Two New Cembranoids from the Chinese Soft Coral Sarcophyton boettgeri.

Two new cembranoids, namely sarcoboettgerols D and E, together with four known related ones, have been isolated from the soft coral Sarcophyton boettgeri collected from Weizhou Island in the South China Sea. Their structures including absolute configurations were elucidated by extensive spectroscopic analysis, quantum mechanical nuclear magnetic resonance methods, time-dependent density functional theory-electronic circular dichroism calculations, as well as comparison with the reported data in the literature. A plausible biogenetic relationship of four cembranoids was proposed. In bioassays, sarcomililatin B exhibited cytotoxic activity against H1299 cell (IC50 =35.0 µM), whereas sarcomililatin B and sarcomililatin A displayed moderate antibacterial activities (MIC 17.4-34.8 µg/mL).

A New Species of Sea Whip Gorgonian-Associated Zoantharian (Cnidaria: Anthozoa: Hexacorallia: Parazoanthidae) from the Ryukyu Islands, Japan, with Subgeneric Subdivision of Genus Umimayanthus.

Symbioses between invertebrates are common in the ocean although usually the diversity and specificity of their interactions are not well understood. Parazoanthidae (Cnidaria: Anthozoa: Zoantharia) is one of the most diverse zoantharian families in terms of numbers of genera and species. Species in this family are commonly associated with various other invertebrates that they utilize as their substrate. Previous studies have re-organized the taxonomy of Parazoanthidae and revealed a strong specificity between many parazoanthid species and genera and their substrates. However, our understanding of the species diversity of Parazoanthidae is far from complete, as parazoanthids are often overlooked in sampling surveys. In this study, we establish three subgenera under the genus Umimayanthus Montenegro, Sinniger, and Reimer, 2015; the nominotypical Umimayanthus, Paraumimayanthus subgen nov., and Gorgoniazoanthus subgen. nov., based on the finding of a new species, Umimayanthus (Gorgoniazoanthus) kanabou sp. nov., associated with the sea-whip gorgonian Ellisella sp. from approximately 30 m depth in shallow mesophotic coral reef communities in Oura Bay on Okinawajima Island and in Oshima Strait near Amami-Oshima Island, in the Ryukyu Islands, southern Japan. We additionally report on gastropods and crustaceans observed in association with U. kanabou, and these species are thought to potentially prey upon the zoantharians or on gorgonian polyps. Umimayanthus kanabou is phylogenetically closely related to congeneric sponge-associated Umimayanthus spp., further supporting the recent hypothesis that substrate preferences may change during the evolutionary history of zoantharians.

Early development and coloniality in Oligophylloides from the Devonian of Morocco-Are Heterocorallia Palaeozoic octocorals?

Heterocorals represent an enigmatic group of Palaeozoic corals, known from relatively short time intervals in the Devonian and Carboniferous periods. The major differences between Heterocorallia and other Palaeozoic corals are the lack of an external theca (epitheca), lack of calices and the presence of dichotomously dividing septa-like structures. Heterocoral skeleton was presumably externally covered by the soft tissue and each branch of their skeleton has, until now, been regarded as a corallite-a skeleton of a single polyp. We investigated upper Famennian Oligophylloides from Morocco, focussing on branching processes, wall structure, previously poorly known initial growth stages and the growing tip, described here for the first time. We demonstrate that Oligophylloides shows a unique colony development not known in any group of anthozoans possessing a septate-like architecture and suggest that the previously postulated homology between true septa in hexa- and rugose corals on one hand, and Oligophylloides on the other, must be rejected. Based on the skeleton structure and branching patterns, we postulate, contrary to former ideas, that the stem and branches of heterocorals represent the skeleton of a multi-polyp colonial coral, similar to many extant octocorals. We found numerous potential homologies with octocoral skeletons (notably the Keratoisidinae within the Isididae) and, as a result, we propose the inclusion of the order Heterocorallia within the subclass Octocorallia. This suggestion requires, however, further research on the other taxa of heterocorals. We also propose some changes to the morphological terminology for the Heterocorallia.

Revisiting the type of Cespitularia stolonifera/ Gohar, 1938 leads to the description of a new genus and a species of the family Xeniidae (Octocorallia, Alcyonacea).

