Colonial Corals Research Articles

The development of the Betton Farm Coral Bed within the Malton Oolite Member (Upper Jurassic, Middle Oxfordian) of the Scarborough District, North Yorkshire, UK

Summary Betton Farm quarries contain, within a small area, a remarkable range of facies associated with the development of a Jurassic coral reef. A NW–SE-trending barrier reef protected the whole area containing the two quarries. Betton Farm North Quarry displays Thamnasteria patch reefs. These consist of scattered, 1 m high masses of colonial coral surrounded by reef debris that were situated behind the barrier within a large reef platform area. In Betton Farm South Quarry, bioclastic sand, consisting largely of coral and bivalve debris, interdigitates with the development of a small ribbon reef made up of the massive colonial coral Thamnasteria . This ribbon reef, only 3 to 4 m wide, sheltered a lagoonal area that accumulated lime mud and was colonized by large gastropods and burrowing bivalves. A fauna of reef-specializing bivalves and echinoids occupied these areas of patch/ribbon reef development, which were periodically swept by nutrient-bearing currents. Competition between the growth of the ribbon of Thamnasteria and the accumulation of fringing sediments saw periods when the Thamnasteria expanded over the coral-shell sand, and periods when the encroaching sediment cut back the growth of the Thamnasteria considerably. Considered initially to represent the Coral Rag Member of the Coralline Oolite Formation, the Betton Farm Coral Bed is now seen to represent localized coral reef developments situated near the base of the Malton Oolite Member, and growing upon antecedent bedrock features such as hard-ground surfaces that formed during pauses in sedimentation of the Malton Oolite.

Biomineralization in Mediterranean Corals: The Role of the Intraskeletal Organic Matrix

The precipitation of calcium carbonate was carried out in the presence of the intraskeletal organic matrix (OM) extracted from Mediterranean corals. They were diverse in growth form and trophic strategy, Balanophyllia europaea and Leptopsammia pruvoti—solitary corals, only the first zooxanthellate coral—and Cladocora caespitosa and Astroides calycularis—colonial corals, only the first zooxanthellate coral. The results showed that, although the OM marked differences among species, the diverse influence over the calcium carbonate precipitation was evident only for B. europaea. This OM was the most prone to favor the precipitation of aragonite in the absence of magnesium ions, according to overgrowth and solution precipitation experiments. In artificial seawater, where magnesium ions were present, this OM, as well the one from A. calycularis, precipitated mainly a form of amorphous calcium carbonate different from that obtained with SOM from L. pruvoti or C. caespitosa. The amorphous calcium carbonate from B...

Analytical pyrolysis-based study on intra-skeletal organic matrices from Mediterranean corals.

Off-line analytical pyrolysis combined with gas chromatography–mass spectroscopy (GC–MS), directly or after trimethylsilylation, along with infrared spectroscopy and amino acid analysis was applied for the first time to the characterization of the intra-skeletal organic matrix (OM) extracted from four Mediterranean hard corals. They were diverse in growth form and trophic strategy namely Balanophyllia europaea and Leptopsammia pruvoti—solitary corals, only the first having zooxanthelle—and Cladocora caespitosa and Astroides calycularis—colonial corals, only the first with zooxanthelle. Pyrolysis products evolved from OM could be assigned to lipid (e.g. fatty acids, fatty alcohols, monoacylglicerols), protein (e.g. 2,5-diketopiperazines, DKPs) and polysaccharide (e.g. anhydrosugars) precursors. Their quantitative distribution showed for all the species a low protein content with respect to lipids and polysaccharides. A chemometric approach using principal component analysis (PCA) and clustering analysis was applied on OM mean amino acidic compositions. The small compositional diversity across coral species was tentatively related with coral growth form. The presence of N-acetyl glucosamine markers suggested a functional link with other calcified tissues containing chitin. The protein fraction was further investigated using novel DKP markers tentatively identified from analytical pyrolysis of model polar linear dipeptides. Again, no correlation was observed in relation to coral ecology. These analytical results revealed that the bulk structure and composition of OMs among studied corals are similar, as it is the textural organization of the skeleton mineralized units. Therefore, they suggest that coral’s biomineralization is governed by similar macromolecules, and probably mechanisms, independently from their ecology.

