Depositional environment, foraminifer content and ESR ages of Quaternary Gediz Delta Sediments (Eastern Aegean Sea, İzmir-Western Turkey)

NASA Astrophysics Data System (ADS)

Gökçe Benli, Ekin; Aydın, Hülya; İşintek, İsmail; Engin, Birol; Şengöçmen, Berna

2016-04-01

Sediments and fossil content of Gediz Delta (Eastern Aegean Sea - İzmir) were examined based on the drilling core samples of the YSK-C and SK-246 drilling. W-SW part of the Delta is represented by continental delta sediments up to 6 meters and shallow marine detritic sediments up to 35 meters in the YSK-C drilling. Continental part consists of an soiled, graveled, muddy and sandy sediment in terms of rich organic substance. As for marine part, it consists of bioclast, muddy, fine graveled sand and by repetition of pebble, sand and bioclast bearing mud layers. Bioclasts comprise of bivalvia, echinoid, ostracod, gastropod, foramifer and bryozoa fragments. Benthic foraminiferal fauna determinated in the marine levels are represented by 55 bethic, 2 planktonic species. These foraminifers and bioclasts reflect that the W-SW part of the delta, has been occured in marine conditions between 8-31m deep. E-NE part of the delta is generally represented by continental sediments up to 43.5m in SK-246 drilling. In addition, it includes marine levels in 18-19 m, 23-24 m and 36-37,5 m intervals. Continental sediments of E-NE part is generally represented by calcareous and sandy mud rocks which mostly includes ash, tuff, and pebble derived from Neogene volcanic rocks. As for marine levels, it is composed of calcareous mud stones and calcareous clay stones including very thin gastropod, bivalvia and ostracod in 18- 19 and 36-37.5 meters whereas it is represented by sandy mud stones including a great deal of bentic foraminifer, bivalvia, bryozoa, echinoid, gastropod in 23-24 metres. Thus show that E-NE part of the delta is usually in continental condition but it is occasionally covered by sea. In aging studies of YSK-C core done by ESR method, age of 8-9 m interval is determined to be 11. 376 ± 0,067 Ka; however ages of 10-11m and 24-25 m intervals are revealed to be 16.466 ± 0,016 Ka and 15.344 ± 0,021 Ka respectively; finally age of 25-26 m interval is found to be 19.995 ± 0,022 Ka. This results reflect while the W-SW part of the delta is in marine condition between 20 and 11 Ka, in the E-NE part of the delta, continental and marine conditions were repeated.

Early detection of marine invasive species, Bugula neritina (Bryozoa: Cheilostomatida), using species-specific primers and environmental DNA analysis in Korea.

PubMed

Kim, Philjae; Kim, Donghwan; Yoon, Tae Joong; Shin, Sook

2018-08-01

The bryozoan, Bugula neritina, is one of the most widespread sessile marine invasive species. Since its first discovery in Korea in 1978, the gradual increase in the distribution and abundance of this species resulted in a significant damage to growth of aquaculture. Environmental DNA (eDNA) is a potentially useful tool for species detection including rare, invasive and threatened native species. In this study, species-specific primers and probe were designed to amplify a 185-bp region based on mitochondrial COI of B. neritina for monitoring, and tested on environmental samples from 35 harbors of Korea in 2017. Among 35 sites monitored, B. neritina colonies were detected in 27 sites during field survey. However, B. neritina DNA was detected in all examined eDNA isolated from seawater. These results suggested that eDNA-based methods coupled with simple seawater sampling could be suitable for determining the distribution and abundance of B. neritina as complementary traditional monitoring. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fouling assemblage of benthic plastic debris collected from Mersin Bay, NE Levantine coast of Turkey.

PubMed

Gündoğdu, Sedat; Çevik, Cem; Karaca, Serkan

2017-11-15

The Mediterranean is an ecosystem that faces more and more microplastic pollution every day. This causes the whole of the Mediterranean to face the negative effects of plastic pollution. This study examines the state of plastic debris and fouling organisms found on it in one of the areas most affected by plastic pollution, Mersin Bay. As a result, a total of 3.88kg plastic (mean=0,97kg; n=120; 2670item/km 2 ; 86,3kg/km 2 ) was collected and based on the ATR-FTIR analysis, it was determined that this total contained 9 types of plastics. 17 different fouling species belonging to 6 phylum (Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria, Mollusca) 7 class and 11 order were discovered on plastics. Spirobranchus triqueter, Hydroides sp. and Neopycnodonte cochlear were the most abundant species. In the end, the example of Mersin Bay shows that plastic debris as a substrate can contain a very high diversity of life just like natural substrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trait-based characterization of species transported on Japanese tsunami marine debris: Effect of prior invasion history on trait distribution.

PubMed

Miller, Jessica A; Gillman, Reva; Carlton, James T; Murray, Cathryn Clarke; Nelson, Jocelyn C; Otani, Michio; Ruiz, Gregory M

2018-01-12

Nearly 300 coastal marine species collected from >630 debris items from the 2011 Great East Japan earthquake and tsunami have landed alive along the North American Pacific coast and the Hawaiian Archipelago. We synthesized life history, environmental, and distributional traits for 103 of these species and compared species with (n=30) and without (n=62) known invasion histories. The species represent 12 phyla, and Mollusca, Crustacea, and Bryozoa accounted for 71 of the 103 species. The majority are native to the Northwest Pacific and the Central Indo-Pacific. Species with known invasion history were more common on artificial and hardpan substrates, in temperate reef, fouling, and flotsam habitats, at subtropical and tropical temperatures, and exhibited greater salinity tolerance than species with no prior invasion history. Thirty-five Japanese tsunami marine species without prior invasion history overlapped in ordination trait space with known invaders, indicating a subset of species in this novel assemblage that possess traits similar to species with known invasion history. Copyright © 2018 Elsevier Ltd. All rights reserved.

Agent of Whirling Disease Meets Orphan Worm: Phylogenomic Analyses Firmly Place Myxozoa in Cnidaria

PubMed Central

Nesnidal, Maximilian P.; Helmkampf, Martin; Bruchhaus, Iris; El-Matbouli, Mansour; Hausdorf, Bernhard

2013-01-01

Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are Myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic “orphan worm” Buddenbrockia plumatellae parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of Buddenbrockia also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of Myxobolus cerebralis firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias. PMID:23382916

Early Eocene biota (ostracoda, foraminifera) and paleoenvironment of the Blue Marls in the Corbieres Hills (Aude, France): building a framework for the identification of early Eocene hyperthermals in continental margin records.

NASA Astrophysics Data System (ADS)

Pirkenseer, C.; King, C.; Steurbaut, E.; Speijer, R.

2009-04-01

The Corbières Foreland Basin represents the southeastern-most extension of the Aquitanian Basin and is thus palaeo(bio)geographically related to the West-European Cenozoic Basin. During the Ypresian (‘Ilerdien') a succession of marine carbonates (e.g., Calcaires blancs à Alvéolines), marine marls (Blue Marls, Marnes à Térebratulides), brackish marls to sandstones and subsequent fluvio-lacustrine sediments (e.g., Montlaur Molasse) were deposited in the Corbières Hills (Aude, France) area in several depositional sequences. The present study focuses on the upper part of the open marine Blue Marls and the overlying brackish marls and sandstones spanning about 120m thickness close to the village Pradelles-en-Val. Over one hundred samples were collected in 1m intervals in order to document the early Eocene biogeographical and paleoenvironmental evolution of this open marine sequence, through a quantitative analysis of the ostracod assemblages. Furthermore, we aim at identifying anomalous environmental conditions that might be expected to be associated with the early Eocene hyperthermals known as Elmo- (ETM2) and X-event (ETM3). These events are subordinate to the best known hyperthermal, the Paleocene-Eocene thermal maximum, which has been recorded in deep-sea to non-marine depositional settings. ETM2 and ETM3, however, have until now only been demonstrated in deep-sea sequences, not in shelf deposits. In accordance with biostratigraphical data derived from other outcrops in the region, the sampled succession is attributed to the interval of calcareous nannofossil zones NP10-NP12. The occurrences of planktonic foraminifera of the Morozovella subbotinae-group are in agreement with this stratigraphic position (P6-7) for the lower part of the profile. Recorded fossil groups include generally abundant marine ostracoda, bryozoa, benthic and planktonic foraminifera, fragments of echinoderms including ophiuroidea, moulds of gastropods (often pyritised), large dinocysts, crab claws and few otoliths. The ostracod assemblages contain common shelf-dwelling genera, such as Acanthocythereis, Bairdoppilata, Cytherella, Echinocythereis, Eopaijenborchiella, Horrificiella, Krithe, Loxoconcha, Paracypris, Pterygocythereis throughout the section in variable numbers. Bairdoppilata and Horrificiella appear to represent the most abundant taxa. Towards the top of the section, an upward shallowing is recorded by the increase in clastic input and macrofossils sich as larger foraminifera, cerithid gastropoda and bryozoa and the disappearance of planktic foraminifera. Future work will focus on a high-resolution sampling of potential early Eocene hyperthermal events, including stable isotopic (d18O, d13C) analyses. This project is funded by the Swiss National Science Foundation (project-nr. PBFR22-116947) and further supported by the K.U.Leuven Research Fund.

