USGS Western Ecological Research Center

Home Who We Are Where We Are What We Do Products Search Outreach Jobs Contacts

Body size evolution simultaneously creates and collapses species boundaries in a clade of scincid lizards

Released: 2007
Citation:
Richmond, JQ, EL Jockusch. 2007. Body size evolution simultaneously creates and collapses species boundaries in a clade of scincid lizards. Proceedings of the Royal Society B 274(1619): 1701-1708. doi: 10.1098/rspb.2007.0364

Speciation is generally viewed as an irreversible process, although habitat alterations can erase reproductive barriers if divergence between ecologically differentiated species is recent. Reversed speciation might also occur if geographical contact is established between species that have evolved the same reproductive isolating barrier in parallel. Here, we demonstrate a loss of intrinsic reproductive isolation in a clade of scincid lizards as a result of parallel body size evolution, which has allowed for gene flow where large-bodied lineages are in secondary contact. An mtDNA phylogeny confirms the monophyly of the Plestiodon skiltonianus species complex, but rejects that of two size-differentiated ecomorphs. Mate compatibility experiments show that the high degree of body size divergence imposes a strong reproductive barrier between the two morphs; however, the strength of the barrier is greatly diminished between parallel-evolved forms. Since two large-bodied lineages are in geographical contact in the Sierra Nevada Mountains of California, we were also able to test for postzygotic isolation under natural conditions. Analyses of amplified fragment length polymorphisms show that extensive gene exchange is occurring across the contact zone, resulting in an overall pattern consistent with isolation by distance. These results provide evidence of reversed speciation between clades that diverged from a common ancestor more than 12 Myr ago.


Information about this product can be downloaded from this location:
http://dx.doi.org/10.1098/rspb.2007.0364

Bookmark and Share

Share


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: webmaster@werc.usgs.gov

References to non-U.S. Department of Interior (DOI) products do not constitute an endorsement by the DOI.

* DOI and USGS link policies apply.