Viaje a las profundidades del Océano (VIDEO) + Extrañas criaturas marinas (FOTOS)

  Pero, ¿qué es un Océano? U n océano es una enorme masa de agua salada que representa un importante ecosistema para el equilibrio ecológico de la Tierra y que constituye el  71% de la superficie terrestre , gracias a los 360,132,000 km² de su extensión. Y,  ¿cuántos océanos existen? Lo que cubre gran parte de la superficie de la Tierra, es en sí, un solo océano. Es decir, una sola masa de agua. Para un mejor estudio, el hombre dividió esta enorme masa en 5 partes de acuerdo a su ubicación geográfica. Por ello, la expresión “los océanos”, es correcta. Importancia de los océanos *Absorben entre un 25 y 30% del dióxido de carbono emitido a la atmósfera, por lo que Equilibran el clima de toda la Tierra. *Representan numerosos ecosistemas para diversas formas de vida animal, vegetal, bacteriana, protista y fúngica. *Son hogar para miles de especies, conocidas y aún desconocidas. Existen aproximadamente 250,000 especies conocidas, pero se cree que puedan haber 750,000 más. *Proveen fuentes

New to nature No 99: Phagocata flamenca

English article
This Andalucian flatworm, with its flamenco ruffles, is among six new species discovered on the Iberian peninsula

Phagocata flamenca: its billowing sides called to mind a flamenco dancer’s dress. (Photograph)

Planarians are freshwater flatworms of the order Tricladida, scavengers and predators on other invertebrates, hermaphroditic, and capable of both sexual and asexual reproduction. They are distinguished from other flatworms by their trifurcate digestive tract and ovaries positioned in front of the brain.

Familiar laboratory animals noted for their regenerative properties, they can be cut in half transversely with both head and tail halves developing into new whole worms, or split at the front to induce the development of two complete heads. Geneticists have recently identified key genes responsible for regeneration of the intestines with the hope of new insights into possible internal organ regeneration. And planarians caused quite a sensation in the 1960s when those conditioned to flashes of light and a simple maze retained the "memory" in regenerated worms and passed memory to other worms when eaten. While planarians remain fascinating laboratory subjects, much remains to be learned about their diversity in the wild.

A newly discovered species, Phagocata flamenca, is a case in point. It was found in large numbers in Granada, Spain, in the well of an artificial spring fed by irrigation channels. The species is unusual, immediately recognisable, and memorably named. Its undulating lateral margins are approached only in one other freshwater planarian, Phagocata undulata from Lake Ohrid on the border of Macedonia and Albania. The latter species shares the wave-like folds along the margin but also has a bordering row of short, cone-shaped papillae absent in the new species.

The species was described by Dr Miquel Vila Farré of the Universitat de Barcelona in collaboration with three colleagues from the University of Amsterdam, the European Molecular Biology Laboratory in Heidelberg, and the Museo Nacional de Ciencias Naturales in Madrid. The team conducted the most extensive inventory of freshwater planarians in the Iberian peninsula to date, describing six new species from Spain and assessing the status and distributions of five others. Their study reinforced the established view that lake species common elsewhere in Europe are indeed rare in Spain, adding periodic flooding and drought to previously offered explanations for their absence. Their work casts doubt on earlier records of three lake species in Spain and Portugal that were identified by external morphology alone and did not show up in new sampling. They did reveal the presence of a surprisingly diverse planarian stream fauna in the peninsula. In addition, their paper names two new species from Greece where the planarian fauna is similarly poorly studied.

Source: The Guardian


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