Signals from the deep-sea: Genetic structure, morphometric analysis, and ecological implications of Cyclothone braueri (Pisces, Gonostomatidae) early life stages in the Central Mediterranean Sea

Cyclothone braueri (Stomiiformes, Gonostomatidae) is a widely distributed fish inhabiting the mesopelagic zone of marine tropical and temperate waters. Constituting one largest biomasses ocean, C. key element in most ecological processes occurring twilight layer. We focused on linked to early life stages relation pelagic environmental drivers (temperature, salinity, food availability geostrophic currents) considering different regions Central Mediterranean Sea. A multivariate morphometric analysis was carried out using six parameters with aim discerning larval morphotypes, while fragment 367 bp representing 12S ribosomal RNA gene used perform molecular analyses aimed at determining intraspecific genetic variability. Analysis highlighted two geographically distinct morphotypes not genetically discernible related nutritional conditions due spatial heterogeneities terms temperature availability. The body depth (BD) emerged as an appropriate parameter detect condition this species. Molecular moderate divergence population, showing recurrence phylogroups separated.