Richness, systematics, and distribution of molluscs associated with the macroalga Gigartina skottsbergii in the Strait of Magellan, Chile: A biogeographic affinity study

Abstract

Knowledge about the marine malacofauna in the Magellan Region has been gained from many scientific expeditions that were carried out during the 19th century. However, despite the information that exists about molluscs in the Magellan Region, there is a lack of studies about assemblages of molluscs co-occurring with macroalgae, especially commercially exploitable algae such as Gigartina skottsbergii, a species that currently represents the largest portion of carrageenans within the Chilean industry. The objective of this study is to inform about the richness, systematics, and distribution of the species of molluscs associated with natural beds in the Strait of Magellan. A total of 120 samples from quadrates of 0.25 m2 were obtained by SCUBA diving at two sites within the Strait of Magellan. Sampling occurred seasonally between autumn 2010 and summer 2011: 15 quadrates were collected at each site and season. A total of 852 individuals, corresponding to 42 species of molluscs belonging to Polyplacophora (9 species), Gastropoda (24), and Bivalvia (9), were identified. The species richness recorded represents a value above the average richness of those reported in studies carried out in the last 40 years in sublittoral bottoms of the Strait of Magellan. The biogeographic affinity indicates that the majority of those species (38%) present an endemic Magellanic distribution, while the rest have a wide distribution in the Magellanic-Pacific, Magellanic-Atlantic, and Magellanic-Southern Ocean. The molluscs from the Magellan Region serve as study models for biogeographic relationships that can explain long-reaching patterns and are meaningful in evaluating possible ecosystemic changes generated by natural causes or related to human activities.

Latitudinal distribution of polyplacophorans along the South-eastern Pacific coast: unravelling biases in geographical diversity patterns

“…For instance, so far there is only one study describing the composition of polyplacophorans in both the Guayaquil (Ibáñez et al 2016) and Central Peru (Uribe 2013) ecoregions. Conversely, the sampling effort in the Chiloense and the Channels and Fjords ecoregions has been high (Reid and Osorio 2000;Aldea and Valdovinos 2005;Schwabe et al 2006;Sirenko 2006;Rosenfeld et al 2015), although taxonomic inconsistencies in these regions are still frequent. Overall, inconsistencies could be due to the high intraspecific phenotypic variability associated with habitat heterogeneity and the subsequent assignment of different names to the same phenotypes (e.g.…”

Variations on primary metabolites of the carrageenan-producing red algae Sarcopeltis skottsbergii from Chile and Sarcopeltis antarctica from Antarctic Peninsula

“…Besides carrageenan production, S. skottsbergii revealed to be a source of R-phycoerythrin and antioxidant activity, with potential for application as a bioactive ingredient for the food industry (Castro-Varela et al, 2022). S. skottsbergii occurs frequently in the sublittoral zone, forming beds which are important for the marine biodiversity conservation by providing shelter and breeding places for many species of invertebrates and fishes (Rosenfeld et al, 2015;Rosenfeld et al, 2017). Similar to S. antarctica, the life history of S. skottsbergii is also triphasic with isomorphic diploid tetrasporophytes and haploid gametophytes (Avila et al, 1999).…”

Diversity of benthic marine mollusks of the Strait of Magellan, Chile (Polyplacophora, Gastropoda, Bivalvia): a historical review of natural history

“…However, a list of species is not provided and only the classes Gastropoda and Bivalvia are included. Between the year 2000 and the present there have been several studies that have provided more information about the diversity of mollusks in the Strait of Magellan (e.g., Ríos et al 2003;Ríos et al 2005;Ríos et al 2007;Thatje and Brown 2009;Rosenfeld et al 2013;Rosenfeld et al 2015), presenting new records of species. Several taxonomic revisions of specific groups have been published in recent years, where erroneous records, changes in nomenclature, synonymized species and descriptions of new species have been made (e.g., Sirenko 2006a;Zelaya and Geiger 2007;Aranzamendi et al 2009;Zelaya 2009;González-Wevar et al 2011;Güller et al 2016;Pastorino 2016;Güller and Zelaya 2017;Korshunova et al 2017).…”