Solitary Corals Research Articles

KD IRAK’TA İLK KEZ TANIMLANAN RUDİSTLER (BIVALVIA): SİSTEMATİK PALEONTOLOJİ VE PALEOBİYOCOĞRAFYA

The Maastrichtian Aqra Formation around Mawat-Chwarta (Sulaimaniya city) in NE Iraq consists mainly of coarse grained detrital limestone, locally containing terrigenous clastics, and is characterized by abundant rudists in life position. The rudist biostromes are very common in the formation and benthic foraminifers, gastropods and non-rudist bivalves with scarcer echinoderms and solitary corals are associated with the rudists. This first determination of rudists from NE Iraq recognizes the following species, Dictyoptychus aff. morgani, Sauvagesia somalica, Hippurites cornucopiae, Praeradiolites subtoucasi and Lapeirousia jouanneti, as well as some indeterminable radiolitid sections. This rudist fauna is assigned to the Hippurites cornucopiae interval zone indicating a mid to Late Maastrichtian age. Dictyoptychus is an endemic rudist genus for the Arabian Plate, to which Sauvagesia somalica also seems to be limited. Other determined species are recorded mostly from the central-eastern Mediterranean Tethys, and to a lesser extend from the Arabian Plate. The determination of rudists from NE Iraq fills an important gap in terms of the taxonomic database and palaeobiogeography. The data on the rudist fauna reveals the existence of a shallow marine dispersal route for rudist larvae during the Maastrichtian along the area of the present Zagros fold-thrust belt from SE Turkey across NE Iraq towards SW Iran

A Vertical Wall Dominated by Acesta excavata and Neopycnodonte zibrowii, Part of an Undersampled Group of Deep-Sea Habitats

We describe a novel biotope at 633 to 762 m depth on a vertical wall in the Whittard Canyon, an extensive canyon system reaching from the shelf to the deep sea on Ireland’s continental margin. We explored this wall with an ROV and compiled a photomosaic of the habitat. The assemblage contributing to the biotope was dominated by large limid bivalves, Acesta excavata (mean shell height 10.4 cm), and deep-sea oysters, Neopycnodonte zibrowii, at high densities, particularly at overhangs. Mean density of N. zibrowii increased with depth, with densities of the most closely packed areas of A. excavata also increasing with depth. Other taxa associated with the assemblage included the solitary coral Desmophyllum dianthus, cerianthid anemones, comatulid crinoids, the trochid gastropod Margarites sp., the portunid crab Bathynectes longispina and small fish of the family Bythitidae. The scleractinian coral Madrepora oculata, the pencil urchin Cidaris cidaris and a species of Epizoanthus were also common. Prominent but less abundant species included the flytrap anemone Actinoscyphia saginata, the carrier crab Paramola cuvieri, and the fishes Lepidion eques and Conger conger. Observations of the hydrography of the canyon system identified that the upper 500 m was dominated by Eastern North Atlantic Water, with Mediterranean Outflow Water beneath it. The permanent thermocline is found between 600 and 1000 m depth, i.e., in the depth range of the vertical wall and the dense assemblage of filter feeders. Beam attenuation indicated nepheloid layers present in the canyon system with the greatest amounts of suspended material at the ROV dive site between 500 and 750 m. A cross-canyon CTD transect indicated the presence of internal waves between these depths. We hypothesise that internal waves concentrate suspended sediment at high concentrations at the foot of the vertical wall, possibly explaining the large size and high density of filter-feeding molluscs.

