Mitogenomic and Ecological Perspectives on the Wide-Ridged Indo-Pacific Finless Porpoise Neophocaena phocaenoides: Toward Emerging Conservation Strategies.

Prior to this study, the narrow-ridged finless porpoise (Neophocaena asiaeorientalis) had been extensively studied across East Asia, whereas the wide-ridged finless porpoise (Neophocaena phocaenoides) remained comparatively poorly characterized throughout its broad geographic range, particularly in the Indian Ocean. This study addresses this gap through morphological, mitogenomic, and ecological analyses of an N. phocaenoides carcass from Kozhikode Beach, Arabian Sea, India. The specimen was identified as N. phocaenoides based on the absence of a dorsal fin, a broad dorsal ridge, a blunt beakless head, spade-shaped teeth, and a short broad rostrum. The comparative analysis of Neophocaena revealed conserved vertebrate gene organization, A + T-rich composition, diverse codon usage, strong purifying selection across all protein-coding genes, and nucleotide variation in the control region. The overall mean interspecific genetic distance among Neophocaena species and subspecies was 0.005. The Bayesian phylogenetic analysis and haplotype network reconstruction revealed high haplotype diversity (Hd = 0.9957) and consistently clustered the newly generated mitogenome with the previously reported Arabian Sea sequence, forming a distinct lineage separated from the Pacific populations. Additionally, multiple species delimitation analyses recovered six Operational Taxonomic Units across geographic regions, although broader sampling is required to validate these patterns across the Indian Ocean. Furthermore, ensemble Species Distribution Modeling identified 378,540 km2 of suitable habitat, primarily driven by bathymetry (61.92%). While significant adequate habitats were identified in China, Indonesia, and the Arabian Sea, only 23.37% of these areas overlap with existing Marine Protected Areas and Important Marine Mammal Areas. Moreover, high anthropogenic pressure was detected in high-suitability regions, particularly in the South China Sea and Persian/Arabian Gulf. These findings underscore the vulnerability of N. phocaenoides and support the need for adaptive, regionally coordinated conservation strategies aligned with Convention on Biological Diversity and IUCN-Cetacean Specialist Group frameworks.