Water-borne sperm trigger vitellogenic egg growth in two sessile marine invertebrates.

PubMed

Bishop, J D; Manríquez, P H; Hughes, R N

2000-06-22

A diverse array of sessile marine invertebrates mate by passive dispersal of sperm which fertilize the brooded eggs of neighbours. In two such species, a sea-mat (phylum Bryozoa) and an ascidian (phylum Chordata), vitellogenic egg growth is absent in reproductively isolated specimens, but is triggered by a water-borne factor released by conspecifics. In both of these colonial, hermaphroditic species, the active factor can be removed from water by filtration. The effect involves self-/non-self-recognition: water conditioned by a separate subcolony of the same genetic individual does not prompt oocyte growth. In each species, allosperm move from the surrounding water to the ovary and are then stored in close association with the growing oocytes. We concluded that sperm themselves are the water-borne factor that triggers the major phase of female reproductive investment. This mechanism is, to our knowledge, previously undescribed in animals, but has parallels with the initiation of maternal investment in flowering plants following the receipt of compatible pollen. The species studied may be representative of many other aquatic invertebrates which mate in a similar way. The stimulation of egg growth by allosperm could lead to intersexual conflict during oogenesis.

Water-borne sperm trigger vitellogenic egg growth in two sessile marine invertebrates.

PubMed Central

Bishop, J D; Manríquez, P H; Hughes, R N

2000-01-01

A diverse array of sessile marine invertebrates mate by passive dispersal of sperm which fertilize the brooded eggs of neighbours. In two such species, a sea-mat (phylum Bryozoa) and an ascidian (phylum Chordata), vitellogenic egg growth is absent in reproductively isolated specimens, but is triggered by a water-borne factor released by conspecifics. In both of these colonial, hermaphroditic species, the active factor can be removed from water by filtration. The effect involves self-/non-self-recognition: water conditioned by a separate subcolony of the same genetic individual does not prompt oocyte growth. In each species, allosperm move from the surrounding water to the ovary and are then stored in close association with the growing oocytes. We concluded that sperm themselves are the water-borne factor that triggers the major phase of female reproductive investment. This mechanism is, to our knowledge, previously undescribed in animals, but has parallels with the initiation of maternal investment in flowering plants following the receipt of compatible pollen. The species studied may be representative of many other aquatic invertebrates which mate in a similar way. The stimulation of egg growth by allosperm could lead to intersexual conflict during oogenesis. PMID:10902681

Benthic meiofaunal composition and community structure in the Sethukuda mangrove area and adjacent open sea, East coast of India

NASA Astrophysics Data System (ADS)

Thilagavathi, Balasubramanaian; Das, Bandana; Saravanakumar, Ayyappan; Raja, Kuzhanthaivel

2011-06-01

The ecological aspects of meiofaunal communities in the Muthupettai mangrove forest, East coast of India, has not been investigated in the last two decades. Surface water temperature ranged from 23.5 °C to 31.8 °C. Salinity varied from 24 to 34 ppt, while water pH fluctuated from 7.4 to 8.3. Dissolved oxygen concentration ranged from 3.86 to 5.33 mg/l. Meiofauna analysis in this study identified a total of 106 species from the mangrove and adjacent open sea area of Sethukuda. Among these, 56 species of foraminiferans, 20 species of nematodes, 7 species of harpacticoid copepods, 4 species of ostrocodes, and 2 species of rotifers were identified. Furthermore, a single species was identified from the following groups: ciliophora, cnidaria, gnathostomulida, insecta, propulida, bryozoa and polychaete larvae. Meiofaunal density varied between 12029 to 23493 individuals 10 cm/m2. The diversity index ranged from 3.515 to 3.680, species richness index varied from 6.384 to 8.497, and evenness index varied from 0.839 to 0876 in the mangrove area and adjacent open sea.

FROM INCIPIENT TO SUBSTANTIAL: EVOLUTION OF PLACENTOTROPHY IN A PHYLUM OF AQUATIC COLONIAL INVERTEBRATES

PubMed Central

Ostrovsky, Andrew N; Fairbairn, D

2013-01-01

Matrotrophy has long been known in invertebrates, but it is still poorly understood and has never been reviewed. A striking example of matrotrophy (namely, placentotrophy) is provided by the Bryozoa, a medium-sized phylum of the aquatic colonial filter feeders. Here I report on an extensive anatomical study of placental analogues in 21 species of the bryozoan order Cheilostomata, offering the first review on matrotrophy among aquatic invertebrates. The first anatomical description of incipient placentotrophy in invertebrates is presented together with the evidence for multiple independent origins of placental analogues in this order. The combinations of contrasting oocytic types (macrolecithal or microlecithal) and various degrees of placental development and embryonic enlargement during incubation, found in different bryozoan species, are suggestive of a transitional series from the incipient to the substantial placentotrophy accompanied by an inverse change in oogenesis, a situation reminiscent of some vertebrates. It seems that matrotrophy could trigger the evolution of sexual zooidal polymorphism in some clades. The results of this study show that this phylum, with its wide variety of reproductive patterns, incubation devices, and types of the simple placenta-like systems, offers a promising model for studying parallel evolution of placentotrophy in particular, and matrotrophy in general. PMID:23617914

Photographic evaluation of the impacts of bottom fishing on benthic epifauna

USGS Publications Warehouse

Collie, J.S.; Escanero, G.A.; Valentine, P.C.

2000-01-01

The gravel sediment habitat on the northern edge of Georges Bank (East coast of North America) is an important nursery area for juvenile fish, and the site of a productive scallop fishery. During two cruises to this area in 1994 we made photographic transects at sites of varying depths that experience varying degrees of disturbance from otter trawling and scallop dredging. Differences between sites were quantified by analyzing videos and still photographs of the sea bottom. Videos were analyzed for sediment types and organism abundance. In the still photos, the percentages of the bottom covered by bushy, plant-like organisms and colonial worm tubes (Filograna implexa) were determined, as was the presence/absence of encrusting bryozoa. Non-colonial organisms were also identified as specifically as possible and sediment type was quantified. Significant differences between disturbed and undisturbed areas were found for the variables measured in the still photos; colonial epifaunal species were conspicuously less abundant at disturbed sites. Results from the videos and still photos were generally consistent although less detail was visible in the videos. Emergent colonial epifauna provide a complex habitat for shrimp, polychaetes, brittle stars and small fish at undisturbed sites. Bottom fishing removes this epifauna, thereby reducing the complexity and species diversity of the benthic community. (C) 2000 International Council for the Exploration of the Sea.

Three species of Reteporella (Bryozoa: Cheilostomata) in a diapiric and mud volcano field of the Gulf of Cádiz, with the description of Reteporella victori n. sp.

