Flamingo-like footprints and the problem of addressing biological diversity in the past

Abstract

In this work we present new avian fossil footprints preserved in the Vinchina Formation at del Yeso Creek, La Rioja, Argentina. To understand the morphological variation of very similar footprints not organizaed in trackways, we use statistical analyses combined with taphonomic analyses, resulting in a more refined classification of the ichnotaxa. Accordingly, the monospecific ichnogenus Phoenicopterichnum rector Aramayo and Manera de Blanco 1987 assigned to flamingoes, has two new ichnospecies, P. lucioi isp. nov. and P. vinchinaensis isp. nov. In addition, footprints produced by anatids, Anatipeda ips, are also reported. The predictive clustering analysis allow us to propose new ichnospecies by identifying which variables are of statistical significance to differentiate morphotypes. We defined two taphonomic groups and plotted it on the cluster analysis, inferring that the taphonomic input do not influence the morphologic analysis. Finally, we recommend testing statistically which variables are in fact of more influence in distinguishing morphotypes and/or ichnotaxa. That increase the value of paleobiological and/or ichnotaxonomical interpretations. By using these tools, we can achieve a better identification of footprint morphologies and consequently their trackmakers and the assignation of ichnotaxa to help address biological diversity in the past.