Complete chloroplast genomes of two closely related diatoms, <i>Nitzschia nienhuisii</i> and <i>Epithemia catenata</i>

We report the complete chloroplast genomes of two closely related taxa, Nitzschia nienhuisii and Epithemia catenata. The plastids share 96.85% nucleotide similarity and exhibit similar genomic structure. The N. nienhuisii plastome is 128,415 bp with 129 protein-coding genes, whereas E. catenata plastome is 140,525 bp with 130 protein-coding genes, including a duplicated psaJ in the inverted repeat. Both genomes encode 30 tRNAs, one tmRNA, six rRNAs, and two pseudogenes (tyrC and ycf42). The larger E. catenata genome likely reflects 12 unique ORFs. Maximum likelihood phylogenetic analysis supports a close relationship between these taxa.