Kirkegaardia Blake, 2016 (Annelida: Cirratulidae) from Southeastern Brazil with description of nine new species.

This is the first taxonomic study of cirratulid polychaetes of the genus Kirkegaardia Blake, 2016 from Brazil. Nine new species of the genus are described from the Southern Brazilian coast (50-3000 m deep). The genus Kirkegaardia is generally subdivided into three distinct groups of species (Kirkegaardia dorsobranchialis-heterochaeta, Kirkegaardia baptisteae-tesselata and Kirkegaardia luticastella) and several out-group species for which relationships remains to be defined. In this study, new species were included in the Kirkegaardia dorsobranchialis-heterochaeta and Kirkegaardia baptisteae-tesselata groups. Kirkegaardia dorsobranchialis-heterochaeta is characterized by thoracic parapodia elevated producing a channel between the notopodia, elongate pre-setigerous region that is either entirely smooth or modified with a dorsal ridge and/or rings, and noto- and neurosetae capillaries denticulated. As belonging to this group, K. blakei sp. nov., K. brisae sp. nov., K. goytaca sp. nov., K. jongo sp. nov. and K. papaveroi sp. nov. are described here. Kirkegaardia baptisteae-tesselata includes species that lack thoracic parapodia elevated and mid-dorsal thoracic groove, although a dorsal ridge is sometimes developed. In the pre-setigerous region dorsal ridges and rings are present or absent. Most species in this group have neurosetae denticulated, and notosetae capillaries of other types. This study adds K. helenae sp. nov., K. medusa sp. nov., K. nupem sp. nov. and K. zafirae sp. nov. to the latter species group. In addition, two new records are provided for K. hampsoni. A key to cirratulid polychaete species reported from Brazilian waters is provided.

Bycatch of Asteroidea from shrimp trawl fishery in the southwestern Atlantic Ocean ­ Brazil

Shrimp trawling is considered a significant negative impact on the marine ecosystem, especially on the benthic community. Sea stars (Echinodermata: Asteroidea) are one of the most affected groups by unintentional catches. This study was performed at the Santana Archipelago, a Marine Protected Area in the northern region of Rio de Janeiro State, between 2008-2009. Sea stars accidentally caught by trawling were collected during open and closed season of the shrimp fisheries (Xiphopenaeus kroyeri) at depths of 5-60 m. A generalized linear zero-inflated model was applied to test for differences in capture between fishing seasons and depths. A total of 158 sea star specimens were captured. These specimens were identified as Asterina stellifera, Astropecten acutiradiatus, Astropecten brasiliensis, Astropecten cingulatus, Luidia alternata alternata, Luidia clathrata, Luidia ludwigi scotti, Luidia senegalensis. The sea stars A. brasiliensis and L. senegalensis are currently considered as vulnerable species in the Brazilian official list of threatened species. The higher capture of sea stars was shown in deepest areas, and there was no significant difference in the number of specimens between seasons. This is the first study about asteroids accidentally captured by shrimp trawling.(AU)

Effects of GSK3ß inhibition in the regeneration of Syllis malaquini (Syllidae, Annelida).

The Wnt/ß-catenin signaling pathway has been widely associated to the reestablishment of anteroposterior body polarities in the embryonic development and regeneration in animals. For instance, in annelids, cellular proliferation, wound healing, and blastema development can be affected when this pathway is disrupted. However, very little is known about the genetic regulatory processes involved in these anomalies. Here, we investigate the morphological effects of 1-azakenpaullone, a pharmacological inhibitor of GSK3ß that is supposed to over-activate the Wnt/ß-catenin pathway, during the anterior and posterior regeneration of the annelid Syllis malaquini. The results showed that high concentrations of 1-azakenpaullone affect the stages of blastema differentiation and resegmentation. Therefore, GSK3ß-associated gene regulatory networks are candidate to investigate the genetic mechanisms involved in the regular course of S. malaquini regeneration.

Cellular proliferation dynamics during regeneration in Syllis malaquini (Syllidae, Annelida).

BACKGROUND: In syllids (Annelida, Syllidae), the regenerative blastema was subject of many studies in the mid and late XXth century. This work on syllid regeneration showed that the blastema is developed by a process of dedifferentiation of cells near the wound, followed by their proliferation and redifferentiation (cells differentiate to the original cell type) or, in some specific cases, transdifferentiation (cells differentiate to a cell type different from the original). Up to date, participation of stem cells or pre-existing proliferative cells in the blastema development has never been observed in syllids. This study provides the first comprehensive description of Syllis malaquini's regenerative capacity, including data on the cellular proliferation dynamics by using an EdU/BrdU labelling approach, in order to trace proliferative cells (S-phase cells) present before and after operation. RESULTS: Syllis malaquini can restore the anterior and posterior body from different cutting levels under experimental conditions, even from midbody fragments. Our results on cellular proliferation showed that S-phase cells present in the body before bisection do not significantly contribute to blastema development. However, in some specimens cut at the level of the proventricle, cells in S-phase located in the digestive tube before bisection participated in regeneration. Also, our results showed that nucleus shape allows to distinguish different types of blastemal cells as forming specific tissues. Additionally, simultaneous and sequential addition of segments seem to occur in anterior regeneration, while only sequential addition was observed in posterior regeneration. Remarkably, in contrast with previous studies in syllids, sexual reproduction was not induced during anterior regeneration of amputees lacking the proventricle, a foregut organ widely known to be involved in the stolonization control. CONCLUSIONS: Our findings led us to consider that although dedifferentiation and redifferentiation might be more common, proliferative cells present before injury can be involved in regenerative processes in syllids, at least in some cases. Also, we provide data for comparative studies on resegmentation as a process that differs between anterior and posterior regeneration; and on the controversial role of the proventricle in the reproduction of different syllid lineages.

