Comment on “Quantitative biochronology of the Permian–Triassic boundary in South China based on conodont unitary associations” by Brosse et al. (2016)

Recently, Brosse et al. (2016) have proposed the use of conodont Unitary Associations Zones (UAZs) to substantially modify the biostratigraphy of the Permian–Triassic transition and to redefine the Permian–Triassic boundary (PTB). However, in our opinion, the UAZ analysis presented by Brosse et al. (2016) is based on unreliable taxonomic data sets with unjustified taxonomic re-assessments. No evidence shows that the UAZ approach improves the biozone biostratigraphy currently used to date the PTB.