Because of the problematical identity and status of the type of the xeniid soft coral genus Cespitularia Milne-Edwards Haime, 1850, the species C. stolonifera Gohar, 1938 is revised. Examination of the type colonies has led to the establishment of the new genus Unomia gen. n. which is described and depicted. This genus features a stalk, commonly divided into branches featuring a diffuse polypiferous part consisting of distal clustered polyps and proximal individual ones on the stalk or the basal membranous part of the colonies. The sclerites are ellipsoid platelets composed of dendritic calcite rods whose tips are distinct on the surface of the platelets. Freshly collected material from Venezuelan reefs where the species is invasive was subjected to molecular phylogenetic analysis, the results of which substantiate the taxonomic assignment of the new genus under U. stolonifera comb. n. A new species, U. complanatis, from Japan and Green Island (Taiwan) is described and further illustrates the extent of the interspecific morphological variation within the genus. The results reveal that the biogeographic distribution of Unomia gen. n. includes Pacific Ocean reefs in addition to the previously reported invaded Caribbean reefs.

Upper Barremian-lower Aptian scleractinian corals of central Europe (Schrattenkalk Fm., Helvetic Zone, Austria, Germany, Switzerland).

From the Schrattenkalk Formation (upper Barremian-lower Aptian) of southern Germany, western Austria, and Switzerland, new coral material is taxonomically described, belonging to 56 species from 35 genera of 21 families: Actinastrea pseudominima (Koby); A. subornata (d'Orbigny); Paretallonia bendukidzeae Sikharulidze; Eugyra (Felixigyra) crassa (de Fromentel) (new combination); E. (F.) patruliusi (Morycowa); E. (F.) picteti (Koby) (new combination); E. rariseptata Morycowa; Myriophyllia propria Sikharulidze; Thecosmilia dichotoma Koby; Clausastrea plana (de Fromentel); Complexastrea cf. lobata Geyer; Paraclausastrea chevalieri Zlatarski; P. kaufmanni (Koby); P. vorarlbergensis Baron-Szabo; ?Montlivaltia sp.; Diplogyra subplanotabulata Sikharulidze; Hydnophora styriaca (Michelin); Dermosmilia fiagdonensis Starostina Krasnov; D. cf. laxata (Étallon); D. trichotoma Eguchi; D. tuapensis Baron-Szabo Gonzalez.-León; Placophyllia grata Bugrova; Cairnsipsammia merbeleri Baron-Szabo; Morphastrea ludovici (Michelin) (emended herein); Ahrdorffia ornata (Morycowa); Astraeofungia tirnovoriana (Toula) (new combination); Actinaraea (Camptodocis) brancai (Dietrich); A. tenuis Morycowa; Rhipidomeandra bugrovae Morycowa Masse; Comoseris aptiensis Baron-Szabo; Comoseris jireceki Toula; Polyphylloseris mammillata Eguchi; Ellipsocoenia barottei (de Fromentel) (new combination); Ellipsocoenia haimei (de Fromentel) (new combination); Dimorphastrea tenustriata de Fromentel; Latomeandra cf. plicata (Goldfuss); Microphyllia gemina Eliásová; Thalamocaeniopsis stricta (Milne Edwards Haime)(new combination); Trigerastraea haldonensis (Duncan) (new combination); Heliocoenia rozkowskae Morycowa; H. vadosa (Pocta); Stylosmilia corallina Koby; Cyathophora decipiens ramosa (Hackemesser) (new combination); C. mirtschinkae Kuzmicheva; Cladophyllia clemencia de Fromentel; C. conybearei Milne Edwards Haime; C. crenata (Blanckenhorn); C. furcifera Roemer; C. rollieri (Koby); C. stutzi (Koby) (new combination); Amphiaulastrea conferta (Ogilvie); A. rarauensis (Morycowa); Heterocoenia inflexa (Eichwald); H. minima d'Orbigny; Acanthogyra aptiana Turnsek; as well as the new species Columnocoenia falkenbergensis. In addition, all the information about previously described taxa from the Schrattenkalk was evaluated with regard to their taxonomic assignment, stratigraphic and paleogeographic distribution, and paleoenvironmental relationships to faunas from other geographic areas and time periods. A total of 122 species belonging to 53 genera and 24 families are recognized from Schrattenkalk localities (western Austria, southern Germany, Switzerland). These include the taxa of both the Lower and Upper Schrattenkalk, and the intercalated Rawil Member. The Schrattenkalk coral fauna nearly exclusively consists of colonial forms of three general categories of polyp integration: cerioid-plocoid (33.6%); branching (18%); and (hydno-) meandroid-thamnasterioid (46.7%). Only two specimens were doubtfully assigned to solitary taxa. Corallite diameters range from less than 1 mm to over 20 mm and fall into three major corallite-size groups: small (up to 2.4 mm), medium (2.4-9.5 mm), and large (9.5 mm). The fauna is distinctly dominated by forms with medium-size corallites (68%), followed by forms having small-size corallites (26%). Together with the potential solitary taxa, corals with large-size corallites are of minimal importance to the total fauna. On the genus-level, the Schrattenkalk corals show closest affinities to coral assemblages of central (especially France; 55%), eastern and southern Europe (44‒49%), as well as Central America (47%). On the species-level, closest affinities are to coral assemblages of central, southeastern, and eastern Europe (16‒25.5%), as well as Central America (14%), but nearly a third of the Schrattenkalk species (30%) was restricted to the upper Barremian-lower Aptian of the Schrattenkalk Formation; this suggests that the Schrattenkalk platform sensu lato was a diversity center and a crucial reservoir for coral recruitment. The majority (86%) of the Schrattenkalk corals thrived in a shallow-water, reefal to perireefal, subtropical marine environment. In general, the Schrattenkalk coral assemblages are characteristic of moderate- to high-energy environments of the inner shelf to shore zone, having morphotype associations that typically prevail down to 10-15 m depth. In contrast, for the Upper Schrattenkalk coral fauna of central Switzerland (Hergiswil), a non-reefal paleoenvironment at a depth of several tens of meters is suggested by the morphotypes of the taxa and types of microfacies present. The corals of the Schrattenkalk Formation occurred in both photozoan (Lower and Upper Schrattenkalk members) and heterozoan (Rawil member) carbonate-producing communities. With regard to taxonomic diversity, the Schrattenkalk coral fauna is comparable to the most species-rich Upper Jurassic reef assemblages and represents the last major coral-reef development of the Mesozoic.