Pilargidae (Annelida: Phyllodocida) from coastal and deep waters of the Southwestern Atlantic, with descriptions of two new species.

We describe seven species of Pilargidae from the coast and deep sea (300-1400 m deep) of southeastern Brazil, belonging to the genera Ancistrosyllis McIntosh, 1878, Cabira Webster, 1879, Glyphohesione Friedrich, 1950, Hermundura Müller, 1858, and Pilargis Saint-Joseph, 1899. Of those, two are new species (Glyphohesione campensis sp. nov. and Pilargis falconae sp. nov.) and two are new records of Ancistrosyllis for Brazil. Glyphohesione campensis sp. nov. is distinguished from its congeners by fewer neurochaetae, the anteriormost appearance of first notopodial spines, and intermediate relative length of dorsal and ventral cirri. Pilargis falconae sp. nov. is diagnosed by the presence of parapodial glands from the first chaetiger on the dorsal surface and from the sixth chaetiger on the ventral surface; and neurochaetae smooth capillaries and limbates with unidentate tips. Keys to pilargid species reported from, or likely to occur in, Brazilian waters are provided.

Sex-specific gene expression differences in reproducing Syllis prolifera and Nudisyllis pulligera (Annelida, Syllidae).

Syllidae is an annelid family characterized by its complex life cycles involving some of the most outstanding annelid reproductive strategies. Syllid reproductive modes sometimes imply the modification of the posterior body to form independent reproductive units (schizogamy) or the development of swimming adults (epigamy). These modes of sexual reproduction have been studied for more than 150 years, and yet, little is known regarding their molecular background. Notably, while several studies during the last three decades have revealed details about molecular mechanisms involved in the reproduction of some few model annelids, studies focusing on syllids remain limited. Thus, we performed differential gene expression analyses of female, male, and non-reproducing individuals of Syllis prolifera (schizogamic) and Nudisyllis pulligera (epigamic), as representatives of two different reproductive strategies. For that, transcriptomes from specimens of three conditions (non-reproducing, male, female) were de novo assembled and annotated for S. prolifera and N. pulligera. We found rather similar gene expression profiles for female and non-reproducing individuals, while male gene expression is clearly different. Although previous studies have suggested that femininity in syllids might require additional signalling, our analyses support a scenario, where masculinity may also involve several specific genetic processes.

Comparative transcriptomics in Syllidae (Annelida) indicates that posterior regeneration and regular growth are comparable, while anterior regeneration is a distinct process.

BACKGROUND: Annelids exhibit remarkable postembryonic developmental abilities. Most annelids grow during their whole life by adding segments through the action of a segment addition zone (SAZ) located in front of the pygidium. In addition, they show an outstanding ability to regenerate their bodies. Experimental evidence and field observations show that many annelids are able to regenerate their posterior bodies, while anterior regeneration is often limited or absent. Syllidae, for instance, usually show high abilities of posterior regeneration, although anterior regeneration varies across species. Some syllids are able to partially restore the anterior end, while others regenerate all lost anterior body after bisection. Here, we used comparative transcriptomics to detect changes in the gene expression profiles during anterior regeneration, posterior regeneration and regular growth of two syllid species: Sphaerosyllis hystrix and Syllis gracilis; which exhibit limited and complete anterior regeneration, respectively. RESULTS: We detected a high number of genes with differential expression: 4771 genes in S. hystrix (limited anterior regeneration) and 1997 genes in S. gracilis (complete anterior regeneration). For both species, the comparative transcriptomic analysis showed that gene expression during posterior regeneration and regular growth was very similar, whereas anterior regeneration was characterized by up-regulation of several genes. Among the up-regulated genes, we identified putative homologs of regeneration-related genes associated to cellular proliferation, nervous system development, establishment of body axis, and stem-cellness; such as rup and JNK (in S. hystrix); and glutamine synthetase, elav, slit, Hox genes, ß-catenin and PL10 (in S. gracilis). CONCLUSIONS: Posterior regeneration and regular growth show no significant differences in gene expression in the herein investigated syllids. However, anterior regeneration is associated with a clear change in terms of gene expression in both species. Our comparative transcriptomic analysis was able to detect differential expression of some regeneration-related genes, suggesting that syllids share some features of the regenerative mechanisms already known for other annelids and invertebrates.

A new species of Paraonis and an annotated checklist of polychaetes from mangroves of the Brazilian Amazon Coast (Annelida, Paraonidae).

The polychaete fauna from the mangroves of the Amazon Coast in Maranhão state, Brazil, is reported in this study. Fourteen species are listed, namely Alitta succinea (Leuckart, 1847); Arabella (Arabella) iricolor Montagu, 1804; Capitella capitata (Fabricius, 1780) complex; Exogone (Exogone) breviantennata Hartmann-Schröder, 1959; Heteromastus filiformis (Claparède, 1864); Isolda pulchella Müller, 1858; Mediomastus californiensis Hartman, 1944; Namalycastis fauveli Nageswara Rao, 1981; Namalycastis geayi (Gravier, 1901); Namalycastis senegalensis (Saint-Joseph, 1901); Nephtys simoni Perkins, 1980; Paraonis amazonicasp. n.; Sigambra bassi (Hartman, 1945); and Sigambra grubii Müller, 1858. Among them, Namalycastis fauveli and Namalycastis geayi are recorded for the first time in Brazil. Paraonis amazonicasp. n. is a new species for science, characterized by a rounded prostomium, 4-8 pairs of foliaceous branchiae, absent eyes, and two types of modified neurochaetae, acicular and hook-shaped.