Microendolithic structures from the Fort Payne Formation (lower Mississippian), Kentucky and Tennessee: Implications for the paleoenvironment of carbonate mud-mounds

Resin cast embedment and naturally occurring internal molds have revealed an assemblage of microendoliths from the Lower Mississippian Fort Payne Formation. Microendoliths produced by the heterotrophs Orthogonum lineare, Orthogonum giganteum, and Saccomorpha clava dominate this unit, as well as the phototroph-produced traces Ichnoreticulina elegans and Fascichnus dactylus, a chlorophyte (Ostreobium quekettii) and cyanobacterium (Hyella caespitosa), respectively. They were found within a variety of fossil substrates, including solitary corals, bryozoans, brachiopods, and gastropods, with a notable absence in all trilobites and echinoderms. The Fort Payne from the Lake Cumberland/Dale Hollow region of southern Kentucky–northern Tennessee contains a suite of fossiliferous green shale deposits with isolated locations of enigmatic carbonate mud-mounds. The latter, commonly referred to as ‘Waulsortian’ mounds in other geographical areas, have been the center of much speculation in the past few decades, and the paleoenvironmental parameters behind their formation remain controversial. Using the aforementioned microendoliths, a sense of the light availability within the Illinois Basin can be determined. The assemblage of ichnotaxa uncovered is representative of light conditions spanning from dysphotic to aphotic. Using previously constrained depth parameters that indicate a depth of no more than 100m, a dysphotic environment suggests that the water column was eutrophic, presumably due to high productivity within the Illinois Basin. This would seem to corroborate several other inferences about the Early Mississippian, including the growing number of suspension feeding echinoderms, the restructuring of phytoplanktonic communities and increased nutrient flux from a developing terrigenous floral weathering regime in the Early Mississippian.

Lower Carboniferous rugose corals from the Arabian Plate: An insight from the Hakkari area (SE Turkey)

The Köprülü Formation of the Hakkari area (SE Turkey) is composed of a mixed carbonate–siliciclastic succession of Early Carboniferous age. The lower part of the formation yielded an abundant but poorly diversified coral fauna composed of small non-dissepimented solitary rugose corals, namely Rotiphyllum cf. simulatumFedorowski 2009, Zaphrentites parallela (Carruthers, 1910), cf. Gorizdronia, gen. et sp. indet., Amplexizaphrentis sp. and Amplexizaphrentis zapense sp. nov. and specimens of Caninia cf. cornucopiaeMichelin in Gervais 1840, a dissepimented solitary coral showing a counter septum-related columella. The lower part of the Köprülü Formation is of supposed late Tournaisian age based on micropaleontological data. However, the coral assemblage indicates rather an early Viséan age. The Hakkari corals form a strongly facies-related association (“Cyathaxonia fauna”) and are compared to other areas with some difficulties. The most similar, time-equivalent faunal associations is that of the Sinai Peninsula (NE Egypt). Both localities belonged, during Early Carboniferous times, to the Arabian Platform situated along the northern margin of Gondwana. The Gondwana-related Taurides units (Aladağ), North Iran Block and Afghanistan, characterized by a dominant carbonate facies and more diversified coral faunas, formed during these times, the distal parts of the Arabian Platform.

Resource Partitioning and Paleoecology of Neogene Free-Living Corals as Determined from Skeletal Stable Isotope Composition

Changes in the Caribbean coral fauna associated with Plio-Pleistocene extinctions are unique in that origination preceded extinction. This pattern is particularly evident in free-living solitary and flabello-meandroid (FSFM) corals. Here we use the stable isotopes of carbon and oxygen to assess the paleoautecology of pre-turnover FSFM corals from the Cibao Basin, northern Dominican Republic. We assess photosymbiosis and resource utilization within FSFM corals and how changing Neogene paleoclimatic and paleoceanographic conditions may have contributed to originations and extinctions within this unique ecological group. Measurements of[deltha]13C and [deltha]18O were compared between two known zooxanthellate coral species, two known azooxanthellate species, and six FSFM species of the Cibao Basin. Skeletal[deltha]13C provided the best indicator of resource utilization by FSFM corals. For both modern reef corals and Mio-Pliocene reef corals from the Cibao Basin, values of [deltha]13C fall between 0%o and -2%o whereas the [deltha]13C values of azooxanthellate corals generally fall between -3%o and -9%o. Both modern and fossil FSFM corals lie intermediate to these end members. FSFM values of [deltha]13C fall between -1%o and -4%o and suggest reduced photosymbiosis in comparison to typical reef corals. Reduced photosymbiosis of FSFM corals in comparison to reef corals is also reflected in a stronger covariation between [deltha]13C and [deltha]18O. Though FSFM corals are clearly utilizing translocated carbon from associated algal symbionts, the more depleated values of [deltha]13C and covariation with [deltha]18O suggest a greater dependence on heterotrophic feeding. This ecological lifestyle likely has made FSFM corals sensitive to changes in primary productivity that characterize the Caribbean Neogene.