Collective Pulsing in Xeniid Corals: Part I-Using Computer Vision and Information Theory to Search for Coordination.

Xeniid corals (Cnidaria: Alcyonacea), a family of soft corals, include species displaying a characteristic pulsing behavior. This behavior has been shown to increase oxygen diffusion away from the coral tissue, resulting in higher photosynthetic rates from mutualistic symbionts. Maintaining such a pulsing behavior comes at a high energetic cost, and it has been proposed that coordinating the pulse of individual polyps within a colony might enhance the efficiency of fluid transport. In this paper, we test whether patterns of collective pulsing emerge in coral colonies and investigate possible interactions between polyps within a colony. We video recorded different colonies of Heteroxenia sp. in a laboratory environment. Our methodology is based on the systematic integration of a computer vision algorithm (ISOMAP) and an information-theoretic approach (transfer entropy), offering a vantage point to assess coordination in collective pulsing. Perhaps surprisingly, we did not detect any form of collective pulsing behavior in the colonies. Using artificial data sets, however, we do demonstrate that our methodology is capable of detecting even weak information transfer. The lack of a coordination is consistent with previous work on many cnidarians where coordination between actively pulsing polyps and medusa has not been observed. In our companion paper, we show that there is no fluid dynamic benefit of coordinated pulsing, supporting this result. The lack of coordination coupled with no obvious fluid dynamic benefit to grouping suggests that there may be non-fluid mechanical advantages to forming colonies, such as predator avoidance and defense.

Collective Pulsing in Xeniid Corals: Part II-Using Computational Fluid Dynamics to Determine if There are Benefits to Coordinated Pulsing.

Coordinated movements have been shown to enhance the speed or efficiency of swimming, flying, and pumping in many organisms. Coordinated pulsing has not been observed in many cnidarians (jellyfish, anemones, corals), as is the case for the xeniid corals considered in our corresponding paper. This observation opens the question as to whether xeniid corals, and cnidarians in general, do not coordinate their pulsing behavior for lack of a hydrodynamic advantage or for other reasons. For example, a diffuse nervous system with lack of substantial sensory input may not be capable of such coordination. Similarly, grouping may serve a defensive role rather than a fluid dynamic role. In this paper, the immersed boundary method is used to quantify the volumetric flux of fluid generated by an individual xeniid coral polyp in comparison with a pair of polyps. Both the distances between the polyps and the phase difference between each polyp are considered. More specifically, the fully coupled fluid-structure interaction problem of a coral polyp driving fluid flow is solved using a hybrid version of the immersed boundary method where the Navier-Stokes equations are solved using a finite differences and the elasticity equations describing the coral are solved using finite elements. We explore three possible hypotheses: (1) pulsing in pairs increases upward flow above the polyps and is thus beneficial, (2) these benefits vary with the polyps' pulsing phase difference, and (3) these benefits vary with the distance between the polyps. We find that there is no substantial hydrodynamic advantage to pulsing in a pair for any phase difference. The volumetric flux of fluid generated by each coral also decreases as the distance between polyps is decreased. This surprising result is consistent with measurements taken from another cnidarian with similar behavior, the upside down jellyfish, in which each medusa drives less flow when in a group.

Living evidence of a fossil survival strategy raises hope for warming-affected corals.

