Drivers of Cape Verde archipelagic endemism in keyhole limpets

Oceanic archipelagos are the ideal setting for investigating processes that shape species assemblages. Focusing on keyhole limpets, genera Fissurella and Diodora from Cape Verde Islands, we used an integrative approach combining molecular phylogenetics with ocean transport simulations to infer species distribution patterns and analyse connectivity. Dispersal simulations, using pelagic larval duration and ocean currents as proxies, showed a reduced level of connectivity despite short distances between some of the islands. It is suggested that dispersal and persistence driven by patterns of oceanic circulation favouring self-recruitment played a primary role in explaining contemporary species distributions. Mitochondrial and nuclear data revealed the existence of eight Cape Verde endemic lineages, seven within Fissurella, distributed across the archipelago, and one within Diodora restricted to Boavista. The estimated origins for endemic Fissurella and Diodora were 10.2 and 6.7 MY, respectively. Between 9.5 and 4.5 MY, an intense period of volcanism in Boavista might have affected Diodora, preventing its diversification. Having originated earlier, Fissurella might have had more opportunities to disperse to other islands and speciate before those events. Bayesian analyses showed increased diversification rates in Fissurella possibly promoted by low sea levels during Plio-Pleistocene, which further explain differences in species richness between both genera.FCT - Portuguese Science Foundation [SFRH/BPD/109685/2015, SFRH/BPD/111003/2015]; Norte Portugal Regional Operational Program (NORTE), under the PORTUGAL Partnership Agreement, through the European Regional Development Fund (ERDF) [MARINFO - NORTE-01-0145-FEDER-000031]info:eu-repo/semantics/publishedVersio

Compatibilidad anatómica de Jatropha curcas (L.) injertada en portainjerto de Jatropha cinerea (Ortega) Muell.Arg

El Algoritmo de Recocido Simulado, cristalización simulada o enfriamiento simulado, es un algoritmo de búsqueda metaheurística para problemas de optimización; el objetivo general de este tipo de algoritmos es encontrar una buena aproximación al valor óptimo de una función en un espacio de búsqueda grande. A este valor se lo denomina "óptimo local u óptimo global". El nombre e inspiración viene del proceso de recocido del acero y cerámicas, una técnica que consiste en calentar y luego enfriar lentamente el material para variar sus propiedades físicas. El calor causa que los átomos aumenten su energía y que puedan así desplazarse de sus posiciones iniciales (un mínimo local de energía); el enfriamiento lento les da mayores probabilidades de recristalizar en configuraciones con menor energía que la inicial (mínimo global). El método fue descrito independientemente por Scott Kirkpatrick, C. Daniel Gelatt y Mario P. Vecchi en 198

Compatibilidad anatómica de Jatropha curcas (L.) injertada en portainjerto de Jatropha cinerea (Ortega) Muell.Arg

Graft compatibility of Jatropha curcas on Jatropha cinerea was confirmed by obtaining a high survival (95%) of the total grafted plants. Their regeneration and development was accomplished by histological assays observing compatibility of the vessel tissues. At anatomical level, both species had the same cell types (parenchyma in the external cortex, specific cells forming phloem tissues, vascular and xylem cambium) completely differentiated at the moment of grafting. When comparing different tissues, the parenchyma cells of J. curcas had fewer amounts of starch grains than those of J. cinerea. Another anatomical difference was vascular cambium amplitude, which was greater in J. cinerea than in J. curcas. The results of the histological cuts in the grafted stems showed integration of J. curcas tissue with J. cinerea stock when they developed as one plant only.Se evaluó la compatibilidad de injertos de Jatropha curcas sobre portainjertos de Jatropha cinerea comprobando la compatibilidad de los injertos entre ambas especies con un 95% de supervivencia del total de plantas injertadas y observando la compatibilidad de los tejidos vasculares, su regeneración y desarrollo mediante pruebas histológicas. A nivel anatómico, ambas especies tuvieron los mismos tipos celulares (parénquima en la corteza externa los tipos celulares específicos que forman los tejidos en el floema, cambium vascular y xilema) completamente diferenciados al momento de ser injertadas. Al comparar los diferentes tejidos, las células de parénquima de J. curcas tuvieron menor cantidad de granos de almidón que las de J. cinerea. Otra diferencia anatómica fue la amplitud del cambium vascular en la que J. cinerea presentó mayor área que J. curcas. Los resultados en los cortes histológicos realizados a los tallos injertados mostraron la integración del tejido de J. curcas con el portainjertos de J. cinerea al desarrollarse como una sola planta

A model to explain the formation of catarina scallop (Argopecten circularis) beds, in Magdalena Bay, Mexico

During the years of 1989 and 1990, the yield of the commercial fishery for the catarina scallop, Argopecten circularis (Sowerby, 1835), in Magdalena Bay, was 750 million organisms (5186t of muscles), which were gathered by diving at 12–30m depth. This production is the largest registered to date and accounted for 53% of the total Mexican scallop production since 1981. The formation of large beds in that area is a sporadic phenomenon which needs to be studied. In the present paper, a model to explain the formation of such beds is drawn, in which the bentho-pelagic red crab, Pleuroncodes planipes (Stimpson, 1860), plays a role as primary substrate for the recruitment of the spat and simultaneously is the active transporter of juveniles into the Bay during the winter months of cold years. Apparently exploitable beds are formed only when temperatures of 16°C or lower, are registered deep inside the Bay for at least 2 months. Relating these findings with short and long-term temperature fluctuations, it seems possible to predict future exploitable stocks in the area