Space, Time and their Relevance to Phylogenetic Analyses (Convergencesin Time)

This article is a short, theoretical analysis exploring the possibility of convergences of (similar) organs at identical morphologic positions in different organisms. The latter criterion normally characterizes homology, and is an important character in understanding systematic relations. Homology, however, depends on a shared latest ancestor in common, which in fossils cannot always be proved. We illustrate that organs similar in structure and function may have found different ways along a time axis and in space to have appeared independently in the same morphological position, and although being convergent, they are indistinguishable from homologies.