Metabolism of an Antarctic solitary coral, Flabellum impensum

Few physiological or behavioral studies have been undertaken on the genus Flabellum, particularly on Antarctic species. The present study characterizes the metabolism of the endemic Antarctic coral F. impensum, one of the world's largest solitary corals, with measurements of oxygen consumption rate and metabolic enzyme activity. F. impensum had a low rate of oxygen consumption at 0°C, ranging from 0.06 to 0.64μmolO2g−1h−1 and averaging 0.31μmolO2g−1h−1, calculated using tissue wet mass. Ammonium excretion averaged 4.21nmolNH4+gwm−1h−1 (range: 0.54–13.99nmolNH4+gwm−1h−1). The activity values of the metabolic enzymes citrate synthase (CS), malate dehydrogenase (MDH), and lactate dehydrogenase (LDH) fell within the normal range expected for a cnidarian, averaging 0.13 (range: 0.04–0.32), 1.01(range: 0–3.51), and 0.42 (range: 0.18–0.99) activity units (U) gwm−1, respectively. Skeletal density averaged 22% more than the density of pure aragonite and a count of the growth bands on the calyx suggests that this species has a linear extension rate of approximately 1mm per year. F. impensum is a long-lived, slow-growing coral, with a low metabolic rate.

Early Silurian (Rhuddanian) rugose corals and sponges from the Ak-Kerme Peninsula, Kazakhstan

An assemblage of earliest Silurian (Llandovery, Rhuddanian) fossils from South Kazakhstan (Ak-Kerme Peninsula, Lake Balkhash) contains solitary rugose corals (Calostylis denticulata, Streptelasma? sp., and Cystipaliphyllum sp.) and the demosponge Calycocoelia typicalis, which are described here. This assemblage occurs with previously described brachiopods and constitutes a post extinction survival fauna; such faunas are poorly known and this study fills a gap in our knowledge. All three genera of Rugosa were transitional across the Ordovician–Silurian boundary and are also reported from other parts of Kazakhstan, Uzbekistan, and Tajikistan during the Llandovery. Streptelasma had already been present in Kazakhstan during the Ordovician, while during the Rhuddanian Calostylis immigrated from Baltica or China, and Cystipaliphyllum from the Australian part of Gondwana. Demosponges are rare during the Llandovery but probably had a cosmopolitan distribution. Calycocoelia typicalis marks the first Rhuddanian record of lithistid demosponges, and the first record of Silurian demosponges from Kazakhstan.

Pertumbuhan Fragmen Karang Polyphyllian Talpina Dengan Metode Transplantasi Mini-floating Nursery Di Perairan Teluk Awur Jepara

Ornamental coral trade which is taken directly from nature is a source of revenue for the Indonesian economy, but on the other hand it is also a threat to coral reef conservation. Along with the increasing number of the ornamental coral exports it must be balanced with the conservation effort through coral transplantation. One of coral reef species that can regenerate and widely traded is Polyphillia talpina. Transplantation method used is the mini-floating nursery method, the coral transplantation method performed by a state hovering in the water column. This study aims was to determine the growth of solitary corals which were transplanted by mini-floating nursery method and to determine the process of regeneration that occurs with mini-floating nursery transplant method in Teluk Awur, Jepara. Growth of the highest coral transplant P. talpina seen in coral fragments with the size of 4 cm with a gain of 0,44 cm difference with regeneration process and the addition of the highest number of mouth was also to 70,12%. Statistical analysis showed there were no significant differences (p = 0,652) on growth and the initial size of the two fragments.

