Brazil

Revealing the diversity of Parasmittina Osburn, 1952 (Bryozoa, Cheilostomatida) from the Southwest Atlantic: Species complexes, non-native and new species

Parasmittina is the most representative cheilostome genus of the family Smittinidae, often reported in the fouling non-indigenous marine community. Here, we present a review of Parasmittina species reported in the Southwestern Atlantic including the characterization of one species from Argentina (P. dubitata) and ten from the Brazilian coast: P. abrolhosensis, P. alba, P. bimucronata, P. ligulata comb. nov., P. longirostrata, P. pinctatae, P. serrula, P. simpulata, P. winstonae and the new species Parasmittina falciformis sp. nov. The new species is characterized by a smooth distally primary orifice with 1-2 oral spines, large lyrula, serrated condyles with hooked tips, and two types of avicularia-small and subtriangular and large sublanceolate. This study does not recognize four species previous recorded in Brazil: reports of P. betamorphaea and P. trispinosa are now assigned to P. pinctatae; records of P. munita belong to P. falciformis sp. nov.; and reports of P. spathulata encompass at least two taxa, including P. abrolhosensis and P. simpulata. In this study, five species complexes (P. alba, P. longirostrata, P. serrula, P. simpulata and P. winstonae) were identified and require further investigations. While six species characterized here were first described based on specimens from the Southwestern Atlantic (P. abrolhosensis, P. alba, P. dubitata, P. ligulata comb. nov., P. simpulata and P. falciformis sp. nov.), the remaining species are mainly known from the Indo-Pacific. These taxa are here recognized as exotic (P. longirostrata) and cryptogenic (P. bimucronata, P. pinctatae, P. serrula and P. winstonae) in the studied area. Most of the non-native taxa are widespread along the Brazilian coast, growing on both artificial and natural surfaces, indicating that they are well-established in the area. As non-native bryozoans can negatively influence the environment, affecting human economic activities and beach usage, further studies on the fauna presented here are suggested to determine the origin of these taxa and help prevent bioinvasion events along the SW Atlantic.

Calcium carbonate production in the southernmost subtropical Atlantic coral reef

Emerging evidence have been supporting the idea that the better known South Atlantic coral reefs (located between 18°S and 24°S) are now essentially senescent structures that have experienced little or no additional vertical reef growth over the past millennia. This has often coincided with a shift to a dominance of non-coral calcifying organisms becoming the main CaCO₃ producers in these high latitude and marginal marine settings. Here, we used Calcification Accretion Units (CAUs) and census-based methods to measure non-coral rates of CaCO₃ production on the geologically senescent reef and adjacent rhodolith beds within the southernmost subtropical Atlantic reef (i.e., Queimada Grande Reef, QGR). The reef habitat is currently producing CaCO₃ at rates of ∼126 g m^-2 yr^-1. In contrast, fragments of dead corals skeletons deposited adjacent to the reef over the last ∼2000 years are now colonized by crustose coralline red algae. These form a rhodolith bed that produces CaCO₃ at rates of 858 g m^-2 yr^-1. Our results indicate that, whilst not sufficient to promote active net framework accumulation, CaCO₃ production by coralline algae and bryozoans on the QGR appears to be sufficient to at least limit net large-scale erosion of the underlying reef structure, allowing the reef structure to persist in a state close to budgetary stasis. Finally, our results are also of relevance for providing insights regarding the balance of CaCO₃ production/dissolution/erosion processes in coral reefs, especially in these less understood marginal reefs.

Influence of depth on bryozoan richness and distribution from the continental shelf of the northern coast of Bahia State, north-eastern Brazil

Biological and abiotic processes influence ecosystem structure and species distribution. For bryozoan assemblages, depth, substratum and habitat structure are among the main factors influencing their distribution. Ecological studies on bryozoan fauna from Brazil are scarce and factors affecting the distribution and/or diversity of this common group are obscure. Here we attempted to verify the influence of bathymetry on bryozoan richness on the north shore of Bahia State, north-eastern Brazil. We identified 57 bryozoan taxa, comprising 35 families and 50 genera, all belonging to the Cheilostomata. Retevirgula multipunctata Winston, Vieira & Woollacott, 2014 and Tetraplaria dichotoma (Osburn, 1914) and the genus Aimulosia Jullien, 1888 were recorded for the first time from Bahia State. Species growing as encrusting sheets were dominant at all depths. There was a significant difference in richness among samples at different depths, with highest values of richness at 40 meters (Kruskal-Wallis Test). Analysis of similarities revealed a significant difference among the bryozoan assemblages, mainly when comparing assemblages from 10 and 20 meters with deeper ones. Also, shallower assemblages composition varied much than assemblages from 30 and 40 meters. Since depth is a proxy for several environmental parameters, further studies are needed to identify other factors influencing bryozoan distribution.

A new species of Cellaria (Bryozoa: Cheilostomata) from northeastern Brazil, with a tabular identification key to the Atlantic species

A new species of the erect cheilostome bryozoanCellariaEllis & Solander, 1786 is described from Bahia, NE Brazil.Cellaria oraneaesp. nov. is the first formally characterized species of the genus reported from Northeastern coast of Brazil, distinguished from all congeners by the combination of hexagonal autozooids and rhomboid fertile zooids, hexagonal interzooidal avicularium with sagittate foramen, completely immersed ovicell with oval aperture and proximal rectangular lip. A brief discussion of the diversity ofCellariafrom the Atlantic Ocean and a tabular identification key to these species are also provided.