the common toad Rhinella arenarum is widely distributed in Argentina, where it is utilised as an autochthonous model in ecotoxicological research and environmental toxicology. However, the lack of a reference genome makes molecular assays and gene expression studies difficult to carry out on this non-model species. to address this issue, we performed a genome-wide transcriptome analysis on R. arenarum larvae through massive RnA sequencing, followed by de novo assembly, annotation, and gene prediction. We obtained 57,407 well-annotated transcripts representing 99.4% of transcriptome completeness (available at http://rhinella.uncoma.edu.ar). We also defined a set of 52,800 highconfidence lncRNA transcripts and demonstrated the reliability of the transcriptome data to perform phylogenetic analysis. our comprehensive transcriptome analysis of R. arenarum represents a valuable resource to perform functional genomic studies and to identify potential molecular biomarkers in ecotoxicological research. Amphibians are poikilothermic vertebrates with morphological and ecological adaptations that allow them to occupy diverse terrestrial environments associated with humid ecosystems 1,2. They are the only terrestrial vertebrates that preserve free-living larvae and produce large oocytes with a transparent vitelline membrane that allows for the direct observation of the different stages of embryonic development. These characteristics have been exploited in various research areas such as toxicology, physiology, ecology, and evolution 3-7. The South American common toad Rhinella arenarum [ex. Bufo arenarum (Hensel, 1867)] is amply distributed in Argentina and breeds in shallow-water areas such as ponds and ditches 5,8,9. Amphibian research models can be easily and inexpensively established. However, only six anuran genomes are available to date: Pyxicephalus adspersus 10 , Nanorana parkeri 11 , Rana catesbeiana 6 , Rhinella marina (Bioproject: PRJEB24695, ID: 445546), Xenopus laevis 12 , and Xenopus tropicalis 13. Furthermore, several conserved morphological characteristics shared by anurans make both taxonomic classification and phylogenetic analysis difficult to perform 14. This stresses the need for combining novel genomic information with morphological and karyological data, as well as mitochondrial DNA sequencing, in order to improve accuracy in phylogenetic studies. Next Generation Sequencing (NGS) provides a cost-effective and rapid method to sequence and analyse complete genomes. However, amphibians have a very high DNA content and a large proportion of repetitive and non-coding sequences 15 ; thus, whole-genome assembly is still expensive and bioinformatically challenging. In contrast, high-throughput RNA-sequencing (RNA-Seq) is an affordable NGS technique that provides a convenient platform for transcript profiling and transcriptome sequencing in non-model amphibian species like R. arenarum 16,17. Here, we report for the first time the de novo assembly of R. arenarum transcriptome using massive RNA-Seq, followed by gen...