Phylogeography of the reef fish Cephalopholis argus(Epinephelidae) indicates Pleistocene isolation across the indo-pacific barrier with contemporary overlap in the coral triangle

Abstract

BackgroundThe Coral Triangle (CT), bounded by the Philippines, the Malay Peninsula, and New Guinea, is the epicenter of marine biodiversity. Hypotheses that explain the source of this rich biodiversity include 1) the center of origin, 2) the center of accumulation, and 3) the region of overlap. Here we contribute to the debate with a phylogeographic survey of a widely distributed reef fish, the Peacock Grouper (Cephalopholis argus; Epinephelidae) at 21 locations (N = 550) using DNA sequence data from mtDNA cytochrome b and two nuclear introns (gonadotropin-releasing hormone and S7 ribosomal protein).ResultsPopulation structure was significant (ΦST = 0.297, P < 0.001; FST = 0.078, P < 0.001; FST = 0.099, P < 0.001 for the three loci, respectively) among five regions: French Polynesia, the central-west Pacific (Line Islands to northeastern Australia), Indo-Pacific boundary (Bali and Rowley Shoals), eastern Indian Ocean (Cocos/Keeling and Christmas Island), and western Indian Ocean (Diego Garcia, Oman, and Seychelles). A strong signal of isolation by distance was detected in both mtDNA (r = 0.749, P = 0.001) and the combined nuclear loci (r = 0.715, P < 0.001). We detected evidence of population expansion with migration toward the CT. Two clusters of haplotypes were detected in the mtDNA data (d = 0.008), corresponding to the Pacific and Indian Oceans, with a low level of introgression observed outside a mixing zone at the Pacific-Indian boundary.ConclusionsWe conclude that the Indo-Pacific Barrier, operating during low sea level associated with glaciation, defines the primary phylogeographic pattern in this species. These data support a scenario of isolation on the scale of 105 year glacial cycles, followed by population expansion toward the CT, and overlap of divergent lineages at the Pacific-Indian boundary. This pattern of isolation, divergence, and subsequent overlap likely contributes to species richness at the adjacent CT and is consistent with the region of overlap hypothesis.

Vicariance across major marine biogeographic barriers: temporal concordance and the relative intensity of hard versus soft barriers

“…The reconstruction points to a barrier, or series of barriers that have historically affected lineages from the Late Miocene, with an increasing impact towards the end of the Pliocene. The ongoing nature of this barrier may be evident in rspb.royalsocietypublishing.org Proc R Soc B 280: 20131541 population studies across the two regions, with temporal clades containing haplotypes from both regions [43,66]. However, the nature and location of the barrier is hard to identify.…”

Phylogeography of the neon damselfish Pomacentrus coelestis indicates a cryptic species and different species origins in the West Pacific Ocean

“…Most of the past research supports the Center of Origin hypothesis (Barber et al 2006, Williams 2007, Timm & Kochzius 2008, Nuryanto & Kochzius 2009). In contrast, relatively few cases substantiate the Center of Overlap (Teske et al 2005, Gaither et al 2011) and Center of Accumulation hypotheses (Wilson et al 2001, Drew & Barber 2009). Barber (2009 suggested that the central West Pacific's diversity is likely the result of multiple evolutionary processes, working either simultaneously or over different time periods, being dominated by different processes.…”

From endemism to widespread distribution: phylogeography of three amphidromous Sicyopterus species (Teleostei: Gobioidei: Sicydiinae)

“…to sea level fluctuations, island emersion and submergence). These barriers mainly act on species displaying dispersal potential through the marine environment as larvae, juveniles or adults (Gaither et al 2010(Gaither et al , 2011. This is, for example, the case for many fish (Briggs 1974, Planes & Fauvelot 2002, Bay et al 2004, Craig et al 2007, Gaither et al 2010, Winters et al 2010) and invertebrates (Lavery et al 1995, Lessios et al 2001, 2003, Barber et al 2002 across the Indo-Malay archipelago, widely recognised as the Indo-Pacific Barrier (IPB; an intermittent barrier of throughflow current and chain of islands, depending on sea level fluctuations over the geological time scale) that separates the Indian and the Pacific Oceans.…”