Postglacial Early Permian (late Sakmarian–early Artinskian) shallow-marine carbonate deposition along a 2000 km transect from Timor to west Australia

Late Sakmarian to early Artinskian (Early Permian) carbonate deposition was widespread in the marine intracratonic rift basins that extended into the interior of Eastern Gondwana from Timor in the north to the northern Perth Basin in the south. These basins spanned about 20° of paleolatitude (approximately 35°S to 55°S). This study describes the type section of the Maubisse Limestone in Timor-Leste, and compares this unit with carbonate sections in the Canning Basin (Nura Nura Member of the Poole Sandstone), the Southern Carnarvon Basin (Callytharra Formation) and the northern Perth Basin (Fossil Cliff Member of the Holmwood Shale). The carbonate units have no glacial influence and formed part of a major depositional cycle that, in the southern basins, overlies glacially influenced strata and lies a short distance below mudstone containing marine fossils and scattered dropstones (perhaps indicative of sea ice). In the south marine conditions became more restricted and were replaced by coal measures at the top of the depositional sequence. In the north, the carbonate deposits are possibly bryozoan–crinoidal mounds; whereas in the southern basins they form laterally continuous relatively thin beds, deposited on a very low-gradient seafloor, at the tops of shale–limestone parasequences that thicken upward in parasequence sets. All marine deposition within the sequence took place under very shallow (inner neritic) conditions, and the limestones have similar grain composition. Bryozoan and crinoidal debris dominate the grain assemblages and brachiopod shell fragments, foraminifera and ostracod valves are usually common. Tubiphytes ranged as far south as the Southern Carnarvon Basin, albeit rarely, but is more common to the north. Gastropod and bivalve shell debris, echinoid spines, solitary rugose corals and trilobite carapace elements are rare. The uniformity of the grain assemblage and the lack of tropical elements such as larger fusulinid foraminifera, colonial corals or dasycladacean algae indicate temperate marine conditions with only a small increase in temperature to the north.The depositional cycle containing the studied carbonate deposits represents a warmer phase than the preceding glacially influenced Asselian to early Sakmarian interval and the subsequent cool phase of the “mid” Artinskian that is followed by significant warming during the late Artinskian–early Kungurian. The timing of cooler and warmer intervals in the west Australian basins seems out-of-phase with the eastern Australian succession, but this may be a problem of chronostratigraphic miscorrelation due to endemic faunas and palynofloras.

Telomere Shortening in the Colonial CoralAcropora digitiferaDuring Development

To test whether telomere length can be used in estimating the age of colonial corals, we used terminal restriction fragment (TRF) length analysis to compare the telomere lengths of the coral Acropora digitifera at three developmental stages: sperm, planula larvae, and polyps of adult colonies. We also compared the mean TRF lengths between branches at the center and periphery of tabular colonies of A. digitifera. A significant difference was observed in the mean TRF lengths in sperm, planulae, and polyps. The mean TRF length was longest in sperm and shortest in polyps from adult colonies. These results suggest that telomere length decreases during coral development and may be useful for estimating coral age. However, the mean TRF length of branches at the center of a table-form colony tended to be longer than that of peripheral branches, although this difference was not statistically significant. This suggests that both the chronological age of polyps and cell proliferation rate influence telomere length in polyps, and that estimating coral age based on telomere length is not a simple endeavor.

