PHYLOGENY AND EVOLUTION OF THE AUKS (SUBFAMILY ALCINAE) BASED ON MITOCHONDRIAL-DNA SEQUENCES

The genetic divergence and phylogeny of the auks was assessed by mitoc hondrial DNA sequence comparisons in a study using 19 of the 22 auk sp ecies and two outgroup representatives. We compared more than 500 nucl eotides from each of two mitochondrial genes encoding 12S rRNA and the NADH dehydrogenase subunit 6. Divergence times were estimated from tr ansversional substitutions. The dovekie (Alle alle) is related to the razorbill (Alca torda) and the murres (Uria spp). Furthermore, the Xan tus's murrelet (Synthliboramphus hypoleucus) and the ancient (Synthlib oramphus antiquus) and Japanese murrelets (Synthliboramphus wumizusume ) are genetically distinct members of the same main lineage, whereas b rachyramphine and synthliboramphine murrelets are not closely related. An early adaptive radiation of six main species groups of auks seems to trace back to Middle Miocene. Later speciation probably involved ec ological differentiations and geographical isolations.