Journal of Molecular Evolution

, Volume 46, Issue 4, pp 382–388

The mitochondrial DNA molecule of the hagfish (myxine glutinosa) and vertebrate phylogeny


DOI: 10.1007/PL00006317

Cite this article as:
Rasmussen, AS., Janke, A. & Arnason, U. J Mol Evol (1998) 46: 382. doi:10.1007/PL00006317


The vertebrates are traditionally classified into two distinct groups, Agnatha (jawless vertebrates) and Gnathostomata (jawed vertebrates). Extant agnathans are represented by hagfishes (Myxiniformes) and lampreys (Petromyzontiformes), frequently grouped together within the Cyclostomata. Whereas the recognition of the Gnathostomata as a clade is commonly acknowledged, a consensus has not been reached regarding whether or not Cyclostomata represents a clade. In the present study we have used newly established sequences of the protein-coding genes of the mitochondrial DNA molecule of the hagfish to explore agnathan and gnathostome relationships. The phylogenetic analysis of Pisces, using echinoderms as outgroup, placed the hagfish as a sister group of Vertebrata sensu stricto, i.e., the lamprey and the gnathostomes. The phylogenetic analysis of the Gnathostomata identified a basal divergence between gnathostome fishes and a branch leading to birds and mammals, i.e., between “Anamnia” and Amniota. The lungfish has a basal position among gnathostome fishes with the teleosts as the most recently evolving lineage. The findings portray a hitherto unrecognized polarity in the evolution of bony fishes. The presently established relationships are incompatible with previous molecular studies.

Key words

Molecular phylogeny Vertebrate evolution Cyclostomata Gnathostomata Pisces “Anamnia” Amniota 

Copyright information

© Springer-Verlag New York Inc 1998

Authors and Affiliations

  • Ann-Sofie Rasmussen
    • 1
  • Axel Janke
    • 1
  • Ulfur Arnason
    • 1
  1. 1.Division of Evolutionary Molecular Systematics, Department of GeneticsUniversity of LundLundSweden

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