Contreras-Díaz, RobertoRobertoContreras-DíazBarahona-Segovia, Rodrigo M.Rodrigo M.Barahona-SegoviaCatalán-Garrido, RicardoRicardoCatalán-GarridoAraya, Juan FranciscoJuan FranciscoArayaArias-Aburto, MarianaMarianaArias-AburtoPizarro-Gacitúa, CésarCésarPizarro-Gacitúa2026-10-082026-10-082026-09-01Contreras-Díaz, Roberto; Barahona-Segovia, Rodrigo M.; Catalán-Garrido, Ricardo; Araya, Juan Francisco; Arias-Aburto, Mariana; Pizarro-Gacitúa, César (2026-09-01). Mitochondrial genomes and phylogenomic analysis of Plectostylus broderipii and Bostryx erythrostoma (Gastropoda, Stylommatophora, Orthalicoidea) from the Atacama Desert, Chile. ZooKeys, 1291(1291), 1-18. https://doi.org/10.3897/zookeys.1291.1979831313-29701313-2989https://hdl.handle.net/20.500.12740/24935We report the first mitochondrial genomes of two Orthalicoidea land snails from the Atacama Desert of northern Chile, Bostryx erythrostoma and Plectostylus broderipii . Using Illumina short-read sequencing, we assembled and annotated mitochondrial genomes of 15,525 bp and 14,978 bp, respectively, with strong A+T bias (69.75% in B. erythrostoma ; 72.08% in P. broderipii ). Both genomes retain the standard metazoan mitochondrial complement of 37 genes, including 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs, with differences in total length mainly due to variation in non-coding regions rather than coding-gene content. Comparative analysis showed that the two species share the same order of the 13 PCGs, whereas differences are concentrated in local tRNA/rRNA rearrangements and intergenic architecture. Both mitogenomes also exhibit negative AT skew and positive GC skew under a standardized orientation. Phylogenetic inference based on a concatenated 13-PCG nucleotide supermatrix resolved both taxa within Orthalicoidea with strong support: B. erythrostoma grouped with a congeneric Bostryx reference, and this clade clustered with Rabdotus mooreanus and Naesiotus nux , whereas P. broderipii was inferred as sister to this orthalicoid cluster.http://purl.org/coar/access_right/c_abf2http://creativecommons.org/licenses/by/4.0/Atacama DesertBothriembryontidaeBulimulidaeland snailsmitogenome annotationmitogenomicsnext-generation sequencingArticulohttps://doi.org/10.3897/zookeys.1291.197983