Phylogeography of the rocky intertidal periwinkle Echinolittorina paytensis through a biogeographic transition zone in the Southeastern Pacific

Abstract

Barriers to dispersal are recognized to play an important role in the differentiation of populations and ultimately in speciation. In the southeast Pacific, on the northern coast of Peru, a transition zone between the Peruvian and Panamic marine biogeographic provinces exists. Here, the convergence between two contrasting surface currents could generate a barrier effect for the larval dispersal of meroplanktonic invertebrates, which could in turn generate differentiated populations or genetic lineages on both sides of the transition zone. To address this, we studied to Echinolittorina paytensis, an abundant rocky intertidal periwinkle that spans both biogeographic provinces. A total of 95 individuals from Ecuador (2°19′S) to central Peru (7°31′S), covering the Panamic Province, the Peruvian Province, and the transition zone between, were collected. The mitochondrial markers cytochrome c oxidase I and 16SrRNA were sequenced in order to investigate phylogeography and genetic structuring. In general, no genetic structuring was found across the transition zone, suggesting this biogeographic boundary would not be acting as a barrier in this species. Factors such as a high larval dispersal capability and the occurrence of El Niño–Southern Oscillation events such as El Niño are discussed.

Trans-Atlantic Distribution and Introgression as Inferred from Single Nucleotide Polymorphism: Mussels Mytilus and Environmental Factors

“…The formation and removal of barriers have occurred repeatedly over geologic time [5] and such broad scale processes modify inter-oceanic migration of shallow coastal marine faunas. Barrier formation fosters speciation as the original range of a species is divided up and divergent changes in the isolated populations are expected [6][7][8][9]. Genetic analyses shed light on the origin of populations and individuals and their range expansion through geological times.…”

Northward shift of a biogeographical barrier on China’s coast

“…For instance, on the southeast coast of Australia, a biogeographical barrier called the Southeast Australian Biogeographic Barrier (SEABB) occurs, which plays an important role in shaping species distribution and phylogeographic patterns (Ayre et al, 2009;Ayre & Rosser, 2021;Waters, 2008). Similar biogeographical barriers occur in the southeast Pacific on the northern coast of Peru (Barahona et al, 2019), the west coast of the United States (Burton, 1998;Palumbi, 1996;Taylor & Hellberg, 2006), the east coast of North America (Pappalardo et al, 2015), the Atlantic-Mediterranean coast (El Ayari et al, 2019), and the coast of China (Dong et al, 2012;Liu, 2013). These barriers are not hard and fast, however, but shift when environmental changes occur.…”

“…A growing amount of evidence has suggested that post-settlement establishment plays a more important role in the maintenance of biogeographic breaks in the oceans than larval dispersal (Keith et al, 2015). Invertebrates usually exhibit high rates of post-settlement mortality, which are mainly due to the delay of metamorphosis, competition, predation, physiological stress (Hunt & Scheibling, 1997) and genetic inviability driven by genotype-environment interactions (Barahona et al, 2019;Plough et al, 2016). Importantly, the capacity of species to tolerate physiologically marginal conditions influences their ability to establish a viable population after successful dispersal (Keith et al, 2015) and the persistence of their present distribution ranges (Dong et al, 2015;Han et al, 2019).…”

Substantial gene flow caused by long-term translocation between wild populations of the Peruvian scallop (Argopecten purpuratus) is supported by RAD-Seq analyses

“…The Peruvian scallop has a moderate pelagic larval duration of 16-25 days in the water column, depending on the water temperature, before settlement (von Brand, Merino, Abarca, & Stotz, 2006). The combination of the northward passive larval displacement caused by the Peruvian Coastal Current (PCC) and the southward displacement caused by the movement of warm water masses during ENSO events could facilitate the bidirectional population connectivity (Barahona et al, 2019). The recolonization of extinct natural beds (Wolff & Mendo, 2000) and the formation of temporal intermediate aggregations (Ysla, 2009) during and after ENSO could increase the genetic connectivity.…”