Climate change is affecting reef-building corals worldwide, with little hope for recovery. However, coral fossils hint at the existence of environmental stress-triggered survival strategies unreported in extant colonial corals. We document the living evidence and long-term ecological role of such a survival strategy in which isolated polyps from coral colonies affected by warming adopt a transitory resistance phase, in turn expressing a high recovery capacity in dead colony areas. Such processes have been described in fossil corals as rejuvenescence but were previously unknown in extant reef-builder corals. Our results based on 16 years of monitoring show the significance of this process for unexpected recoveries of coral colonies severely affected by warming. These findings provide a link between rejuvenescence in fossil and extant corals and reveal that beyond adaptation and acclimatization processes, modern scleractinian corals show yet undiscovered and highly effective survival strategies that help them withstand and recover from rapid environmental changes.

Anthropogenic impact is negatively related to coral health in Sicily (Mediterranean Sea).

Shallow-water marine organisms are among the first to suffer from combined effects of natural and anthropogenic drivers. The orange coral Astroides calycularis is a shallow-water bioconstructor species endemic to the Mediterranean Sea. Although raising conservation interest, also given its special position within the Dendrophylliidae, information about the threats to its health is scant. We investigated the health status of A. calycularis at five locations in northwestern Sicily along a gradient of cumulative human impact and the most probable origin of the threats to this species, including anthropogenic land-based and sea-based threats. Cumulative human impact appeared inversely related to the performance of A. calycularis at population, colony, and polyp levels. Sea-based human impacts appeared among the most likely causes of the variation observed. The reduction in polyp length can limit the reproductive performance of A. calycularis, while the decrease of percent cover and colony area is expected to impair its peculiar feeding behaviour by limiting the exploitable dimensional range of prey and, ultimately, reef functioning. This endangered habitat-forming species appeared susceptible to anthropogenic pressures, suggesting the need to re-assess its vulnerability status. Creating microprotected areas with specific restrictions to sea-based human impacts could be the best practice preserve these bioconstructions.

Mineral formation in the primary polyps of pocilloporoid corals.

In reef-building corals, larval settlement and its rapid calcification provides a unique opportunity to study the bio-calcium carbonate formation mechanism involving skeleton morphological changes. Here we investigate the mineral formation of primary polyps, just after settlement, in two species of the pocilloporoid corals: Stylophora pistillata (Esper, 1797) and Pocillopora acuta (Lamarck, 1816). We show that the initial mineral phase is nascent Mg-Calcite, with rod-like morphology in P. acuta, and dumbbell morphology in S. pistillata. These structures constitute the first layer of the basal plate which is comparable to Rapid Accretion Deposits (Centers of Calcification, CoC) in adult coral skeleton. We found also that the rod-like/dumbbell Mg-Calcite structures in subsequent growth step will merge into larger aggregates by deposition of aragonite needles. Our results suggest that a biologically controlled mineralization of initial skeletal deposits occurs in three steps: first, vesicles filled with divalent ions are formed intracellularly. These vesicles are then transferred to the calcification site, forming nascent Mg-Calcite rod/pristine dumbbell structures. During the third step, aragonite crystals develop between these structures forming spherulite-like aggregates. STATEMENT OF SIGNIFICANCE: Coral settlement and recruitment periods are highly sensitive to environmental conditions. Successful mineralization during these periods is vital and influences the coral's chances of survival. Therefore, understanding the exact mechanism underlying carbonate precipitation is highly important. Here, we used in vivo microscopy, spectroscopy and molecular methods to provide new insights into mineral development. We show that the primary polyp's mineral arsenal consists of two types of minerals: Mg-Calcite and aragonite. In addition, we provide new insights into the ion pathway by showing that divalent ions are concentrated in intracellular vesicles and are eventually deposited at the calcification site.

Microscale light management and inherent optical properties of intact corals studied with optical coherence tomography.

Coral reefs are highly productive photosynthetic systems and coral optics studies suggest that such high efficiency is due to optimized light scattering by coral tissue and skeleton. Here, we characterize the inherent optical properties, i.e. the scattering coefficient, µs, and the anisotropy of scattering, g, of eight intact coral species using optical coherence tomography (OCT). Specifically, we describe light scattering by coral skeletons, coenoarc tissues, polyp tentacles and areas covered by fluorescent pigments (FP). Our results reveal that light scattering between coral species ranges from µs = 3 mm-1 ( Stylophora pistillata) to µs = 25 mm-1 ( Echinopora lamelosa) . For Platygyra pini, µs was 10-fold higher for tissue versus skeleton, while in other corals (e.g. Hydnophora pilosa) no difference was found between tissue and skeletal scattering. Tissue scattering was threefold enhanced in coenosarc tissues ( µs = 24.6 mm-1) versus polyp tentacles ( µs = 8.3 mm-1) in Turbinaria reniformis. FP scattering was almost isotropic when FP were organized in granule chromatophores ( g = 0.34) but was forward directed when FP were distributed diffusely in the tissue ( g = 0.96). Our study provides detailed measurements of coral scattering and establishes a rapid approach for characterizing optical properties of photosynthetic soft tissues via OCT in vivo.

