ABSTRACT
Continental shelves encompass gently sloped seascapes that are highly productive and intensively exploited for natural resources. Islands, reefs and other emergent or quasi-emergent features punctuate these shallow (<100 m) seascapes and are well known drivers of increased biomass and biodiversity, as well as predictors of fishing and other human uses. On the other hand, relict mesoscale geomorphological features that do not represent navigation hazards, such as incised valleys (IVs), remain poorly charted. Consequently, their role in biophysical processes remains poorly assessed and sampled. Incised valleys are common within rhodolith beds (RBs), the most extensive benthic habitat along the tropical and subtropical portions of the mid and outer Brazilian shelf. Here, we report on a multi-proxy assessment carried out in a tropical-subtropical transition region (~20°S) off Eastern Brazil, contrasting physicochemical and biological variables in IVs and adjacent RBs. Valleys interfere in near bottom circulation and function as conduits for water and propagules from the slope up to the mid shelf. In addition, they provide a stable and structurally complex habitat for black corals and gorgonians that usually occur in deeper water, contrasting sharply with the algae-dominated RB. Fish richness, abundance and biomass were also higher in the IVs, with small planktivores and large-bodied, commercially important species (e.g. groupers, snappers and grunts) presenting smaller abundances or being absent from RBs. Overall, IVs are unique and vulnerable habitats that sustain diverse assemblages and important ecosystem processes. As new IVs are detected by remote sensing or bathymetric surveys, they can be incorporated into regional marine management plans as conservation targets and priority sites for detailed in situ surveys.
Subject(s)
Coral Reefs , Ecosystem , Animals , Humans , Biodiversity , Biomass , Water , FishesABSTRACT
Soft corals (Anthozoa: Octocorallia) are discreet components in the Southwestern Atlantic reef communities. In Brazil, the native octocoral shallow-reef fauna is mostly represented by gorgonians. Consequently, except for the nephtheid Neospongodes atlantica, most of the known soft corals from this region are considered non-indigenous. Hitherto, the monotypic genus Neospongodes, which was proposed in the early 1900s, has been considered to be endemic to the Northeastern Brazilian coast. Herein, based on in situ records, we show that N. atlantica is a substrate generalist that has been probably expanding its distribution by dominating extensive shallow and mesophotic sandy and reef bottoms, generally outcompeting other reef benthic organisms, including Brazilian endemic species. Based on previously unidentified museum specimens, new records, and a broad literature review, we provide the most comprehensive modelling of the potential distribution of this species in the Southwestern Atlantic. Based on molecular inference supported by in-depth morphological analysis, the probable non-indigenous and, therefore, ancient introduction of N. atlantica in Brazilian waters is discussed. Finally, these results support that Neospongodes and the Indo-Pacific Stereonephthya are synonyms, which led us to propose the latter as taxonomically invalid.
Subject(s)
Anthozoa , Animals , Brazil , MuseumsABSTRACT
Large gaps in reef distribution may hinder the dispersal of marine organisms, interrupting processes vital to the maintenance of biodiversity. Here we show the presence and location of extensive reef habitats on the continental shelf between the Amazon Reef System (ARS) and the Eastern Brazilian Reef System (ERS), two reef complexes off eastern South America. Formations located 20-50 m deep include both biogenic and geogenic structures. The presence of diverse reef assemblages suggests the widespread occurrence of rocky substrates below 50 m. These habitats represent an expansion of both the ARS and ERS and the closure of the only remaining large-scale gap (~ 1000 km) among West Atlantic reef environments. This indicates that the SW Atlantic harbors a single, yet heterogeneous, reef system that stretches for about 4000 km, and thus, represents one of the largest semi-continuous tropical marine ecosystems in the world.