PubMed

Ramalho, LaÍs V; LÓpez-fÉ, Carlos M; Rueda, JosÉ Luis

2018-01-23

Diapirs and mud volcanoes (MVs) are formed by the migration and extrusion of fluids and mud to the seafloor, respectively. In the Gulf of Cádiz there are ca. 60 MVs and several diapirs with different environmental conditions and seepage activity. Previous studies, mainly on MVs, have demonstrated that the invertebrate fauna associated with these seafloor structures can be very diverse, including chemosymbiotic species, mostly mollusks and frenulate polychaetes, as well as vulnerable suspension feeders, such as cold-water corals and sponges, among others. Previous studies of the bryozoan fauna in this area have recorded species belonging to 28 families. One of these families is Phidoloporidae, which comprises 27 genera worldwide, including the common Rhynchozoon, Reteporellina, and Reteporella. In the present study, two species belonging to Reteporella are redescribed, and a new species is described from diapirs and MVs on the shelf and slope of the Gulf of Cádiz. The samples were collected during several oceanographic expeditions carried out by the Instituto Español de Oceanografia. This genus is well represented in the NE Atlantic Ocean and the Mediterranean Sea, and our study extends its occurrence on MVs and diapirs fields of the Gulf of Cádiz.

The Global Invertebrate Genomics Alliance (GIGA): Developing Community Resources to Study Diverse Invertebrate Genomes

PubMed Central

2014-01-01

Over 95% of all metazoan (animal) species comprise the “invertebrates,” but very few genomes from these organisms have been sequenced. We have, therefore, formed a “Global Invertebrate Genomics Alliance” (GIGA). Our intent is to build a collaborative network of diverse scientists to tackle major challenges (e.g., species selection, sample collection and storage, sequence assembly, annotation, analytical tools) associated with genome/transcriptome sequencing across a large taxonomic spectrum. We aim to promote standards that will facilitate comparative approaches to invertebrate genomics and collaborations across the international scientific community. Candidate study taxa include species from Porifera, Ctenophora, Cnidaria, Placozoa, Mollusca, Arthropoda, Echinodermata, Annelida, Bryozoa, and Platyhelminthes, among others. GIGA will target 7000 noninsect/nonnematode species, with an emphasis on marine taxa because of the unrivaled phyletic diversity in the oceans. Priorities for selecting invertebrates for sequencing will include, but are not restricted to, their phylogenetic placement; relevance to organismal, ecological, and conservation research; and their importance to fisheries and human health. We highlight benefits of sequencing both whole genomes (DNA) and transcriptomes and also suggest policies for genomic-level data access and sharing based on transparency and inclusiveness. The GIGA Web site (http://giga.nova.edu) has been launched to facilitate this collaborative venture. PMID:24336862

Epibiotic relationships on Zygochlamys patagonica (Mollusca, Bivalvia, Pectinidae) increase biodiversity in a submarine canyon in Argentina

NASA Astrophysics Data System (ADS)

Schejter, Laura; López Gappa, Juan; Bremec, Claudia Silvia

2014-06-01

The continental slope of the southern SW Atlantic Ocean has many distinguishable deep submarine canyons, varying in depth and extension. The benthic fauna within one of them, detected in April 2005 by means of a multibeam SIMRAD EM1002 sonar, and located at 43°35‧S to 59°33‧W, 325 m depth, was studied to discuss faunal affinities with the neighbouring Patagonian scallop fishing grounds located at upper slope depths. In order to add faunal information to the previous general study, we studied the epibiotic species settled on Patagonian scallops (the dominant species in the area) collected in the reference sampling site using a 2.5-m mouth-opening dredge, 10 mm mesh size. We sampled 103 scallops with shell heights between 22 and 69 mm; epibionts were recorded on both valves. We found 53 epibiotic taxa, which were most conspicuous on the upper valve. Bryozoa was the most diverse group (34 species) while Polychaeta was the most abundant group, recorded on 94% of the scallops. Stylasteridae (2 species) and Clavulariidae (Cnidaria) conform newly recorded epibionts on Z. patagonica and the sponge Tedania (Tedaniopsis) infundibuliformis also represents a new record for the SW Atlantic Ocean.

The Global Invertebrate Genomics Alliance (GIGA): developing community resources to study diverse invertebrate genomes.

PubMed

Bracken-Grissom, Heather; Collins, Allen G; Collins, Timothy; Crandall, Keith; Distel, Daniel; Dunn, Casey; Giribet, Gonzalo; Haddock, Steven; Knowlton, Nancy; Martindale, Mark; Medina, Mónica; Messing, Charles; O'Brien, Stephen J; Paulay, Gustav; Putnam, Nicolas; Ravasi, Timothy; Rouse, Greg W; Ryan, Joseph F; Schulze, Anja; Wörheide, Gert; Adamska, Maja; Bailly, Xavier; Breinholt, Jesse; Browne, William E; Diaz, M Christina; Evans, Nathaniel; Flot, Jean-François; Fogarty, Nicole; Johnston, Matthew; Kamel, Bishoy; Kawahara, Akito Y; Laberge, Tammy; Lavrov, Dennis; Michonneau, François; Moroz, Leonid L; Oakley, Todd; Osborne, Karen; Pomponi, Shirley A; Rhodes, Adelaide; Santos, Scott R; Satoh, Nori; Thacker, Robert W; Van de Peer, Yves; Voolstra, Christian R; Welch, David Mark; Winston, Judith; Zhou, Xin

2014-01-01

Over 95% of all metazoan (animal) species comprise the "invertebrates," but very few genomes from these organisms have been sequenced. We have, therefore, formed a "Global Invertebrate Genomics Alliance" (GIGA). Our intent is to build a collaborative network of diverse scientists to tackle major challenges (e.g., species selection, sample collection and storage, sequence assembly, annotation, analytical tools) associated with genome/transcriptome sequencing across a large taxonomic spectrum. We aim to promote standards that will facilitate comparative approaches to invertebrate genomics and collaborations across the international scientific community. Candidate study taxa include species from Porifera, Ctenophora, Cnidaria, Placozoa, Mollusca, Arthropoda, Echinodermata, Annelida, Bryozoa, and Platyhelminthes, among others. GIGA will target 7000 noninsect/nonnematode species, with an emphasis on marine taxa because of the unrivaled phyletic diversity in the oceans. Priorities for selecting invertebrates for sequencing will include, but are not restricted to, their phylogenetic placement; relevance to organismal, ecological, and conservation research; and their importance to fisheries and human health. We highlight benefits of sequencing both whole genomes (DNA) and transcriptomes and also suggest policies for genomic-level data access and sharing based on transparency and inclusiveness. The GIGA Web site (http://giga.nova.edu) has been launched to facilitate this collaborative venture.

Study of Upper Miocene Oysters(Plecypoda) From the Mishan Formation in south west of Firuzabad, Fars, Iran(Zagros mountain)

NASA Astrophysics Data System (ADS)

Dehbozorgi, Mehdi; Sabouhi, Mostafa; Nabavi, Hamid

2010-05-01

The out crapes of Mishan Formation located in Aghar area(Firuzabad city) south west of Fars and 70km south west of Firuzabad. this Formation mostly consist of limestone, marly limestone and marlstone with 800m thickness. 6key beds distinctive from limestone beds are recognized in this area. this key beds are useful for local and regional correlation in Zagros mountains. the key beds from base to top are: Red algae, Bryozoa, Gastropoda and Plecypoda, Crabs and Oysters. Mishan Formation in this area is between Gachsaran F.M(Under Formation), Conformable and Aghajari F.M(Upper Formation), Conformable. With due attention to rang and distribution of the Macrofossils, 5 local assmblage biozone were recognized, that is confirming time limit from Early- Upper Miocene. this research cheked and controled a biostrom Plecypoda(Oysters) level by thickness 3- 4m. this biostrom located around 550m the base of section. Ofcurse more of this Plecypoda be assinged to order pterriodia and Genus Oyster. Along with Oysters, Pecten and Venus can be see. This biostrom made up a bioclastic shoal shallow deep in the margin of sea Miocene. This Oysters report from Mishan Formation of Firuzabad, Fars, Zagros, Iran: Ostrea virleti var. crassicostat, Ostrea virleti Desh var. persica, Ostrea digitatai Echiwald var. rohlfsi, Ostrea lamellose. Ostrea cf. biowwondeli. Master of science in Geology (Paleontology), University of Isfahan, Iran.

The Manciano Sandstone: a shoreface deposit of Miocene basins of the Northern Apennines, Italy

NASA Astrophysics Data System (ADS)

Martini, I. P.; Cascella, A.; Rau, A.

