Ensatina Salamanders are not Ring Species

Ensatina Salamander

USGS / Chris Brown

The Ring Species Concept was first suggested in 1905 and then later formalized in the 1940’s. It suggested that the evolutionary process of speciation could be seen across geographic space by showing distant variations of the same animal could not interbreed. In 1949, Robert Stebbins suggested the Ensatina salamanders surrounding the Central Valley of California might qualify as a Ring Species. With further study, it was found that the distant variations do interbreed resulting in fertile offspring and DNA analysis shows genetic isolation rather than the gene flow which is expected in a Ring Species. Therefore, the Ensatina salamanders do not qualify as Ring Species.

Ensatina Salamander Varieties

The Ensatina salamanders, taxonomically known as Ensatina eschscholtzii, live in the mountainous regions of California. The various populations / sub-species form a circle around the dry Central Valley of California with the ends meeting in the Palamar Mountains near San Diego. The salamander populations following the coastal mountains have colorings that mimic those of the posonous newts. The populations following the Sierra Mountains have camoflauge style markings.

Ensatina Salamander Ring Species

Pereira, Monahan, & Wake (2011)

Expected Appearance of Ring Species

By definition, there are several basic characteristics that must be matched by a plant or animal to qualify as a Ring Species. The three most prominent characteristics are: 1) a series of connected populations encircling a geographic barrier, 2) continuous gene flow along both branches of the ring, and 3) the end populations must be sufficiently different to prohibit interbreeding where they come together.

Actual Appearance of Ensatina eschscholtzii

While DNA analysis does support a common ancestor for these salamanders, there are sharp genetic breaks around the ring which suggest these groups are somewhat isolated and do not have the necessary gene flow for a Ring Species. Furthermore, the two ends are able to hybridize in the wild and have fertile offspring. Some have suggested they are not well adapted because they lack both mimicry and camoflauge coloring, but the fact remains they do exist.

Conclusion

The Ensatina salamander complex does not meet two of the main requirements, gene flow and inability to interbreed, necessary to be considered a Ring Species.

Other Ring Species Articles

  • 1) The Ensatina Salamanders surrounding the Central Valley of California
  • 2) The Larus Gulls near the Arctic Circle
  • 3) The Greenish Warbler surrounding the Tibeten Plateau
  • 4) The Crimson Rosella Parrot in Australia
  • 5) The Caribbean Slipper Spurge in Central America.
  • For More Information:

  • 1) Irwin, D., Irwin, J., and Price, T. (2001) Ring Species as bridges between microevolution and Speciation. Genetica 112-113: 223-243, 2001.
  • 2) Pereira, R., Monahan, W., and Wake, D. (2011) Predictors for reproductive isolation in a ring species complex following genetic and ecological divergence. Evolutionary Biology 2011, 11:194 doi:10.1186/1471-2148-11-194
  • XXXIIG. Last Updated: 08/01/2016
    Todd Elder

    Todd Elder

    Todd Elder has a deep desire to understand and experience Creation. As a Baraminologist, his current research includes developing the Katagenos Species Concept, the Natanzera Classification System, and the Floral Formula Method of determining Plant Kinds. As an author and speaker, his books and seminar materials are designed to encourage a growing relationship with the Creator.
    Todd Elder

    Latest posts by Todd Elder (see all)

    Enjoyed this article ? --> Share it .

    If you appreciate this information, please consider donating
    to help defray the costs of this website and ongoing research.