The Magellanic Province and its fish fauna (South America): several provinces or one?

MARÍA B. COUSSEAU; GERMÁN PEQUEÑO; EZEQUIEL MABRAGAÑA; LUIS O. LUCIFORA; PATRICIA MARTINEZ; ANALÍA GIUSSI

JOURNAL OF BIOGEOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

0305-0270

Aim: We assessed the validity of the division of the Magellanic Province into four provinces as proposed by Briggs and Bowen (2012): Southern Chile, Tierra del Fuego, Southern Argentina and Falkland (Malvinas) Islands.We aimed to 1) present an up-to-date list of the fishes from the region known as ?Magellanic Province?, 2) analyze the specific richness of fishes in the Atlantic and Pacific sectors and their degree of endemism, 3) evaluate the validity of the three Provinces proposed for the Atlantic sector. Location: Southern tip of the American continent at latitudes higher than 40ºS in the Atlantic as well as in the Pacific Oceans. Methods: The list of fishes was prepared by consulting more than 140 sources, many related to observations resulting from research cruises, although two ichthyological collections and two ichthyological websites were also used. The South American species with distributions extending outside of the area corresponding to the Magellanic Province, and all cosmopolitan species, were excluded of endemism analyses. For analyzing fish distributions in the Atlantic sector, the data employed are from eight research cruises carried out from 1978 to 2006 from latitudes 37º to 59ºS. A total of 523 fishing trawls have been analyzed, grouped into cells of 1º x 1º cell. The species composition of each cell was evaluated by multivariate analysis (nonmetric multidimensional scaling, cluster, and similarities analyses). Results: The percentage of endemism in each sector (Atlantic 2.87% and Pacific 2.87%) is smaller than the endemism common of both sectors (9.2%). The total of endemic species in the Province is 14.94%, which is bigger than the 10% indicated as the lower limit for defining a biogeographical province suggested by Briggs (1975). In addition, multivariate analyses does not show differences in the species composition, neither between Falkland (Malvinas) Islands and ?Southern Argentina? nor between the latter and Tierra del Fuego.Main conclusions: The ichthyological data indicate only one biogeographical province in the region not four as previously posited.