Late Carboniferous colonial Rugosa (Anthozoa) from Alaska

Late Carboniferous colonial corals from the Moscovian Saginaw Bay Formation and the underlying Bashkirian crinoidal limestone exposed on northeastern Kuiu Island and a nearby islet, part of the Alexander terrane in southeastern Alaska, are described and illustrated for the first time, and are supplemented by revision, re-description and re-illustration of most Atokan specimens from Brooks Range, northern Alaska, first described by Armstrong (1972). New taxa from the Kuiu Island area include the new species Paraheritschioides katvalae and the new genus and species Arctistrotion variabilis, as well as the new Subfamily Arctistrotioninae. The corals Corwenia jagoensis and Lithostrotionella wahooensis of Armstrong (1972) also are redefined and redescribed. Paraheritschioides jagoensis is based on the holotype of ‘C’. jagoensis. P. compositus sp. nov. is based on a “paratype” of ‘C.’ jagoensis. In addition to a redefinition and redescription of ‘L.’ wahooensis as Arctistrotion wahooense, one “paratype” of that species is described as A. simplex sp. nov. The phylogeny and suspected relationships of some fasciculate Carboniferous Rugosa also are discussed. Based on relationships and similarities within the Late Carboniferous colonial Rugosa from the Brooks Range, Kuiu Island and the eastern Klamath terrane, we conclude that all three areas were geographically close enough at that time so that larvae were occasionally dispersed by oceanic currents. Distances between these areas, however, may have been so great and/or isolation so long that individual speciation occurred in all of the various locations. That hypothetical situation is reflected by a common generic, but not a specific, content of the particular faunas.

New Late Carboniferous Heritschioidinae (Rugosa) from the Kuiu Island area and Brooks Range, Alaska

Three new species of the genus Heritschioides, i.e., H. alaskensis sp. nov., H. kuiuensis sp. nov., and H. splendidus sp. nov., and Kekuphyllum sandoense gen. et sp. nov. from the northeastern Kuiu Island area and nearby islets, part of Alexander terrane in southeastern Alaska, and Heritschioides separatus sp. nov. from the Brooks Range, Alaska, are described and illustrated. The three new fasciculate colonial coral species from the Kuiu Island area, collected from the Moscovian Saginaw Bay Formation, are phylogenetically related to those of probable Bashkirian age in the Brooks Range in northern Alaska as shown by the presence of morphologically similar species of Heritschioides. These corals from both areas also are related to one species in the Quesnel terrane in western Canada. Kekuphyllum sandoense from the Saginaw Bay Formation of the Kuiu Island area is the only cerioid-aphroid species within the Subfamily Heritschioidinae described so far. The complete early ontogeny of a protocorallite is for the first time described here on a basis of H. kuiuensis sp. nov. and compared to the hystero-ontogeny in order to show similarities and differences in those processes.

Mixed Tethyan and McCloud Belt rugose corals and fusulinids in an Upper Triassic conglomerate, central Oregon

Colonial rugose corals ranging in age from Carboniferous to Late Triassic and Early Permian (Cisuralian) fusulinids have been recovered from cobbles in a conglomerate in the Upper Triassic Brisbois Member of the Vester Formation in the Izee terrane in central Oregon. Early Permian (late Sakmarian or early Artinskian) fusulinids typical of those present in the Coyote Butte Limestone in the nearby Grindstone terrane (part of the allochthonous McCloud Belt) include Eoparafusulina, Pseudofusulinella, Chalaroschwagerina, and Schwagerina. The presence of these fusulinid genera and the Pennsylvanian coral Heritschioides?, which is mostly restricted to the McCloud Belt, suggest these particular cobbles were derived from limestone in that belt. The Early Permian fusulinids Changmeia bostwicki new species and Changmeia bigflatensis new species, and the Early Permian corals Yokoyamaella? oregonensis new species and Yokoyamaella? sp. 1, all of which have Tethyan affinities, occur rarely in other cobbles. The presence of definitive fossils from the two different realms in a conglomerate associated with beds containing Late Triassic ammonoids indicates that by Late Triassic time a fragment of a Tethyan terrane was close to or had been amalgamated with a terrane belonging to the McCloud Belt.

