"La storia della Pseudorca crassidens (Owen, 1846) nel Mar Mediterraneo svelata dall'analisi genetica di campioni museali"

The false killer whale Pseudorca crassidens (Owen, 1846) is the only living member of the genus Pseudorca (Reinhardt, 1862) as well as the fourth largest species among Delphinids, after killer whale and pilot whales. These Cetaceans are typically found in deep water offshore, despite two insular-associated populations (Hawaiian Archipelago, USA) have been documented. They have a pan-oceanic distribution and, as other highly social Delphinids, false killer whales form very close social groups (pods) characterized by strong bonds of fidelity among their members and in which individuals can spend their whole lifespan. IUCN classifies this species as Near Threatened at global level and Hawaiian resident populations are assessed as Endangered, however population trends for many geographic areas are still missing. In the Mediterranean Sea the conservation status of P. crassidens is not evaluated and no viable populations are known to live and breed regularly in this basin. The species is listed in few dozens reports since the XIX century, therefore the rarity of sightings led to suppose that false killer whale could be a vagrant species, which only occasionally occurs within the Mediterranean. To help characterize the status of this Odontocete in the Mediterranean Sea we have performed genetic analysis based on mitochondrial DNA Control Region (mtDNA CR) on modern and NHC samples coming from Mediterranean specimens. Among the ten samples analyzed, modern sample and five NHC samples produced positive results, instead genetic analysis revealed the misidentification of two NHC samples, belonging to specimens of Grampus griseus (Cuvier, 1812) and Physeter macrocephalus (Linnaeus, 1758). As concerns results obtained from samples actually belonging to P. crassidens, the modern sample shows a Northern Australian haplotype, suggesting a recent colonization from the Suez Canal. All NHC samples share a new Atlantic-like haplotype that might indicate a recurring entrance of Atlantic individuals through the Gibraltar Strait, or the existence of an indigenous Mediterranean population of false killer whale in historical times, which seems to be currently disappeared due to human activity.