Vibrio coralliilyticus infection triggers a behavioural response and perturbs nutritional exchange and tissue integrity in a symbiotic coral.

Under homoeostatic conditions, the relationship between the coral Pocillopora damicornis and Vibrio coralliilyticus is commensal. An increase in temperature, or in the abundance of V. coralliilyticus, can turn this association pathogenic, causing tissue lysis, expulsion of the corals' symbiotic algae (genus Symbiodinium), and eventually coral death. Using a combination of microfluidics, fluorescence microscopy, stable isotopes, electron microscopy and NanoSIMS isotopic imaging, we provide insights into the onset and progression of V. coralliilyticus infection in the daytime and at night, at the tissue and (sub-)cellular level. The objective of our study was to connect the macro-scale behavioural response of the coral to the micro-scale nutritional interactions that occur between the host and its symbiont. In the daytime, polyps enhanced their mucus production, and actively spewed pathogens. Vibrio infection primarily resulted in the formation of tissue lesions in the coenosarc. NanoSIMS analysis revealed infection reduced 13C-assimilation in Symbiodinium, but increased 13C-assimilation in the host. In the night incubations, no mucus spewing was observed, and a mucus film was formed on the coral surface. Vibrio inoculation and infection at night showed reduced 13C-turnover in Symbiodinium, but did not impact host 13C-turnover. Our results show that both the nutritional interactions that occur between the two symbiotic partners and the behavioural response of the host organism play key roles in determining the progression and severity of host-pathogen interactions. More generally, our approach provides a new means of studying interactions (ranging from behavioural to metabolic scales) between partners involved in complex holobiont systems, under both homoeostatic and pathogenic conditions.

Cnidae sizes in the two morphotypes of the giant Caribbean anemone Condylactis gigantea (Actiniaria: Actiniidae) / Tamaños de cnidae en dos morfotipos de la anémona gigante del Caribe Condylactis gigantea (Actiniaria: Actiniidae)

Abstract The sea anemone Condylactis gigantea is an ecologically important member of the benthic community in coral reefs of the tropical Atlantic, and displays two morphotypes with respect to the color in their tentacular tips: the green tip morphotype and the pink/purple tip morphotype. Although some molecular and ecological differences have been found between these morphotypes, no other morphological distinctions have been reported, and currently both are still considered a single taxonomic species. In the present study, we perform an exploration on the variability in the size of cnidae between these two morphotypes and performed statistical analyses to compare the 10 categories of cnidae from specimens hosted in the Cnidarian Collection of Gulf of Mexico and Mexican Caribbean, of the Universidad Nacional Autónoma de México, which were previously collected in several coral reefs localities of the Yucatán Peninsula. Results reveal no significant variation in cnidae size between the two morphotypes, but significant variations were found within each morphotype. In addition, we update the composition of the cnidom of C. gigantea, and the utility of the size of cnidae to distinguish between morphotypes or closely related species is discussed. Rev. Biol. Trop. 66(3): 1055-1064. Epub 2018 September 01.

Resumen La anémona Condylactis gigantea es un miembro ecológicamente importante de la comunidad bentónica en arrecifes de coral del Atlántico tropical, y exhibe dos morfotipos con respecto al color de las puntas de sus tentáculos: el morfotipo de puntas verdes y el morfotipo de puntas rosadas/púrpuras. Aunque se han encontrado algunas diferencias moleculares y ecológicas entre estos morfotipos, no se han reportado otras distinciones morfológicas, y actualmente ambos siguen siendo considerados una sola especie taxonómica. En el presente estudio, realizamos una exploración sobre la variabilidad en el tamaño de los cnidocistos entre estos dos morfotipos y realizamos un análisis estadístico de 10 categorías de cnidocistos a partir de especímenes albergados en la Colección de cnidarios del Golfo de México y Caribe Mexicano, de la Universidad Nacional Autónoma de México, los cuales fueron previamente recolectados en varias localidades arrecifales de la Península de Yucatán. Los resultados no revelan variación significativa en el tamaño de los cnidocistos entre los dos morfotipos, aunque fueron encontradas variaciones significativas dentro de cada morfotipo. Adicionalmente, actualizamos la composición del cnidoma de C. gigantea, y discutimos sobre la utilidad de la talla de los cnidocistos para distinguir entre morfotipos o entre especies estrechamente relacionadas.

A phylogenetic analysis of the Primnoidae (Anthozoa: Octocorallia: Calcaxonia) with analyses of character evolution and a key to the genera and subgenera.

