The vicariant role of Caribbean formation in driving speciation in American loliginid squids: the case of Doryteuthis pealeii (Lesueur 1821)

Speciation processes in the marine environment are often directly associated with vicariant events. In the case of loliginid squids (Cephalopoda: Loliginidae), these processes have been increasingly elucidated in recent years with the development of molecular technologies and increased sampling in poorly studied geographical regions, revealing a high incidence of cryptic speciation. Doryteuthis pealeii is a commercially important squid species for North Atlantic fisheries and has the second broadest geographic distribution in this genus. This study aimed to investigate the evolutionary history of this species and which biogeographic events may have influenced its diversification by assessing mitochondrial and nuclear markers. Our findings indicate that two previously detected lineages diverged from one another ~ 8 million years, compatible with the formation of the Caribbean and the establishment of the Amazon plume. Furthermore, separation between a North Atlantic and a Gulf of Mexico lineage during the Pleistocene period was noted. The inadequate classification of this cryptic diversity may have negative implications for the development of effective conservation and fisheries measures.