From sea to land and beyond – New insights into the evolution of euthyneuran Gastropoda (Mollusca) (original) (raw)
Related papers
2013
Abstract The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial-temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces.
Gastropods on land: phylogeny, diversity and adaptive morphology
The biology of terrestrial molluscs
New phylogenetic hypotheses of adaptive radiation in Gastropoda and basic gastropod organization are discussed. Gastropods on land i.e. Archaeogastropod Neritopsina, Architaeniglossan caenogastropods, Sorbeoconch caenogastropods, Ellobioid pulmonates, Onchidioidean pulmonates, Rathouisioidean pulmonates, Succineoidean pulmonates and Stylommatophoran pulmonates.
Patterns of speciation in marine gastropods: A review of the phylogenetic evidence for localized radiations in the sea, 2011
Modern speciation theory is heavily infl uenced by Mayr’s postulate that prolonged geographical isolation is necessary for differentiated populations to evolve reproductive isolation. Present-day distributions of sister species are consistent with allopatric or peripatric speciation in many terrestrial and freshwater animal groups. However, the oceans present few obstacles to dispersal for marine taxa with planktonic larvae, and sister species are not often split at biogeographical breakpoints in the sea. Theory predicts that disruptive selection on habitat choice or resource use can split a population into divergent ecotypes without physical separation, yet sympatric speciation is still often viewed as improbable. Here, I review phylogenetic evidence from diverse marine gastropods to test Mayr’s prediction that recently diverged sister species should not be sympatric over most of their ranges. In contrast to expectations, young sister species are often broadly sympatric in many gastropod groups, suggesting that classical models of allopatric divergence are insuffi cient to explain marine speciation. I discuss four mechanisms that may contribute to this deviation from predicted biogeographical patterns: transient allopatry along continuous coastlines, rapid evolution of gamete recognition proteins, shifts to non-planktonic development, and ecological divergence. The available evidence argues that patterns of marine speciation depend on complex interactions between geography, life history, and ecology, often resulting in local radiations within a basin or endemic to an island group. Whether selection acts on ecotypes in sympatry or on populations during secondary contact, ecological factors may promote speciation in the sea at smaller spatial scales than expected. I highlight areas for future study to improve our understanding of the forces generating marine biodiversity, and why the geography of speciation may be fundamentally different for shallow-water animals.
Molecular phylogenetics and evolution, 2010
Pulmonate snails occupy a wide range of marine, estuarine, freshwater and terrestrial environments. Non-terrestrial forms are supposed to be basal in pulmonate evolution but the group's phylogeny is not well resolved either morphologically or on the basis of available DNA sequence data. The lack of a robust phylogeny makes it difficult to understand character polarization and habitat transformation in pulmonates. We have investigated pulmonate relationships using 27 new sequences of 28S rRNA from pulmonates and outgroups, augmented with data from GenBank. The complete alignments comprised about 3.8kb. Maximum parsimony, maximum likelihood and Bayesian analyses of alignments generated under different assumptions are reported. Complete alignments appear to have a degree of substitution saturation so where there is conflict between hypothesised relationships more weight is given to analyses where regions of random similarity are excluded and which are not affected by this complicat...
Systematic Biology, 2014
Ancient oceanic archipelagos of similar geological age are expected to accrue comparable numbers of endemic lineages with identical life history strategies, especially if the islands exhibit analogous habitats. We tested this hypothesis using marine snails of the genus Conus from the Atlantic archipelagos of Cape Verde and Canary Islands. Together with Azores and Madeira, these archipelagos comprise the Macaronesia biogeographic region and differ remarkably in the diversity of this group. More than 50 endemic Conus species have been described from Cape Verde, whereas prior to this study, only two nonendemic species, including a putative species complex, were thought to occur in the Canary Islands. We combined molecular phylogenetic data and geometric morphometrics with bathymetric and paleoclimatic reconstructions to understand the contrasting diversification patterns found in these regions. Our results suggest that species diversity is even lower than previously thought in the Canary Islands, with the putative species complex corresponding to a single species, Conus guanche. One explanation for the enormous disparity in Conus diversity is that the amount of available habitat may differ, or may have differed in the past due to eustatic (global) sea level changes. Historical bathymetric data, however, indicated that sea level fluctuations since the Miocene have had a similar impact on the available habitat area in both Cape Verde and Canary archipelagos and therefore do not explain this disparity. We suggest that recurrent gene flow between the Canary Islands and West Africa, habitat losses due to intense volcanic activity in combination with unsuccessful colonization of new Conus species from more diverse regions, were all determinant in shaping diversity patterns within the Canarian archipelago. Worldwide Conus species diversity follows the well-established pattern of latitudinal increase of species richness from the poles towards the tropics. However, the eastern Atlantic revealed a striking pattern with two main peaks of Conus species richness in the subtropical area and decreasing diversities toward the tropical western African coast. A Random Forests model using 12 oceanographic variables suggested that sea surface temperature is the main determinant of Conus diversity either at continental scales (eastern Atlantic coast) or in a broader context (worldwide). Other factors such as availability of suitable habitat and reduced salinity due to the influx of large rivers in the tropical area also play an important role in shaping Conus diversity patterns in the western coast of Africa.