BACKGROUND: Previous phylogenetic analyses of primnoid octocorals utilizing morphological or molecular data have each recovered evolutionary relationships among genera that are largely incongruent with each other, with some exceptions. In an effort to reconcile molecular-based phylogenies with morphological characters, phylogenetic reconstructions were performed with 33 of 43 primnoid genera using four loci (mtMutS, COI, 28S and 18S), and ancestral state reconstructions were performed using 9 taxonomically relevant characters. In addition, an updated illustrated key to the current 48 genus-level (43 genera, 5 subgenera) primnoids is presented. RESULTS: Ancestral state reconstruction recovered the ancestral colony shape of primnoids as dichotomous planar. Convergence was detected among all 9 characters, and reversals to the character state of the common ancestor occurred in 4 characters. However, some characters were found to be informative. For example, the weak ascus scale of Metafannyella is not likely homologous to the ascus scales of Onogorgia and Fannyella, and the monophyly of two subgenera within Thouarella, which contain polyps in either whorls or an isolated arrangement, was supported. Phylogenetic analyses were generally consistent with previous studies, and resulted in the synonymy of one genus and a subgenus, the elevation of two subgenera, and the transfer of two species back to an original genus. For example, body wall ornamentation of Fanellia was re-evaluated, indicating a synonymy with Callogorgia; the utility of polyp arrangement for the subgenus Plumarella (Dicholaphis) was not supported, and is synonymized with the nominate subgenus Plumarella (Plumarella); the subgenera Plumarella (Faxiella) and Plumarella (Verticillata) are raised to generic status; and the two Plumarella species (P. diadema and P. undulata) are transferred back to Thouarella based on the homology of their marginal scales. CONCLUSIONS: Altogether, and similar to other octocorallian groups, these results indicate that many of the morphological characters examined among primnoids, particularly colony morphology, are labile and exhibit complex evolutionary histories. However, some morphological characters such as coordination of polyps, presence of the ascus body wall scale, number of rows of body wall scales, and number of marginal scales help identify many clades, and are suitable for robust systematic assessments among primnoids.

Population dynamics of Siderastrea stellata Verrill, 1868 from Rocas Atoll, RN: implications for predicted climate change impacts at the only South Atlantic atoll

ABSTRACT Coral reefs are one of the most vulnerable ecosystems to ocean warming and acidification, and it is important to determine the role of reef building species in this environment in order to obtain insight into their susceptibility to expected impacts of global changes. Aspects of the life history of a coral population, such as reproduction, growth and size-frequency can contribute to the production of models that are used to estimate impacts and potential recovery of the population, acting as a powerful tool for the conservation and management of those ecosystems. Here, we present the first evidence of Siderastrea stellata planulation, its early growth, population size-frequency distribution and growth rate of adult colonies in Rocas Atoll. Our results, together with the environmental protection policies and the absence of anthropogenic pressures, suggest that S. stellata population may have a good potential in the maintenance and recovery in the atoll. However, our results also indicate an impact on corals' recruitment, probably as a consequence of the positive temperature anomaly that occurred in 2010. Thus, despite the pristine status of Rocas Atoll, the preservation of its coral community seems to be threatened by current global changes, such as more frequent thermal stress events.

Species boundaries in the absence of morphological, ecological or geographical differentiation in the Red Sea octocoral genus Ovabunda (Alcyonacea: Xeniidae).

The development of coalescent-based and other multilocus methods for species delimitation has facilitated the identification of cryptic species complexes across the tree of life. A recent taxonomic revision of the ecologically important soft coral genus Ovabunda validated 11morphospecies, all with type localities and overlapping geographic ranges in the Red Sea. A subsequent molecular phylogenetic analysis using mitochondrial and 28S nrDNA genes divided the genus into just two clades, with no apparent genetic distinctions among morphospecies. To further explore species boundaries among morphospecies of Ovabunda we sequenced three additional nuclear genes (ITS, ATPSα, ATPSß), and obtained data for 1332 unlinked SNPs from restriction-site associated DNA sequencing. Both coalescent-based and allele-sharing species delimitation analyses supported four species of Ovabunda, each of which included multiple morphotypes encompassing the full range of morphological variation observed within the genus. All four species occurred over the same depth range of 5-41m, and were sympatric at sites separated by 1100km in the Red Sea. The only characters that have been found to distinguish three of the four species are diagnostic substitutions in the nuclear genome; the fourth differs by exhibiting polyp pulsation, a behavioral trait that can be assessed only in live colonies. The lack of any obvious morphological, life history, ecological or geographical differences among these four species begs the question of what drove the evolution and maintenance of reproductive isolating mechanisms in this cryptic species complex.

