Shell variations in the gastropod,Monodonta labio, in the North-western Pacific: the important role of temperature in the evolution process

Abstract

Molluscan shells showing phenotypic variations are ideal models for studying evolution and plasticity. In north-eastern Asia, genetic and morphological diversity of the gastropod, Monodonta labio, were assumed to be influenced by both palaeoclimatic changes and current ecological factors. In this study, we examined spatial variations in shell shape of M. labio using general measurement and geometric morphometric analysis. We also investigated whether shell shape variation is best explained by environmental gradients or by genetic structuring, based on our prior molecular phylogeographic study. Two common morphological forms were observed among Chinese populations and in the adjacent Asian areas. Both the analyses revealed separation patterns in morphological variations of shell shape among the clades and populations. Environmental modelling analysis showed a significant correlation between shape variations and local maximum temperatures of the warmest month, indicating the role of natural selection in the evolution of this species. Data obtained in this study, combined with the cytochrome oxidase subunit I (COI) molecular phylogenetic data from the prior study, showed that morphological variations in M. labio were constrained by both local adaptation and phenotypic plasticity. We hypothesized that geographic separation by the Dongshan Landbridge was the first step towards its diversification, and that the temperature gradient between the East China Sea and South China Sea probably was the selective force driving the divergence of its morphological variations.

Application of Shape Analyses to Recording Structures of Marine Organisms for Stock Discrimination and Taxonomic Purposes

“…The GM-based methods are widely applied to investigate variation in the shape of gastropod shells. The main fields of application include the study of intraspecific variability (Vuolo et al, 2011;Madeira et al, 2012;Moneva et al, 2012b;Sepúlveda and Ibáñez, 2012;Vogler et al, 2012;Avaca et al, 2013;Camama et al, 2014;Jamasali et al, 2014;Sobrepeña and Demayo, 2014;Cazenave and Zanatta, 2016;Zhao et al, 2019;Tuset et al, 2020) and assessment of environmental impacts (Sepúlveda and Ibáñez, 2012;Vogler et al, 2012;Vasallo et al, 2013;Camama et al, 2014;Cazenave and Zanatta, 2016;Amini-Yekta et al, 2019;Zhao et al, 2019), including the effect of pollution (Márquez et al, 2011;Abdelhady, 2016;Primost et al, 2016). Nevertheless, GM was also used for identification of mollusks (Doyle et al, 2018), evaluation of interspecific variability (Dommergues et al, 2003;Carvajal-Rodríguez et al, 2005;Vuolo et al, 2011;Cruz et al, 2012;Vogler et al, 2012;Silos et al, 2014;Becker et al, 2016;Miller, 2016), ontogenetic and individual variation (Moneva et al, 2012a;Avaca et al, 2013;Sobrepeña and Demayo, 2014), and to characterize phylogenetic relationships (Smith and Hendricks, 2013;…”

“…Despite the fact that landmarkbased GM has been used in studies of gastropod mollusks for about 30 years (Johnston et al, 1991), this method truly flourished only during the last decade, when the development of imaging technologies improved the quality and resolution of digital images, allowing for a sufficient number of landmarks to be distinguished in the images. In a number of studies (Moneva et al, 2012b;Sepúlveda and Ibáñez, 2012;Zhao et al, 2019), environmental factors determining such variability were analyzed. Zhao et al (2019) indicated that temperature was the key environmental factor determining the variability of the Monodonta labio shell.…”

“…In a number of studies (Moneva et al, 2012b;Sepúlveda and Ibáñez, 2012;Zhao et al, 2019), environmental factors determining such variability were analyzed. Zhao et al (2019) indicated that temperature was the key environmental factor determining the variability of the Monodonta labio shell. Other studies (Moneva et al, 2012b;Sepúlveda and Ibáñez, 2012) concluded that the shape of the shell is determined by a combination of factors, including temperature, chemical characteristics of the water, and the impact of currents.…”

Checklist of mangrove snails (Mollusca: Gastropoda) in South Coast of Pamekasan, Madura Island, East Java, Indonesia

“…Morphologically, this species is characterized by a highly pointed apex and prominent granules on the spiral ribs. Shell color is highly variable, with a typically yellowish brown, greenish, or reddish background (Zhao et al 2019). Found on sediment surface in the mid intertidal zone.…”

Species density and shell morphology of gold ring cowry (Monetaria annulus, Linnaeus, 1758) (Mollusca: Gastropoda: Cypraeidae) in the coastal waters of Ambon Island, Indonesia

“…These relatively protected conditions cause the sizes of the length, width, and height of the shell of M. annulus to be relatively similar. The same environmental conditions and geographical locations made the shells of gastropods have the same structure and shape (Trussell 1997;Tissot 1984;Cazenave and Zanatta 2016;Zhao et al 2019). In addition, variations of the shapes of gastropods shells are influenced by the body size and the sex differences (Avaca et al 2013).…”