Recognizing morphospecies in the heliolitid coral Plasmoporella

Multivariate analysis, which has often been used effectively in paleontological work, was performed on 17 specimens of Plasmoporella collected from a bed of the Xiazhen Formation in the Zhuzhai section of Yushan area, China. Frequency histograms, simple correlation analysis, and principal component analysis (PCA) showed that five morphological characters, i.e., diameter of tabularium (DC), distance between neighboring septa (DNS), distance between opposite septa (DOS), distance between corallites (DBC), and number of corallites per cm² (N) were suitable for cluster analysis. Moreover, PCA suggested that the coralla could be divided into two groups. Cluster analysis with squared Euclidean distances calculated based on the selected five morphological characters was conducted on the raw matrix to discriminate “morphospecies”. As a result, two groups were extracted in the dendrogram. The validity or distinctiveness of the groups was tested by discriminant analysis (DA). The analysis confirmed that the assemblage of coralla can be divided successfully into two groups, which are interpreted as two morphospecies. A qualitative comparison between two reported species and the studied morphospecies showed that morphospecies A is Plasmoporella shiyanshanensis Lin and Chow, 1977 and B is Plasmoporella kasachstanica Bondarenko, 1958. In addition, DA indicated that DOS and DNS were effective to distinguish the two morphospecies. Bivariate plots based on the two morphospecies were used to illustrate the range of variation, which showed that intraspecific variation in these characters was obvious but interspecific variation was not.     

Strong relationship between coral bleaching and growth anomalies in massive Porites

Reports of coral diseases are increasing and may result from human land use and climate change conditions such as increased water temperature, coral bleaching, runoff from land, and changes in the ecology of heavily fished reefs. We examined a stable coral syndrome or a growth anomaly [ Porite growth anomaly (PGA)] (skeletal tissue anomaly, hyperplasia, or 'tumor') that was present in 0–15% of massive Porites colonies in 12 Kenyan reef lagoons. At the level of the calice morphology, this growth anomaly showed larger calices with less distance between calices and some calices with higher than normal numbers of septa, which indicate the influence of microboring organisms. Scanning electron micrographs of affected corals revealed a high abundance of fungal hyphae, a potential microboring pathogenic agent. To test the hypothesis that the PGA covaries with environmental variables, we evaluated its prevalence in relationship to 16 parameters of water quality, temperature, intensity of bleaching, benthic composition, and management at the end of the 2005 warm season. Stepwise regression models found eight environmental variables significantly associated with the frequency of the PGA, and the site's bleaching intensity was the most strongly associated variable. When bleaching intensity was removed from the dataset, the concentration of phosphorus was the one significant and positively associated variable, which suggest that the other significant environmental variables were associated with bleaching and not the growth anomalies. Our hypothetical model of causation is that the patchy loss of symbionts, often associated with bleaching, reduces calcification, increases susceptibility to pathogens, and allows endolithic fungi to perforate the skeleton creating a porous and anomalous growth of the skeleton. Consequently, we suggest that the frequency of skeletal growth anomalies is expected to increase with the frequency of coral bleaching.     

Growth characteristics of Protoheliolites norvegicus (Tabulata; Upper Ordovician; Estonia)

