Corallimorpharians (Anthozoa: Corallimorpharia) from the Argentinean Sea.

Corallimorpharians are a relative small group of anthozoan cnidarians, also known as jewel sea anemones. They resemble actiniarian sea anemones in lacking a skeleton and being solitary, but resemble scleractinian corals in external and internal morphology, and they are considered to be the sister group of the stony corals. Corynactis carnea (=Sphincteractis sanmatiensis) is a small, common and eye catching species that inhabits the shallow water of northern Patagonia and the Argentinean shelf up to 200 m depth. Corallimorphus rigidus is registered for the first time from the southwestern Atlantic Ocean. It is a rather big and rare species that inhabits only the deep sea. Only two specimens were found at 2934 m depth in Mar del Plata submarine canyon, in an area under the influence of the Malvinas current, which may explain its occurrence. These two species are the only two known jewel sea anemones in the Argentinean sea and are reported and described herein.

Tooth microstructure and feeding biology of the brittle star Ophioplocus januarii (Echinodermata: Ophiuroidea) from northern Patagonia, Argentina / Microestructura dental y biología alimentaria del Ophioplocus januarii (Echinodermata: Ophiuroidea) del norte de Patagonia, Argentina

Abstract Ophioplocus januarii is a common brittle star on soft and hard substrates along the Argentinian and Brazilian coasts. Based on stomach contents, tooth microstructure and field observations we identified its food. Opposed to previous suggestions, O. januarii appears to be a microphagous species feeding on macroalgal fragments (found in 60.0 % of the analyzed stomachs with content), plant debris (28.0 %), animal cuticle structures (13.0 %), and unidentifiable material (30.7 %). Less frequent items found were foraminiferans, ostracods, an amphipod, a juvenile bivalve, and other crustaceans. Electronic microscope revealed digested material, diatoms and small crustacean appendices. Thus, O. januarii is an omnivorous species, feeding mainly on algae, complemented opportunistically with other items. Suspension feeding was observed in the field. It has an fenestrated arrangement intermediate between the previously described uniform and compound teeth. Rev. Biol. Trop. 63 (Suppl. 2): 353-360. Epub 2015 June 01.

Resumen El ofiuroideo Ophioplocus januarii se distribuye a lo largo de las costas de Argentina y Brasil, encontrándose tanto en substratos duros como blandos. En base al análisis de contenidos estomacales y la microestructura de los dientes, junto a observaciones de campo, se describe el comportamiento alimentario de esta especie. Opuesto a suposiciones previas, O. januarii es una especie micrófaga que se alimenta de fragmentos de macroalgas (encontrados en el 60.0 % de los estómagos analizados que presentaban contenido), detritos vegetales (28.0 %), estructuras cuticulares animales (13.0 %) y material inidentificable (30.7 %). Menos frecuente, se encontraron foraminíferos, ostrácodos, un anfípodo, un bivalvo juvenil y otros crustáceos. Pequeñas porciones del material inidentificable fueron analizadas en el microscopio electrónico de barrido, resultando ser material digerido, diatomeas y pequeños apéndices de crustáceos. Así, O. januarii es una especie omnívora, que se alimenta principalmente de algas, complementando su dieta de manera oportunista con otros ítems. Las observaciones de campo revelaron alimentación suspensívora. El análisis de la microestructura del estereoma del diente resultó en un arreglo del tipo fenestrado intermedio, que se encuentra entre los dos tipos de arreglos descriptos hasta ahora, los dientes de tipo uniforme y los compuestos. De estos últimos, el primero ha sido encontrado en especies macrófagas mientras que el segundo se corresponde a ofiuroideos micrófagos. En el presente trabajo, se propone la existencia de un nuevo tipo de arreglo intermedio en la matriz dental de los ofiuroideos.

Benthodytes violeta, a new species of a deep-sea holothuroid (Elasipodida: Psychropotidae) from Mar del Plata Canyon (south-western Atlantic Ocean).

A new species of elasipodid holothuroid, Benthodytes violeta sp. nov., is described from the Mar del Plata Canyon off Buenos Aires Province (around 38ºS-54ºW). It was taken at four locations at depths ranging from 1500 to 1950 m. This new species has a violet gelatinous body of up to 200 mm in length, with eight pairs of dorsal appendages, lateral festooned edges and four rows of tube feet ventrally. Body wall ossicles comprise rods and crosses with three or four arms and a central bipartite apophysis borne on the primary cross; tentacles and gonad deposits comprise rods and crosses with three and four arms. This is the first report of a holothuroid from the Mar del Plata Canyon area.

A new species of Havelockia Pearson, 1903 from the Argentine Sea (Holothuroidea: Dendrochirotida: Sclerodactylidae).

Havelockia pegi sp. nov., is here described from shallow waters of the Argentine Sea. This new species is distinctive in the purple colouration of its tentacles, scarcity of body wall ossicles and the presence of rosette-shaped ossicles in both the introvert and the tentacles. It is not closely related to any of its congenors. This is the first record of a true sclerodactylid from Argentina. Thandarum hernandezi Martinez & Brogger, 2012, described in the family Sclerodactylidae, is now classified in the family Sclerothyonidae.