First record of Alternatipathes bipinnata (Cnidaria: Antipatharia) in the Southern Hemisphere

Abstract

Antipatharians are still poorly documented in the southeastern Pacific, with just eleven species reported in Chilean waters, all of them distributed in subtidal areas from 70 to 2000 m depth (Häussermann & Försterra, 2007; Cañete & Häussermann, 2012; Araya et al. 2016a). Among the family Schizopathidae Brook, 1889, which is characterized by polyps elongated in the direction of the axis and having a transverse diameter of 2 mm or more (Opresko, 2002), the recently described deep-water genus Alternatipathes Molodtsova & Opresko, 2017, encompasses two recognized species, Alternatipathes alternata (Brook, 1889), reported from abyssal basins (2670 to 5089 m depth) of the Indian and Pacific Oceans, and Alternatipathes bipinnata (Opresko, 2005), known from a few specimens collected in deep waters (1130 to 2846 m) off the Pacific coasts of northern Mexico and southern USA (Opresko, 2005; Molodtsova & Opresko, 2017). In the present work, as part of ongoing studies reviewing deep-water macroinvertebrates from the bycatch of fisheries operating off northern Chile (Araya, 2013, 2016; Araya et al. 2016b, 2016c, 2016d; Araya & Catalán, 2016; Reiswig & Araya, 2014), we present the first record of A. bipinnata in the Southern Hemisphere, based on a single colony which was found entangled in a demersal longline used in the fishery for the Patagonian Toothfish Dissostichus eleginoides Smith, 1898, at about 2000 m depth, off Caldera, northern Chile. This record extends the known geographical range of the species by about 57° (more than 8152 km) in a southward direction along the western coast of South America, and it is also the twelfth confirmed black coral species record for Chile