Protoheliolites is an early heliolitine coral characterized by closely spaced corallites separated in places by sparse coenenchyme. Growth characteristics in the type species, P. norvegicus, are revealed by detailed analysis based on serial peels and thin sections of coralla from the uppermost Katian of north‐western Estonia. Colonies of this species had a strong ability to recover from damage and partial mortality, resulting in various forms of rejuvenation, regeneration, fusion and reorganization of corallites; in some cases, this involved relatively large areas of undifferentiated soft parts. The shells of commensal cornulitids became enclosed in host coralla during colony growth. Coralla of P. norvegicus exhibit distinctive growth cycles due to responses to seasonal changes. The production of new corallites by coenenchymal increase usually occurred in low‐density bands, in which corallites generally display round to subrounded transverse outlines. In high‐density bands, the corallites became crenulated, their wall thickness increased, septal development was more pronounced, and the amount of coenenchyme increased. In addition to these cyclomorphic changes, there were significant astogenetic changes during growth. Compared with the early stage of colony development, distinctive characteristics in the late astogenetic stage include a decrease in the growth rate of the colony, better coordination among corallites, maximum development of corallite crenulations and septa in high‐density bands, more numerous coenenchymal tubules and a greater proportion of corallum area occupied by coenenchyme. In general, the role of polyps in determining morphological characteristics of individual corallites, such as tabularium area, corallite crenulations and wall thickness, was subordinate to the astogeny of the colony. Growth characteristics including colony‐wide coordination of polyp behaviour and subjugation of individuals to restore the colony following damage suggest a strong astogenetic control and high level of colony integration. Protoheliolites probably arose from a heliolitine genus rather than from a nonheliolitine group as some authors have proposed.     

Origin and phylogeny of Guyniidae (Scleractinia) in the light of microstructural data

The set of skeletal characters of the Recent azooxanthellate coral Guynia annulata Duncan, 1872 is unique among extant scleractinians and encompasses: (a) undifferentiated septal calcification centers (in most extant scleractinians calcification centers are clearly separated); (b) completely smooth septal faces (septa of almost all extant scleractinians bear granular ornamentation); (c) deeply recessed septa in respect to the epithecal rim in the adult coralla (in adults of the majority of extant scleractinians the relationships between septa and wall are the reverse); and (d) an aseptal part of the initial ontogenetic stage, just above the basal plate (almost all known scleractinians have a septate initial coralla). Skeletal features of five other extant traditional guyniids are typical of other caryophylliines (and of Scleractinia). However, the wall types present in different species of traditional guyniids exceed limits traditionally attributed to one caryophylliine family: i.e., Stenocyathus and Truncatoguynia have a marginothecal wall like the Flabellidae, whereas Schizocyathus and Temnotrochus usually have an entirely epithecal wall, as in Gardineriidae (Volzeioidea). Moreover, Pourtalocyathus and Schizocyathus show intraspecific variation in distribution of septal calcification centers (separated vs. non-separated) and in wall types (epithecal vs. consisting of large spherulite-like bodies). These major differences in skeletal architecture form the basis for a new, threefold taxonomical subdivision of the traditional guyniids: (1) Guyniidae Hickson, 1910, containing only monospecific Guynia with an epithecal wall, and septa with non-separated calcification centers; (2) Schizocyathidae fam.n., groups Microsmilia Schizocyathus, Pourtalocyathus, Temnotrochus, which have an epithecal wall and septa with usually well-separated calcification centers; and (3) Stenocyathidae fam.n. with Stenocyathus and Truncatoguynia which have a marginothecal wall and septa with well-separated calcification centers. Despite differences in the basic architecture of the skeleton, all taxa attributed to these families have 'thecal pores' formed by selective dissolution of the skeleton. I propose two hypotheses for evolutionary relationships among Guyniidae, Schizocyathidae, and Stenocyathidae: (1) Hypothesis A: the three families are not phylogenetically related and 'pores' originated independently in different scleractinian lineages: e.g., Guyniidae may represent distant zardinophyllid or gigantostyliid descendants, Schizocyathidae may be a volzeioid offshoot, whereas Stenocyathidae may be a flabellid descendant; (2) Hypothesis B: the three families are phylogenetically related and 'thecal pores' are synapomorphic for the clade (superfamily Guynioidea). Additional approaches, such as anatomical observations, molecular studies on guyniid DNA sequences, and in-depth studies on scleractinian biomineralization will be necessary to test these hypotheses.     