Serpula aggregates and their role in deep-sea coral communities in the southern Adriatic Sea

We document a remarkable abundance of the tubeworm Serpula vermicularis Linnaeus, 1767, in bathyal coral habitats from the Bari Canyon System in the southern Adriatic Sea. Here, the specimens of S. vermicularis grow from muddy substrate either as isolated individuals or as localized clusters of multiple individuals. Peculiar tube aggregations are also associated with Madrepora oculata build-ups and other stony corals including Desmophyllum dianthus. Three types of coral-serpulid (C–S) frameworks have been recognized based upon size and shape. The abundance of S. vermicularis increases with the size of C–S frameworks, which results from superimposition, overgrowth, and/or intergrowth of scleractinians and serpulids. Several generations of S. vermicularis contribute to the C–S frameworks, each most probably accounting for more than 8 years and presumably existing in the area for the last hundreds of years. At a meso-scale, the distribution pattern of serpulids seems to be mainly governed by currents and siltation. A further constraint is the co-occurring solitary coral D. dianthus within frameworks. The successful sea-bottom colonization by S. vermicularis and associated C–S frameworks is possibly related to a high oxygen content and food supply derived from the North Adriatic Dense Water (NAdDW). The flourishing populations of S. vermicularis as well as the peculiarity of C–S frameworks suggest that deep-sea canyons provide important benthic habitats in bathyal environments.

Early Permian rugose coral Cyathaxonia faunas from the Sibumasu Terrane (Southeast Asia) and the southern Sydney Basin (Southeast Australia): Paleontology and paleobiogeography

The Sibumasu Terrane consists of allochthonous blocks located between Gondwana and Eurasia and had a tectonic evolutionary history characterized by rifting from Gondwana during the Early Permian, northward drifting during the Mid–Late Permian, and final amalgamation with Eurasia during the Triassic. The rugose coral Cyathaxonia faunas, which are typically composed of small, solitary, and non-dissepimented rugose corals, occur in the Lower Permian of the Sibumasu Terrane in Southeast Asia and the southern Sydney Basin of southeastern Australia. These Cyathaxonia faunas suggest cold or cool water shallow marine conditions, which is also supported by the occurrence of glaciomarine dropstones and diamictites in associated sediments and immediately underlying strata. Significant differences in the composition of coral faunas between the Sibumasu Terrane and the Cathaysian continent (comprising tectonic blocks such as South China and Indochina) indicate that the Sibumasu was probably located at the northern margin of Gondwana during the Early Permian, as opposed to Cathaysia then located near the Paleo-equator in the eastern Paleotethys. The Middle Permian coral faunas in the Sibumasu Terrane are dominated by both solitary and compound Waagenophyllidae. The latter is a common element in the Cathaysian continent. But, some distinctive and endemic taxa occurred in the Sibumasu Terrane during this time, suggesting that it was still an independent (isolated) paleobiogeographical entity, located at a certain distance from the Cathaysian continent. A total of eleven small solitary coral species from the Sibumasu Terrane and the southern Sydney Basin are described in detail. Of these five are new (Ufimia khaokaeonoi, Zaphrentites shidianense, Euryphyllum khaokaeoyai, E. kanchanaburi, and ?Claviphyllum baoshanense).

