Consequences of marine barriers for genetic diversity of the coral‐specialist yellowbar angelfish from the Northwestern Indian Ocean

Abstract

Ocean circulation, geological history, geographic distance, and seascape heterogeneity play an important role in phylogeography of coral‐dependent fishes. Here, we investigate potential genetic population structure within the yellowbar angelfish (Pomacanthus maculosus) across the Northwestern Indian Ocean (NIO). We then discuss our results with respect to the above abiotic features in order to understand the contemporary distribution of genetic diversity of the species. To do so, restriction site‐associated DNA sequencing (RAD‐seq) was utilized to carry out population genetic analyses on P. maculosus sampled throughout the species’ distributional range. First, genetic data were correlated to geographic and environmental distances, and tested for isolation‐by‐distance and isolation‐by‐environment, respectively, by applying the Mantel test. Secondly, we used distance‐based and model‐based methods for clustering genetic data. Our results suggest the presence of two putative barriers to dispersal; one off the southern coast of the Arabian Peninsula and the other off northern Somalia, which together create three genetic subdivisions of P. maculosus within the NIO. Around the Arabian Peninsula, one genetic cluster was associated with the Red Sea and the adjacent Gulf of Aden in the west, and another cluster was associated with the Arabian Gulf and the Sea of Oman in the east. Individuals sampled in Kenya represented a third genetic cluster. The geographic locations of genetic discontinuities observed between genetic subdivisions coincide with the presence of substantial upwelling systems, as well as habitat discontinuity. Our findings shed light on the origin and maintenance of genetic patterns in a common coral reef fish inhabiting the NIO, and reinforce the hypothesis that the evolution of marine fish species in this region has likely been shaped by multiple vicariance events.

Population Genomic Analyses of the Sea Urchin Echinometra sp. EZ across an Extreme Environmental Gradient

“…2017a ). Finally, a study on the yellowbar angelfish, Pomacanthus maculosus , generated a SNP data set with 10,225 SNPs and found that the F ST between the two seas was 0.015 ( Torquato et al. 2019 ).…”

Genetic analysis of whole mitochondrial genome of Lateolabrax maculatus (Perciformes: Moronidae) indicates the presence of two populations along the Chinese coast

“…The effects of IBD in the genetic differentiation of populations was originally illustrated in 1948 (Wright 1943). Since then, IBD has been observed and reported in many population genetic studies, for example, the population genetic studies Nile Tilapia throughout west Africa and the coral-specialist yellowbar angelfish from the Northwestern Indian Ocean, the genetic distances between populations were clearly correlated to their geographic distance (Lind et al 2019, Torquato et al 2019. In this study, the IBD test performed by Mantel tests showed a significant correlation between genetic and geographical distances among L. maculatus populations.…”

Physical-biological interactions underlying the phylogeographic patterns of coral-dependent fishes around the Arabian Peninsula

“…This result corroborates with previous population genetic studies. For example, phylogeographic investigations on fish species such as Scomberomorus commerson (van Herwerden et al, 2006); Cephalopholis hemistiktos (Priest et al, 2016) and Pomacanthus maculosus (Torquato et al, 2019), used different genetic markers and found a significant discontinuity positioned in southern Oman. Moreover, in our models the strength of this barrier increased when the taxa are spawning during the summer monsoon.…”

“…The main hypotheses to explain faunal and genetic differences between both sides of the peninsula usually involve seascape features and/or ocean circulation off Oman (Torquato et al 2019). The seascape is characterized by to coral colonies in southern Omani coast being weakly developed and represented by a reduced number of species (Burt et al, 2016; Sheppard & Salm, 1988), such that the lack of coral-habitat creates an unbridgeable gap for coral-dependent species (Priest et al, 2016).…”

“…These boundaries described by multispecies distribution records, are also logical places in relation to present-day barriers for gene flow between populations (Baums et al, 2006). Indeed, population genetic studies carried out in the Northwestern Indian Ocean (NIO) have revealed similarities in the geographical position of barriers previously proposed (DiBattista et al, 2013, 2015, 2017; Nanninga et al, 2014; Priest et al, 2016; Saenz-Agudelo et al, 2015; Torquato et al, 2019).…”