Subject(s)
Biodiversity , Ecosystem , Animals , Aquatic Organisms , Brazil , Coral Reefs , FishesABSTRACT
Black corals (Cnidaria: Hexacorallia: Antipatharia) occur in all oceans of the globe, especially at depths greater than 50 m. However, their richness is underestimated due to the scarcity of studies on this group, especially in deep waters. The south Atlantic is one of the most depauperate regions in terms of our knowledge of antipatharians. Herein, we report 34 antipatharian species for the Southwestern Atlantic. Additionally, based on the examination of museum specimens, three species are new records in the Atlantic (Parantipathes laricides; Stichopathes paucispina and S. spiessi); and 17 had their distribution expanded, representing six families (Antipathidae, Cladopathidae, Leiopathidae, Myriopathidae, Schizopathidae and Stylopathidae). Additionally, the richness, distribution and associations of antipatharians are briefly discussed. An artificial key to South Atlantic antipatharians is included.
Subject(s)
Anthozoa , Animals , Atlantic Ocean , Oceans and SeasABSTRACT
The genus Trichogorgia (Cnidaria: Octocorallia) is composed of mesophotic gorgonians, and has been traditionally included in the Family Chrysogorgiidae. The family is polyphyletic and in need of generic morphological reassessments. Herein, two new species of that genus are described, based on material deposited in the National Museum of Natural History-Smithsonian Institution. Additionally, we provide a taxonomic key to all species of Trichogorgia, also briefly discussing important characters of the group and closely related taxa.
Subject(s)
Anthozoa , AnimalsABSTRACT
The World Register of Marine Species (WoRMS) is an online resource, which provides the most comprehensive database of scientific names of marine organisms (WoRMS, 2018). WoRMS is regularly retrieved by multidisciplinary researchers around the globe, regarded as a source of reliable taxonomic information. The database is continuously improved by taxonomic experts, which frequently have to address issues raised by users and other editors (Costello et al., 2013). This study is a result of one of these exchanges of knowledge stimulated by WoRMS.
Subject(s)
Anthozoa , Aquatic Organisms , Animals , Databases, FactualABSTRACT
As part of an ongoing reassessment of the genus Callogorgia, we describe C. lucaya sp. nov. from the western Atlantic, with a distribution so far restricted to the Straits of Florida and northern Caribbean. The species was partially described in an unfinished manuscript of Dr. Frederick Bayer and differs from all other western Atlantic species by commonly lacking outer-lateral body wall scales, having a small number of abaxials, and having body wall sclerites that are externally almost smooth. (Species Zoobank LSID: urn:lsid:zoobank.org:act:CF8F92FC-8F8A-4A8C-AF4A-52E12B58F7B1).
Subject(s)
Anthozoa , Decapoda , Animals , Caribbean Region , FloridaABSTRACT
A new genus and species of unbranched golden coral, Flagelligorgia gracilis, is described based on several specimens collected off the southeastern coast of the United States. The genus is provisionally included in the family Chrysogorgiidae, pending molecular confirmation. Flagelligorgia morphologically resembles other unbranched chrysogorgiids, such as Distichogorgia, Chalcogorgia, Helicogorgia and Radicipes, to which it is compared. The type species is illustrated and its distribution mapped.
ABSTRACT
Current knowledge about the Brazilian deep-water octocoral fauna remains scarce, fragmented, and mostly based on unpublished, regional scale surveys. The present work provides the first comprehensive study of the family Chrysogorgidae Verrill, 1883 in Brazil, based on morphological analysis of specimens collected in the last decade and those currently placed in museums. Members of this family are common mainly at great depths and remarkable for the iridescent aspect of their colonies. In Brazil, to the present, only four species were reported: Chrysogorgia elegans (Verrill, 1883), Chrysogorgia multiflora Deichmann, 1936, Stephanogorgia rattoi Castro, Medeiros & Loiola, 2010 and Trichogorgia brasiliensis Castro, Medeiros & Loiola, 2010-the last two are shallow-water species. In this study, three new deep-water species are described, Chrysogorgia tuberculata, Chrysogorgia upsilonia and Radicipes kopelatos, and a new record to Brazil is reported, Chrysogorgia fewkesii Verrill, 1883, as well as latitudinal expansions in distributions of Chrysogorgia elegans and Chrysogorgia multiflora are presented.
