175 research outputs found
Diversity and geographic distribution of benthic foraminifera: a molecular perspective
The diversity and distribution of modern benthic foraminifera has been extensively studied in order to aid the paleoecological interpretation of their fossil record. Traditionally, foraminiferal species are identified based on morphological characters of their organic, agglutinated or calcareous tests. Recently, however, new molecular techniques based on analysis of DNA sequences have been introduced to study the genetic variation in foraminifera. Although the number of species for which DNA sequence data exist is still very limited, it appears that morphology-based studies largely underestimated foraminiferal diversity. Here, we present two examples of the use of DNA sequences to examine the diversity of benthic foraminifera. The first case deals with molecular and morphological variations in the well-known and common calcareous genus Ammonia. The second case presents molecular diversity in the poorly documented group of monothalamous (single-chambered) foraminifera. Both examples perfectly illustrate high cryptic diversity revealed in almost all molecular studies. Molecular results also confirm that the majority of foraminiferal species have a restricted geographic distribution and that globally distributed species are rare. This is in opposition to the theory that biogeography has no impact on the diversity of small-sized eukaryotes. At least in the case of foraminifera, size does not seem to have a main impact on dispersal capacities. However, the factors responsible for the dispersal of foraminiferal species and the extension of their geographic ranges remain largely unknow
Taxonomy and biogeography of living species of the Family Notorotaliidae (Notorotalia, Parrellina, Porosorotalia, Buccella, Cristatavultus)
DNA sequencing shows that species of the genera Notorotalia, Porosorotalia and Buccella form a distinct branch
(Notorotaliidae) of Rotaloidea, and cluster as sister to Elphidiidae. In this review we report on the sequencing of three species of
Buccella (from the Arctic Ocean, Patagonia and Chile) and one each of Notorotalia (New Zealand) and Porosorotalia (Chile). This information
has been combined with all the morphological descriptive information on species of these genera plus the genera
Cristatavultus and Parrellina to provide a global synthesis of living species of the Notorotaliidae.
We recognize 11 species of the southern hemisphere genus Notorotalia, which has a centre of diversity around New Zealand (8
species). A second southern-hemisphere-restricted genus, restricted to eastern Australia is Parrellina (3 species) although specimens
(possibly introduced) have been recorded from the Mediterranean Sea. Cristatavultus has a single species, with a tropical west Pacific
distribution.We synonymize Cribrorotalia under Porosorotalia, which has a disjunct distribution with one species in the northwest Pacific
and a second around the southern parts of South America. Buccella is the most diverse and widespread genus (16 species recognized)
with its greatest abundance in the Arctic Ocean and around subantarctic-temperate South America. Five species of Buccella live
in a belt along the west coast of central America, from USAto Peru, with some spillage into the Caribbean Sea and Gulf of Mexico. Two
new species of Buccella are recognized: B. dejardini (from South Georgia) and Buccella n. sp. A (from Chile)
Xenophyophores (Rhizaria, Foraminifera), including four new species and two new genera, from the western Clarion-Clipperton Zone (abyssal equatorial Pacific)
The Clarion-Clipperton Zone (CCZ) occupies a vast swathe of the Pacific with extensive polymetallic nodule deposits. Eastern and central parts host diverse assemblages of xenophyophores (megafaunal agglutinated foraminifera). Here we describe xenophyophores obtained using a Remotely Operated Vehicle from the western CCZ. Eleven distinct forms include two known species, Stannophyllum zonarium Haeckel, 1888 and Aschemonella monile Gooday and Holzmann in Gooday et al., 2017b. Another four are described as new species based on morphological and genetic data. In Abyssalia foliformis gen. nov., sp. nov. and Abyssalia sphaerica sp. nov. the flattened or spherical test comprises a homogeneous framework of sponge spicules. Psammina tenuis sp. nov. has a delicate, thin, plate-like test. Moanammina semicircularis gen. nov., sp. nov. has a stalked, fan-shaped test and is genetically identical to ‘Galatheammina sp. 6’ of Gooday and co-workers from the eastern CCZ. Sequence data revealed a spherical ‘mudball’, which disintegrated and cannot be formally described, to be a novel xenophyophore. Finally, four morphospecies are represented by dead tests: Psammina spp., Reticulammina sp., and an unknown genus with a unique test structure. This collection enhances our knowledge of Pacific xenophyophore diversity and provides the first genetic confirmation of wide geographic ranges for abyssal species