ROTATORY COLONIES OF THE CORALS SIDERASTREA RADIANS AND SOLENASTRAEA SSP. (CNIDARIA, SCLERACTINIA), FROM THE PLEISTOCENE BERMONT FORMATION, SOUTH FLORIDA, USA

Abstract:  Study of corallum shape in Siderastrea and Solenastraea colonies collected from Pleistocene Bermont strata in western Palm Beach County, Florida, indicates that the corals are rotatory, formed by rolling during growth on the Pleistocene sea floor. Growth of a radial and centrifugal nature away from the corallum centre suggests that rolling was sufficiently frequent and energetic to maintain the health of individual polyps along the skeleton's entire spherical surface with no evidence of growth stoppage. Post-mortem sponge boring accompanied by that of sipunculid worms and boring by the bivalves Gastrochaena and Lithophaga during coral colony life is common. Colonization by cirripeds (barnacles) on some live colonies also occurred, but these are most commonly overgrown. Boring of rotatory coralla decreased the mass of the skeleton and probably increased the ease and frequency of rolling. Comparison with modern rotatory specimens of S. radians from Rodriguez Bank indicates that the Pleistocene corals were not greatly modified during diagenesis, given their comparable densities. Diameters of both groups of corals are utilised to calculate levels of shear velocities necessary to move them, based on hydrodynamics of rounded sediment of comparable size. The presence of these rotatory coralla, by analogy, strongly suggest that Bermont sediments in the study area accumulated on shallow shelf areas populated by numerous other free-living corals along with fewer fixed corals, accompanying a diverse molluscan assemblage, all indicative of a Thalassia (turtle-grass) community. Nearshore, wave data recorded along Florida's present-day east coast, in contrast to conditions along the west coast, indicate that sufficient wave-generated velocities are present to cause regular rotation of Siderastrea and Solenastraea , and would likely have done so during the Pleistocene.     

Local and regional scale recovery of Diadema promotes recruitment of scleractinian corals

The phase change from coral to macroalgal dominance on many Caribbean reefs was exacerbated by the mortality of the echinoid Diadema antillarum in 1983–1984, and until recently, this sea urchin has remained rare on reefs throughout the western Atlantic. By the late 1990s, Diadema started to reappear in large numbers on some Jamaican reefs, and by 2000, the high densities were correlated with significantly greater abundances of juvenile corals. Here, we show that dense populations of Diadema now occur over a multi-kilometre-wide scale at six locations scattered along a 4100 km arc across the entire Caribbean. In all cases, these dense populations are found in shallow water (< 6 m depth) on outer reef communities and are associated with reduced macroalgal cover and enhanced coral recruitment. We conclude that population recovery of Diadema is occurring at both local and regional scales, and that grazing by this echinoid is creating conditions favouring the recruitment of corals.     

Unusual tabulate‐crinoid biocoenosis from the Lower Devonian of Morocco

The Early Devonian (Pragian: sulcatus to pireneae conodont zones) crinoid–coral biocoenosis from Hamar Laghdad, Morocco contains fragments of crinoid stalks of various taxa encrusted by spherical and ellipsoidal coralla of the tabulate coral Hamarilopora minima. These corals were encrusting host crinoids syn vivo, and this is evidenced by pluricolumnals exceeding 30 elements overgrown from all sides. Most known to date crinoid–epibiont associations display various types of reaction to the epibiont, such as swellings and deformations. In the case discussed here, no clear interaction is visible; therefore, this association can be classified as paroecia. It can be inferred, however, that due to a change in mechanical properties of the crinoid stalk (losing flexibility), the epizoan influence on the host was negative, while the coral was profiting from the elevated position over the seafloor and nutrient‐bearing water currents. It can be supposed that this interaction was close to parasitism. No strict species‐specific relationship between the epizoan and the host was observed.     