Upper Triassic corals from Nevada, western North America, and the implications for paleoecology and paleogeography

Late Carnian–early Norian corals from the Luning and Osobb formations in west-central Nevada represent an important Late Triassic fauna for understanding the paleoecology and the paleogeography of the eastern Panthalassa region during Late Triassic time. The corals occur in bedded limestone representing biostromes and patch reefs and their composition presages the important global changeover of faunas of the intra-Norian interval. A taxonomic analysis of over 60 specimens reveals a majority of colonial corals ranging from cerioid, astreoid (i.e., cerioid-plocoid lacking walls), meandroid and thamnasterioid types. Surprisingly, remnants of the original aragonite microstructure remain in some specimens, allowing a better comparison with more remote Tethyan corals. In total, 14 genera have been identified from Nevada while two genera remain undetermined. The fauna is composed of species considered typical of both the North American Cordillera and cratonal South America. The following genera and species are new and endemic to the Americas: Khytrastrea silberlingi and K. cuifiamorpha, Flexastrea serialis, Nevadoseris punctata, Areaseris nevadaensis and a new genus Minasteria (with Astrocoenia shastensis Smith, 1927 as type species). Likewise are the new species: Margarogyra silberlingi and Curtoseris dunlapcanyonae. Genera Meandrovolzeia, Margarogyra, Ceriostella, Ampakabastraea, Retiophyllia, Distichomeandra, Curtoseris, Thamnasteria and Astraeomorpha provide important links to the former Tethys province. The revised coral fauna changes previous views of the close taxonomic similarity with the Tethys, instead producing a paleogeographic pattern emphasizing a much greater degree of endemism. This pattern emphasizes the isolation of Nevada from the Tethys and the similarities with some outboard terranes of the Cordillera.

The geochemistry of deep-sea coral skeletons: A review of vital effects and applications for palaeoceanography

Deep-sea corals were discovered over a century ago, but it is only over recent years that focused efforts have been made to explore the history of the oceans using the geochemistry of their skeletal remains. They offer a promising archive of past oceanic environments given their global distribution, layered growth patterns, longevity and preservation as well as our ability to date them using radiometric techniques. This paper provides an overview of the current state-of-the-art in terms of geochemical approaches to using deep-sea coral skeletons to explore the history of the ocean. Deep-sea coral skeletons have a wide array of morphologies (e.g. solitary cup corals, branching colonial corals) and materials (calcite, aragonite and proteins). As such their biomineralization strategies are diverse, leading to complex geochemistry within coral skeletons. Notwithstanding these complications, progress has been made on developing methods for reconstructing the oceanographic environment in the past using trace elements and isotopic methods. Promising approaches within certain coral groups include clumped isotopes and Mg/Li for temperature reconstructions, boron isotopes and radiocarbon for carbon cycling, εNd, and radiocarbon for circulation studies and δ15N, P/Ca and Ba/Ca for nutrient tracer studies. Likewise there is now a range of techniques for dating deep-sea corals skeletons (e.g. U-series, radiocarbon), and determining their growth rates (e.g. radiocarbon and 210Pb). Dating studies on historic coral populations in the Atlantic, Southern Ocean and Pacific point to climate and environmental changes being dominant controls on coral populations over millennial and orbital timescales. This paper provides a review of a range of successes and promising approaches. It also highlights areas in which further research would likely provide new insights into biomineralization, palaeoceanography and distribution of past coral populations.

An integrate analysis of an Hauterivian coral biostrome from the Agrio Formation, Neuquén Basin, west-central Argentina

