Temporal information, fossil record and phylogeny

Fossils, i.e. remains of living organisms, provide critical data to reconstruct the history of life on Earth because they are the source of unique information concerning the past. Fossils allow statements to be made about morphological features that would otherwise remain unknown, that also help clarifying the phylogenetic relationships of organisms, which results in a better knowledge of the fossil record and, partly, of the stratigraphic record. The latter constitutes the basic source for palaeontologists in order to reconstruct the History of Life. Some palaeontologists consider that the stratigraphical record provides us with essential information necessary to propose phylogenetic hypotheses and to build evolutionary scenarios. However, this point of view is not generally accepted, some authors putting forward that the fossil record is too fragmentary to be accurate (see, e.g.: G.J. Nelson, N.I. Platnick, Systematics and Biogeography: Cladistics and Vicariance, Columbia University Press, New York, 1981; K.J. Peterson, A phylogenetic test of the calcichordate scenario, Lethaia 28 (1995) 25–38). We critically analyze the indices used to estimate the quality of the fossil record and the fit of phylogenetic hypotheses to stratigraphy. We use the concept of temporal paralogy to explain why all these measurements are biased.