Species richness and biogeographical affinities of the marine molluscs from Bahía de Chamela, Mexico

Abstract

For more than 10 years (2007-2018), the benthic macroinvertebrates of Bahía de Chamela (Mexican Pacific) were sampled at 31 sites (0-25 m depth). A total of 308 species of the five main classes of benthic molluscs were obtained (106 bivalves, 185 gastropods, 13 polyplacophorans, two scaphopods and two cephalopods). This is a significant increase in the number of species (246 new records) compared to the 62 species previously recorded more than 10 years ago. The distribution in the 31 localities of the bay is given for the first time for most of the species, together with information on its ecological rarity (incidence in the samples). Two families of bivalves (Veneridae and Mytilidae) and three families of gastropods (Calyptraeidae, Muricidae and Collumbellidae) comprised ~ 30% of all species. Ecological rarity was evident with 45 families (45.0%) with only one species and 178 species (57.8%) collected in one site and 67 (21.8%) in two sites. The molluscs of Bahía de Chamela represent 12.2% of all species recorded in the Mexican Pacific. Their biogeographic affinities are mostly related to the Tropical Eastern Pacific (TEP) including the oceanic islands and a few are restricted to the Tropical Mexican Pacific (TMP). Some have broader distributions to adjacent northern and southern temperate regions of the American Pacific, one to the western Atlantic, two pantropical (PAN) and two cosmopolitans (COS). The range distribution of each species was reviewed and updated, thus finding that seven species have extended their ranges of geographic distribution.

Equinodermos de la colección biológica del Laboratorio de Ecología Molecular, Microbiología y Taxonomía (LEMITAX) de la Universidad de Guadalajara, México

“…En cuanto a los registros nuevos para Bahía de Chamela, destaca el numeroso aporte de holoturoideos (nueve), lo que equivale a un aumento del 45.0 % a la riqueza previa reportada para esta clase (Ríos-Jara et al, 2013;Solís-Marín et al, 2018). La notoria cantidad de registros nuevos de holoturoideos se puede atribuir al mayor esfuerzo de muestreo realizado en esta localidad asociado a proyectos enfocados en la generación de inventarios de la biodiversidad de los macroinvertebrados bentónicos de Bahía de Chamela por aproximadamente 10 años (2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018), así como a los diferentes métodos de muestreo aplicados, ya que se realizaron recolectas manuales con buceo libre y SCUBA, con búsquedas debajo de rocas, además de efectuar arrastres de fondo sobre sustratos arenosos (E. Ríos-Jara, comunicación personal, 2023;Ríos-Jara et al, 2020). Por otro lado, aunque no corresponde a un registro nuevo, es preciso señalar que la colección incluye paratipos del pepino de mar L. imbricata, especie descrita con base en ejemplares recolectados en Bahía de Chamela, y que, hasta el momento, únicamente ha sido registrada en esta ANP (Solís-Marín et al, 2018).…”

Assessing evolutionary history and species boundaries in a polymorphic tropical lizard, the Aspidoscelis lineattissimus species complex (Squamata, Teiidae)

“…Based on the biotic provinces of Mexico (Ferrusquía‐Villafranca, 1990), a regionalization that is based on biotic and topographic characteristics, sampling localities were grouped into four discrete areas according to the distinct provinces and sub‐provinces recognized throughout the distributional range of Aspidoscelis lineattissimus (Figure 1): (A) the Balsas River basin, which comprises the lowlands between the Trans‐Mexican Volcanic Belt and Sierra Madre del Sur, the lower‐lying parts of which are located at 300 m above sea level (masl); (B) the Southwestern Coastal Plain, which is characterized by a discontinuous narrow plain, in which mountainous areas and cliffs with prominent slopes predominate; (C) Cocinas Island, an island in Chamela Bay (Hernández‐Salinas et al, 2014; Miranda et al, 2011; Ríos‐Jara et al, 2020) that, due to its disjunct location in relation to the Southwestern Coastal Plain, was considered as a discrete area; and (D) the Northern Coastal Plain province that extends north of the intrusion of the Trans‐Mexican Volcanic Belt to the mouth of the Colorado River (Figure 1).…”