The digestive system of the stony coral Stylophora pistillata.

Because hermatypic species use symbiotic algal photosynthesis, most of the literature in this field focuses on this autotrophic mode and very little research has studied the morphology of the coral's digestive system or the digestion process of particulate food. Using histology and histochemestry, our research reveals that Stylophora pistillata's digestive system is concentrated at the corals' peristome, actinopharynx and mesenterial filaments (MF). We used in-situ hybridization (ISH) of the RNA transcript of the gene that codes for the S. pistillata digestive enzyme, chymotrypsinogen, to shed light on the functionality of the digestive system. Both the histochemistry and the ISH pointed to the MF being specialized digestive organs, equipped with large numbers of acidophilic and basophilic granular gland cells, as well as acidophilic non-granular gland cells, some of which produce chymotrypsinogen. We identified two types of MF: short, trilobed MF and unilobed, long and convoluted MF. Each S. pistillata polyp harbors two long convoluted MF and 10 short MF. While the short MF have neither secreting nor stinging cells, each of the convoluted MF display gradual cytological changes along their longitudinal axis, alternating between stinging and secreting cells and three distinctive types of secretory cells. These observations indicate the important digestive role of the long convoluted MF. They also indicate the existence of novel feeding compartments in the gastric cavity of the polyp, primarily in the nutritionally active peristome, in the actinopharynx and in three regions of the MF that differ from each other in their cellular components, general morphology and chymotrypsinogen excretion.

Influence of sediments and tungsten traces on the skeletal structure of Pseudodiploria: a reef building scleractinian coral from the Veracruz Reef System National Park, Mexico / Influencia de los sedimentos y trazas de tungsteno en la estructura del esqueleto de Pseudodiploria un coral escleractinio constructor de arrecifes del Parque Nacional Sistema Arrecifal Veracruzano, México

Abstract:Coral reefs are under intense conditions of stress caused by the anthropogenic activities in coastal areas and the increase of human population. Water effluents from urban and industrial areas carry large amounts of sediments and pollutants affecting corals populations, inducing bioerosion, increasing diseases and promoting the development of algae that compete for space with corals. In the Veracruz Reef System National Park (VRSNP) coral reefs are strongly affected by human activities carried out in the area. Gallega and Galleguilla reefs are among the most affected by wastewater discharges from the industrial (petrochemical and metallurgical) and urban areas in their vicinity. To assess the potential impact of this contamination on corals in the VRSNP, a chemical composition and morphology study of 76 Pseudodiploria colonies collected in reefs Gallega, Galleguilla, Isla Verde and Isla de Enmedio, was performed. Fragments of ~10 cm2 were collected and boric acid at 0.5 % was used to remove tissue from the skeleton; once clean, the morphology of each sample was determined with a scanning electron microscope (SEM). Subsequently, to test the chemical composition, an energy dispersion spectroscopy of X-ray chemical microanalysis (EDSX) was performed in the SEM. We found that corals from Gallega and Galleguilla reefs, located closer to human populations, presented high levels of tungsten and the skeleton exhibited multiple perforations. In contrast, corals from the farthest offshore reefs (Isla Verde and Isla de Enmedio) exhibited lower levels of tungsten and fewer perforations in their skeleton. These results demonstrated that anthropogenic activities in the NPVRS are affecting corals skeleton, highly damaging and promoting their bioerosion. The presence of traces of tungsten in the skeleton of corals is an evidence of the damage that waste discharges are causing to coral reefs. Discharges of large amounts of contaminants promoted the growth of harmful species that grow and develop into the corals skeleton, causing its bioerosion, and making them susceptible to disease and physical damage. This study is the first evidence of the effects of contamination on these species; therefore, further studies are necessary to determine the impact of pollution on their biology and survival. Rev. Biol. Trop. 64 (3): 1077-1089. Epub 2016 September 01.

