Revision of the skeletal morphology of Eodiscoglossus santonjae, an early Cretaceous frog from northeastern Spain, with comments on its phylogenetic placement

Abstract

The holotype of the “archaeobatrachian” (i.e., non-neobatrachian) frog Eodiscoglossus santonjae VILLALTA, 1954 is redescribed herein, with focus on some features that have been misinterpreted. The specimen is articulated and poorly preserved as fragmentary bones and impressions, and is from the Early Barremian La Pedrera de Rúbies Lithographic Limestones Formation at Santa Maria de Meià, Lleida Province. Other specimens from the same fossil site and unit are also examined and their former allocation to the same species critically reconsidered, with the conclusion that more than one taxon might be represented in this sample. Previous viewpoints on the systematic placement of E. santonjae, usually considered a discoglossid, are assessed. However, a full revision of the Jurassic and Cretaceous specimens ascribed to the genus is required in order to resolve its phylogenetic position. Hence, E. santonjae is provisionally considered as Anura incertae sedis.