Adenomera frogs in the putumayo: description of three new species of the A. simonstuarti complex from the Colombian Amazonia

Abstract

The Amazon is one of the most biodiverse regions on the planet, and in Colombia, it occupies 42.3% of the continental territory. In the western part of the Colombian Amazon is the department of Putumayo, a region characterized by a great variety of ecosystems, such as the very humid tropical forests and the Andean-Amazonian piedmont, both recognized for their high biological diversity. Although in recent times there have been advances in the knowledge of Amazonian anurans, there are still important challenges related to understanding their specific richness (deficit Linnean) and distribution patterns (deficit Wallacean). Part of this difficulty is due to the presence of cryptic species complexes which has led to an underestimation of the true diversity. A clear example of this phenomenon is the case of Adenomera, a genus of terrestrial foam frogs, distributed in South America and on the eastern slopes of the Andes, which currently has 32 recognized species. This genus comprises eight main clades distributed throughout South America, including the Adenomera andreae clade, endemic to Amazonia. Within this clade is a complex of species grouped under the name Adenomera simonstuarti, distributed mainly in western Amazonia. This study analyzes, using an integrative taxonomic approach based on acoustic, morphological, and genetic characteristics, the undescribed diversity of the A. simonstuarti complex in the department of Putumayo, western Amazonia, Colombia. The phylogenetic analysis based on mitochondrial and nuclear genes allowed the identification of eleven lineages, including A. albarena and A. simonstuarti. Acoustic data revealed three putative new species in the Putumayo. These findings underline a significant underestimation of the diversity of the genus Adenomera in Colombia. The divergence in advertisement calls constitutes the main evidence for the specific delimitation of the identified lineages. Each of the three proposed species presented unique acoustic patterns within the genus, differences that reinforce their status as independent evolutionary units, despite some inconsistencies in the mitochondrial data, possibly attributable to contamination or recent cladogenesis events. In addition to its taxonomic relevance, this study documents changes in habitat use patterns, recording for the first time the presence of lineages of the A. andreae clade in open areas, both natural and anthropized, in Putumayo. These habitats are typically occupied by species associated with open formations in other Amazonian localities, suggesting a possible regional ecological replacement of the A. hylaedactyla clade, which is absent in the area. Finally, the results provide key knowledge and highlight the importance of fieldwork, especially in poorly explored regions such as the department of Putumayo, where specific richness is still poorly documented. The identification of undescribed species and the recognition of their distribution patterns represent fundamental inputs for decision-making and the design of conservation strategies in highly biodiverse and threatened landscapes.