Resilience of cold-water scleractinian corals to ocean acidification: Boron isotopic systematics of pH and saturation state up-regulation

The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high δ11B compositions ranging from 23.2‰ to 28.7‰. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pHcf), being elevated by ∼0.6–0.8units (ΔpH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower δ11B composition of 15.5‰, with a corresponding lower ΔpH value of ∼0.3units, reflecting the importance of mineralogical control on biological pH up-regulation.The solitary coral D. dianthus was sampled over a wide range of seawater pHT and shows an approximate linear correlation with ΔpHDesmo=6.43−0.71pHT (r2=0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where ΔpHDesmo=1.09−0.14Ωarag (r2=0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pHcf, and consequently Ωcf, of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca2+-ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (δ11Bcarb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium.We also show that the relatively strong up-regulation of pH and consequent elevation of the internal carbonate saturation state (Ωcf ∼8.5 to ∼13) at the site of calcification by cold-water corals, facilitates calcification at or in some cases below the aragonite saturation horizon, providing a greater ability to adapt to the already low and now decreasing carbonate ion concentrations. Although providing greater resilience to the effects of ocean acidification and enhancing rates of calcification with increasing temperature, the process of internal pHcf up-regulation has an associated energetic cost, and therefore growth-rate cost, of ∼10% per 0.1 pH unit decrease in seawater pHT. Furthermore, as the aragonite saturation horizon shoals with rapidly increasing pCO2 and Ωarag<1, increased dissolution of the exposed skeleton will ultimately limit their survival in the deep oceans.

The puzzling presence of calcite in skeletons of modern solitary corals from the Mediterranean Sea

The skeleton of scleractinian corals is commonly believed to be composed entirely of aragonite due to the current Mg/Ca molar ratio of seawater, which thermodynamically favours the deposition of this polymorph of calcium carbonate (CaCO3). However, some studies have shown that other forms of CaCO3 such as calcite can be present in significant amount (1–20%) inside tropical coral skeletons, significantly impacting paleo-reconstructions of SST or other environmental parameters based on geochemical proxies. This study aims at investigating for the first time, (1) the skeletal composition of two Mediterranean solitary corals, the azooxanthellate Leptopsammia pruvoti and the zooxanthellate Balanophyllia europaea, across their life cycle, (2) the distribution of the different CaCO3 forms inside skeletons, and (3) their implications in paleoclimatology. The origin of the different forms of CaCO3 observed inside studied coral skeletons and their relationships with the species’ habitat and ecological strategies are also discussed. CaCO3 composition of L. pruvoti and B. europaea was investigated at six sites located along the Italian coasts. Skeleton composition was studied by means of X-ray powder diffraction and Fourier transform infrared spectroscopy. A significant amount of calcite (1–23%) was found in more than 90% of the studied coral skeletons, in addition to aragonite. This calcite was preferentially located in the basal and intermediate areas than at the oral pole of coral skeletons. Calcite was also mainly located in the epitheca that covered the exposed parts of the coral in its aboral region. Interestingly in B. europaea, the calcite content was negatively correlated with skeleton size (age). The presence of calcite in scleractinian corals may result from different mechanisms: (1) corals may biologically precipitate calcite crystals at their early stages in order to insure their settlement on the substrate of fixation, especially in surgy environments; (2) calcite presence may result from skeletons of other calcifying organisms such as crustose coralline algae; and/or (3) calcite may result from the infilling of galleries of boring microorganisms which are known to colonize coral skeletons. We suggest that more than one of the above mentioned processes are involved.