A coral biostrome from the lower Hauterivian of the Neuquén Basin, west-central Argentina, was examined in detail. Taxonomic analysis established it as a monospecific assemblage of the scleractinian colonial coral Stereocaenia triboleti (Koby). Palaeoecological analysis of the species allows us to infer that it was an opportunistic species, capable of thriving in mixed carbonate-siliciclatic environments, on a soft substrate under a moderate to low sedimentation rate showing great regenerative capacity. Taphonomic analysis, together with lithofacies and microfacies analysis, allowed us to establish that the coral biostrome was deposited in a middle ramp setting under open marine and well-oxygenated conditions. Corals colonized a soft substrate during a transgressive phase and reaching its climax in the maximum flooding zone under lowest clastic input. They managed to form a low coral meadow of ramose forms of up to 30 cm in height. Coral remains were exposed on the interface after death and thus were subject to severe encrustation and bioerosion. The coral biostrome is interpreted as a mixed biogenic-sedimentologic skeletal concentration deposited by an interplay of an initial biogenic concentration through later episodes of physical reworking, probably storms, which yielded a largely parautochthonous fossil assemblage with minimum lateral transport. As sedimentation rate increased during a highstand interval, the coral-dominated community could not cope with it and was finally buried. The described coral biostrome recorded at the base of a shallowing-upwards cycle closely resembles coral biostromes described from the Hauterivian of Peru and Turkmenistan, and differs significantly from framework reef facies recorded in the Hauterivian of the Tethys region from the Paris Basin to Crimea.

How to explain a decapod crustacean diversity hotspot in a mid-Cretaceous coral reef

The mid-Cretaceous (late Albian) decapod crustacean fauna from the Koskobilo quarry in Spain is the most diverse decapod fauna known thus far from the Cretaceous. This may be related to the coral reef environment in which these decapods were found within the Aldoirar patch reef. This diversity hotspot was further investigated by a detailed paleoecological study focusing on variation in lithology throughout the quarry using carbonate rock hand samples, thin sections, and acetate peels; and by studying decapod-rich sites within the quarry. The northern and stratigraphically oldest part of the Koskobilo quarry contained mostly wackestones and biomicrites, the middle to southern part contained floatstones and biosparites or biomicrites with many sponge remains, whereas the southernmost and stratigraphically youngest part consisted of coral-rich boundstones and biolithites. Fossils were more abundant and generally larger in the southern part of the quarry. Decapod-rich sites were restricted to the southern part of the quarry, possibly in part because of an increased possibility for shelter and food in a coral-rich area in the southernmost part of the quarry. Water depth was estimated to be between 20 and 80m for at least the southern part, with energy levels apparently increasing from the northern to the southern part of the quarry. Systematic collecting was performed at four decapod-rich sites in the quarry to investigate differences in decapod diversity, composition, and size (width). The decapod fauna from the site within the coral-rich boundstones and biolithites appears to be the most diverse based on several diversity measures, has a statistically different faunal composition, contains species that were not found in other parts of the quarry, and consists of smaller decapods compared to other sites. More specimens of species with a smaller maximum width were found here as well as fewer specimens with a large maximum width. Smaller, presumed juvenile specimens of the crab Goniodromites laevis were also excavated here. This shows that decapod size can vary within a reef. Paguroids (hermit crabs) were mostly restricted to this coral-rich site. Some of the many decapods at this site may have been obligatory associates with the mostly branching corals. One site within the floatstone and biosparite zone contained hardly any decapods, which may be related to the abundance of hard-to-eat corallinacean red algae. A site in the Olazagutía quarry in the same patch reef consisting of massive colonial corals did not yield any decapods, presumably because of the inaccessible nature of the coral framestone leaving few places as shelter for decapods. The results suggest that different decapod sub- and microenvironments existed within this patch reef, thereby explaining at least in part the high diversity of decapods known from the Koskobilo quarry. This is one of the first times that a detailed paleoecological study has been performed for decapods in a fossilized coral reef. These results concur with modern reefs in that decapod communities also differ among subenvironments. The methodologies introduced herein for studying fossil decapods in reef environments can be used as well to study the paleoecology of decapods as well as other invertebrates from other periods in Earth's history.

