Variabilidad morfológica, distribución espacial y abundancia de las especies de Helicostomella (Ciliophora: Tintinnina) en relación con las condiciones ambientales (Mar Argentino; 40-55ºS)

For the first time a taxonomic and ecological study of species belonging to Helicostomella was performed over a mesoscale spatial distribution by examining ca. 3000 loricae collected in Argentine shelf waters during the austral autumn. Microscopic and statistical analysis revealed that the general shape and the oral diameter remained practically constant in the whole area surveyed, despite a continuous length fluctuation of ca. 300 µm, which includes the entire range present in eight previously reported species. Consequently, we consider that the genus may be represented only by H. subulata, whose strong fluctuations in length (mostly attributed to an increase in the collar length), density and biomass seem to respond to temperature, food availability and front-related processes. In Buenos Aires coastal waters associated with a quasi permanent estuarine front (40-40.5°S), mixed conditions would favour moderate abundances of long loricae, whereas in northern (42.5-45.5°S) and southern (46-54.5°S) Patagonian waters, high (103 ind. L-1) and low (< 5 ind. L-1) densities of short loricae seem to be a consequence of stratification and encystment, respectively. The non-occurrence of the species at 41-42°S, together with a three-fold reduction in length-related parameters between specimens from Buenos Aires and Patagonian waters, suggests a disjunct distribution.Se realizo el primer estudio taxonómico y ecológico de mesoescala sobre las especies del genero Helicostomella, examinando ca. 3000 lorigas colectadas en el Mar Argentino durante el otoño austral. Los análisis microscópicos y estadísticos revelaron que la forma general de la loriga y su diámetro oral permanecen prácticamente constantes en toda el area analizada, mientras que su longitud presenta una variación de ca. 300 μm, incluyendo todo el rango correspondiente a 8 especies previamente reportadas. En consecuencia, el genero estaría representado por una única especie, H. subulata, cuyas variaciones en longitud (atribuidas principalmente a la longitud del cuello), densidad y biomasa responderían a la temperatura, disponibilidad y calidad del alimento y procesos frontales. En aguas costeras de Buenos Aires asociadas a un frente estuarino casi permanente (40-40.5°S), las condiciones de mezcla favorecerían el desarrollo de lorigas largas en abundancias moderadas, mientras que en aguas del Norte (42.5-45.5°S) y del Sur (46-54.5°S) de la Patagonia prevalecen lorigas cortas en densidades elevadas (103 ind. L-1) o muy bajas (< 5 ind. L-1) como consecuencia de procesos de estratificación y enquistamiento, respectivamente. La no detección de la especie entre 41-42ºS, junto con la reducción en 3 veces de los parámetros relacionados con la longitud entre especimenes de las aguas de Buenos Aires y las Patagonicas, sugiere una distribución separada entre ambas áreas

Phylogeny of the order Tintinnida (Ciliophora, Spirotrichea) inferred from small- and large-subunit rRNA genes

Concatenated sequences of small- and large-subunit rRNA genes were used to infer the phylogeny of 29 species in six genera of Tintinnida. We confirmed previous results on the positions of major clusters and the grouping of various genera, including Stenosemella, the paraphyletic Tintinnopsis, the newly investigated Helicostomella, and some species of the polyphyletic Favella. Tintinnidium and Eutintinnus were found to be monophyletic. This study contributes to tintinnid phylogenetic reconstruction by increasing both the number of species and the range of genetic markers analyzed.Fil: Santoferrara, Luciana Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. University of Connecticut; Estados UnidosFil: McManus, George B.. University of Connecticut; Estados UnidosFil: Alder, Viviana Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Cátedra de Ecología General; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Ciliate microzooplankton from the Northeastern Gulf of Mexico

Microzooplankton mediate a critical juncture of autotrophic and heterotrophic microbial production in the water column. Taxonomic and ecological work on this group has been substantial, yet few reports exist for the offshore waters of the Gulf of Mexico (GOM). This report focuses on protists in the phylum Ciliophora collected at stations spanning the continental shelf in the northeastern GOM. We hypothesized that patterns of spatial distribution across the region would be west–east along the coast, rather than north–south coastal to offshore, reflecting major freshwater sources. Samples were obtained by 10 µm plankton net for microscopy and by filtration of seawater for DNA extraction and ciliate-specific clone sequencing. Microscopy and molecular analysis recovered 46 and 156 taxa, respectively. Some visually identified taxa were missing from the sequence analysis and sequences from unknown species dominated molecular results. Differences were apparent with both dominant and rare taxa between February and July sampling and across a trophic gradient from coastal influenced stations to those more representative of the offshore environment. This report provides new data on ciliate microzooplankton richness and distribution in the GOM and adds to our understanding of microzooplankton diversity in the ocean

Combined Genome and Transcriptome Analyses of the Ciliate \u3ci\u3eSchmidingerella arcuata\u3c/i\u3e (Spirotrichea) Reveal Patterns of DNA Elimination, Scrambling, and Inversion

Schmidingerella arcuata is an ecologically important tintinnid ciliate that has long served as a model species in plankton trophic ecology. We present a partial micronuclear genome and macronuclear transcriptome resource for S. arcuata, acquired using single-cell techniques, and we report on pilot analyses including functional annotation and genome architecture. Our analysis shows major fragmentation, elimination, and scrambling in the micronuclear genome of S. arcuata. This work introduces a new nonmodel genome resource for the study of ciliate ecology and genomic biology and provides a detailed functional counterpart to ecological research on S. arcuata

