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Aim Revealing how diversity varies across the depth gradient is key for understanding the role of mesophotic coral ecosystems in the functioning of coral reefs. We quantitatively examined how alpha and beta generic diversity of scleractinian coral assemblages vary across a wide depth gradient for coral reefs. Location Sixteen sites in eight islands of three archipelagos in French Polynesia. Methods We studied generic diversity patterns of scleractinian corals, as derived from the analysis of photo-quadrats, across the seafloor from shallow to lower mesophotic depths (6–120 m) and on a wide geographic scale. Our sampling considered quantitative coral cover to explore the patterns of alpha and beta components of diversity across depth and horizontal space. Results We show that in French Polynesia, mesophotic coral ecosystems host higher alpha and beta generic diversity than shallow reefs despite decreasing coral cover with depth. The variation of coral genus richness across the depth gradient is mainly driven by a mid-domain effect with a peak at 40 m depth. At the same time, we found that the differences in coral genera across islands (spatial beta-diversity) increased steadily along the depth gradient. Main conclusions Our findings report the first quantitative results of coral cover and diversity from mesophotic coral ecosystems in French Polynesia and also present one of the few existing studies to examine the broad breadth of the mesophotic depth gradient. We demonstrate that mesophotic depths can host unexpectedly high generic richness of scleractinian coral assemblages. At the same time, we showed that increasing depth increases the differences in generic diversity composition across islands, whereas shallow reefs are similar in between. While a single island could conserve shallow regional biodiversity, mesophotic depths containing the richest diversity require site-specific measures, suggesting that considering these mesophotic depths in conservation is necessary to maintain regional diversity.

Figure S1: (A) Map of the locations of this study. (B) Proportions of each health-bleaching status at each survey depth. Error bars show standard errors using 95% CI. (D) Bayesian prediction probability of the likelihood of corals to be healthy, pale, bleached or recently dead in function of depth.

Climate change and consequent coral bleaching are causing the disappearance of reef-building corals worldwide. While bleaching episodes significantly impact shallow waters, little is known about their impact on mesophotic coral communities. We studied the prevalence of coral bleaching two to three months after a heat stress event, along an extreme depth range from 6 to 90 m in French Polynesia. Bayesian modelling showed a decreasing probability of bleaching of all coral genera over depth, with little to no bleaching observed at lower mesophotic depths (greater than or equal to 60 m). We found that depth-generalist corals benefit more from increasing depth than depth-specialists (corals with a narrow depth range). Our data suggest that the reduced prevalence of bleaching with depth, especially from shallow to upper mesophotic depths (40 m), had a stronger relation with the light-irradiance attenuation than temperature. While acknowledging the geographical and temporal variability of the role of mesophotic reefs as spatial refuges during thermal stress, we ought to understand why coral bleaching reduces with depth. Future studies should consider repeated monitoring and detailed ecophysiological and environmental data. Our study demonstrated how increasing depth may offer a level of protection and that lower mesophotic communities could escape the impacts of a thermal bleaching event.

Parisa Alidoost Salimi, Pargol Ghavam Mostafavi, Chaolun Allen Chen, Seyed Mohammad Reza Fatemi, and Michel Pichon (2018) There are many islands in the Iranian waters, but little is known about their coral species. This is a first attempt to describe and illustrate the coral species occurring in Abu-Musa and Sirri Islands. Overall, 26 species belonging to 9 families are reported, and three unidentified species and two species are added to coral communities of Iran. This study also provides overall insight on coral fauna in the Persian Gulf.

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 (≤ 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 correlation with maximum latitudinal extent. Species recorded in the mesophotic had a significantly greater than expected probability of also occurring in shaded microhabitats and at higher latitudes, consistent with light as a common limiting factor. The findings suggest an important role for deeper habitats, particularly depths 30-45 m, in preserving evolutionary lineages of Indo-Pacific corals. Deeper reef areas are clearly more diverse than previously acknowledged and therefore deserve full consideration in our efforts to protect the world’s coral reef biodiversity.