ResumenLos arrecifes de coral se encuentran bajo condiciones intensas de estrés causado por las actividades antropogénicas y el incremento de las poblaciones humanas en las zonas costeras. Las descargas de aguas de origen urbano e industrial transportan sedimentos y contaminantes que afectan a las poblaciones de corales, induciendo la bioerosion, el aumento de enfermedades en los corales y promueven el desarrollo de algas que compiten por espacio con los corales. En el Parque Nacional Sistema Arrecifal Veracruzano (NPVRS) los arrecifes de coral son afectados fuertemente por las actividades humanas que se llevan a cabo en la zona. Los arrecifes Gallega y Galleguilla son de los más afectados por las descargas de aguas residuales provenientes de la industria (petroquímica y metalúrgica) y de áreas urbanas que desembocan sus aguas en las proximidades de los arrecifes. Para evaluar el posible impacto de las descargas de aguas en los corales del NPVRS, se realizó un estudio de la composición química y morfología de 76 colonias de Pseudodiploria en los arrecifes Gallega, Galleguilla, Isla Verde e Isla de Enmedio. Se recolectaron fragmentos de ~10 cm2, el tejido del esqueleto fue removido utilizando ácido bórico al 0.5 %. Una vez limpia la muestra, la morfología fue analizada con un microscopio electrónico de barrido (SEM), posteriormente, para analizar la composición química de las muestras, realizamos una espectroscopia de dispersión de energía o micro-análisis químico de rayos X (EDSX) en el SEM. Encontramos que los corales de los arrecifes Gallega y Galleguilla que se encuentran ubicados cerca de poblaciones humanas, presentan altos niveles de tungsteno y el esqueleto exhibe múltiples agujeros. En contraste, los corales de los arrecifes más lejanos (Isla Verde e Isla de En medio) mostraron niveles más bajos de tungsteno y un menor número de agujeros en su esqueleto. Nuestros resultados demuestran que las actividades antropogénicas en el NPVRS, están afectando el esqueleto de los corales y promueven la bioerosión. Las descargas de grandes cantidades de contaminantes hacia las zonas costeras, promueven el crecimiento de especies dañinas que crecen y se desarrollan dentro del esqueleto de los corales, causando bioerosión del esqueleto, haciéndolos susceptibles a enfermedades y daños físicos. Debido a que este estudio es la primera evidencia de los efectos de la contaminación sobre esta especie de corales, son necesarios más estudios para determinar el impacto de la contaminación sobre su biología y la supervivencia de los corales.

Carcinoecium-forming Epizoanthus [Hexacorallia: Zoantharia] and the biology of E. papillosus in the eastern Atlantic, with special reference to the cnidom.

Epizoanthus is a poorly known zoantharian genus in need of further study. Benthic surveys have shown that E. papillosus (until recently considered rare) is quite abundant in the Celtic Sea, Minches and northern North Sea, occurring as carcin-oecia formed in association with Anapagurus laevis (Anomura, Paguridae) and as smaller free-living colonies. It is also extensively distributed in the western Atlantic. A study of the cnidom in tentacles and mesenteric filaments has shown that carcinoecia contained fewer types and smaller numbers of nematocysts (basitrichs, p-mastigophores, and two different holotrich types) and spirocysts than free-living colonies, probably a consequence of being able to scavenge food from the pagurid. A method for obtaining quantitative estimates of spirocyst abundance is described. The mesenteric filaments of two of the three carcinoecia analysed contained numerous unexploded nematocysts (kleptocnidae) sequestered from the scyphomedusan Cyanea (probably C. capillata), presumably derived from the long tentacles trailing over the sea bed. This occurrence has never previously been recorded. The taxonomic study of larger, deep-sea, carcinoecium-forming species of Epizoanthus is complicated by the same paucity of nematocysts noted for E. papillosus.

A taxonomic revision of the genus Primnoisis Studer [& Wright], 1887 (Coelenterata: Octocorallia: Isididae) using morphological and molecular data.

A complete taxonomic revision of the genus Primnoisis (Isididae) is presented herein, based on original type material of all nominal species and additional specimens from deep-water surveys in sub-temperate and Antarctic waters. A multi-disciplinary approach was used combining morphological characteristics such as colonial branching patterns, polyp structure, sclerite form and arrangement, together with phylogenetic reconstructions using two mitochondrial gene regions (mtMutS and igr1-cox1). The genus Primnoisis is retained with 7 of the 8 nominal species validated (P. antarctica Wright & Studer, 1889, P. rigida Wright & Studer, 1889, P. ambigua Wright & Studer, 1889, P. delicatula Hickson, 1907, P. fragilis Kükenthal, 1912, P. formosa Gravier, 1913 and P. mimas Bayer & Stefani, 1987), with the eighth (P. sparsa Wright & Studer, 1889), synonymised with P. antarctica. In addition, the species Mopsea gracilis Gravier, 1913 is reassigned to Primnoisis and an additional five new species are described (P. chatham n. sp., P. erymna n. sp., P. millerae n. sp., P. niwa n. sp. and P. tasmani n. sp). Most of the species fell into two clear groups, defined both by morphology and genetic grouping, for which two new sub-genera are proposed (P. (Primnoisis) n. subg. and P. (Delicatisis) n. subg.). Three species, P. ambigua, P. mimas and P. tasmani, could not be placed reliably in either sub-genus due to distinctive morphological features or genetic dissimilarity. It was not possible to confirm the monophyly of the genus due to unresolved relationships with the closely related genus Notisis Gravier, 1913 and an undescribed genus of Mopseinae.