Phylogeographic and evolutionary history analyses of the warty crab Eriphia verrucosa (Decapoda, Brachyura, Eriphiidae) unveil genetic imprints of a late Pleistocene vicariant event across the Gibraltar Strait, erased by postglacial expansion and admixture among refugial lineages

Temim Deli,Christina Kiel,Christoph D Schubart

doi:10.1186/s12862-019-1423-2

Abstract

BackgroundThe Pleistocene cyclic sea-level fluctuations are thought to have markedly affected the distribution and genetic architecture of Atlanto-Mediterranean biota. Despite the acknowledged key role played by these historical events in shaping population genetic structure of marine species, little is still known about the processes involved in shaping the spatial distribution of genetic variation within intertidal species. We intended in this study to reconstruct the phylogeography of a common and widely distributed coastal species across the East Atlantic and Mediterranean Sea (the warty crab Eriphia verrucosa), aiming to unravel potential microevolutionary processes likely involved in shaping its genetic polymorphism. For this purpose, a total of 155 specimens of E. verrucosa from 35 locations across the entire distribution range were analyzed by comparing a 453 basepairs region of the mitochondrial gene cytochrome oxidase subunit 1 (Cox1).ResultsOur results unveiled the prevalence of high genetic connectivity among East Atlantic and Mediterranean populations, with noticeable genetic distinctiveness of the peripheral population from the Azores. Spatio-temporal patterns of genetic diversification and demographic history allowed retrieving genetic imprints of late Pleistocene vicariant event across the Gibraltar Strait followed by subsequent postglacial expansion events for both the East Atlantic and Mediterranean regions. Integrative evidences from the outcomes of comparison of regional genetic diversification, as well as evolutionary and biogeographic histories reconstructions, support the existence of potential glacial refugia for E. verrucosa in the East Atlantic and western Mediterranean. Our results also revealed low levels of genetic variability along with recent demographic and spatial expansion events for eastern Mediterranean warty crabs, suggesting that the eastern areas within the distribution range of the species might have been recently colonized from putative glacial refugia.ConclusionsThese findings provide new insights into the phylogeography and evolutionary history of a common but poorly studied Atlanto-Mediterranean decapod species. Specifically, they contribute to the understanding of the impact of historical processes on shaping contemporary population genetic structure and diversity in intertidal marine species.

Highlights

The Pleistocene cyclic sea-level fluctuations are thought to have markedly affected the distribution and genetic architecture of Atlanto-Mediterranean biota
Deli et al BMC Evolutionary Biology (2019) 19:105 (Continued from previous page). These findings provide new insights into the phylogeography and evolutionary history of a common but poorly studied Atlanto-Mediterranean decapod species. They contribute to the understanding of the impact of historical processes on shaping contemporary population genetic structure and diversity in intertidal marine species
It has been postulated that habitat fragmentation induced by a lower sea level during glacial maxima could lead to a genetic bottleneck, with geographic isolates persisting in glacial refugia, and to a heterogeneous population structure

Summary

Introduction

The Pleistocene cyclic sea-level fluctuations are thought to have markedly affected the distribution and genetic architecture of Atlanto-Mediterranean biota. The Pleistocene cyclic sea-level fluctuations are thought to have markedly affected the coastal environment and the evolutionary history of its biota [5] and regarded as one of the most important processes involved in shaping the contemporary geographic distribution of genetic variation [6, 9] These historic events have greatly influenced the distribution and evolutionary dynamics of populations [10, 11] following repeated habitat contractions and expansions of marine organisms. Range expansion primed by a rising sea level, following environmental warming during interglacials, could result in rapid population growth and consequent genetic homogeneity as a result of secondary contact between previously isolated evolutionary lineages [11] The impact of these historical factors, intensified by the effects of contemporary environmental and oceanographic gradients, could have been potentially involved in shaping present day genetic variation and population structure in marine species [8, 15]

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