The skeletal structure of Desmophyllum cristagalli: the use of deep-water corals in sclerochronology

Skeletal banding has been found in the deep-water scleractinian coral Desmophyllum cristagalli , an important animal in studies of climate change. This banding pattern sheds light on skeletogenesis and suggests methods by which the record of climate change contained within the coral skeletons may be interpreted. A central wall built of trabeculae forms the interior of the septa and rings the theca. Lamellae form a sheath over the trabecular frame, showing continuity from thecal edge to septum. Skeletal bands are added by the tissue layer, which overlaps and seals the internal coral and upper portion of the outer theca. Truncated inner bands on the outer theca indicate a pattern of skeletal deposition and dissolution dependent on the presence or absence of the live tissue layer. A long-term record will be difficult to collect from D. cristagalli since lamellae are less than 10 μm thick and band position is unpredictable. Density banding in shallow-water coral skeletons has long been recognized as a valuable paleo-oceanographic tool, and deep-water corals are now being used to reconstruct deep-ocean environments. Pattern of skeletal growth must be carefully considered if deep-water corals are to be used as proxy climate recorders.     

Some aspects of the biology of the red bass, Lutjanus bohar (Forsskal), from the Tigak Islands, Papua New Guinea

The growth rate, food, reproduction and mortality rates of the red bass, Lutjanus bohar , are described for fish associated with coral reefs in the Tigak Islands of Papua New Guinea. Spawning intensity by month was investigated by examination of gonad maturation stages. The length–at–maturity of female L. bohar was estimated from the relationship between changes in gonad index with increasing size. Female fish matured at about 45–0 cm fork length. The Petersen method was used to obtain age–at–length data from length frequency data of L. bohar captured by hook–and–line fishing. The growth of L. bohar was described by a von Bertalanffy growth curve with the parameters AT=0.27 and L_∞ = 81.7 cm. There was a positive correlation between water depth (D) and the length of L. bohar (L) that was described by L = 318–8+ 3.050 D . The mortality rates ( Z ) of L. bohar from shallow (≤30m) and deep (≤80m) water were estimated from length converted catch curves and were 1–181 and 0–64 respectively. The high Z value for the shallow water population of L. bohar was ascribed to the migration of larger specimens into deeper water. The deep water population of L. bohar remains unfished and the estimate of Z was believed to be equivalent to the natural mortality rate ( M ). An empirical method of calculating M gave an estimate of 0.59. Lutjanus bohar is a carnivorous piscivore that feeds throughout the water column.     

The two-step mode of growth in the scleractinian coral skeletons from the micrometre to the overall scale

It has been known since the 19th century that coral skeletons are built of aragonite crystals with taxonomy-linked arrangements, but the way by which each coral species controls this crystallization process remains an unsolved question. The problem became still more intriguing when it was shown that isotopic compositions of coral aragonite were subject to taxonomy-linked influences (the "vital effect"). On the other hand, presence of an organic component in coral skeletons is also long known, but localization of these compounds is admittedly restricted to particular structures called "centres of calcifications." Fibres, the largely predominant part of the coral skeletons, are usually considered as purely mineral units. In this paper, it is shown that in both "centres of calcification" and fibres, organic compounds are associated with the mineral material at a deep structural level. A series of variously scaled observations and localized measurements allow recognition of the presence of an organic component at the nanometre scale. Far from being a freely operating process, crystallization of coral fibres is thus permanently controlled by the polyp basal ectoderm through a cyclic two-step process acting at the micrometre-scale. The biomineralization cycle begins by secretion of a proteoglycan matrix. As the composition of these sugars-proteins assemblages has been shown taxonomy dependent, the hypothesis can be made that multiple and long recognized specificities of coral skeletons are linked to this biochemically driven crystallization process. Additionally, this new concept of the biomineralization process in coral skeletons provides us with an access to the long term evolution of the Scleractinia. Remarkably, results of a skeleton-based approach using microstructural criteria (i.e., the spatial relationships of "centres of calcification" and the three-dimensional arrangements of fibres), are consistent with a molecular phylogenetic analysis carried out on the same species. Clearly, at the overall ontogenic level, the two-step growth mode of coral skeletons is also a valuable tool to reconstruct the evolutionary history of Scleractinia.     

