And here it is:
The American Museum accounts (
http://research.amnh.org/herpetology/amphibia/index.html) are the authoritative ones that Amphibiaweb ultimately consults. However, these are done only every other year or so, and in the interim is tried to keep AmphibiaWeb up to date, especially with new species descriptions (note that there is a "counter" on the front page and it changes almost weekly) and major taxonomic changes.
The source for the taxonomic changes noticed is a new book: M. García-París, A. Montori and P. Herrero. 2004. Amphibia Lissamphibia. Fauna Iberica Vol. 24. Madrid: Museo Nacional de Ciencias Naturales and Consejo Superior de Investigaciones Científicas. 639 pp.
The Asesor de Nomenclatura for the Fauna Iberica series is Dr. Miguel A. Alonso-Zarazaga, a member of the International Commission on Zoological Nomenclature. Vol. 24 contains Apéndice 1. Nomenclatura: Lista de Sinónimos y Combinaciones, compiled by M. García-París, A. Monton and M. A. Alonso-Zarazaga. It is in this Appendix that the compilers explicitly make the taxonomic changes, stating, for example: Género Mesotriton Bolkay, 1927, and Mesotriton alpestris (Laurenti, 1768) comb. n.
Everything is done in proper form, and it is for these reasons I accept the book as authoritative and I am sure that Frost at the American Museum will also accept these findings.
Thanks for Dr. David Wake who explained this to me, and he also mentioned that further changes can be expected soon as well, so keep an eye on Amphibiaweb!
all the best, Sergé