Sea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics

San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ∼270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38–36 m (terrace 2a), 33–28 m (terrace 2b), and 13–8 m (terrace 1). Uranium-series dating of solitary corals from these terraces yields three clusters of ages: ∼120 ka on terrace 2a (marine isotope stage [MIS] 5.5), ∼120 and ∼100 ka on terrace 2b (MIS 5.5 and 5.3), and ∼80 ka (MIS 5.1) on terrace 1. We conclude that corals on terrace 2b that date to ∼120 ka were reworked from a formerly broader terrace 2a during the ∼100 ka sea stand. Fossil faunas differ on the three terraces. Isolated fragments of terrace 2a have a fauna similar to that of modern waters surrounding San Nicolas Island. A mix of extralimital southern and extralimital northern species is found on terrace 2b, and extralimital northern species are on terrace 1. On terrace 2b, with its mixed faunas, extralimital southern species, indicating warmer than present waters, are interpreted to be from the ∼120 ka high sea stand, reworked from terrace 2a. The extralimital northern species on terrace 2b, indicating cooler than present waters, are interpreted to be from the ∼100 ka sea stand. The abundant extralimital northern species on terrace 1 indicate cooler than present waters at ∼80 ka.Using the highest elevations of the ∼120 ka platform of terrace 2a, and assuming a paleo-sea level of +6 m based on previous studies, San Nicolas Island has experienced late Quaternary uplift rates of ∼0.25–0.27 m/ka. These uplift rates, along with shoreline angle elevations and ages of terrace 2b (∼100 ka) and terrace 1 (∼80 ka) yield relative (local) paleo-sea level elevations of +2 to +6 m for the ∼100 ka sea stand and −11 to −12 m for the ∼80 ka sea stand. These estimates are significantly higher than those reported for the ∼100 ka and ∼80 ka sea stands on New Guinea and Barbados. Numerical models of the glacial isostatic adjustment (GIA) process presented here demonstrate that these differences in the high stands are expected, given the variable geographic distances between the sites and the former Laurentide and Cordilleran ice sheets. Moreover, the numerical results show that the absolute and differential elevations of the observed high stands provide a potentially important constraint on ice volumes during this time interval and on Earth structure.

The type of Aplosmilia vidali Angelis d’Ossat, 1905 (Scleractinia; Early Cretaceous)

The Early Cretaceous Scleractinian coral species Aplosmilia vidali Angelis d´Ossat, 1905 is revised and a lectotype is designated. The solitary coral belongs to the genus Tiarasmilia and is probably a senior synonym of the type species of this genus, Tiarasmilia casteri Wells, 1932.

Stratal, sedimentary and faunal relationships in the Coniacian 3rd-order sequence of the Iberian Basin, Spain

The Coniacian 3rd-order sequence in the Iberian Basin is represented by a carbonate ramp-like open platform. The biofacies is mainly dominated by nekto-benthic (such as ammonites) and benthic organisms (such as bivalves, mainly rudists) with scarce solitary corals (hermatypics are absent), showing major differences among the Transgressive System Tract (TST) and Highstand Normal Regression (HNR). During the TST, platform environments were dominated by Pycnodonte, other oysters and molluscs (with only subordinate rudists) and ammonites, which were represented by ornamented platycones ( Tissotioides and Prionocycloceras), and by smooth oxycones ( Tissotia and Hemitissotia). During the HNR, shallow water depositional areas were occupied by rudist-dominated associations. Storm- and wind-induced currents and waves acting on these associations produced large amounts of loose bioclastic debris that covered outer platform areas. This facies belt graded landwards into protected, lower-energy settings (inner platform, lagoon and littoral environments). Rudist biostromes were preserved in seaward areas of these protected shallow environments of overall moderate to low hydrodynamic gradient, which was punctuated by storms. In this environment and landwards, large areas of marly substrate favoured the presence of gastropods, other bivalves, echinoderms, benthic foraminifera and solitary corals. Because of the input of siliciclastics and, probably, the lack of nutrients in suspension, the establishment of rudist communities was difficult in more landward areas of the lagoon and in tidal environments. This heterozoan carbonate factory was thus controlled by warm-water conditions and high energy levels, which were responsible for high-nutrient contents in suspension.

