reads_analysed file contains raw nanopore reads extracted from a nanopore dataset readsf or the Tuatara (NCBI accession PRJNA445603) in FASTA format used to determine rDNA unit size.Con_reads files contain nanopore reads individual rDNA unit sequences were extracted from to generate the consensus sequence in FASTA format for the sole extant rhynchocephalia species (Tuatara).Con_indiv_units files contain individual rDNA unit sequences extracted from nanopore reads used to generate the consensus sequence in FASTA format for the sole extant rhynchocephalia species (Tuatara).Consensus_alignment files contains the alignement output in .geneious format.Annotated_Consensus files contains the annotated consensus sequences in .geneious format.align_Tuatara_con_with_ref file contains the rDNA consensus sequence aligned to a reference sequence (Genbank accession X02995)..Average rDNA unit size was generated using the included excel spreadsheet.