Telomere length of the colonial coral Galaxea fascicularis at different developmental stages

The ability to estimate coral age using soft tissue would be useful for population biology or aging studies on corals. In this study, we investigated whether telomere length can be used to estimate coral age. We applied single telomere length analysis to a colonial coral, Galaxea fascicularis, and estimated telomere lengths of specific coral chromosomes at different developmental stages. If the telomere shortened at each cell division, the telomere length of the coral would be longest in sperm and shortest in adult colonies. However, the mean telomere length of sperm, planula larvae, and polyps was approximately 4 kb, with no significant differences among the developmental stages. The telomerase restriction fragment (TRF) analysis also showed no significant difference in the mean TRF length among the developmental stages. Our results suggested that telomere length is maintained during developmental stages and that estimating the age of colonial coral based on telomere length may not be possible. However, our findings can be used to examine avoidance of aging and rejuvenation during regeneration and asexual reproduction in colonial corals.

Paleobathymetry and paleoecology of colonial corals from the Oligocene–early Miocene (?) Qom Formation (Dizlu area, central Iran)

The scleractinian corals from the carbonate facies of the Oligocene–early Miocene (?) Qom Formation in Dizlu area (northern Isfahan), central Iran were described in three separate coral intervals. From the base to the top of the study carbonate sequence, the coral assemblages of the intervals include 1—Madracis, 2—Leptoseris–Stylophora and 3—Poritidae–Faviidae–Siderastreidae. The species identified within the carbonates are dominated by: Goniopora sp., Pachyseris sp., Madracis cf. ornate, Madracis sp., Montastraea parva, Solenastrea cf. desmoulinsi, Tarbellastraea reussiana, Stylophora sp., Siderastrea crenulata and Leptoseris sp. The identified colonial coral species were not colonizing through a strong carbonate reefal structure. Instead, they were distributed as sparse patches or building coral biostromal frameworks. The thin branching colonies of Madracis species and the second coral assemblage (Leptoseris–Stylophora) that is dominated by thin branching and thin platy colonial growth forms reflect deeper depths of a carbonate ramp with low light intensity within the lower photic zone in a depth range of 19–35 m and a maximum flooding surface. The coral associations of the Poritidae–Faviidae–Siderastreidae assemblage are mainly composed of massive colonies indicating the upper photic zone with depth of less than 20 m and a higher energy water regime. The three coral assemblages reflect marine paleotemperature of 19–20° C, respectively.

Upper Jurassic record of Polyphylloseris (Egypt, Northern Sinai)

Genus Polyphylloseris is a scleractinian colonial coral that has been established by d'Orbigny (1849 )f rom the Neocomian of Yonne, France. The genus is characterized by having elevated domal calices that are mammillar or cra- terlike in shape and with porous confluent septa. Columella is absentor rudimentary, and the lower surface ofthe corallumis covered with a thick and wrinkled holotheca. Specimens having the above-mentioned characteristics have beencollect- ed from the Upper Jurassic Arousiah Member of the Masajid Formation (Callovian-Oxfordian) of Gebel Maghara, Northern Sinai, Egypt. They are characterized by having a cupolate colonial form and porous pennulate septa which reach 40-50 in number. Based on these characters and other characters such as density of septa, height, and width of mammillar calices, the studied material is attributed to a new species named Polyphylloseris magharensis .T he new species is a first undoubted record of Polyphylloseris in the Jurassic. Previously recorded undoubted ages of the genus are Early and Late Cretaceous. The fewer number of septa and the smaller-sized and closer mammillar calices allow differentia- tion of the species from other species such as Polyphylloseris icaunensis d'Orbigny and Polyphylloseris convexa

Relative sea-level change, climate, and sequence boundaries: insights from the Kimmeridgian to Berriasian platform carbonates of Mount Salève (E France)