The effect of exogenous factors on morphology and asexual reproduction in laboratory cultures of the intertidal sea anemone, Haliplanella luciae (Verrill) (Anthozoa: Actiniaria) from Delaware

Temperature in combination with different feeding frequencies caused rapid changes in the morphology of experimental culture populations of Haliplanella luciae (Verrill) due to exogenous effects on fission rate (k). A temperature of 15°C permitted few fissions, and only when the anemones were fed at frequent intervals. Conditions which maximized k caused significant decreases in diameter, numbers of septa, and numbers of tentacles after only 26 days in culture. Anemones fed every two days at 15°C showed the least morphological change over the culture period, remaining morphologically similar to field specimens. Asexual reproduction in H. luciae is not as well integrated with organismal growth as in hydroids. The importance of k and environmental regulators of k in determining both morphological structure and population size of H. luciae is discussed. In this study H. luciae were of a previously undescribed color variant, with light longitudinal bands.     

Skeletal microstructure of Galaxea fascicularis exsert septa: a high-resolution SEM study

The deposition of four crystal types at the growth surface of the septa of several color morphs of the coral Galaxea fascicularis was investigated over a 24-h period. Results suggest that nanocrystals, on denticles at the apices of exsert septa, may be the surface manifestation of centers of calcification. These crystals were also found on the septa of the axial corallite of Acropora formosa. The deposition of nanocrystals appears to be independent of diurnal rhythms. Internally and proximal to the septal apices, distinct clusters of polycrystalline fibers originate from centers of calcification and form fanlike fascicles. Upon these fascicles, acicular crystals grow and extend to form the visible fasciculi at the skeletal surface. Deposition of aragonitic fusiform crystals in both G. fascicularis and A. formosa occurs without diurnal rhythm. Nucleation of fusiform crystals appears to be independent of centers of calcification and may occur by secondary nucleation. Formation of semi-solid masses by fusiform crystals suggests that the crystals may play a structural role in septal extension. Lamellar crystals, which have not been reported as a component of scleractinian coral skeletons before, possess distinct layers of polyhedral plates, although these layers also do not appear to be associated with daily growth increments. The relationship of lamellar crystals to other components of the scleractinian coral skeleton and their involvement in skeletal growth is unknown.     

The effect of temperature on the size and population density of dinoflagellates in larvae of the reef coral Porites astreoides

Abstract. Pre-settlement events play an important role in determining larval success in marine invertebrates with bentho-pelagic life histories, yet the consequences of these events typically are not well understood. The purpose of this study was to examine the pre-settlement impacts of different seawater temperatures on the size and population density of dinoflagellate symbionts in brooded larvae of the Caribbean coral Porites astreoides. Larvae were collected from P. astreoides at 14–20 m depth on Conch Reef (Florida) in June 2002, and incubated for 24 h at 15 temperatures spanning the range 25.1°–30.0°C in mean increments of 0.4±0.1°C (±SD). The most striking feature of the larval responses was the magnitude of change in both parameters across this 5°C temperature range within 24 h. In general, larvae were largest and had the highest population densities of Symbiodinium sp. between 26.4°–27.7°C, and were smallest and had the lowest population densities at 25.8°C and 28.8°C. Larval size and symbiont population density were elevated slightly (relative to the minimal values) at the temperature extremes of 25.1°C and 30°C. These data demonstrate that coral larvae are highly sensitive to seawater temperature during their pelagic phase, and respond through changes in size and the population densities of Symbiodinium sp. to ecologically relevant temperature signals within 24 h. The extent to which these changes are biologically meaningful will depend on the duration and frequency of exposure of coral larvae to spatio-temporal variability in seawater temperature, and whether the responses have cascading effects on larval success and their entry to the post-settlement and recruitment phase.     

