Lampreys and hagfishes (cyclostomes) traditionally were considered to be a natural (monophyletic) group. Recently, the consensus of opinion, based largely on morphological analyses, has shifted to a view that lampreys are more closely related to jawed vertebrates (gnathostomes) than to hagfishes. Phylogenetic comparisons of 18S ribosomal RNA sequences from two hagfishes, two lampreys, a tunicate, a lancelet, and a number of gnathostomes support the monophyly of the cyclostomes. These data force a reassessment of several features of early vertebrate evolution.
No takes yet. Share an insight, caveat, or question.
Stock et al. (1992) studied this question.
Synapse has enriched 4 closely related papers on similar clinical questions. Consider them for comparative context: