@article{fdi:010085878, title = {{D}iving into the lower mesophotic coral ecosystems (65-93 m depth) of {R}eunion {I}sland ({S}outhwestern {I}ndian {O}cean) sheds light on the hidden diversity of hydroids ({C}nidaria, {H}ydrozoa)}, author = {{G}ravier-{B}onnet, {N}. and {B}oissin, {E}. and {H}oarau, {L}. and {P}lantard, {P}. and {L}oisil, {C}. and {O}ry, {D}. and {M}ulochau, {T}. and {C}habanet, {P}ascale and {A}djeroud, {M}ehdi and {B}ourmaud, {C}. and {R}ouz{\'e}, {H}.}, editor = {}, language = {{ENG}}, abstract = {{T}his study explored the unknown biodiversity of mesophotic coral ecosystems ({MCE}s) in {R}eunion {I}sland, located in the {S}outhwestern {I}ndian {O}cean. {MCE}s are still largely unexplored whereas they are assumed to shelter a rich and unique biodiversity. {A}s they might likely serve as a source for recolonization after disturbances in shallower reefs, their study is urgently needed. {T}his work focused on an understudied large group of structural and functional ecological importance in reef benthic communities, the hydroids. {P}erforming only 8 deep dives with closed-circuit rebreathers, we recorded 74 species between 65 and 93 m among which 11 species and 3 genera are likely new to science. {F}urthermore, the explorations made in contrasted geographical zones around the island suggest particular eco-physiological traits for some species: specialized vs. widely tolerant. {T}his preliminary report only shows the tip of the iceberg and opens an avenue for exploration and understanding of such extraordinary biodiversity at such depths.}, keywords = {{H}ydrozoan ; {T}ropical ; {L}ow-light environment ; {S}pecies discovery ; {C}itizen science ; {D}eep dives ; {REUNION} ; {OCEAN} {INDIEN}}, booktitle = {}, journal = {{M}arine {B}iodiversity}, volume = {52}, numero = {4}, pages = {38 [9 p.]}, ISSN = {1867-1616}, year = {2022}, DOI = {10.1007/s12526-022-01274-4}, URL = {https://www.documentation.ird.fr/hor/fdi:010085878}, }