Extracting information on the evolution of living- and dead-cell fractions of Salmonella Typhimurium colonies in gelatin gels based on microscopic images and plate-count data

Aims:  The aim of this study was to extract information on cell number and colony volume dynamics of Salmonella Typhimurium colonies.
Methods and Results:  Both cell number and colony volume of Salmonella Typhimurium in gelatin were monitored during the exponential and the stationary phase with varying pH and water activity, by plate counts and microscopic image analysis respectively. The exponential growth rates of cell numbers and colony volumes were correlated. The exponential growth rate of cell numbers was estimated based on this correlation and a secondary model that describes the effect of pH and water activity on the growth rate of the colony volumes. During the stationary phase, the cell number was constant, while colony volume increased, thus indicating the formation of a dead fraction. Models were developed to describe the living and dead population.
Conclusions:  By comparing colony volumes and cell numbers, the formation of dead fraction can be noticed from the beginning of the stationary phase, which indicates that the stationary phase is a dynamic – including both cell death and cell growth – rather than a static phase.
Significance and Impact of the Study:  This study was the first to investigate the proportion of living and dead bacteria within a stationary colony quantitatively.     

Population stability and extinction in a social spider Stegodyphus mimosarum (Araneae: Eresidae)

Nests of social spiders in their natural habitat are clustered and colony clusters may be short-lived. Rapid growth and subsequent extinction of colonies and colony clusters are predicted for social spider populations; however, little quantitative data exist on the longevity of colonies. Furthermore, processes that influence the growth and decline of social spider populations are poorly understood. In this study we followed a population of over 550 nests of S. mimosarum from September 1994 to December 1999 and analysed the changes in relation to abiotic (temperature and rainfall) and biotic (parasitism) factors. We observed two years of apparent population stability (1994–1995), during which nest numbers remained high and constant. This was followed in 1996 by a c. 12% decrease in the numbers of active nests. At the end of 1996 there was a mass dispersal event which was followed in 1997 by a steady decline of the population with no further recovery. Thus, the decline was preceded by dispersal and nest failure, indicating that conditions in the population were unfavourable. The population-wide synchrony of these events reflects the seasonally synchronized development in & mimosarum. However, extrinsic factors related to climate did not explain the extreme events of dispersal and population decline. The potential importance of parasitism, on the one hand, and unknown intrinsic factors on the other, should be considered as alternative explanations that remain to be tested.     

Strength of concave septa and depth limits of fossil cephalopods

Westermann, G. E. G.: Strength of concave septa and depth limits of fossil cephalopods.
Simple septa with spherical curvature are present in the shells of all Endocer-oidea, Actinoceroidea, Bactritoidea, and most Nautiloidea and Coleoidea. Such septa act as quasi-hemispherical concave membranes when subjected to hydrostatic pressure. Since the tensile strength of a spherical membrane is directly proportional to the ratio of its thickness and radius of curvature, measurements of these parameters on polished and thin sections of septa can be used to obtain strength of the septum against implosion. Depth limits of fossil cephalopods can be made by calibrating these measurements in terms of recent implosion data on 'living' Spirula and Nautilus . Estimates of septal strength are augmented by strength estimates for long septal necks and cylindrical to globular connecting rings.
Assuming that actual habitats ranged to approximately two-thirds of the mechanical limits of the shells, the following maximum depth ranges are indicated from this preliminary survey: Endoceroidea 100–450 m; Actinoceroidea 50–150 m; Nautiloidea, Ellesmerocerida 50–200 m, Orthocerida 150–500 m, Oncocer-ida <150, Discosorida <100 m, Tarphycerida <150 m, Nautilida 200–600 m; Bactritoidea c. 400 m; Coleoidea, Aulacocerida 200–900 m, Sepiida 200–1000 m, Belemnitida 50–200 exceptionally 350 m.     

