Resumen Se presenta una lista actualizada de las especies de poliquetos descritos para las costas del Caribe en Colombia con base en la revisión histórica de documentos. La lista taxonómica incluye referencias de nomenclatura, sinonimias, datos de la ecorregión, hábitat y batimetría. Mediante la revisión se pudo determinar que hasta septiembre del 2019 se han descrito 51 familias, 230 géneros y 293 especies con validez científica en la costa del Caribe en Colombia. Eunicidae es la familia con el mayor número de registros de especies, con un total de 33 (11,3 %), seguida de Syllidae, con 23 especies (7,8 %), y Nereididae, con 19 especies (6,5 %). La ecorregión Tayrona fue la que presentó la mayor diversidad, con el 32 % de los registros de especies, seguida de la ecorregión Magdalena, con 23,4 %. Los poliquetos en Colombia se han recolectado en hábitats naturales como manglares, pastos marinos e, incluso, como parásitos y comensales de otros organismos; sin embargo, cerca del 60 % de los registros taxonómicos corresponden a organismos recolectados en fondos blandos y duros, principalmente entre los 0 y 15 m de profundidad. Las descripciones y registros de especies en la costa Caribe colombiana se deben a las importantes contribuciones realizadas en el siglo XIX por investigadores internacionales y nacionales.

Abstract We present an updated list of the polychaete species described for the Caribbean coasts of Colombia after a historical review of the literature. The taxonomic list includes references to the nomenclature, the synonymies, the data from the ecoregion, the habitat and the bathymetry. Based on the review, we were able to determine that up to September 2019, 51 families, 230 genera, and 293 species with scientific validity had been described for the Colombian Caribbean coast. Eunicidae is the family with the highest number of records, with a total of 33 (11.3%) species, followed by Syllidae with 23 species (7.8%) and Nereididae with 19 species (6.5%). The Tayrona ecoregion presented the greatest diversity, with 32% of species records, followed by the Magdalena ecoregion with 23.4%. Polychaetes in Colombia have been collected in natural habitats such as mangroves, seagrasses, and even as parasites and commensals of other organisms; however, about 60% of the taxonomic records correspond to organisms collected in soft and hard bottoms, mainly between 0 and 15 m deep. The descriptions and records of species on the Colombian Caribbean coast are due to the important contributions made in the 19th century by international and national researchers.

Resumen Un total de 298 especies de poliquetos han sido registradas para Colombia. Sin embargo, solo la familia Protodrilidae ha sido reportada para el medio marino intersticial. El objetivo de este estudio fue identificar los anélidos intersticiales que habitan en playas arenosas de la región de Santa Marta hasta la categoría taxonómica más precisa, basados en observaciones al microscopio de luz. Las muestras fueron recolectadas en la zona intermareal de tres playas turísticas en el departamento del Magdalena (La bahía de Santa Marta, bahía de Rodadero y bahía de Taganga), resultando un total de 83 especímenes, los cuales fueron asignados a cinco familias, diez géneros y nueve especies. De estos, dos familias, ocho géneros y las especies Hesionides gohari, Neogyptis mediterranea, Neopetitia amphothalma, Westheidesyllis gesae y Syllis beneliahuae representan nuevos registros para la fauna de Colombia. Este trabajo debería ser considerado como el primer paso hacia el conocimiento de la diversidad de anélidos intersticiales en Colombia y los resultados contribuyen significativamente a llenar el vacío de información en el tema, sugiriendo una alta diversidad de especies comparable con la de áreas mejor conocidas del Caribe y de la costa atlántica de Brasil. En este trabajo se provee una breve diagnosis, comentarios sobre la distribución y ecología, y anotaciones para cada registro, con el propósito de facilitar la re-identificación de las especies.

Abstract A total of 298 species of polychaetes have been recorded from Colombia. However, only the family Protodrilidae has been reported from the marine interstitial realm. We here aim at identifying the interstitial annelids inhabiting the sandy beaches in Santa Marta region to the most accurate taxonomic level based on light microscopy examinations. Our samples, collected from the intertidal zone at three touristic beaches in the department of Magdalena (Santa Marta Bay, Rodadero Bay, and Taganga Bay), yielded a total of 83 specimens, which we assigned to five families, ten genera and nine species. From those, two families, eight genera, and the species Hesionides gohari, Neogyptis mediterranea, Neopetitia amphophthalma, Westheidesyllis gesae, and Syllis beneliahuae represent new records for the Colombian fauna. This survey should be considered as a first step towards a complete knowledge of the Colombian diversity of interstitial annelids, and our results significantly contribute to fill the gap of our current knowledge, suggesting a high diversity of species comparable to this in better-known areas of the Caribbean and the Atlantic coasts of Brazil. A brief diagnosis, comments on distribution and ecology, and remarks are provided for each record, in order to facilitate the re-identification of the species. Rev. Biol. Trop. 66(2): 658-673. Epub 2018 June 01.

The nervous systems of flatworms have diversified extensively as a consequence of the broad range of adaptations in the group. Here we examined the central nervous system (CNS) of 12 species of polyclad flatworms belonging to 11 different families by morphological and histological studies. These comparisons revealed that the overall organization and architecture of polyclad central nervous systems can be classified into three categories (I, II, and III) based on the presence of globuli cell masses -ganglion cells of granular appearance-, the cross-sectional shape of the main nerve cords, and the tissue type surrounding the nerve cords. In addition, four different cell types were identified in polyclad brains based on location and size. We also characterize the serotonergic and FMRFamidergic nervous systems in the cotylean Boninia divae by immunocytochemistry. Although both neurotransmitters were broadly expressed, expression of serotonin was particularly strong in the sucker, whereas FMRFamide was particularly strong in the pharynx. Finally, we test some of the major hypothesized trends during the evolution of the CNS in the phylum by a character state reconstruction based on current understanding of the nervous system across different species of Platyhelminthes and on up-to-date molecular phylogenies.