1995-09-01

Well exposed, diamond-line cut, quarry-exposures of the Manciano Sandstone allow a detailed analysis of sandy, fossiliferous, nearshore deposits of the shelf of the Northern Apennines. The Manciano Sandstone is characterized by medium to very coarse, washed, fairly well sorted, lithic sandstone, with thin interlayers of sandy conglomerates. It displays two principal, rhythmically alternating sandy facies: (a) slightly burrowed (mostly Macaronichnus, Ophiomorpha, Skolithos) units, trough cross-bedded, locally showing possible tidal bundles with few whole Scutella (echinoid) shells reworked on foresets, or occasional large-scale (approximately 2 m) planar cross-bedded, bar-accretion units; and (b) slightly finer, darker-coloured reddish-brown sandstone units, heavily bioturbated ( Cruziana-Skolithos) ichnofauna) representing slightly more sheltered settings. Large oysters are present in near-living position in a few thin layers and, more commonly, as reworked, comminuted fragments in sandy layers. Many calcareous pebbles and oyster fragments are bored. Other fossils consist of echinoids ( Scutella), some balanids and reworked foraminifera and bryozoa. The Manciano sands were deposited primarily in a wave-dominated shoreface, containing migrating bars/ridges and affected by wave-induced, possibly tidal-enhanced currents. This tidal influence confirms the opening of the Miocene Apenninic Sea to oceans, both the developing Atlantic Ocean to the west and, through a long, narrow seaway, the Asian portion of the Tethys Sea to the east.

Broad Phylogenetic Occurrence of the Oxygen-Binding Hemerythrins in Bilaterians

PubMed Central

Schrago, Carlos G.; Halanych, Kenneth M.

2017-01-01

Abstract Animal tissues need to be properly oxygenated for carrying out catabolic respiration and, as such, natural selection has presumably favored special molecules that can reversibly bind and transport oxygen. Hemoglobins, hemocyanins, and hemerythrins (Hrs) fulfill this role, with Hrs being the least studied. Knowledge of oxygen-binding proteins is crucial for understanding animal physiology. Hr genes are present in the three domains of life, Archaea, Bacteria, and Eukaryota; however, within Animalia, Hrs has been reported only in marine species in six phyla (Annelida, Brachiopoda, Priapulida, Bryozoa, Cnidaria, and Arthropoda). Given this observed Hr distribution, whether all metazoan Hrs share a common origin is circumspect. We investigated Hr diversity and evolution in metazoans, by employing in silico approaches to survey for Hrs from of 120 metazoan transcriptomes and genomes. We found 58 candidate Hr genes actively transcribed in 36 species distributed in 11 animal phyla, with new records in Echinodermata, Hemichordata, Mollusca, Nemertea, Phoronida, and Platyhelminthes. Moreover, we found that “Hrs” reported from Cnidaria and Arthropoda were not consistent with that of other metazoan Hrs. Contrary to previous suggestions that Hr genes were absent in deuterostomes, we find Hr genes present in deuterostomes and were likely present in early bilaterians, but not in nonbilaterian animal lineages. As expected, the Hr gene tree did not mirror metazoan phylogeny, suggesting that Hrs evolutionary history was complex and besides the oxygen carrying capacity, the drivers of Hr evolution may also consist of secondary functional specializations of the proteins, like immunological functions. PMID:29016798

Environmental impact of bleufin tuna aquaculture on benthic assemblages in the western coast of Baja California, Mexico

NASA Astrophysics Data System (ADS)

Diaz-Castaneda, V.

2013-05-01

Sea-cage farming results in a constant rain of organic waste onto the surrounding benthos. In Baja California there is growing concern over the effects of sea-cages on the local environment: sediment chemistry and benthic communities. Samples were taken in 18 stations using a Van veen grab (0.1 m2) in Bahía Salsipuedes, Baja California in 2003, 2004, 2006 and 2008. Organisms belonging to 7 Phyla were collected: Polychaeta, Mollusca, Crustacea, Echinodermata, Cnidaria, Sipuncula and Bryozoa. Polychaetes were the dominant group followed by crustaceans and mollusks. Polychaetes were represented by 37 families and 157 species. Best represented families were Paraonidae, Cirratulidae, Spionidae, Glyceridae and Maldanidae. This study shows that in the NW area of the bay organic carbon (2.54%) and organic nitrogen (0.95%) are being accumulated (higher concentrations and lower Eh values) and smaller opportunistic species are increasing rapidly near the tuna pens. It is crucial to maintain "healthy" macrofaunal populations in order to enhance decomposition of organic matter and to prevent its excessive accumulation. The most abundant polychaete species were Aphelochaeta multifinis, Mediomastus ambiseta, Prionospio steenstrupi Spiophanes bombyx, Apoprionospio pygnaea, Paraonella sp, Monticellina sp, Aricidea (Allia) ramosa, Spiophanes bombyx and Levinsenia gracilis. The dominant trophic groups were deposit-feeders and carnivores. The buildup of organic matter on the seafloor has attracted scavenger species particularly peracarid crustaceans. Non-metric multidimensional scaling (MDS) separated stations depending of the distance to the tuna pens.

Breakdown of Phylogenetic Signal: A Survey of Microsatellite Densities in 454 Shotgun Sequences from 154 Non Model Eukaryote Species

PubMed Central

Meglécz, Emese; Nève, Gabriel; Biffin, Ed; Gardner, Michael G.

2012-01-01

Microsatellites are ubiquitous in Eukaryotic genomes. A more complete understanding of their origin and spread can be gained from a comparison of their distribution within a phylogenetic context. Although information for model species is accumulating rapidly, it is insufficient due to a lack of species depth, thus intragroup variation is necessarily ignored. As such, apparent differences between groups may be overinflated and generalizations cannot be inferred until an analysis of the variation that exists within groups has been conducted. In this study, we examined microsatellite coverage and motif patterns from 454 shotgun sequences of 154 Eukaryote species from eight distantly related phyla (Cnidaria, Arthropoda, Onychophora, Bryozoa, Mollusca, Echinodermata, Chordata and Streptophyta) to test if a consistent phylogenetic pattern emerges from the microsatellite composition of these species. It is clear from our results that data from model species provide incomplete information regarding the existing microsatellite variability within the Eukaryotes. A very strong heterogeneity of microsatellite composition was found within most phyla, classes and even orders. Autocorrelation analyses indicated that while microsatellite contents of species within clades more recent than 200 Mya tend to be similar, the autocorrelation breaks down and becomes negative or non-significant with increasing divergence time. Therefore, the age of the taxon seems to be a primary factor in degrading the phylogenetic pattern present among related groups. The most recent classes or orders of Chordates still retain the pattern of their common ancestor. However, within older groups, such as classes of Arthropods, the phylogenetic pattern has been scrambled by the long independent evolution of the lineages. PMID:22815847

Flotsam samples can help explain the δ13C and δ15N values of invertebrate resting stages in lake sediment

NASA Astrophysics Data System (ADS)

van Hardenbroek, Maarten; Rinta, Päivi; Wooller, Matthew J.; Schilder, Jos; Stötter, Tabea; Heiri, Oliver

2018-06-01

The stable isotopic composition of chitinous remains of Cladocera (water fleas) and freshwater Bryozoa (moss animals) preserved in lake sediment records can provide supporting insights into past environmental and ecosystem changes in lakes. Here we explore whether analyses of these remains isolated from lake flotsam can provide information on the driving variables affecting the isotopic composition of these remains. We collected flotsam in 53 lakes and found enough material in 33 lakes to measure the stable carbon and nitrogen isotope ratios (expressed as δ13C and δ15N values, respectively) of resting stages. These values were compared with lake characteristics, water chemistry measurements, and the isotopic composition of sedimentary organic matter (SOM) in the lakes. Mean δ13C values of cladoceran ephippia and SOM were correlated and both were also negatively correlated with deep water methane concentrations and indicators of lake stratification. This supports the findings of previous studies that methane-derived carbon can provide a significant proportion of carbon entering planktonic food webs. Mean δ15N values of bryozoan statoblasts and SOM were correlated, suggesting that both reflect the δ15N values of phytoplankton. Our results provide information on how environmental variables in lakes can influence the δ13C and δ15N values in resting stages, but flotsam samples can also potentially be used to assess seasonal stable isotope variability of resting stages. Both types of information are important to improve palaeoenvironmental interpretations of stable isotope records based on these remains in lake sediments.

