Abstract
Spurilla braziliana MacFarland 1909 is a morphologically diverse nudibranch found in the Pacific and Western Atlantic. The complete mitochondrial genome of S. braziliana has been constructed using next-generation sequencing technology. The mitochondrial genome is 14,291 bp and contains 13 protein-coding genes, 2 rRNA genes, and 23 tRNA genes. Molecular phylogenetic analysis using the maximum likelihood method revealed that S. braziliana is included in the superfamily Aeolidioidea and forms a monophyletic group with Berghia stephanieae, a nudibranch of the family Aeolidiidae. This study reinforces existing taxonomic insights and provides a basis for further molecular phylogenetic analysis.