Giant protists (xenophyophores, Foraminifera) are exceptionally diverse in parts of the abyssal eastern Pacific licensed for polymetallic nodule exploration
Xenophyophores, giant, fragile, agglutinated foraminifera (protists), are major constituents of the abyssal megafauna in the equatorial Pacific Clarion-Clipperton Zone (CCZ), a region where seabed mining of polymetallic nodules may occur in the future. As part of a baseline study of benthic communities we made extensive collections of xenophyophores in two areas (UK-1 and OMS) licensed for exploration by the International Seabed Authority. Based on test morphology, we distinguished 36 morphospecies (34 new to science) among 130 specimens. Twenty of these morphospecies yielded 184 DNA sequences, a 14-fold increase in genetic data for xenophyophores that confirms their high diversity in the eastern CCZ. A further 15 morphospecies (8 new to science) were recognised in samples from two other areas (APEI-6 and Russian exploration license area) within or adjacent to the CCZ. This large number of species confirms that the CCZ is a focal area for xenophyophore diversity. More broadly, it represents an unprecedented increase in the known global diversity of xenophyophores and suggests that many species remain undiscovered in the World's oceans. Xenophyophores are often sessile on nodules in the CCZ, making these delicate organisms particularly vulnerable to mining impacts. They can also play a crucial role in deep-sea ecosystems, providing habitat structures for meiofaunal and macrofaunal organisms and enhancing the organic content of sediments surrounding their tests. The loss of xenophyophores due to seabed mining may therefore have wider implications for the recovery of benthic communities following major human disturbances on the abyssal seafloor
Five new species and two new genera of xenophyophores (Foraminifera: Rhizaria) from part of the abyssal equatorial Pacific licensed for polymetallic nodule exploration
Based on a combination of morphological and molecular data, we describe five new species and two new genera of xenophyophores from the Clarion–Clipperton Zone (abyssal eastern Pacific), an area with commercially valuable seafloor deposits of polymetallic nodules. Bizarria bryiformis gen. et sp. nov. displays unusual features, notably an organic-walled test, largely devoid of agglutinated particles, comprising interconnected branches growing upwards from the nodule substrate; the bases of the branches contain dark masses of waste material (stercomare) and pale strands of cytoplasm (granellare), the whitish, tuft-like extremities contain sediment particles. Tendalia reteformis gen. et sp. nov. forms a delicate network of agglutinated tubes. Shinkaiya contorta sp. nov. is characterized by a contorted, partly reticulated plate-like test while the simpler plate-like test of Galatheammina interstincta sp. nov. combines characters typical of Galatheammina and Psammina. In Semipsammina mattaeformis sp. nov., a thin, delicate test with one or more tubular extensions forms a flat canopy over the mat-like stercomare encrusting the nodule substrate. Tendalia reteformis and S. contorta are free-living; the other species are sessile on nodules. Together, they illustrate the considerable morphological diversity of xenophyophores in a region where they dominate the megafauna, and highlight some major taxonomic challenges posed by these giant monothalamous foraminifera
Molecular and morphological diversity of monothalamous foraminifera from South Georgia and the Falkland Islands: Description of four new species
Based on molecular and morphological data, we describe three new genera and four new species of monothalamids from the sublittoral zone (21–250 m) in South Georgia fjords that belong to different monothalamid clades. Limaxia alba gen. nov. sp. nov. (Clade A) has an elongate, subcylindrical test, 359–688 µm long, with some detritus attached to the organic wall. Hilla argentea gen. nov. sp. nov. (Clade Y) has a cylindrical, finely agglutinated test, 535–755 µm long. Pseudoconqueria lenticularis gen. nov. sp. nov. branches separately. It has a spindle-shaped, finely agglutinated test, 280–574 µm long. Bathyallogromia olivacea sp. nov. (Clade C) has an ovate organic-walled test, 369–433 µm long. We present the first genetic data on two monothalamid species originally described from South Georgia, Hippocrepinella alba (Clade C) and Hippocrepinella hirudinea (Clade D), as well as a single sequence for C. delacai (Clade J) originally described from McMurdo Sound, Antarctica. In addition, we report nine undescribed species branching in six different monothalamid clades (A, B, BM, C, J, Y), eight of them sampled around South Georgia and one collected from the Falkland Islands near Stanley