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 correlation with maximum latitudinal extent. Species recorded in the mesophotic had a significantly greater than expected probability of also occurring in shaded microhabitats and at higher latitudes, consistent with light as a common limiting factor. The findings suggest an important role for deeper habitats, particularly depths 30–45 m, in preserving evolutionary lineages of Indo-Pacific corals. Deeper reef areas are clearly more diverse than previously acknowledged and therefore deserve full consideration in our efforts to protect the world's coral reef biodiversity.

Le contexte géologique et topographique du site de La Forgeais, implanté sur les hautes terrasses alluviales de la Vienne, en pied de versant à faible pente et surplombant de quelques dizaines de centimètres à peine les zones d'affluences du Réveillon (dont le lit actuel s'écoule environ 300 m au nord), a favorisé la conservation d'une séquence sédimentaire incluant des occupations depuis le Mésolithique jusqu'au Moyen Âge.L'occupation mésolithique de la Forgeais reste assez fugace, signalée uniquement par la présence de très rares pièces lithiques, dont une armature géométrique et un micro-burin.Si les lieux semblent simplement fréquentés par les populations du Mésolithique, leurs lointains descendants, au Néolithique ancien, occupent de façon plus pérenne le site. Un bâtiment, fondé sur six poteaux, peut être rattaché à cette phase. Quelques foyers et un mobilier abondant complètent l'ensemble. Le site de la Forgeais est ensuite abandonné, avant de connaître des fréquentations plus ou moins soutenues successivement au Néolithique récent, au Néolithique final, au Bronze ancien et au Bronze moyen. Pour chacune de ces phases, la structuration de l'espace est plus complexe à saisir et repose sur l'examen détaillé de la répartition des mobiliers. Au nord du site se met progressivement en place une zone humide postérieurement aux occupations néolithiques.L'âge du Bronze final marque une reprise nette de l'occupation de la zone. Plusieurs grandes fosses se répartissent autour d'une concentration de près de 200 m², l'ensemble se fixant en bordure de la zone humide.La mise en place d'un vaste enclos quadrangulaire au début du Haut Empire constitue la première manifestation d'occupations antiques qui s'étaleront jusqu'à la fin du Ier siècle de notre ère. Le réseau de fossés, creusés en priorité dans la zone humide, témoigne d'une volonté de drainage du secteur. Plusieurs indices suggèrent la présence d'une ferme gallo-romaine. Un fossé courbe délimite les espaces externes et internes, des quartiers de bovidés sont jetés au fond de fosses, ainsi que des fragments de meules rotatives et un abondant mobilier céramique, de qualité.Entre les IIe et IVe siècles, le site semble de nouveau abandonné. Quelques restes céramiques et de tuiles témoignent de brefs passages durant l'Antiquité tardive, limités au quart sud-ouest de l'emprise de fouille. C'est sur la même zone que se superposent une concentration de matériel mérovingien et carolingien, un nouveau parcellaire dont l'orientation dévie de quelques degrés de la trame antique, et les restes d'un bâtiment. Celui-ci est implanté sur une nécropole carolingienne. Les sépultures, en pleine terre, sont alignées sur le parcellaire et déposées directement dans un fossé ou dans des fosses qui jouxtent ce dernier.À l'est de ces indices, le plan d'un vaste bâtiment sur poteaux de près de 120 m² a été topographié. Sa datation précise n'est pas assurée, mais il est postérieur aux occupations antiques. Il est tentant d'y voir une grange, ou étable, qui complèterait le parcellaire et la nécropole du Haut Moyen Âge. Tous ces témoignages marqueraient l'extension maximale, vers le nord, d'un site se développant dans l'emprise du site du Perrou 1.

