Examinando por Autor "Sellanes, Javier"

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    Diversidad de poliplacóforos tropicales del sur de la Provincia Panameña
    (UNIVERSIDAD CATOLICA DE VALPARAISO, 2016-09) Ibáñez, Christian; Sellanes, Javier; Pardo-Gandarillas, M. Cecilia
    Por primera vez se hace un catastro exhaustivo sobre la diversidad de poliplacóforos en la zona sur de la Provincia Panameña (Ecuador-Perú), correspondiente a la ecorregión de Guayaquil. Se recolectaron quitones de cinco localidades y se estimó su diversidad y similitud de los ensambles. Durante invierno de 2013 y verano 2013-2014 se recolectó un total de 539 quitones pertenecientes a 11 especies. La diversidad disminuyó de norte a sur debido a un fuerte recambio de especies y la dominancia local de algunos taxa. El análisis de ordenación sugiere dos grupos faunísticos, uno compuesto por las localidades de Montañita y Santa Rosa en Ecuador, y Bonanza en Perú, y otro compuesto por las localidades peruanas de Pocitas y Lobitos. Las especies que más contribuyen a la diferenciación son Ischnochiton dispar, Acanthopleura echinata y Acanthochitona ferreirai. La diversidad de poliplacóforos en esta parte de la Provincia Panameña es pobre comparada con el mayor número de especies reportadas en Chile, México y Puerto Rico. Se sugiere que el tipo de hábitat y la oferta ambiental de alimento serían factores importantes en las diferencias en diversidad.
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    Environmental and ecological factors mediate taxonomic composition and body size of polyplacophoran assemblages along the Peruvian Province
    (Nature Publishing Group, 2019-12) Ibáñez, Christian M.; Waldisperg, Melany; Torres, Felipe I.; Carrasco, Sergio A.; Sellanes, Javier; Pardo-Gandarillas, M. Cecilia; Sigwart, Julia D.
    Intertidal communities’ composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S–39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages. © 2019, The Author(s).
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    Ítem
    The island rule and the body size of the polyplacophoran Plaxiphora mercatoris in Rapa Nui
    (Universidad De Valparaíso, Chile, 2022-12-25) Cornejo, Claudio F.; Vargas, Tomás; Curaz, Stephanny; Sellanes, Javier; Ibáñez, Christian M.
    To test the island rule, the body size of P. mercatoris and P. aurata was measured, then statistical test and generalized linear models (GLM) were performed to explore changes in body length of both species. A smaller body length was evidenced in P. mercatoris supporting insular dwarfism. Additionally, P. mercatoris showed a trend of decreasing body size over time. This is the first report of the island rule in polyplacophorans. The temporal decrease in the size of P. mercatoris suggests a possible increase anthropogenic pressure, which should be studied to facilitate conservation and monitoring strategies. ©The author(s).