaur”, that has a great website with interactives and videos, including the entire program. Originally airing last year, it was just recently shown again on my local PBS station, so check to see if it may be showing again in your area too.

Most of the specimens of feathered dinosaurs, as well as many true birds, have come from the fossil beds of Liaoning in northeastern China. The American Museum of Natural History has a nice website on the Liaoning fossil biota.  The Liaoning deposits have become one of the most important and interesting of what are called Lagerstatten (singular: Lagerstatte), a German word for a fossil deposit with extraordinary conditions of preservation. Such deposits, because they reveal structures (such as soft parts like feathers) and organisms (those lacking hard parts) otherwise missing from the fossil record, are often of crucial importance in studying the history of life on Earth.  Other famous Lagerstatten include the Pre-Cambrian Ediacara Hills of Australia, the Cambrian Burgess Shale in British Columbia and Chengjiang in China, and the Jurassic Solnhofen Limestone of Bavaria. These Lagerstatten have revealed, respectively, an early multicellular fauna, the Cambrian Explosion, including the earliest vertebrates, and Archaepoteryx, the first bird.