TY - JOUR

T1 - Recent diversification of a marine genus (Tursiops spp.) Tracks habitat preference and environmental change

AU - Moura, Andre E.

AU - Nielsen, Sandra Cathrine Abel

AU - Mouatt, Julia Thidamarth Vilstrup

AU - Moreno Mayar, José Victor

AU - Gilbert, Tom

AU - Gray, Howard W. I.

AU - Natoli, Ada

AU - Möller, Luciana

AU - Hoelzel, A. Rus

PY - 2013/11

Y1 - 2013/11

N2 - Understanding the evolution of diversity and the resulting systematics in marine systems is confounded by the lack of clear boundaries in oceanic habitats, especially for highly mobile species like marine mammals. Dolphin populations and sibling species often show differentiation between coastal and offshore habitats, similar to the pelagic/littoral or benthic differentiation seen for some species of fish. Here we test the hypothesis that lineages within the polytypic genus Tursiops track past changes in the environment reflecting ecological drivers of evolution facilitated by habitat release. We used a known recent time point for calibration (the opening of the Bosphorus) and whole mitochondrial genome (mitogenome) sequences for high phylogenetic resolution. The pattern of lineage formation suggested an origin in Australasia and several early divisions involving forms currently inhabiting coastal habitats. Radiation in pelagic environments was relatively recent, and was likely followed by a return to coastal habitat in some regions. The timing of some nodes defining different ecotypes within the genus clustered near the two most recent interglacial transitions. A signal for an increase in diversification was also seen for dates after the last glacial maximum. Together these data suggest the tracking of habitat preference during geographic expansions, followed by transition points reflecting habitat shifts, which were likely associated with periods of environmental change.

AB - Understanding the evolution of diversity and the resulting systematics in marine systems is confounded by the lack of clear boundaries in oceanic habitats, especially for highly mobile species like marine mammals. Dolphin populations and sibling species often show differentiation between coastal and offshore habitats, similar to the pelagic/littoral or benthic differentiation seen for some species of fish. Here we test the hypothesis that lineages within the polytypic genus Tursiops track past changes in the environment reflecting ecological drivers of evolution facilitated by habitat release. We used a known recent time point for calibration (the opening of the Bosphorus) and whole mitochondrial genome (mitogenome) sequences for high phylogenetic resolution. The pattern of lineage formation suggested an origin in Australasia and several early divisions involving forms currently inhabiting coastal habitats. Radiation in pelagic environments was relatively recent, and was likely followed by a return to coastal habitat in some regions. The timing of some nodes defining different ecotypes within the genus clustered near the two most recent interglacial transitions. A signal for an increase in diversification was also seen for dates after the last glacial maximum. Together these data suggest the tracking of habitat preference during geographic expansions, followed by transition points reflecting habitat shifts, which were likely associated with periods of environmental change.

U2 - 10.1093/sysbio/syt051

DO - 10.1093/sysbio/syt051

M3 - Journal article

C2 - 23929779

VL - 62

SP - 865

EP - 877

JO - Systematic Biology

JF - Systematic Biology

SN - 1063-5157

IS - 6

ER -