The study, published in the journal ‘PNAS’, has been outlined in the latest issue of Science. The research was led by the CSIC researcher Isabel Sanmartin, who works at the Royal Botanical Garden (CSIC) in Madrid, in collaboration with Alexander Anton Elli, University of Gothenburg (Sweden),. Sanmartín clarifies the reasons that prompted the work: “The Neotropical region, covering South America, includes the largest tropical rain forest on the planet. For example, one third of all flowering plants are in the region, testifies to its importance as a biodiversity reserve. However, we still do not know exactly what were the processes responsible for such extraordinary diversity. ” Traditionally, the scientific community has blamed the rich neotropical ecological factors, such as a higher rate of light, temperature and humidity. “The environmental scenarios do not address the possibility that current environmental conditions are the same that were given millions of years ago and also assumes that not all species react to such conditions as the environment. Therefore, in recent years, there have been more inclusive hypotheses that attempt to explain the wealth of the region in historical or evolutionary terms, “says the researcher. These theories, explains Sanmartin, aimed at first to the Amazon River as a catalyst for the region and, in recent years have begun to recognize the influence of the Andes, although as a single event focused exclusively on diversification high mountain plants. The hypothesis Samaritan and his companions defend claims a role for the mountain. Their conclusions were based on the evolutionary study of the plant family Rubiaceae, from which the coffee plant, widespread in the region. The authors analyzed DNA sequences of plants, combining the results with geological evidence, pale ontological or weather by using a new method of biogeographical analysis. Data from the research suggest that the Rubiaceae migrated from Laurasia (Europe, North America and Asia) to South America in the mid-Tertiary, about 40 million years. To do this they used the uprising of the Northern Andes. There, these plants would remain until the Miocene, about 23 million years. New evidence Also, the study provides new evidence about the existence, in prehistoric times, of two geographic whose presence in the area is disputed by geologists and pale geographers. They are the West Portal of the Andes, a geographic barrier to the height of southern Ecuador, and Lake Pebas, a large lake system with an area of around a million square kilometers located in the western Amazon basin. The fact that the Rubiaceae not disperse southward from the Andes to the Miocene seem to support the existence of the doorway, a lowland region between the Northern Andes and Central Andes that was often invaded by the waters of the Pacific . Confirmed its existence, the portal would have prevented the passage of animals and plants between the two sectors of the range until the middle Miocene, there was the lifting of the Cordillera Oriental of the Andes, a phenomenon that opened the way species mountains to the south. Samaritan explains the close of the Miocene Andean portal coincided with the formation in the western half of the Amazon basin (between the current Peru, Colombia and Brazil) Pebas Lake. The isolation of both the portal and the lake explained, according to the study, two areas currently two points coincide with one of the highest rates of accumulation of plants and animals native to South America, Huancabamba region, south of Ecuador and the western Amazon basin.
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