The amathiiform Ctenostomata (phylum Bryozoa) of New Zealand--including four new species, two of them of probable alien origin.

PubMed

Gordon, Dennis P; Spencer-Jones, Mary

2013-01-01

The status of the vesiculariid ctenostome genus Amathia in New Zealand has been evaluated on the basis of all known material, including historic specimens in museums and those newly collected during formal surveillance of ports, harbours and vessels for possible alien species. Eight species are recognised, four of them new to science. Amathia gracei n. sp. and Amathia zealandica n. sp. are the only apparently endemic species. Amathia chimonidesi n. sp. appears to be a previously unrecognised alien species and is known only from shipping harbours and/or yacht marinas and some nearby beaches. Amathia similis n. sp. has been known in the Auckland area since the 1960s but was confused with A. distans Busk. Amathia bicornis (Tenison-Woods), A. biseriata Krauss, A. lamourouxi Chimonides and A. wilsoni Kirkpatrick are Australasian species that occur naturally on both sides of the Tasman Sea. Of this latter group, A. bicornis was discovered only at a single locality on the southwest coast of North Island in 1983 on a fucoid seaweed and it may be relatively re-cently self-introduced. A specimen of A. lendigera (Linnaeus) in the Museum of New Zealand, purportedly from Napier, is considered to be based on a misunderstanding or a labelling error and does not represent a failed alien introduction. The Amathia-like vesiculariid Bowerbankia citrina (Hincks) sensu lato is newly recorded for New Zealand. Keys are provided to the amathiiform (i.e. Amathia and Amathia-like) Ctenostomata of New Zealand and to the worldwide species of Amathia and Bowerbankia with zooid clusters spiralled on stoloniform axes.

An introduction to loricifera, cycliophora, and micrognathozoa.

PubMed

Kristensen, Reinhardt Møbjerg

2002-07-01

Loriciferans, cycliophorans and micrognathozoans are amongst the latest groups of animals to be discovered. Other than all being microscopic, they have very different body plans and are not closely related. Loriciferans were originally assigned to the Aschelminthes. However, both new molecular and ultrastructural researches have shown that Aschelminthes consist of two unrelated groups, Cycloneuralia and Gnathifera. Cycloneuralia may be included in the Ecdysozoa, including all molting invertebrates, and Gnathifera are more closely related to Platyhelminthes. The phylum Loricifera shares many apomorphic characters (e.g., scalids on the introvert) with both Priapulida and Kinorhyncha, and can be included in the taxon Scalidophora, a subgroup of Cycloneuralia. Cycliophora was originally allied to the Entoprocta and Ectoprocta (Bryozoa) based on ultrastructual research. Subsequent molecular data show they may be related to Rotifera and Acanthocephala, within the taxon Gnathifera. The phylogenetic position of Cycliophora is therefore not settled, and more ultrastructural and molecular data are needed. Micrognathozoa is the most recent major group of animals to be described. They show strong affinities with both Rotifera and Gnathostomulida (within the taxon Gnathifera), especially in the fine structure of the pharyngeal apparatus, where the jaw elements have cuticular rods with osmiophilic cores. Furthermore the micrognathozoans have two rows of multiciliated cells that form a locomotory organ, similar to that seen in some gastrotrichs and interstitial annelids. This character is never seen in Rotifera or in the monociliated Gnathostomulida. Rotifera and Acanthocephala always have a syncytial epidermis (Syndermata). Micrognathozoa lack this characteristic feature. Therefore, they are postulated to be placed basally in the Gnathifera, either as a sister-group to Gnathostomulida or as a sister-group to Rotifera + Acanthocephala.

Broad Phylogenetic Occurrence of the Oxygen-Binding Hemerythrins in Bilaterians.

PubMed

Costa-Paiva, Elisa M; Schrago, Carlos G; Halanych, Kenneth M

2017-10-01

Animal tissues need to be properly oxygenated for carrying out catabolic respiration and, as such, natural selection has presumably favored special molecules that can reversibly bind and transport oxygen. Hemoglobins, hemocyanins, and hemerythrins (Hrs) fulfill this role, with Hrs being the least studied. Knowledge of oxygen-binding proteins is crucial for understanding animal physiology. Hr genes are present in the three domains of life, Archaea, Bacteria, and Eukaryota; however, within Animalia, Hrs has been reported only in marine species in six phyla (Annelida, Brachiopoda, Priapulida, Bryozoa, Cnidaria, and Arthropoda). Given this observed Hr distribution, whether all metazoan Hrs share a common origin is circumspect. We investigated Hr diversity and evolution in metazoans, by employing in silico approaches to survey for Hrs from of 120 metazoan transcriptomes and genomes. We found 58 candidate Hr genes actively transcribed in 36 species distributed in 11 animal phyla, with new records in Echinodermata, Hemichordata, Mollusca, Nemertea, Phoronida, and Platyhelminthes. Moreover, we found that "Hrs" reported from Cnidaria and Arthropoda were not consistent with that of other metazoan Hrs. Contrary to previous suggestions that Hr genes were absent in deuterostomes, we find Hr genes present in deuterostomes and were likely present in early bilaterians, but not in nonbilaterian animal lineages. As expected, the Hr gene tree did not mirror metazoan phylogeny, suggesting that Hrs evolutionary history was complex and besides the oxygen carrying capacity, the drivers of Hr evolution may also consist of secondary functional specializations of the proteins, like immunological functions. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Combined effects of warming and ocean acidification on coral reef Foraminifera Marginopora vertebralis and Heterostegina depressa

NASA Astrophysics Data System (ADS)

Schmidt, Christiane; Kucera, Michal; Uthicke, Sven

2014-09-01

Warming and changes in ocean carbonate chemistry alter marine coastal ecosystems at an accelerating pace. The interaction between these stressors has been the subject of recent studies on reef organisms such as corals, bryozoa, molluscs, and crustose coralline algae. Here we investigated the combined effects of elevated sea surface temperatures and pCO2 on two species of photosymbiont-bearing coral reef Foraminifera: Heterostegina depressa (hosting diatoms) and Marginopora vertebralis (hosting dinoflagellates). The effects of single and combined stressors were studied by monitoring survivorship, growth, and physiological parameters, such as respiration, photochemistry (pulse amplitude modulation fluorometry and oxygen production), and chl a content. Specimens were exposed in flow-through aquaria for up to seven weeks to combinations of two pCO2 (~790 and ~490 µatm) and two temperature (28 and 31 °C) regimes. Elevated temperature had negative effects on the physiology of both species. Elevated pCO2 had negative effects on growth and apparent photosynthetic rate in H.depressa but a positive effect on effective quantum yield. With increasing pCO2, chl a content decreased in H. depressa and increased in M. vertebralis. The strongest stress responses were observed when the two stressors acted in combination. An interaction term was statistically significant in half of the measured parameters. Further exploration revealed that 75 % of these cases showed a synergistic (= larger than additive) interaction between the two stressors. These results indicate that negative physiological effects on photosymbiont-bearing coral reef Foraminifera are likely to be stronger under simultaneous acidification and temperature rise than what would be expected from the effect of each of the stressors individually.

Reconstructing the muscular ground pattern of phylactolaemate bryozoans: first data from gelatinous representatives.

PubMed

Gawin, Natalie; Wanninger, Andreas; Schwaha, Thomas

2017-11-07

Phylactolaemata is commonly regarded the earliest branch within Bryozoa and thus the sister group to the other bryozoan taxa, Cyclostomata and Gymnolaemata. Therefore, the taxon is important for the reconstruction of the bryozoan morphological ground pattern. In this study the myoanatomy of Pectinatella magnifica, Cristatella mucedo and Hyalinella punctata was analysed by means of histology, f-actin staining and confocal laser-scanning microscopy in order to fill gaps in knowledge concerning the myoanatomy of Phylactolaemata. The retractor muscles and muscles of the aperture, gut, body wall, tentacle sheath, lophophore constitute the most prominent muscular subsets in these species. The lophophore shows longitudinal muscle bands in the tentacles, lophophoral arm muscles, epistome musculature and hitherto undescribed muscles of the ring canal. In general the muscular system of the three species is very similar with differences mainly in the body wall, tentacle sheath and epistome. The body wall contains an orthogonal grid of musculature. The epistome exhibits either a muscular meshwork in the epistomal wall or muscle fibers traversing the epistomal cavity. The whole tentacle sheath possesses a regular mesh of muscles in Pectinatella and Cristatella, whereas circular muscles are limited to the tentacle sheath base in Hyalinella. This study is the first to describe muscles of the ring canal and contributes to reconstructing muscular features for the last common ancestor of all bryozoans. The data available suggest that two longitudinal muscle bands in the tentacles, as well as retractor muscles and longitudinal and circular muscles in the tentacle sheath, were present in the last common bryozoan ancestor. Comparisons among bryozoans shows that several apomorphies are present in the myoanatomy of each class- level taxon such as the epistomal musculature and musculature of the lophophoral arms in phylactolaemates, annular muscles in cyclostomes and parietal muscles in gymnolaemates.