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Systematic and ecologic study of planktonic ciliates (protista, ciliophora) of the Argentine Sea and Drake Passage

Esta tesis, que representa el primer estudio sistemático y ecológico de la comunidad de ciliados aloricados y loricados del Mar Argentino y Pasaje Drake (36º-62º S), se centra en el análisis de la estructura taxonómica, la distribución espacial y la abundancia de dichos protozoos en relación con las condiciones ambientales del verano (2002 y 2003) y el otoño (2002). Se determinaron 57 taxones y se conformaron 12 grupos morfológicos ubicados jerárquicamente en las clases Oligotrichea, Litostomatea y Prostomatea. Mediante el revelado de caracteres citológicos por tinción con Protargol, se describieron 4 taxones que podrían constituir nuevas especies y se redescribieron 2 especies. La densidad y la biomasa de los ciliados oscilaron entre ca. 40 - 20000 ind. l⌃-1 y 0,01 - 25 μg C l⌃-1, respectivamente, con valores máximos asociados a zonas frontales del Mar Argentino, el cual albergó densidades promedio dos veces superiores que el Pasaje Drake, siguiendo la tendencia de la concentración de clorofila. La tasa de división potencial máxima de los oligotricos aloricados descendió de 2 a 0,2 d⌃-1 en sentido norte-sur, y su producción potencial promedio fue de 2 μg C l⌃-1 d⌃-1. En términos de densidad, se observó una contribución similar de nanociliados y microciliados, un predominio marcado de oligotricos aloricados sobre los loricados y otros ciliados, destacándose el aporte de 4 grupos morfológicos y de 1 especie (oligotricos A, estrombídidos A, B y C y Helicostomella subulata). La contribución en biomasa, en cambio, se atribuyó mayormente a ciliados microplanctónicos aloricados, principalmente Laboea strobila y Spirotontonia grandis. La composición específica y abundancia de los ciliados loricados permitió definir siete zonas biogeográficas y un sector de transición localizado en el extremo sur del Mar Argentino, caracterizado por los máximos valores de riqueza taxonómica y diversidad (13 y 2,1 respectivamente).The present work, which represents the first systematic and ecological study of aloricate and loricate ciliates of Argentine Sea and Drake Passage waters (36º-62º S), is based on the analysis of the taxonomic structure, spatial distribution and abundance of these protozoans, in relation to the summer (2002 and 2003) and autumn (2002) environmental conditions. A total of 57 taxa have been determined and 12 morphologic groups have been conformed, belonging to the classes Oligotrichea, Litostomatea y Prostomatea. By means of the observation of cytological characters using Protargol stain, 4 taxa which could represent new species were described, and 2 species were redescribed. Total ciliate density and biomass ranged on ca. 40 - 20000 ind. l⌃-1 and 0,01 - 25 μg C l⌃-1, with maximum values associated to frontal areas of the Argentine Sea, which reached mean densities two-fold higher than Drake Passage ones, following the chlorophyll trend. Maximum potential division rates of aloricate oligotrichs decreased from 2 to 0,2 d⌃-1, following the north-south latitudinal gradient examined. In terms of density, it has been seen a similar contribution of nanociliates and microciliates, with a dominance of the aloricate oligotrichs over the loricate ones and other ciliates, principally 4 morphologic groups and 1 species (oligotrichs A, strombidiids A, B and C, and Helicostomella subulata). Highest biomass contributions, however, resulted mostly from microplanktonic aloricate ciliates, mainly Laboea strobila and Spirotontonia grandis. Species composition and abundances of loricate ciliate allowed the differentiation of seven biogeographic zones and one transition sector located at the southernmost part of Argentine Sea, characterized by the highest values of taxonomic richness and diversity (13 and 2.1 respectively).Fil: Santoferrara, Luciana F.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Ciliate abundance in waters of the Argentine shelf and the Drake Passage, the south-western Atlantic

Ciliates from sub-surface waters of the Argentine shelf and the Drake Passage under austral summer and autumn conditions were examined and compared for the first time. In both environments, the taxonomic structure of ciliates was related to temperature and salinity, and aloricate oligotrichs dominated in density (80%) over loricate oligotrichs, litostomatids and prostomatids, while the microplanktonic fraction prevailed in terms of biomass (90%) over the nanociliates. Myrionecta rubra was found all along the Argentine shelf only in autumn, but showed isolated peaks of abundance (10**3 ind./L) during summer. Mean values of density and biomass of total ciliates decreased ca. 2-fold from the shelf-slope to oceanic waters, while potential maximum production of aloricate oligotrichs decreased 9-fold, in relation with the drop in chlorophyll a concentration and the latitudinal decline of temperature, also reflected in maximum growth rates. Fifty percent of total ciliate abundance was represented by local increases (maximum: 20 000 ind./L and 25 µg C/L), which were spatially superimposed with ranges of seawater temperature and chlorophyll a concentrations of 10-15°C and 0.6-6 µg/L, respectively and were found in the nearby of fronts located on the shelf and the slope