Species delimitation within the genus Porcellana (Anomura, Galatheoidea, Porcellanidae) in the East Atlantic and systematic implications

Abstract The porcelain crab Porcellana africana was originally identified as a subspecies of Porcellana platycheles , a species widely distributed in the eastern Atlantic Ocean and the Mediterranean Sea. A study characterizing the recent invasion of P. africana in South Africa places doubts on the identification and previously reported distribution of populations of the two species of Porcellana , which could have implications for the conservation and management of the species. Here, we aimed to delineate the Porcellana species from the East Atlantic to gain a better understanding of their distribution, which will help in conservation decision-making. Molecular analyses based on two mitochondrial genes and a nuclear gene confirmed that P. africana is a well-defined species and that its distribution extends further north, including the Canary Islands. A time divergence estimation indicates the cladogenesis between P. platycheles and P. africana occurred during the Neogene, likely linked to drastic climatic and environmental changes that took place during the Pliocene. Both species are morphologically very close, but can be distinguished by the shape of the third thoracic sternite.