Is there any phylogenetic relationship between teleosts and the elasmobranchs?

For many years, numerous investigators have been trying to better understand the evolution of the vertebrates, especially the phylogeny of the tetrapods or land vertebrates. Most of the information comes from paleontological or anatomic work. Nucleic acid and protein sequence analyses are very recent techniques and are providing new information on the subject (Bernardi et al., 1992). The relationship of the Chondrichthyes to other groups of fishes has been a topic of discussion for more than a century. For example, Schaeffer and Williams (1977) suggest that the Elasmobranchii and the Holocephalii are sister groups, and that the Chondrichthyes are more closely related to the Teleostomi than the Placodermi based on certain characteristics of the skull, skeleton, fin supports and fins.