Author Archives: Ben Wielstra
PhD thesis defended
On 3 October 2012 I defended my PhD thesis, which can be found here.
Species displacement in crested newts
A regular observation around the zones where closely related species meet, mate and produce offspring (hybrid zones) is that mitochondrial DNA of one of the species extents into part of the range of the other species (asymmetric mitochondrial DNA introgression). … Continue reading
Genetically distinct newts also show ecological divergence
Geographical groups characterised by distinct mitochondrial DNA may still belong to a single species. However, if they are also ecologically distinct, this supports their species status. In a paper published in PLoS ONE we explore ecological differences among the three … Continue reading
A highly supported crested newt phylogeny
Crested newts comprise four ‘morphotypes’: 1) the Triturus karelinii-group, 2) T. carnifex + T. macedonicus, 3) T. cristatus, and 4) T. dobrogicus. These four morphotypes range from sturdy to slender bodies. Body build is reflected by the number of rib-bearing … Continue reading
Crested newt body building
In a paper in the Journal of Zoological Systematics and Evolutionary Research we explore the evolution of body form in crested newts. In general crested newts started out with large bodies with a short trunk and a wide head. Over … Continue reading
Genetic differentiation in a single crested newt species
Within the crested newt assemblage, known as the Triturus cristatus superspecies, T. karelinii has been severely understudied. Limited data suggests there might me more than one species involved and the systematic position within the crested newt superspecies is unclear. Furthermore, … Continue reading
Where to draw the line?
Male crested newt of the T. karelinii-group (now called T. ivanbureschi). Picture by Michael Fahrbach. The Triturus karelinii-group of crested newts has sometimes been considered to comprise two species, ‘T. karelinii proper’ in the east and ‘T. arntzeni’ in the … Continue reading
Another stab at the crested newt phylogeny
As the crested newts radiated in a short temporal interval, a relatively long time ago, it has proven extremely difficult to resolve their phylogenetic relationships. This might mean they truly did split simultaneously, or the amount of data studies may … Continue reading
Simultaneous origin of crested newt species?
The genus Triturus comprises the marbled newts (such as T. pygmaeus on the left) and the crested newts (such as T. karelinii on the right). Pictures by Michael Fahrbach. Despite the genus Triturus (in my humble opinion) being a model … Continue reading