Late Eocene transgressive sedimentation in the western Swiss Alps: Records of autochthonous and quasi-autochthonous biofacies on a karstic rocky shore

Carbonate karst unconformities represent primary sequence-stratigraphic boundaries but, where sealed by marine sedimentary successions, also signify ancient rocky shores. During the Late Eocene (Priabonian), a shallow sea flooded the deeply karstified and brecciated Cretaceous carbonate bedrocks of the western Swiss Alps. Transgression resulted in the formation of a rocky archipelago of basement highs with elevations of up to 20m and dip angles varying from sub-horizontal to sub-vertical. Although rocky coasts are commonly subjected to vigorous waves, strong currents and storm surges, protected and restricted narrow embayments existed between these islands. The new habitats thus created were colonized by intertidal and shallow subtidal macrobiota, which can be grouped into four biofacies associations: 1) endolithic; 2) epilithic; 3) intertidal; and 4) shallow subtidal. The endolithic biofacies corresponds to an impoverished ichnoassemblage composed of Gastrochaenolites and Entobia borings. The epilithic biofacies is made up of well-preserved rocky-shore biota such as oysters and corals exhibiting an encrusting lifestyle. The intertidal biofacies is composed of wholly preserved shells of potamidid gastropods (Tympanotonos? sp.). The biota present in these biofacies are monospecific or show a very poor species diversity. This fact is in agreement with the pioneer character of the organisms and the sheltered and restricted environments they inhabited. The shallow subtidal biofacies has higher diversity and is characterized by dasycladaceans, oysters, cardiid bivalves, potamidid, ampullinid and Campanile giganteum gastropods, echinoids and solitary corals. The transgressive carbonates evolve upwards into sandy limestones and sandstones displaying sedimentary structures formed in high-energy conditions. This progressive lithofacies change coincides with the opening of the coastal system once the irregular palaeotopography was filled. The transgressive deposits reported here are of significance in that they contain remarkable examples of shallow subtidal and intertidal autochthonous and quasi-autochthonous biofacies associations generated in rocky coast and soft-sediment environments. To our knowledge, this is the first study documenting in detail a rocky shore in the Priabonian.

Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

The prolific macroalgal forests in shallow (< 20 m), warm-temperate, marine environments off southern Yorke Peninsula, South Australia have two carbonate-producing habitats, 1) upward-facing, exposed rock surfaces beneath large phaeophytes, and 2) concealed rock surfaces under overhangs, on rock walls, in crevasses, and indentations that all lie behind a curtain of brown macroalgae. Exposed surfaces have three growth tiers; 1) a basal, cm-high veneer or turf of crustose corallines, geniculate corallines, and short fleshy red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5–20 cm-high community of fleshy red algae, and 3) a 20–100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in adjacent seagrass factories. Particles produced in the macroalgal factory are shed onto the adjacent seafloor, where they form the requisite sandy substrates for quick colonization by seagrasses. Thus, over time the sediment in this shallow but hydrodynaically energetic environment becomes a mixture of materials from the two sources with seagrasses contributing gastropods, large benthic foraminifers, spirorbids, bryozoans and articulated corallines to the sediment milieu. If this system is a typical example, then warm-temperate Neogene carbonate facies related to macroalgal factories should be a mixture of materials from the rocky substrates, a calcareous infauna, and marine seagrasses.

Carboniferous-Permian rugose coral Cyathaxonia faunas in China

The Cyathaxonia faunas are widely distributed in the Carboniferous and Permian strata in China. The fauna in China contains 12 families and 40 genera, and can be recognized as three episodes from Early Carboniferous to the end-Permian in terms of their occurrence and composition: 1) Mississippian; 2) Pennsylvanian-Early Permian; 3) Middle Permian-Late Permian. They were relatively abundant in episodes 1 and 2. A decrease of family Antiphyllidae and an increase of family Hapsiphyllidae can be observed from Early Carboniferous to the end-Permian. Two case studies are given to illustrate the bio-facies of the Cyathaxonia faunas, which are from the Mississippian of Baoshan, West Yunnan and the Mississippian of Chaohu, South Anhui. In both areas, Cyathaxonia faunas occur just below the large dissepimented solitary and compound coral assemblages in a continuous sequence in a single section, which implies that the occurrence of these small, non-dissepimented solitary corals is not strictly related with Gondwanan or Peri-gondwanan cold water environment, but might be controlled by such benthic conditions as deeper, mud-rich, quieter, and darker sedimentary environments.

