biostudies-literatureMuir PRCatlin Group Limited20181987https://www.ebi.ac.uk/biostudies/studies/S-EPMC6304044biostudies-literatureUnknown285(1893)Coral reefs are increasingly threatened by thermal bleaching and tropical storm events associated with rising sea surface temperatures. Deeper habitats offer some protection from these impacts and may safeguard reef-coral biodiversity, but their faunas are largely undescribed for the Indo-Pacific. Here, we show high species richness of scleractinian corals in mesophotic habitats (30-125 m) for the northern Great Barrier Reef region that greatly exceeds previous records for mesophotic habitats globally. Overall, 45% of shallow-reef species (less than or equal to 30 m), 78% of genera, and all families extended below 30 m depth, with 13% of species, 41% of genera, and 78% of families extending below 45 m. Maximum depth of occurrence showed a weak relationship to phylogeny, but a strong correlProceedings. Biological sciencesHigh species richness and lineage diversity of reef corals in the mesophotic zone.PMC6304044(DECRA) DE160101433Muir PRPichon MBongaerts PWallace CCfalseHigh species richness and lineage diversity of reef corals in the mesophotic zone.Coral reefs are increasingly threatened by thermal bleaching and tropical storm events associated with rising sea surface temperatures. Deeper habitats offer some protection from these impacts and may safeguard reef-coral biodiversity, but their faunas are largely undescribed for the Indo-Pacific. Here, we show high species richness of scleractinian corals in mesophotic habitats (30-125 m) for the northern Great Barrier Reef region that greatly exceeds previous records for mesophotic habitats globally. Overall, 45% of shallow-reef species (less than or equal to 30 m), 78% of genera, and all families extended below 30 m depth, with 13% of species, 41% of genera, and 78% of families extending below 45 m. Maximum depth of occurrence showed a weak relationship to phylogeny, but a strong correl2018-01-01T00:00:00Z2018 Dec2026-05-02T14:14:42.911Z2025-02-19T05:00:41.424ZS-EPMC63040443096390510.1098/rspb.2018.1987