Caenorhabditis species diversity has been surveyed in several places around the world and tends to be higher in subtropical and tropical regions. Vietnam is a long country with complex topography and a climate largely influenced by the northeast monsoon from the Siberian plateau. Here, we report the first Caenorhabditis survey in Ta Kou Nature Reserve located in south-central Vietnam, where we have found two isolates of a new species, Caenorhabditis sp. 71. Whole genome skimming of one isolate using a combination of the Oxford Nanopore Technologies MinION long read and Illumina short read sequencing platforms allowed us to assemble a complete mitochondrial genome that is 13,654 bp in length. Annotation of the mitochondrial genome revealed 12 protein coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 control region. Phylogenetic analysis, based on the concatenated sequences of the 12 mitochondrial protein coding genes, suggests that Caenorhabditis sp. 71 is the sister species to C. imperialis. Our findings not only contribute to the understanding of Caenorhabditis diversity in Vietnam but also highlight the ecological significance of isolated habitats, such as Ta Kou Mountain. These fragile environments are essential for biodiversity conservation and require dedicated protection to preserve their unique and diverse ecosystems.



