The dinosaurian origin of feathers
- December 2003 The dinosaurian origin of feathers: perspectives from
dolphin (Cetacea) collagen fibers Theagarten Lingham-Soliar
Abstract The early origin of birds is a hotly disputed debate and may be
broadly framed as a conflict between paleontologists and ornithologists.
The paleontological emphasis has shifted from Archaeopteryx and its
origins to recent finds of Cretaceous birds and feathered dinosaurs from
The identification of alleged feathers has, however, relied principally
on the visual image. Some workers have interpreted these integumentary
structures as collagen fibers. To test the latter hypothesis, using light
microscopy, collagen from the hypodermis (blubber) and subdermal
connective tissue sheath was examined from a dolphin that had been buried
for a year as part of an experiment. Within the blubber, toward the
central thicker parts of the material, the collagen fibers had compacted
and the three-dimensional latticework of normal blubber had more or less
collapsed. Chromatographic analysis of the blubber revealed pronounced
oxidation of the unsaturated lipids, probably accounting for the collapse
of the latticework. Fibers normally bound together in bundles became
separated into individual fibers or smaller bundles by degradation of the
glue-like substance binding them together.
These degraded collagen fibers show, in many instances, feather-like
patterns, strikingly reminiscent of many of those identified as either
protofeathers or modern feathers in dromaeosaurid dinosaurs. The findings
throw serious doubt on the virtually complete reliance on visual image by
supporters of the feathered dinosaur thesis and emphasize the need for
more rigorous methods of identification using modern feathers as a frame
of reference. Since collagen is the main fiber type found in most
supporting tissues, the results have wide implications regarding the
degradation and fossilization of vertebrate integument, such as that of
the ichthyosaurs, dinosaurs and birds.
Naturwissenschaften DOI: 10.1007/s00114-003-0483-7 Issue: Volume
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