The morphometric and molecular boundaries between twelve Psammocora (Cnidaria, Scleractinia) nominal species were addressed. The type specimens of Psammocora haimianaMilne Edwards & Haime, 1851, P. togianensisUmbgrove, 1940, P. foliumUmbgrove, 1939, P. digitataMilne Edwards & Haime, 1851, Maeandroseris australiaeRousseau, 1854, P. samoensisHoffmeister, 1925, P. superficialisGardiner, 1898, P. profundacellaGardiner, 1898, P. nierstrasziVan der Horst, 1921, P. verrilliVaughan, 1907, and P. albopictaBenzoni, 2006, were analysed together with specimens from museum collections, including those depicted in widely cited taxonomic descriptions, and material collected for this study in different parts of the Indo-Pacific. Morphometric analyses of the dimensions of skeletal structures allowed the identification of groups of specimens with similar morphologies. Congruency between these groups and current species whose synonymies and descriptions were found in recent taxonomic references was, hence, investigated and the species revised. Finally, the phylogenetic relationships of a representative subset of specimens were reconstructed based on rDNA and COI, thus allowing a direct link between morphologic and genetic information. Incongruence between type of morphology and literature descriptions was evidenced for some widely recognised species. Based on this integrated approach, five species were unambiguously identified. © 2010 The Linnean Society of London.

often difficult and even experts sometimes experience difficulties to separate closely related species. Although morphometric data have sometimes been used in the past, they were in most instances restricted to simple data sets used to back up evidence derived from mere comparisons of morphological characters. Two nominal species of Pocillopora, Pocillopora verrucosa (Ellis & Solander, 1786) and P. meandrina, Dana, 1846 have been considered in the past either as one species or as two distinct species. The strategy used to unravel this taxonomic wrangle relies (1) on an analysis in a multidimensional space of morphometric data collected on the whole colonies and on individual branches, and (2) on unimodal statistical tests. Three types of analyses have been carried out: (1) A principal component analysis which has allowed to extract and visualize the most structuring variables, (2) a discriminant analysis which has allowed to classify each specimen within one of the two groups of specimens, and (3) a series of t tests (comparisons of means) to validate the differences identified between each group. The results obtained clearly show that Pocillopora verrucosa and P. meandrina can easily be separated on a morphometric basis. Our results should be confirmed by the combination of investigations focusing on other biological aspects such as ecological, molecular and physiological characteristics.

2. Scolymia cubensis (Milne Edwards & Haime, 1849) Material examined: USNM 47644 (Carrie Bow Cay, Belize), UFBA 487 -CNI (Recife do Guageru, Sergipe State, Brazil) Diagnosis: Wells (1971): 960���963, figs. 1,3, 5,7 Distribution: Cura��ao, Bonaire, Jamaica, Cuba, Bahamas, South Florida. In Brazil: Sergipe State. In: Lang (1971), Wells (1971), Humann (1993), Zlatarski and Estalella (1982, as S. lacera lacera forma cubensis) Holotype: Museum National d���Histoire Naturelle, Paris (lost, no number) Description: Solitary attached corallum varying from flat to slightly convex forms; sharp awl-shaped dentition (septal teeth numerous, regularly distributed), primary and secondary septa thickned with inner ends often porous; diameter in adult individuals around 7���10 cm (maximum of about 12 cm); parathecal walls, costae coarsely spined, septa lateral spines finer, longer and more scattered (visible to the naked eye), spongy columella usually rounded. Remarks: According to Lang (1971) where S. cubensis and S. lacera co-occur, the former are commonly 5 to 15 times as abundant as the latter., Published as part of Neves, Elizabeth, Johnsson, Rodrigo, Sampaio, Claudio & Pichon, Michel, 2006, The occurrence of Scolymia cubensis in Brazil: revising the problem of the Caribbean solitary mussids, pp. 45-54 in Zootaxa 1366 on page 49, DOI: 10.5281/zenodo.174809, {"references":["Milne Edwards, H., Haime, J. (1849) Recherches sur les polypiers. Annales de Sciences Naturalles, Zoologie, 12, 95 - 197.","Wells, J. W. (1971) Note on the scleractinian corals Scolymia lacera and S. cubensis in Jamaica. Bulletin of Marine Science, 21 (4), p. 960 - 963.","Lang, J. (1971) Interspecific aggression by scleractinian corals. The rediscovery of Scolymia cubensis (Milne Edwards & Haime). Bulletin of Marine Science, 21, 4, 952 - 959.","Humann, P. (1993) Reef coral identification, Florida, Caribbean, Bahamas. New World Publications, Inc., Florida, 239 pp.","Zlatarski, V. N. & Estalella, N. M. (1982) Les scleractiniaires de Cuba avec des donnees sur les organismes associes. Academie des Sciences de Cuba, Inst. d'Oceanologie. Editions de l'Academie Bulgare des Science, Sofia, 472 pp."]}