Reproductive periodicity, spawning and development of the deep-sea scleractinian coral Flabellum angulare

Increasing threats to deep-sea corals highlight the need to expand knowledge of these taxa so that conservation measures can be developed. The present study focused on the reproductive patterns of the deep-sea solitary coral Flabellum angulare. A series of samples (n = 398) collected in 2006–2008 in the northwest Atlantic at depths of 925–1,430 m revealed that gametogenesis was synchronous among males and females and fluctuated seasonally. Initiation of gamete synthesis was estimated to be in August–September and spawning in June. Further analysis and daily monitoring of 30–60 individuals maintained in a flow-through mesocosm showed that gamete release occurred in March–June with a peak in May. Release of oocytes coincided with rising seawater temperatures and high deposition rates indicative of elevated water column productivity. Oocytes (900–1,200 μm diameter) were released through the oral cavity, generally in bundles of 3–5 surrounded by mesenterial filaments and attached to a thread (30–50 mm long). As oocytes became free in the water column, ovulation occurred followed by fertilization. Eggs/embryos initially remained on the tentacles of the spawner before either falling onto the substratum or floating to the surface. The embryos developed into planula larvae measuring 2–3 mm in length within about 24 h. Together, these findings shed new light on the strategies used by deep-sea corals to maximize their reproductive success.

Genesis and internal architecture of the Middle to Upper Devonian Gwirat Al Hyssan reef-mound (Western Sahara)

On the southern flanks of the Tindouf Basin (Western Sahara) reefal complexes of various sizes were developed, mostly of Givetian age but possibly reaching into the early Frasnian. Surrounding sedimentary rocks were dominantly sandstones, siltstones and marls. The larger reef complexes in the northeastern part of Western Sahara show three reef cycles within the Givetian and lowermost Frasnian, interrupted by marly sedimentation. Farther to the west, more isolated reef structures in open shelf settings occur often showing smaller dimensions. The present study focuses on one of these western reefal build-ups. Besides large-scale reefs dominated by stromatoporoids (NE), several smaller bioherms have been investigated, such as the Gwirat Al Hyssan reef-mound near Smara. Initial reef growth was of late Givetian age as indicated by corals (e.g. Heliolites). The main reef builders were the corals Alveolites, Thamnopora, Aulopora, Frechastraea, Phillipsastrea, and, to a lesser degree, Heliolites, Scoliopora, and Roemerolites. Stromatoporoids also contributed, but were less frequent. Chaetetids (e.g. Rhaphidopora) acted as pioneer stabilizers on bare sediment surfaces. Preservation in life position was frequently observed in both groups of organisms. Crinoids are not rare, but only present as debris. In distinct areas of the reef (depressions) concentrations of brachiopods and small solitary corals occur. The reef-mound has a present elevation of 17 m and measures about 370 m in diameter. Vertical as well as horizontal zonation could be recognized in detail. The initial reef growth started on a submarine shoal of siliciclastic sediments, containing various trace fossils and sedimentary structures such as cross-bedding and wave ripples; interference ripples suggest generation in very shallow water. The initial reef-building organisms were encrusting chaetetids, followed by platy Frechastraea colonies; thamnoporids were also present. The overlying reef limestones consist of different corals and, to a minor degree, stromatoporoids. The latter are sparsely distributed vertically as well as horizontally, depending on their position within the reef. Growth forms are more robust (bulbous) towards higher hydrodynamic conditions at the southern reef front. Reef growth is interrupted by debris limestones of thamnoporid and crinoid bioclasts, intercalated with detrital platy stromatoporoids. Generally, the debris was not transported over long distances, as demonstrated by the presence of relatively large fragments. This ‘debris phase’ (early Frasnian) is overlain by the last documented stage in reef development represented by medium- to thin-bedded coral-rich limestones. The onset of the carbonate production of the Gwirat Al Hyssan reef-mound is maybe related to the global transgressive Givetian–Frasnian Boundary Event.