Giant protists (xenophyophores, Foraminifera) are exceptionally diverse in parts of the abyssal eastern Pacific licensed for polymetallic nodule exploration
Giant protists (xenophyophores, Foraminifera) are exceptionally diverse in parts of the abyssal eastern Pacific licensed for polymetallic nodule exploratio
Estrategias de abordaje virtual y presencial entre extensionistas e investigadores para aportar soluciones al fruticultor, en el marco de la pandemia COVID 19
En octubre 2020 un fruticultor contactó al INTA porque tenía mortandad de ramas y plantas posiblemente debidas a inconvenientes de riego y drenaje, destacando que hacía tiempo seguía nuestros trabajos en la web y redes sociales. Dada la ASPO decretada por covid-19, en forma virtual se recabó la información necesaria para el diagnóstico predial, con georreferenciación, RENSPA, mapas de suelos, redes de riego y drenaje, imágenes satelitales, mensajes, audios y fotos, utilizando Whatsapp y plataformas como Zoom, Meet, etc. Se realizó un abordaje interdisciplinario entre extensionistas e investigadores de la EEA A.V. sosteniendo un contacto virtual fluido con el fruticultor. Con la información recabada, entre especialistas y extensionistas, se delineó un plan de manejo fitosanitario, fertilización y mejoras de infraestructura de riego y drenaje. En el mismo mes una extensionista realizó la primera visita a campo, que resultó clave para definir la estrategia de intervención sumada al intercambio presencial. Luego en modo virtual se avanzó entre los técnicos y elaboró un informe con propuestas de mejoras. Durante el retorno a la presencialidad parcial, en agosto 2021 se realizó una visita a campo, donde se observó el nuevo desagüe interno y el desmonte del cuadro problemático, acciones basadas en las recomendaciones de INTA. Frente a un nuevo evento de lluvias torrenciales en la temporada de cosecha del verano 2022, el fruticultor reconoció su conformidad con las tareas realizadas, dado que notó recuperación del cuadro y que no hubo avance en la mortandad de plantas. Podemos concluir que si el abordaje se realiza en forma interdisciplinaria, independientemente sea virtual o presencial, sostiene los lazos de confianza para que el fruticultor implemente cambios y mejoras. La visita a campo fue determinante y fundamental para la cristalización de la propuesta. La convicción de éste para realizar gran parte de la implementación se basó en esta interacción permanente.EEA Alto ValleFil: Aguilar, Neuquén Lautaro. Instituto Nacional Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle. Agencia de Extensión Rural General Roca; ArgentinaFil: Di Masi, Susana Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Holzmann, Rosa de Lima. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Urraza, María Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle. Agencia de Extensión Rural Cipolletti; Argentin
Caracterização fenotípica de suínos crioulos da região Centro-Sul do Paraná, Brasil
This research aimed to phenotypically characterize 55 pigs from traditional communities, called Faxinal With each pig, 24 variables were measured: 8 qualitative morphological, 16 quantitative / zoometric and 5 zoometric indices were determined. According to the frequency tables of the qualitative variables, it was observed that most pigs showed similarities to the morphological patterns observed in the Brazilian breeds Moura, Piau and Canastra. For the data of the zoometric variables and the zoometric indices, descriptive statistical analysis and variance analysis were applied using two different sources of variation: sex and Faxinal. There was a great morphological variability of the studied creole pigs, with the highest values of the variation coefficients observed for croup length and width, live weight and snout length. According to the averages obtained, the pigs were classified as elliptical, mesocephalic, longilinous, concavilinous. Significant differences between Faxinal were observed for croup width, body length, snout and croup, croup height and interorbital distance and cephalic, facial and pelvic indices. Significant differences between sexes were observed for withers height, snout length, shin girth and interorbital distance. There was significant between Faxinal *sex interaction for some zoometric variables, but not for the indexes. For body measurements, the correlations were high and significant, with the thoracic perimeter, abdominal perimeter and body length being the characteristics that best correlated with live weight. Cranial measurements (lengths of