The Herpetological Journal

pp. 24-30
Authors: Themudo, G. Espregueira & Arntzen, J.W.

Abstract: The marbled newts Triturus marmoratus and T. pygmaeus are common and readily diagnosed species occurring in central Portugal, but difficult to survey in large and deep ponds. Conversely, embryos of both species are easy to locate but morphologically indistinguishable. We studied a panel of nuclear genetic loci by starch gel electrophoresis (the enzymes Pep-A, Pep-B and Pep-D) and isoelectric focusing techniques (the enzyme Ldh-2, post-embryonic stages only) that together yield a species-specific signature (Cohen's kappa = 1.00). On a locus by locus basis, the scores for correct classification range from kappa = 0.12 to kappa = 0.97. The method allows the reliable, fast and cheap identification of both species across life stages, with better behaviour and performance than mtDNA sequencing (i.e. bar-coding) and nuclear DNA microsatellite profiling. The observed distribution of T. marmoratus and T. pygmaeus over 25 aquatic breeding sites in the Caldas da Rainha area in western Portugal is parapatric, with no mixed populations and no F₁ interspecific hybrids. This demonstrates that T. marmoratus and T. pygmaeus are genetically isolated, even when populations are within the #dispersal##distance##per##generation# range of one another. We consider the data adequate for supporting the species status of T. marmoratus and T. pygmaeus under the Biological Species Concept.

Keywords: ALLOZYMES, PRINCIPAL COORDINATE ANALYSIS, AMPHIBIA