These authors made equal contributions to this work
DO LARVAL TRAITS RE-EVOLVE? EVIDENCE FROM THE EMBRYOGENESIS OF A DIRECT-DEVELOPING SALAMANDER, PLETHODON CINEREUS
Article first published online: 13 SEP 2011
© 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution.
Volume 66, Issue 1, pages 252–262, January 2012
How to Cite
Kerney, R. R., Blackburn, D. C., Müller, H. and Hanken, J. (2012), DO LARVAL TRAITS RE-EVOLVE? EVIDENCE FROM THE EMBRYOGENESIS OF A DIRECT-DEVELOPING SALAMANDER, PLETHODON CINEREUS. Evolution, 66: 252–262. doi: 10.1111/j.1558-5646.2011.01426.x
- Issue published online: 3 JAN 2012
- Article first published online: 13 SEP 2011
- Accepted manuscript online: 29 JUL 2011 02:12PM EST
- Received January 28, 2011, Accepted July 9, 2011
- direct development;
- Dollo's Law;
- evolutionary developmental biology;
- life history evolution;
Recent molecular phylogenies suggest the surprising reacquisition of posthatching metamorphosis within an otherwise direct-developing clade of lungless salamanders (family Plethodontidae). Metamorphosis was long regarded as plesiomorphic for plethodontids, yet the genus Desmognathus, which primarily includes metamorphosing species, is now nested within a much larger clade of direct-developing species. The extent to which the putative reacquisition of metamorphosis in Desmognathus represents a true evolutionary reversal is contingent upon the extent to which both larva-specific features and metamorphosis were actually lost during the evolution of direct development. In this study we analyze development of the hyobranchial skeleton, which is dramatically remodeled during salamander metamorphosis, in the direct-developing red-backed salamander, Plethodon cinereus. We find dramatic remodeling of the hyobranchial skeleton during embryogenesis in P. cinereus and the transient appearance of larva-specific cartilages. Hyobranchial development in this direct-developing plethodontid is highly similar to that in metamorphosing plethodontids (e.g., Desmognathus). The proposed reacquisition of hyobranchial metamorphosis within Desmognathus does not represent the “re-evolution” of a lost phenotype, but instead the elaboration of an existing developmental sequence.