This scientific contribution formally proposes the discovery and establishment of Stenella mediterranea sp. nov., a new pseudocryptic dolphin species endemic to the Mediterranean basin, previously assigned to the cosmopolitan taxon Stenella coeruleoalba. Through a strictly transdisciplinary approach, the research integrates genomic, osteometric, and bioacoustic data with historical-archaeological records dating back to Ancient Greece, demonstrating how the closed Mediterranean Sea acted as an incubator for an independent evolutionary trajectory. Molecular analyses reveal a total halt of maternal gene flow from the Atlantic and a remarkably high fixation index (FST greater than or equal to 0.67), highlighting a paraphyletic structure. Phenotypically, isolation triggered marked geographic dwarfism and accelerated skeletal development (heterochrony), coupled with a clear divergence in acoustic dialects. The theoretical core of the study redefines the role of interspecific mating: systematic introgressive hybridization with sympatric species, particularly Delphinus delphis and Tursiops truncatus, is not interpreted as taxonomic noise, but rather as the evolutionary engine that shaped the new entity. This reticulate evolution provided the population with a genetic rescue against inbreeding, becoming the foundational biological and diagnostic trait of Stenella mediterranea. Recognizing this taxon redefines the dynamics of speciation in closed basins and updates conservation priorities for pelagic biodiversity.
Giulio Francesco Lauro Maria Alberoni (Fri,) studied this question.