Genus-level taxonomic inflation in Asian horned frogs (Amphibia: Megophryidae: Megophrys ): a critical re-evaluation of recent proposals to split one genus into ten

Abstract The Asian horned frogs form a monophyletic genus (Megophrys) within the family Megophryidae. In recent years, molecular phylogenetic studies have identified genetic structuring within Megophrys that heavily influenced proposals to split Megophrys into multiple genera. The recent proposals to recognize up to 10 genera within Megophrys are critically reassessed, including morphological, molecular, chromosomal, and biological justifications. Based on a comprehensive study of specimens and literature, it is demonstrated that almost all purported diagnostic characteristics assigned to the proposed genus-level clades do not hold up to scrutiny when accounting for variation within species or ‘genera’. These results demonstrate that the proposed splitting of Megophrys was predicated on inadequate literature review, biased sampling of examined specimens, and erroneous data, presenting a false perception of evidence or justification. In this study, Grillitschia and Sarawakiphrys are proposed to represent synonyms of Xenophrys and Pelobatrachus, respectively. A proposal is made to downgrade the taxonomic rank of the remaining seven genera (Atympanophrys, Boulenophrys, Brachytarsophrys, Jingophrys, Ophryophryne, Pelobatrachus, and Xenophrys) to the rank of subgenera within Megophrys to stabilize the taxonomy of the group and provide a practical and functional taxonomy. Most of the recently proposed higher-level (genus and subgenus) names are found either to have been formed incorrectly or to have meanings that differ from what the authors originally intended (when indicated) and thus are clarified for their translations and gender (where necessary). This study further highlights a growing culture in the field of taxonomy and systematics to atomize monophyletic genera based primarily on normal and expected internal phylogenetic structure rather than necessity, without consideration for downstream end-users of the taxonomy. Readers are encouraged not to adopt disruptive large-scale taxonomic rearrangements at the genus level when such proposals are based on preliminary (or no) evidence and/or subjective justifications that do not clearly improve taxonomic stability.