Ontogeny of 'epithecal' and septal structures in scleractinian corals

The ontogenetic development of a solitary scleractinian coral, Flabellum distinctum Edwards & Haime, has been studied in serial thin section, with special attention being paid to epithecal nature in relation to septal growth. The term 'epitheca' has been confusingly used for two different skeletal structures: epitheca ( sensu stricto ) and marginotheca. The latter is here newly proposed. 'epitheca' is defined as a calcareous investment developed on the outside of other skeletal structures of a corallite. It can be distinguished from the marginotheca in section by lacking a dark line (calcification centre) and by being unrelated to the formation of septa. 'marginotheca' defines the outer margin of the main skeletal structures of a corallite. It has a dark line which functionally coincides with that of the eutheca. It is of primary origin, preceding formation of septa and provides the origin of the septa. The marginotheca is one of the more important and fundamental skeletal structures for coral classification.     

Reef-building corals act as long-term sink for microplastic

The pollution of the marine environment with microplastics is pervasive. However, microplastic concentrations in the seawater are lower than the number of particles entering the oceans, suggesting that plastic particles accumulate in environmental sinks. Yet, the exact long-term sinks related to the “missing plastic” phenomenon are barely explored. Sediments in nearshore biogenic habitats are known to trap large amounts of microplastics, but also the three-dimensional structures of coral reefs might serve as unique, living long-term sinks. The main framework builders, reef-building corals, have been shown to ingest and overgrow microplastics, potentially leading to a deposition of particles in reef structures. However, little is known about the number of deposited particles and the underlying processes determining the permanent deposition in the coral skeletons. To test whether corals may act as living long-term sink for microplastic, we exposed four reef-building coral species to polyethylene microplastics (200 particles L^?1) in an 18-month laboratory experiment. We found microplastics in all treatment specimens, with low numbers of particles trapped in the coral tissue (up to 2 particles per cm²) and much higher numbers in the skeleton (up to 84 particles per cm³). The numbers of particles accumulated in the coral skeletons were mainly related to coral growth (i.e., skeletal growth in volume), suggesting that deposition is a regularly occurring stochastic process. We estimate that reef-building corals may remove 0.09%–2.82% of the bioavailable microplastics from tropical shallow-reef waters per year. Our study shows for the first time that microplastic particles accumulate permanently in a biological sink, helping to explain the “missing plastic” phenomenon. This highlights the importance of coral reefs for the ecological balance of the oceans and reinforces the need to protect them, not only to mitigate the effects of climate change but also to preserve their ecosystem services as long-term sink for microplastic.     

Cyphastrea kausti sp. n. (Cnidaria,Anthozoa, Scleractinia), a new species of reef coral from the Red Sea

A new scleractinian coral species, Cyphastrea kausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea.     

Environmental distribution of colony growth form in the favositid Pleurodictyum americanum

Pandolfi, John M. & Burke, Collette D. 1989 01 15: Environmental distribution of colony growth form in the favositid Pleurodictyum americanum. Lethaia , Vol. 22, pp. 69–84. Oslo. ISSN 0024–1164.
Colony growth form is of fundamental importance to understanding the ecology of both modern and ancient marine sessile colonial animals. Fourier shape analysis of the coral Pleurodictyun americantum (Tabulata: Favositida) from the Middle Devonian Hamilton Group of New York State, indicates that colony growth form is variable between environments. Discriminate function analysis of harmonics 2–6 of 51 assemblages of Pleurodictyum americanum (N = 1900) shows that this species displays an onshore to offshore gradient in colony shape. Offshore environments characterized by low levels of turbidity, oxygen, and light contain more flattened, less hemispherical growth forms, whereas onshore environments characterized by high levels of turbidity, oxygen, and light contain more hemispherical, less flattened growth forms. Harmonic shape analysis detected subtle differences among samples of P. americanum from different environments, but also showed that distinctive morphotypes are distributed within horizons. as well as between them. In fact, no one-to-one correspondence in growth form to environment is apparent; growth forms are distributed within environments, suggesting that genetic factors may have had a greater influence over coral growth form than environment. In tabulate corals, patterns of within species variability must be determined before growth form may be useful in interpreting ancient environments. □ Tabulate coral, Fourier shape analysis, morphological variability, growth form, Devonian, Hamilton Group, New York .