Early Carboniferous (Tournasian-early Visean) global paleogeography, Paleostorm tracts, and the distribution of Waulsortian and Waulsortian-like carbonate mud mounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, D.T. Jr.

1990-05-01

Tournasian-early Visean mud mounds (i.e., Waulsortian and Waulsortian-like mounds) are unlike other carbonate buildups in the stratigraphic record because they lack an identifiable frame-building organism. Waulsortian mounds are comprised mainly of carbonate mud; Waulsortian-like mounds are mud-rich and contain a significant percent of skeletal grains, especially crinoids and bryozoa. This study has revealed that all of the reported Waulsortian and Waulsortian-like mounds developed in low paleolatitudes either on the southern shelf margin of the Laurussian paleocontinent or in the Laurussian interior seaway. Waulsortian and Waulsortian-like mounds are specifically not present in low-latitude regions of other paleocontinents. As Tournasian-early Visean carbonatemore » deposition was widespread in the range of 30{degree}N to 10{degree}S, the very restricted paleogeographic distribution of Waulsortian and Waulsortian-like mound locations suggests a mechanism or set of conditions that effectively limited the distribution of mud mounds. Considering the Tournasian-early Visean distribution of paleocontinents and the principles that govern the movement of modern hurricanes, tropical storms, and winter storms, the tracts of hurricanes, tropical storms, and winter storms probably crossed all main submerged paleocontinental areas except the southern Laurussian shelf margin and the Laurussian interior seaway, the two areas where mud mounds developed. The lack of storm energy in these two large areas of Laurussia provided long-term stability and thus enhanced the growth prospects of the frame-deficient Waulsortian and Waulsortian-like mud mounds. Lack of extensive periodic wave reworking and other storm-induced devastation helps to account for enigmatic features such as general mound symmetry, great size, high depositional relief (as much as 220 m), and side steepness (as steep as 50{degree}).« less

Evolutionary Determinants of Morphological Polymorphism in Colonial Animals.

PubMed

Simpson, Carl; Jackson, Jeremy B C; Herrera-Cubilla, Amalia

2017-07-01

Colonial animals commonly exhibit morphologically polymorphic modular units that are phenotypically distinct and specialize in specific functional tasks. But how and why these polymorphic modules have evolved is poorly understood. Across colonial invertebrates, there is wide variation in the degree of polymorphism, from none in colonial ascidians to extreme polymorphism in siphonophores, such as the Portuguese man-of-war. Bryozoa are a phylum of exclusively colonial invertebrates that uniquely exhibit almost the entire range of polymorphism, from monomorphic species to others that rival siphonophores in their polymorphic complexity. Previous approaches to understanding the evolution of polymorphism have been based on analyses of (1) the functional role of polymorphs or (2) presumed evolutionary costs and benefits based on evolutionary theory that postulates polymorphism should be evolutionarily sustainable only in more stable environments because polymorphism commonly leads to the loss of feeding and sexual competence. Here we use bryozoans from opposite shores of the Isthmus of Panama to revisit the environmental hypothesis by comparison of faunas from distinct oceanographic provinces that differ greatly in environmental variability, and we then examine the correlations between the extent of polymorphism in relation to patterns of ecological succession and variation in life histories. We find no support for the environmental hypothesis. Distributions of the incidence of polymorphism in the oceanographically unstable Eastern Pacific are indistinguishable from those in the more stable Caribbean. In contrast, the temporal position of species in a successional sequence is collinear with the degree of polymorphism because species with fewer types of polymorphs are competitively replaced by species with higher numbers of polymorphs on the same substrata. Competitively dominant species also exhibit patterns of growth that increase their competitive ability. The association between degrees of polymorphism and variations in life histories is fundamental to understanding of the macroevolution of polymorphism.

Triploblastic relationships with emphasis on the acoelomates and the position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognatha: a combined approach of 18S rDNA sequences and morphology.

PubMed

Giribet, G; Distel, D L; Polz, M; Sterrer, W; Wheeler, W C

2000-09-01

Triploblastic relationships were examined in the light of molecular and morphological evidence. Representatives for all triploblastic "phyla" (except Loricifera) were represented by both sources of phylogenetic data. The 18S ribosomal (rDNA) sequence data for 145 terminal taxa and 276 morphological characters coded for 36 supraspecific taxa were combined in a total evidence regime to determine the most consistent picture of triploblastic relationships for these data. Only triploblastic taxa are used to avoid rooting with distant outgroups, which seems to happen because of the extreme distance that separates diploblastic from triploblastic taxa according to the 18S rDNA data. Multiple phylogenetic analyses performed with variable analysis parameters yield largely inconsistent results for certain groups such as Chaetognatha, Acoela, and Nemertodermatida. A normalized incongruence length metric is used to assay the relative merit of the multiple analyses. The combined analysis having the least character incongruence yields the following scheme of relationships of four main clades: (1) Deuterostomia [((Echinodermata + Enteropneusta) (Cephalochordata (Urochordata + Vertebrata)))]; (2) Ecdysozoa [(((Priapulida + Kinorhyncha) (Nematoda + Nematomorpha)) ((Onychophora + Tardigrada) Arthropoda))]; (3) Trochozoa [((Phoronida + Brachiopoda) (Entoprocta (Nemertea (Sipuncula (Mollusca (Pogonophora (Echiura + Annelida)))))))]; and (4) Platyzoa [((Gnathostomulida (Cycliophora + Syndermata)) (Gastrotricha + Plathelminthes))]. Chaetognatha, Nemertodermatida, and Bryozoa cannot be assigned to any one of these four groups. For the first time, a data analysis recognizes a clade of acoelomates, the Platyzoa (sensu Cavalier-Smith, Biol. Rev. 73:203-266, 1998). Other relationships that corroborate some morphological analyses are the existence of a clade that groups Gnathostomulida + Syndermata (= Gnathifera), which is expanded to include the enigmatic phylum Cycliophora, as sister group to Syndermata.

Evidence for Polyphyly of the Genus Scrupocellaria (Bryozoa: Candidae) Based on a Phylogenetic Analysis of Morphological Characters

PubMed Central

Vieira, Leandro M.; Spencer Jones, Mary E.; Winston, Judith E.; Migotto, Alvaro E.; Marques, Antonio C.