The present study analyses the stratal architecture of the Late Jurassic (Kimmeridgian) to Early Cretaceous (Berriasian) sedimentary succession of Mount Saleve (E France), and four Berriasian stratigraphic intervals containing four sequence-boundary zones reflecting lowering trends of the relative sea-level evolution. Massive Kimmeridgian limestones characterized by the presence of colonial corals appear to be stacked in an aggrading pattern. These non-bedded thick deposits, which are interpreted to have formed in balance between relative sea-level rise and carbonate accumulation, suggest a keep-up transgressive system. Above, well-bedded Tithonian-to-Berriasian peritidal carbonates reflect a general loss of accommodation. These strata are interpreted as a highstand normal-regressive unit. During the early phase of this major normal regression, the vertical repetition of upper intertidal/lower supratidal lithofacies indicates an aggrading depositional system. This is in agreement with an early stage of a highstand phase of relative sea level. The Berriasian sequence-boundary zones investigated (up to 4 m thick) developed under different climatic conditions and correspond to higher-frequency, forced- and normal-regressive stages of relative sea-level changes. According to the classical sequence-stratigraphic principles, these sequence-boundary zones comprise more than one candidate surface for a sequence boundary. Three sequence-boundary zones studied in Early Berriasian rocks lack coarse siliciclastic grains, contain a calcrete crust, as well as marly levels with higher abundances of illite with respect to kaolinite, and exhibit fossilized algal-microbial laminites with desiccation polygons. These sedimentary features are consistent with more arid conditions. A sequence-boundary zone interpreted for the Late Berriasian corresponds to a coal horizon. The strata above and below this coal contain abundant quartz and marly intervals with a higher kaolinite content when compared to the illite content. Accordingly, this Late Berriasian sequence-boundary zone was formed under a more humid climate. The major transgressive–regressive cycle of relative sea level identified and the climate change from more arid to more humid conditions recognized during the Late Berriasian have been reported also from other European basins. Therefore, the Kimmeridgian to Berriasian carbonate succession of Mount Saleve reflects major oceanographic and climatic changes affecting the northern margin of the Alpine Tethys ocean and thus constitutes a reliable comparative example for the analysis of other coeval sedimentary records. In addition, the stratigraphic intervals including sequence-boundary zones characterized in this study constitute potential outcrop analogues for sequence-boundary reflectors mapped on seismic profiles of subsurface peritidal carbonate successions. The detailed sedimentological analyses provided here highlight that on occasions the classical principles of sequence stratigraphy developed on seismic data are difficult to apply in outcrop. A sequence-boundary reflector when seen in outcrop may present successive subaerial exposure surfaces, which formed due to high-frequency sea-level changes that were superimposed on the longer-term trend of relative sea-level fall.

Middle Pennsylvanian rugose corals from the Baird Formation, Klamath Mountains, northwestern California

Four new species of colonial corals, one previously described coral, and two other unidentified species of coral have been recovered from the Baird Formation in the Klamath Mountains of northwestern California. The newly erected species areHeritschioides armstrongin. sp.,Pararachnastraea klamathensisn. sp.,P. watkinsin. sp., andP. kabyaiensisn. sp. These corals are associated with the fusulinidsMillerella marblensisThompson, 1944,ParamillerellaThompson, 1951, andPseudostaffellaThompson, 1942, emend Groves, 1984, suggesting an early Atokan (Bashkirian) age. Both the coral and foraminiferal faunas bear a resemblance to those of similar age in the Brooks Range, Alaska, which could suggest geographic proximity between the two terranes at that time. These corals also represent the earliest known occurrence of the Family Durhamididae.

The impact of seawater temperature on coral growth parameters of the colonial coral Cladocora caespitosa (Anthozoa, Scleractinia) in the eastern Adriatic Sea

The scleractinian coral Cladocora caespitosa deserves a special place among the major carbonate bioconstructors of the Mediterranean Sea. Annual coral skeleton growth, coral calcification, and skeleton density of the colonial coral C. caespitosa taken from 25 locations in the eastern Adriatic Sea were analyzed and compared with annual sea surface temperatures (SST). The growth rates of the coral C. caespitosa from the 25 stations in the Adriatic Sea ranged from 1.92 to 4.19 mm per year, with higher growth rates of the investigated corallites in the southern part of the Adriatic Sea. These growth rates are similar to those measured in other areas of the Mediterranean Sea. The correlation between coral growth and sea temperatures in the Adriatic Sea is seen as follows: An X-radiograph analysis of coral growth in C. caespitosa colonies that are over 60 years old showed that higher growth rates of this coral coincided with a warmer period in the Mediterranean Sea. A positive significant correlation exists between corallite growth rates and SST and coral calcification and SST. A negative correlation exists between coral density and SST. Coral growth rates also showed a correlation with higher eutrophication caused by nearby fish farms, along with a greater depth of the investigated colonies and high bottom currents.