1. Scolymia lacera (Pallas, 1766) Material examined: USNM 53149 (Gulf of Mexico, Florida, USA). Diagnosis: Wells (1964): 381���382, pl. XXII, figs. 5, 6 Distribution: Cura��ao, Bonaire, Jamaica, Cuba, Bahamas, South Florida. In: Wells (1964,1971), Lang (1971), Zlatarski and Estalella (1982) Holotype: lost (no number) Description: Solitary attached corallum varying from concave, slightly flabelloid to discoidal forms, rounded; thick primary septa, wide triangular-shaped dentition (septal teeth numerous, regularly distributed); diameter in adult individuals around 10���12 cm (maximum of about 15 cm); parathecal walls; costae coarsely spined; septa lateral spines are low and concentrated along midline of the dentations, spongy columella usually elliptical. Remarks: According to Lang (1971) ���fleshy Scolymia ��� (S. lacera) shows highly agressive interactions with ���smooth Scolymia ��� (S. cubensis), also attacking other neighboring corals by extruding the mesenterial filaments. Scolymia lacera has been reported in deeper zones being eventually abundant in depths of 30 to 60 m on Jamaican reefs (known bathymetric range: 25 to 140 m). Largest solitary monostomodeal coral in the West Indies. Dentition more regular than that of S. cubensis and S. wellsi., Published as part of Neves, Elizabeth, Johnsson, Rodrigo, Sampaio, Claudio & Pichon, Michel, 2006, The occurrence of Scolymia cubensis in Brazil: revising the problem of the Caribbean solitary mussids, pp. 45-54 in Zootaxa 1366 on page 48, DOI: 10.5281/zenodo.174809, {"references":["Pallas, P. S. (1766) Elenchus Zoophytorum. Varrentrapp F, Hagae-Comitum, 451 pp.","Wells, J. W. (1964) The recent solitary mussid scleractinian corals. Zoologische Mededelingen, 39, 375 - 384.","Lang, J. (1971) Interspecific aggression by scleractinian corals. The rediscovery of Scolymia cubensis (Milne Edwards & Haime). Bulletin of Marine Science, 21, 4, 952 - 959.","Zlatarski, V. N. & Estalella, N. M. (1982) Les scleractiniaires de Cuba avec des donnees sur les organismes associes. Academie des Sciences de Cuba, Inst. d'Oceanologie. Editions de l'Academie Bulgare des Science, Sofia, 472 pp."]}

Order Scleractinia Bourne, 1900 Family Mussidae Ortmann, 1890 Genus Scolymia Haime, 1852, Published as part of Neves, Elizabeth, Johnsson, Rodrigo, Sampaio, Claudio & Pichon, Michel, 2006, The occurrence of Scolymia cubensis in Brazil: revising the problem of the Caribbean solitary mussids, pp. 45-54 in Zootaxa 1366 on page 48, DOI: 10.5281/zenodo.174809, {"references":["Haime, J. (1852) Catalogue raisonne des fossiles nummulitiques du Comte de Nice. Memoires de la Societe de Geologique de France, 4, 279 - 290."]}