2014-01-01

The bryozoan genus Scrupocellaria comprises about 80 species in the family Candidae. We propose a hypothesis for the phylogenetic relationships among species assigned to Scrupocellaria to serve as framework for a phylogenetic classification using 35 morphological characters. Our results suggest that the genus Scrupocellaria is polyphyletic. Scrupocellaria s. str. is redefined according to four morphological features: vibracular chamber with a curved setal groove, ooecium with a single ectooecial fenestra, two axillary vibracula, and a membranous operculum with a distinct distal rim. Thus, the genus includes only 11 species: Scrupocellaria aegeensis, Scrupocellaria delilii, Scrupocellaria harmeri, Scrupocellaria incurvata, Scrupocellaria inermis, Scrupocellaria intermedia, Scrupocellaria jullieni, Scrupocellaria minuta, Scrupocellaria puelcha, Scrupocellaria scrupea, and Scrupocellaria scruposa. The monophyly of Cradoscrupocellaria is supported and five new genera are erected: Aquiloniella n. gen., Aspiscellaria n. gen., Paralicornia n. gen., Pomocellaria n. gen. and Scrupocaberea n. gen. Two other new genera, Bathycellaria n. gen. and Sinocellaria n. gen., are erected to accommodate two poorly known species, Scrupocellaria profundis Osburn and Scrupocellaria uniseriata Liu, respectively. Scrupocellaria congesta is tentatively assigned to Tricellaria. Fifteen species are reassigned to Licornia: Licornia cookie n. comb., Licornia micheli n. comb., Licornia milneri n. comb., Licornia curvata n. comb., Licornia diegensis n. comb., Licornia drachi n. comb., Licornia mexicana n. comb., Licornia pugnax n. comb., Licornia raigadensis n. comb., Licornia regularis n. comb., Licornia resseri n. comb., Licornia securifera n. comb., Licornia spinigera n. comb., Licornia tridentata n. comb., and Licornia wasinensis n. comb. Notoplites americanus n. name is proposed as a replacement name for Scrupocellaria clausa Canu & Bassler. Three fossil species are reassigned to Canda: Canda rathbuni n. comb., Canda triangulata n. comb. and Canda williardi n. comb. A species is reassigned to Notoplites, Notoplites elegantissima n. comb. The generic assignment of eleven species of Scrupocellaria, including Scrupocellaria macandrei, remains uncertain. PMID:24747915

Phylogenomics of Lophotrochozoa with Consideration of Systematic Error.

PubMed

Kocot, Kevin M; Struck, Torsten H; Merkel, Julia; Waits, Damien S; Todt, Christiane; Brannock, Pamela M; Weese, David A; Cannon, Johanna T; Moroz, Leonid L; Lieb, Bernhard; Halanych, Kenneth M

2017-03-01

Phylogenomic studies have improved understanding of deep metazoan phylogeny and show promise for resolving incongruences among analyses based on limited numbers of loci. One region of the animal tree that has been especially difficult to resolve, even with phylogenomic approaches, is relationships within Lophotrochozoa (the animal clade that includes molluscs, annelids, and flatworms among others). Lack of resolution in phylogenomic analyses could be due to insufficient phylogenetic signal, limitations in taxon and/or gene sampling, or systematic error. Here, we investigated why lophotrochozoan phylogeny has been such a difficult question to answer by identifying and reducing sources of systematic error. We supplemented existing data with 32 new transcriptomes spanning the diversity of Lophotrochozoa and constructed a new set of Lophotrochozoa-specific core orthologs. Of these, 638 orthologous groups (OGs) passed strict screening for paralogy using a tree-based approach. In order to reduce possible sources of systematic error, we calculated branch-length heterogeneity, evolutionary rate, percent missing data, compositional bias, and saturation for each OG and analyzed increasingly stricter subsets of only the most stringent (best) OGs for these five variables. Principal component analysis of the values for each factor examined for each OG revealed that compositional heterogeneity and average patristic distance contributed most to the variance observed along the first principal component while branch-length heterogeneity and, to a lesser extent, saturation contributed most to the variance observed along the second. Missing data did not strongly contribute to either. Additional sensitivity analyses examined effects of removing taxa with heterogeneous branch lengths, large amounts of missing data, and compositional heterogeneity. Although our analyses do not unambiguously resolve lophotrochozoan phylogeny, we advance the field by reducing the list of viable hypotheses. Moreover, our systematic approach for dissection of phylogenomic data can be applied to explore sources of incongruence and poor support in any phylogenomic data set. [Annelida; Brachiopoda; Bryozoa; Entoprocta; Mollusca; Nemertea; Phoronida; Platyzoa; Polyzoa; Spiralia; Trochozoa.]. © The Author(s) 2016. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Please mind the gap - Visual census and cryptic biodiversity assessment at central Red Sea coral reefs.

PubMed

Pearman, John K; Anlauf, Holger; Irigoien, Xabier; Carvalho, Susana

2016-07-01

Coral reefs harbor the most diverse assemblages in the ocean, however, a large proportion of the diversity is cryptic and, therefore, undetected by standard visual census techniques. Cryptic and exposed communities differ considerably in species composition and ecological function. This study compares three different coral reef assessment protocols: i) visual benthic reef surveys: ii) visual census of Autonomous Reef Monitoring Structures (ARMS) plates; and iii) metabarcoding techniques of the ARMS (including sessile, 106-500 μm and 500-2000 μm size fractions), that target the cryptic and exposed communities of three reefs in the central Red Sea. Visual census showed a dominance of Cnidaria (Anthozoa) and Rhodophyta on the reef substrate, while Porifera, Bryozoa and Rhodophyta were the most abundant groups on the ARMS plates. Metabarcoding, targeting the 18S rRNA gene, significantly increased estimates of the species diversity (p < 0.001); revealing that Annelida were generally the dominant phyla (in terms of reads) of all fractions and reefs. Furthermore, metabarcoding detected microbial eukaryotic groups such as Syndiniophyceae, Mamiellophyceae and Bacillariophyceae as relevant components of the sessile fraction. ANOSIM analysis showed that the three reef sites showed no differences based on the visual census data. Metabarcoding showed a higher sensitivity for identifying differences between reef communities at smaller geographic scales than standard visual census techniques as significant differences in the assemblages were observed amongst the reefs. Comparison of the techniques showed no similar patterns for the visual techniques while the metabarcoding of the ARMS showed similar patterns amongst fractions. Establishing ARMS as a standard tool in reef monitoring will not only advance our understanding of local processes and ecological community response to environmental changes, as different faunal components will provide complementary information but also improve the estimates of biodiversity in coral reef benthic communities. This study lays the foundations for further studies looking at integrating traditional reef survey methodologies with complementary approaches, such as metabarcoding, which investigate other components of the reef community. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Diversity and Activity of Communities Inhabiting Plastic Debris in the North Pacific Gyre.

PubMed

Bryant, Jessica A; Clemente, Tara M; Viviani, Donn A; Fong, Allison A; Thomas, Kimberley A; Kemp, Paul; Karl, David M; White, Angelicque E; DeLong, Edward F

2016-01-01

Marine plastic debris has become a significant concern in ocean ecosystems worldwide. Little is known, however, about its influence on microbial community structure and function. In 2008, we surveyed microbial communities and metabolic activities in seawater and on plastic on an oceanographic expedition through the "great Pacific garbage patch." The concentration of plastic particles in surface seawater within different size classes (2 to 5 mm and >5 mm) ranged from 0.35 to 3.7 particles m -3 across sampling stations. These densities and the particle size distribution were consistent with previous values reported in the North Pacific Ocean. Net community oxygen production (NCP = gross primary production - community respiration) on plastic debris was positive and so net autotrophic, whereas NCP in bulk seawater was close to zero. Scanning electron microscopy and metagenomic sequencing of plastic-attached communities revealed the dominance of a few metazoan taxa and a diverse assemblage of photoautotrophic and heterotrophic protists and bacteria. Bryozoa , Cyanobacteria , Alphaproteobacteria , and Bacteroidetes dominated all plastic particles, regardless of particle size. Bacteria inhabiting plastic were taxonomically distinct from the surrounding picoplankton and appeared well adapted to a surface-associated lifestyle. Genes with significantly higher abundances among plastic-attached bacteria included che genes, secretion system genes, and nifH genes, suggesting enrichment for chemotaxis, frequent cell-to-cell interactions, and nitrogen fixation. In aggregate, our findings suggest that plastic debris forms a habitat for complex microbial assemblages that have lifestyles, metabolic pathways, and biogeochemical activities that are distinct from those of free-living planktonic microbial communities. IMPORTANCE Marine plastic debris is a growing concern that has captured the general public's attention. While the negative impacts of plastic debris on oceanic macrobiota, including mammals and birds, are well documented, little is known about its influence on smaller marine residents, including microbes that have key roles in ocean biogeochemistry. Our work provides a new perspective on microbial communities inhabiting microplastics that includes its effect on microbial biogeochemical activities and a description of the cross-domain communities inhabiting plastic particles. This study is among the first molecular ecology, plastic debris biota surveys in the North Pacific Subtropical Gyre. It has identified fundamental differences in the functional potential and taxonomic composition of plastic-associated microbes versus planktonic microbes found in the surrounding open-ocean habitat. Author Video : An author video summary of this article is available.