Miocene scleractinian corals from a mixed siliciclastic–carbonate system: Bakhtiari succession, Zagros Basin (central-western Iran)

Colonial scleractinian corals were sampled from three levels within a Miocene marine unit of the Bakhtiari succession, Zagros Basin, central-western Iran. The first two coral-bearing intervals, A and B, contain small-scale scattered colonies and show a poor coral diversity, whereas the third, consisting of a strongly lithified limestone package, reflects a well-developed biostromal framework with higher coral skeletal volume within the Bakhtiari succession. The Bakhtiari succession coral assemblages are characterized by Porites sp. cf. P. maigensis, Porites sp. cf. P. mancietensis, Porites sp. cf. P. collegniana, Tarbellastraea reussiana, Favia sp., Montastrea sp. cf. P. tchihatcheffi, Favites sp. cf. P. neugeboreni, Favites sp. cf. P. neuvillei, Agathiphyllia sp. and Acropora sp. Sedimentological and palaeontological data indicate that the depositional environment is consistent with a mixed carbonate–siliciclastic ramp that was gently deepening basinwards from the shoreline. The hemispherical and massive growth forms of colonies and sparse branching forms dominated the well-illuminated euphotic zone. Abundant domestone and dense pillarstone coral growth fabrics interdigitating with coarse-grained terrigenous sediments developed in the shallow inner ramp environment. Branching forms and meandroid branching colonies together with some massive forms mostly inhabited the low-energy conditions of the lower euphotic to oligophotic zones of the middle ramp. In the middle parts of the mixed carbonate–siliciclastic ramp, sparse pillarstone together with domestone comprises a mixstone coral growth fabric. Fluctuations in nutrient and clastic sediment input, salinity and the growth of red algae likely terminated coral growth.

Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula

Sentoku, A. & Ezaki, Y. 2011: Constraints on the formation of colonies of the extant azooxanthellate scleractinian coral Dendrophyllia arbuscula. Lethaia, Vol. 45, pp. 62–70. Scleractinia display a variety of growth forms, whether zooxanthellate or azooxanthellate, as the consequence of the combined effects of both intrinsic and extrinsic factors. New modules arise in colonial corals through asexual reproduction, including budding and division. The azooxanthellate, branching dendrophylliid Dendrophyllia arbusculavan der Horst 1922, is a good species to investigate intrinsic regularities in budding, because: (1) the lateral corallites always occur in the vicinity of four primary septa, excluding the two directive primary septa; (2) the two directive septa in lateral corallites tend to be oriented almost perpendicular to the growth orientation of parental corallites; (3) the lateral corallites grow more-or-less diagonally upwards; and (4) these regularities are retained from the axial to the derived lateral corallites during colony growth. Accordingly, a colony of apparently complex dendroid corals is formed according to certain universal rules that apply to successive generations of corallites. The presence of two opposite sectors in which budding do not occur seems to be common to other azooxanthellate scleractinian families. Regularities, other than the orientation of the directive septa, are also commonly found at least in other azooxanthellate dendrophylliid genera. These regularities suggest the presence of strict developmental constraints on the asexual reproduction of the Scleractinia, both extant and extinct. These regularities by azooxanthellate scleractinians, as one of the representative colonial metazoan groups, provide us with fundamental data with which we can understand how colonies are constructed. □Azooxanthellate coral, budding, colony, Dendrophyllia arbuscula, regularity.