Contributions to Zoology, 79 (3) 93-106 (2010) Phylogenetic relationships among extinct and extant turtles: the position of Pleurodira and the effects of the fossils on rooting crown-group turtles

The origin and evolution of the crown-group of turtles (Crypto-dira + Pleurodira) is one of the most interesting topics in turtle evolution, second perhaps only to the phylogenetic position of turtles among amniotes. The present contribution focuses on the former problem, exploring the phylogenetic relationships of extant and extinct turtles based on the most comprehensive phylogenetic dataset of morphological and molecular data ana-lyzed to date. Parsimony analyses were conducted for different partitions of data (molecular and morphological) and for the combined dataset. In the present analysis, separate analyses of the molecular data always retrieve Pleurodira allied to Trio-nychia. Separate analysis of the morphological dataset, by con-trast, depicts a more traditional arrangement of taxa, with Pleu-rodira as the sister group of Cryptodira, being Chelonioidea th