Census of Octocorallia (Cnidaria: Anthozoa) of the Azores (NE Atlantic) with a nomenclature update

Abstract

Zoological nomenclature revisions are essential for biodiversity studies and indispensable to avoid naming and description of already described species and should be valued in all subsequent studies considering biology, molecular biology, ecology or habitat mapping of deep-sea species. Herein, a thorough revision of the taxonomic literature on Octocorallia since the beginning of deep-sea exploration in the Azores is provided. Since 1870, when the first octocoral, Virgularia mirabilis (Müller, 1776), was recorded in the Azores a cyclic pattern on the taxonomical study of octocorals reveals the deep-sea investigation efforts made on the region at different periods: Prince Albert I of Monaco, Biaçores and recent expeditions. The first decade of this millennium was the peak on taxonomic research of cold-water octocorals in the Azores with 11 publications targeting gorgonians and soft corals (Alcyonacea) and specific sub-orders within it. Ninety-eight names of Octocorallia were found to be given in the economic exclusive zone of the Azores. While 25 names were changed or added to the known Azorean octocoral diversity, 3 species identified in the region and unreported in the reviewed literature, increase the number to 101 species. Twenty-five names were synonymized while three species names were unmasked as errors in need of taxonomical clarification. This is the highest species richness of Octocorallia found in Europe and in any Northern Atlantic archipelago so far, representing ~60% of the most diverse center of endemism of South Africa, with a part in the Eastern Atlantic. Further research on taxonomy may reveal new species to science.

Natural history collections as a basis for sound biodiversity assessments: Plexauridae (Octocorallia, Holaxonia) of the Naturalis CANCAP and Tyro Mauritania II expeditions

“…CANCAP and Tyro Mauritania II are the 20 th Century’s most comprehensive scientific expeditions after the earlier campaigns of Prince Albert I of Monaco in the Northeast Atlantic Ocean (Sampaio et al 2019). By visiting NBC and examining the octocoral specimens collected during the CANCAP and Tyro Mauritania II expeditions, reliable and new taxonomic records were discovered, and a complete dataset was built based on the specimens and their labels in the museum collection.…”

“…While the easier taxonomic assignments were found in Azorean specimens, the most difficult were found in Cape Verdean specimens (Figures 3, 4). Easier taxonomic assignments were found in Azorean specimens due to the higher deep-sea exploration and the effort in octocoral taxonomy within the region (Sampaio et al 2019). Nonetheless, difficult taxonomic assignments were found for the Cape Verdean specimens due to the lack of knowledge on octocoral diversity of that archipelago (Figures 3, 4).…”

“…Nonetheless, difficult taxonomic assignments were found for the Cape Verdean specimens due to the lack of knowledge on octocoral diversity of that archipelago (Figures 3, 4). The sampling and research effort of Azorean octocorals is much higher than those in other southern areas of the NE Atlantic Ocean, like Cape Verde, which explains why the octocoral fauna of those areas is mostly unknown (Pérez et al 2016; Sampaio et al 2019). As expected based on previous knowledge for the area, Azorean CANCAP plexaurids have a high species and genus richness and have revealed a new record for the region (Sampaio et al 2019).…”

“…Museum scientists and technicians were consulted to clarify questions regarding the metadata or to add additional information like catalogue numbers to uncatalogued specimens. Species names and taxonomy were cross-checked using World Register of Marine Species (WoRMS) Cordeiro et al (2019) in addition to Grasshoff (1977) and Sampaio et al (2019) to include only valid scientific names. Unidentified specimens were identified based on the revision of the family Plexauridae (Grasshoff 1977), the original descriptions of each species of Plexauridae known to occur in the NE Atlantic Ocean, and reference material from various museums.…”

Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic

“…The afore mentioned turbulent ENACW-MOW boundary might allow the transport of coral larvae along the NE Atlantic margins (Somoza et al, 2014). At the Mid Atlantic Ridge, the Azores region hosts an exceptional biodiversity of CWCs (Figure 2), mostly gorgonians (75% of the octocoral species of European waters), with a greater affinity to the Lusitanian-Mediterranean biogeographic region (71% shared species) and to a lesser extent to the NW Atlantic (Braga-Henriques et al, 2013;Sampaio et al, 2019). The presence of multiple intermediate and deep water masses (NACW, subpolar origin waters, MOW, AAIW, NADW; Johnson and Stevens, 2000;Amorim et al, 2017) along the slopes of many seamounts are hypothesized to shape composition and bathymetrical distribution of coral gardens in the Azores (Braga-Henriques et al, 2013).…”