I had posted about the taxonomic problem caused by the loss of the holotype specimen Machaeroprosopus validus before with a plea for people to help look for the specimen. Come to find out a careful reading of the literature and the ICZN demonstrates that the specimen is not as important as previously believed regarding the taxonomic status of the name Machaeroprosopus. It will take awhile for Triassic and phytosaur workers to get used to using the name again and I am sure that some will just flat out refuse, but according to the ICZN the name Machaeoroprosopus is the proper one if the holotype specimen of "Belodon" buceros is truly diagnosable and if the other nominal species of "Pseudopalatus" are referable to the same genus represented by "B." buceros.
Parker, W. G., Hungerbühler, A., and J. W. Martz. 2013. The taxonomic status of the phytosaurs (Archosauriformes) Machaeroprosopus and Pseudopalatus from the Late Triassic of the western United States. Earth and Environmental Science Transactions of the Royal Society of Edinburgh First View Article. DOI: http://dx.doi.org/10.1017/S1755691013000339
Abstract - The genus Machaeroprosopus has long been considered invalid because the type specimen of the Late Triassic phytosaur species, M. validus, has been lost. Re-examination of the primary literature regarding the establishment of the Late Triassic phytosaur genus Machaeroprosopus demonstrates that M. buceros is the correct type species, not M. validus. Thus, the genus level name Machaeroprosopus has priority over the genera Pseudopalatus and Arribasuchus and all nominal species should be reassigned. Reassignment of these species to Machaeroprosopus satisfies the requirements of the International Code of Zoological Nomenclature (ICZN) and preserves historical context. The name Pseudopalatinae is retained as the valid clade name for these phytosaurs because its usage falls outside of the ICZN.
11 hours ago in The Phytophactor