Diversidad de poliplacoforos tropicales del sur de la Provincia Panamena

Abstract

RESUMEN.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. Palabras clave: Polyplacophora, moluscos, diversidad, Ecuador, Perú. Tropical polyplacophoran diversity from south of the Panamian ProvinceABSTRACT. For the first time a comprehensive record on the diversity of polyplacophorans in the south of the Province of Panama (Ecuador-Peru), corresponding to the Guayaquil ecoregion, was made. Chitons were collected from five locations and their diversity and the similarity of the assemblies were estimated. During winter 2013 and summer 2013-2014 a total of 539 chitons belonging to 11 species were collected. The diversity decreases from north to south due to a strong replacement of species and to the local dominance of some taxa. The ordination analysis suggests two faunal groups, one composed of the locations of Montañita and Santa Rosa form Ecuador, and Bonanza from Peru, while the second is composed of the Peruvian locations of Pocitas and Lobitos. The species that contribute most to the differentiation are Ischnochiton dispar, Acanthopleura echinata and Acanthochitona ferreirai. Polyplacophorans diversity at this part of Province of Panama is poor compared to the greatest number of species reported in Chile, Mexico and Puerto Rico. It is suggested that the type of habitat and environmental food supply would be key in explaining differences in diversity.

Latitudinal distribution of polyplacophorans along the South-eastern Pacific coast: unravelling biases in geographical diversity patterns

“…As evidenced here, nearby localities tended to have similar species, with the exception of the high turnover across the biogeographical break between the Panamian and Peruvian provinces (Guayaquil-Central Peru ecoregions) where species composition varied significantly as the distance between localities increased. The same pattern has been observed by Ibáñez et al (2016) and by Fenberg and Rivadeneira (2019) suggesting that the type of habitat and environmental influence would be key in explaining differences in composition and diversity. Along the Peruvian and Chilean ecoregions, species replacement did not show a latitudinal pattern since few chitons had small geographical ranges, and the dissimilarity between close localities remained low through the latitudinal gradient with a moderate increment in the Araucanian ecoregion.…”

“…A thorough examination of the literature indicates that inaccuracies in distribution ranges and species richness estimates are mainly due to uneven sampling efforts along the SEP coast. For instance, so far there is only one study describing the composition of polyplacophorans in both the Guayaquil (Ibáñez et al 2016) and Central Peru (Uribe 2013) ecoregions. Conversely, the sampling effort in the Chiloense and the Channels and Fjords ecoregions has been high (Reid and Osorio 2000;Aldea and Valdovinos 2005;Schwabe et al 2006;Sirenko 2006;Rosenfeld et al 2015), although taxonomic inconsistencies in these regions are still frequent.…”

“…The first dataset was obtained from a literature review (LIT) compiled from published studies of the SEP region. All chiton species records included in this study are available in Kaas and Van Belle (1987), Bullock (1988a, b), Valdovinos (1999), Sirenko (2006), Kaas et al (2006), Schwabe et al (2006), Schwabe (2009) and Ibáñez et al (2016). Our second dataset included identifications using morphological species (MS) aided with genetic data (determining Operational Taxonomic Units, OTUs).…”

First comparative assessment of the reproductive cycle of three species of Chiton on a temperate rocky shore of the southeastern Pacific

“…Along the southeastern Pacific (SEP) coast, chitons are also common, and several species exhibit broad geographic distributions, occurring in numerous ecoregions and in more than one biogeographical province (Ibáñez et al, 2019). Only recently have chitons been subject to more detailed studies, which have focused mainly on their cytogenetics (Northland-Leppe et al, 2010), ecology (e.g., Aguilera & Navarrete, 2007Camus et al, 2008Camus et al, , 2012Ibáñez et al, 2016;Ibáñez et al, 2019;Sanhueza et al, 2008), taxonomic records (Araya & Araya, 2015;Sanhueza & Ibáñez, 2016;Tobar-Villa & Ibáñez, 2013), or morphometric and allometric variations (Ibáñez et al, 2018;Torres et al, 2018). Despite these recent advances, the reproductive cycles of most species remain unknown or poorly understood.…”