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

Abstract

Aim We assessed the validity of the division of the Magellanic Province into the four provinces as proposed by Briggs & Bowen (J Biogeogr 39 12–30, 2012): Southern Chile, Tierra del Fuego, Southern Argentina and Falkland (Malvinas) Islands. We aimed to (a) present an updated list of the fishes from the region known as ‘Magellanic Province’, (b) analyse the specific richness of fishes in the Atlantic and Pacific sectors and their degree of endemism and (c) evaluate statistically the validity of the three Provinces proposed for the Atlantic sector. Location Southern tip of the American continent at latitudes higher than 40° S in the Atlantic as well as in the Pacific Oceans. Taxon 348 South American marine fish species. 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 analysing fish distributions in the Atlantic sector, the data employed are from eight research cruises carried out from 1978 to 2006 from 37° to 55° south. A total of 523 fishing trawls have been analysed, grouped into cell of 1° × 1° cells. The species composition of each cell was evaluated by multivariate analysis (non‐metric multidimensional scaling, cluster and similarity analyses). Results The percentage of endemism in each sector (Atlantic 2.87% and Pacific 2.87%) is smaller than the endemism common to 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 biogeographic province suggested by Briggs (Marine Zoogeography, 1974). In addition, multivariate analyses do 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 biogeographic province in the region not four as previously posited.

Uso de BRUVS para describir el ensamble de peces y su estacionalidad en dos caletas marinas poco profundas dentro de áreas protegidas de la Patagonia, Argentina

“…Menni et al (2010) also confirmed the two biogeographic provinces based on distribution patterns of chondrichthyans (sharks, rays, and chimaeras). More recently, two studies by Cousseau et al (2019) and Sabadin et al (2020) analyzed updated distribution patterns, richness and endemism of fish and chondrichthyans in the Magellanic Province respectively, corroborating the originally proposed biogeographic units. Note that one study (Briggs and Bowen 2012) has proposed a different biogeographic pattern for the region, but it is currently disregarded because it did not consider previous literature and it was not based on fish distribution data.…”

Scale(s) matter: Deconstructing an area of endemism for Middle American freshwater fishes

“…To delineate endemic areas within the study region, we used multivariate clustering methods (Kreft & Jetz, 2010) to identify geographical clusters of river sub‐basins based on assemblages (sensu Fauth et al., 1996) of freshwater fishes. These methods provide a quantitative and objective first step in identification and delineation of biogeographical regions and have been widely used for aquatic ecosystems (Cousseau et al, 2019; Ennen, Agha, Matamoros, Hazzard, & Lovich, 2016; Ennen et al., 2020; Matamoros et al., 2016; Matamoros, Kreiser, & Schaefer, 2012). First, we performed a hierarchical cluster analysis of the river sub‐basins based on an unweighted pair group method analysis with arithmetic means (UPGMA) on a dissimilarity matrix based on Jaccard index from our presence/absence dataset using the hclust function implemented in the R package ‘vegan’.…”

“…To delineate endemic areas within the study region, we used multivariate clustering methods (Kreft & Jetz, 2010) to identify geographical clusters of river sub-basins based on assemblages (sensu Fauth et al, 1996) of freshwater fishes. These methods provide a quantitative and objective first step in identification and delineation of biogeographical regions and have been widely used for aquatic ecosystems (Cousseau et al, 2019;Ennen, Agha, Matamoros, Hazzard, & Lovich, 2016;Ennen et al, 2020;Matamoros et al, 2016;Matamoros, Kreiser, & Schaefer, 2012).…”

Assemblage structure and spatial diversity patterns of kelp forest-associated fishes in Southern Patagonia

“…cunninghami , Calliclinus geniguttatus , Piedrabuenia ringueleti ) not previously recorded in this region. Percentage of species endemic to the Magellanic Province was high (60%) when compared to the total endemic species pool in the province (15%) [ 26 ]. According to Cousseau et al [ 26 ], the fish families that best represent endemicity in the Magellanic Province are Nototheniidae and Zoarcidae, which were also the most specious families in our study.…”

“…More than 120 fish species have been recorded in the shallow waters (< 20 m) of the southern cone of South America [ 26 , 27 ]. Thirty-five of these fish species have been recorded in association with giant kelp [ 6 , 28 – 33 ].…”