snout, ear and head and interorbital distance) were moderate to low. To infer the population structure, a statistical model was applied based on a bayesian approach according to the Structure Harvest software. It was possible to identify three phenotypic groupings, corroborating the results of qualitative variables. Genetic characterization studies should be carried out in these populations to serve as a basis for defining strategic actions for conservation and sustainable use of these genetic resources.Para caracterizar fenotípicamente a 55 cerdos de las comunidades tradicionales Faxinal, se midieron 24 variables: 8 morfológicas cualitativas, 16 cuantitativas / zoométricas y se determinaron 5 índices zoométricos. En la mayoría de los cerdos mostraron similitudes con los patrones morfológicos observados en las razas brasileñas Moura, Piau y Canastra. Para los datos de las variables zoométricas y los índices zoométricos se aplicó análisis descriptivo y estadístico de varianza. Hubo gran variabilidad morfológica de los cerdos criollos estudiados, observándose los valores más altos de los coeficientes de variación para largo y ancho de rabadilla, peso vivo y largo de hocico. De los promedios obtenidos, los cerdos se clasificaron en elipométricos, mesocefálicos, alargados, concavilinos. Se observaron diferencias significativas entre Faxinal para el ancho de la rabadilla, la longitud del cuerpo, el hocico y la rabadilla, la altura de la rabadilla y la distancia interorbital, y para los índices cefálico, facial y pélvico. Se observaron diferencias significativas entre sexos para la altura a la cruz, la longitud del hocico, el perímetro de la espinilla y la distancia interorbital. Hubo una interacción significativa del sexo Faxinal * para algunas variables zoométricas. Para las medidas corporales, las correlaciones fueron altas y significativas, siendo el perímetro torácico, el perímetro abdominal y la longitud corporal los que mejor se correlacionaron con el peso vivo. Las medidas craneales (longitud del hocico, oreja y cabeza y distancia interorbital) fueron de moderadas a bajas. Para inferir la estructura de la población se aplicó un modelo estadístico basado en un enfoque bayesiano según el software Structure Harvester. Fue posible identificar tres grupos fenotípicos, corroborando los resultados de las variables cualitativas. Se deben realizar estudios de caracterización genética en estas poblaciones que sirvan de base para definir acciones estratégicas para programas de conservación y uso sostenible de estos recursos genéticos.Esta pesquisa teve como objetivo caracterizar fenotipicamente 55 suínos provenientes de comunidades tradicionais, chamadas de Faxinal. Em cada suíno foram mensuradas 24 variáveis: 8 morfológicas qualitativas, 16 quantitativa / zoométrica e determinado 5 índices zoométricos. De acordo com as tabelas de frequência das variáveis qualitativas, observou-se que a maioria dos suínos apresentaram semelhanças aos padrões morfológicos observados nas raças brasileiras Moura, Piau e Canastra. Para os dados das variáveis zoométricas e os índices zoométricos foram aplicados a análise estatística descritiva e a de variância. Verificou-se grande variabilidade morfológica dos suínos crioulos estudados, sendo os maiores valores dos coeficientes de variação observados para comprimento e largura da garupa, peso vivo e comprimento de focinho. Através das médias obtidas os suínos foram classificados como elipométricos, mesocefálicos, longilíneos, concavilíneos. Foram observadas diferenças significativas entre Faxinal para largura de garupa, comprimento do corpo, focinho e garupa, altura da garupa e distância interorbital, e dos índices cefálico, facial e pélvico. As diferenças significativas entre sexo foram observadas para altura da cernelha, comprimento do focinho, perímetro da canela e distância interorbital. Verificou-se interação significativa de Faxinal*sexo para algumas variáveis zoométricas. Para as medidas corporais as correlações foram altas e significativas, sendo o perímetro torácico, o perímetro abdominal e o comprimento do corpo as que melhor se correlacionaram com o peso vivo. Já as medidas cranianas (comprimento do focinho, orelha e cabeça e a distância interorbital) foram de moderadas a baixas. Para inferir a estrutura populacional foi aplicado um modelo estatístico baseado em uma abordagem bayesiana de acordo com o software Structure Harvester. Foi possível identificar três agrupamentos fenotípicos, corroborando com os resultados das variáveis qualitativas. Estudos de caracterização genética deverão ser realizados nestas populações para que sirvam de base na definição de ações estratégicas para programas de conservação e uso sustentável desses recursos genéticos
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