David B. Wake and
Christopher J. Schneider, 1998,
Taxonomy of the Plethodontid Salamander Genus Ensatina.
Herpetologica, Vol.54(2), pp. 279-298.
ABSTRACT
Highton (1998)
argued that published data warrent a taxonomic revision of the Ensatina
complex. The complex comprises units that have varying degrees of phenetic
and phylogenetic differentiation, but morphological/coloration, protein, and
mtDNA data sets are less concordant than Highton believed. We employ different
criteria to discover species than did Highton. His proposed species do not fill
our criteria. Several are not diagnosable, nor do they have identity
as evolutionarily independent lineages or as genetically cohesive units.
Furthermore, he misinterpreted Stebbins' (1949)
conception of a ring species, which was an evolutionary and biogeographic hypothesis.
As observed as long ago as Stebbins' original work, taxonomic resolution of
the complex is neither simple nor will a changed taxonomy solve the biological
problems identified. The biological complexity of Ensatina argues
against a simple taxonomic resolution because the evolutionary realities of
diversification in old and persistent complexes reqire compromises if Linnean
taxonomies are to be used. We prefer a taxonomy that calrifies the evolutionery
relationships among the components and that highlights, rather than obscures,
the complex interactions of the past and the present. Accordingly, while
we recognise that a new taxonomy may be required when studies in progress are
concluded, for the present we recommend continued recognition of the Ensatina
complex as a single taxonomic species.