06/03/17 Duncan Murdock (Univ. Oxford)
The role of experimental taphonomy in the interpretation of controversial fossils.
If fossils are to realize their full potential in reconstructing the tree of life we must understand how our view of ancient organisms is obscured by taphonomic filters of decay and preservation. In most cases, processes of decay will leave behind either nothing or only the most decay resistant body parts, and even in those rare instances where soft tissues are fossilized we cannot assume that the resulting fossil, however exquisite, represents a faithful anatomical representation of the animal as it was in life. Recent experiments have shown that the biases introduced by decay can be far from random; in chordates, for example, the most phylogenetically informative characters are also the most decay-prone, resulting in ‘stemward slippage’. But how widespread is this phenomenon, and are there other non-random biases linked to decay? Furthermore, to what extent can we use the results of decay experiments to inform the fossil record as a whole? Intuitively, we make assumptions about the likelihood of different kinds of characters to survive and be preserved, with knock-on effects for anatomical and phylogenetic interpretations. To what extent are these assumptions valid? From our experiments, and those of others, we have a growing database of patterns of character loss in a range of organisms across the tree of life, with which to test these assumptions. These data are widely applicable to the fossil record – allowing us to ground-truth some of the assumptions involved in describing exceptionally preserved fossil material.
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