Paleoenvironmental reconstruction of the Oligocene-Miocene deposits of the Tethyan Seaway, Qom Formation, Central Iran

NASA Astrophysics Data System (ADS)

Dabaghi Sadr, Fatemeh; Schmiedl, Gerhard

2017-04-01

The Cenozoic climate transition from greenhouse to icehouse conditions was associated with major paleogeographic changes in the Tethyan realm. The closure of the Tethyan Seaway and its Iranian gateways during the terminal Paleogene and early Neogene, between approximately 28 and 18 million years, influenced the latitudinal exchange of water masses and energy and is documented in sediment successions of the Qom formation in central Iran. Little is known on the spatial expression and the exact depositional histories of the Qom Formation on orbital time-scales, including a lack of quantitative sea-level reconstructions and studies on the impact of climatic and tectonic changes on marine ecosystems and sedimentation processes. The PhD project focuses on the investigation of lithostratigraphy, biostratigraphy, paleoecology and paleoenvironmental evolution of the Iranian gateways based on late Oligocene to early Miocene foraminiferal faunas and carbonate facies from selected sediment sections of the Qom Basin. The Qom Formation was deposited in the Central Iranian back-arc basin during the Oligocene-Miocene. In this study foraminiferal faunas and carbonate microfacies were studied based on total 191 samples of two section of Qom Formation. One of them is Molkabad section, which is located northwest of Molkabad mountains, southeast of Garmsar. The section mainly consists of limestones, calcareous marls, marls, and gypsum-bearing marls with a total thickness of 760 meters. The Qom Formation at Molkabad section overlies Eocene rocks with an unconformity and consists of the following lithostratigraphic units (from the lower to upper part): Lithothamnium Limestone, Lower Marl Limestone, Bryozoa Limestone, and Upper Marl Group. The Molkabad fault separates the Qom Formation from the overlying Upper Red Formation. The other section is located at Navab anticline in Qom Formation .The section mainly consist of limestone, marl, and gypsum with a total thickness of 318 meters Navab anticline section overlies Eocene rocks with an unconformity. In a novel approach, ecological information from recent faunas of the Persian Gulf will be applied to the assessment of changes in paleo-water depth and paleo-salinity. Based on these data, global glacio-eustatic signals will be separated from regional tectonic events. This information can be used to better assess potential impacts of the closure of the Tethyan Seaway on Cenozoic paleooceanography and paleoclimate.

Unity in diversity: a survey of muscular systems of ctenostome Gymnolaemata (Lophotrochozoa, Bryozoa).

PubMed

Schwaha, Thomas F; Wanninger, Andreas

2018-01-01

Myoanatomical studies of adult bryozoans employing fluorescent staining and confocal laser scanning microscopy (CLSM) have been chiefly conducted on freshwater bryozoans. The diversity of muscular systems in the marine bryozoans is currently not well known with only two species being studied in more detail. The aim of this study is to unravel the diversity of muscle systems of 15 ctenostome bryozoans by phalloidin-coupled fluorescence stainings combined with CLSM. In general, the myoanatomy of the selected ctenostomes shows significant similarities and consists of 1) muscles associated with the body wall, 2) apertural muscles, 3) lophophoral muscles, 4) tentacle sheath muscles, 5) digestive tract muscles and 6) the prominent retractor muscles. Differences are present in the arrangement of the apertural muscles from generally three muscles sets of four bundles, which in some species can be partially reduced or modified into a bilateral arrangement. The cardiac region of the digestive tract shows a distinct sphincter in four of the six studied clades. In some cases the cardiac region forms a prominent proventriculus or gizzard. Tentacle sheath muscles in victorelloideans and walkerioideans are arranged diagonally and differ from the simple longitudinal muscle arrangements common to all other taxa. Lophophoral base muscles consist of four sets that vary in the size of the sets and in the shape of the inner lophophoral ring, which either forms a complete ring or separate, intertentacular muscle bundles. The stolon-forming walkeridiodean ctenostomes show prominent transverse muscles in their stolons. These are always present in the shorter side stolons, but their occurrence in the main stolon seems to depend on the colony form, being present in creeping but absent in erect colony forms. This study represents the first broad survey of muscular systems in adult ctenostome bryozoans and shows a certain degree of conservation in a series of diverse colony forms belonging to five major clades. However, several myoanatomical features such as the cardiac sphincter, basal (possibly transitory) cystid muscles, tentacle sheath muscles or apertural muscle arrangement vary across taxa and thus show a high potential for the assessment of character evolution within ctenostomes. As such, this study represents an essential contribution towards determining and reconstructing the character states of the bryozoan ground pattern once a reliable phylogenetic tree of the whole phylum becomes available.

Diversity and Activity of Communities Inhabiting Plastic Debris in the North Pacific Gyre

PubMed Central

Bryant, Jessica A.; Clemente, Tara M.; Viviani, Donn A.; Fong, Allison A.; Thomas, Kimberley A.; Kemp, Paul; Karl, David M.; White, Angelicque E.

2016-01-01

ABSTRACT Marine plastic debris has become a significant concern in ocean ecosystems worldwide. Little is known, however, about its influence on microbial community structure and function. In 2008, we surveyed microbial communities and metabolic activities in seawater and on plastic on an oceanographic expedition through the “great Pacific garbage patch.” The concentration of plastic particles in surface seawater within different size classes (2 to 5 mm and >5 mm) ranged from 0.35 to 3.7 particles m−3 across sampling stations. These densities and the particle size distribution were consistent with previous values reported in the North Pacific Ocean. Net community oxygen production (NCP = gross primary production − community respiration) on plastic debris was positive and so net autotrophic, whereas NCP in bulk seawater was close to zero. Scanning electron microscopy and metagenomic sequencing of plastic-attached communities revealed the dominance of a few metazoan taxa and a diverse assemblage of photoautotrophic and heterotrophic protists and bacteria. Bryozoa, Cyanobacteria, Alphaproteobacteria, and Bacteroidetes dominated all plastic particles, regardless of particle size. Bacteria inhabiting plastic were taxonomically distinct from the surrounding picoplankton and appeared well adapted to a surface-associated lifestyle. Genes with significantly higher abundances among plastic-attached bacteria included che genes, secretion system genes, and nifH genes, suggesting enrichment for chemotaxis, frequent cell-to-cell interactions, and nitrogen fixation. In aggregate, our findings suggest that plastic debris forms a habitat for complex microbial assemblages that have lifestyles, metabolic pathways, and biogeochemical activities that are distinct from those of free-living planktonic microbial communities. IMPORTANCE Marine plastic debris is a growing concern that has captured the general public’s attention. While the negative impacts of plastic debris on oceanic macrobiota, including mammals and birds, are well documented, little is known about its influence on smaller marine residents, including microbes that have key roles in ocean biogeochemistry. Our work provides a new perspective on microbial communities inhabiting microplastics that includes its effect on microbial biogeochemical activities and a description of the cross-domain communities inhabiting plastic particles. This study is among the first molecular ecology, plastic debris biota surveys in the North Pacific Subtropical Gyre. It has identified fundamental differences in the functional potential and taxonomic composition of plastic-associated microbes versus planktonic microbes found in the surrounding open-ocean habitat. Author Video: An author video summary of this article is available. PMID:27822538

Marine biodiversity of Aotearoa New Zealand.

PubMed

Gordon, Dennis P; Beaumont, Jennifer; MacDiarmid, Alison; Robertson, Donald A; Ahyong, Shane T

2010-08-02

The marine-biodiversity assessment of New Zealand (Aotearoa as known to Māori) is confined to the 200 nautical-mile boundary of the Exclusive Economic Zone, which, at 4.2 million km(2), is one of the largest in the world. It spans 30 degrees of latitude and includes a high diversity of seafloor relief, including a trench 10 km deep. Much of this region remains unexplored biologically, especially the 50% of the EEZ deeper than 2,000 m. Knowledge of the marine biota is based on more than 200 years of marine exploration in the region. The major oceanographic data repository is the National Institute of Water and Atmospheric Research (NIWA), which is involved in several Census of Marine Life field projects and is the location of the Southwestern Pacific Regional OBIS Node; NIWA is also data manager and custodian for fisheries research data owned by the Ministry of Fisheries. Related data sources cover alien species, environmental measures, and historical information. Museum collections in New Zealand hold more than 800,000 registered lots representing several million specimens. During the past decade, 220 taxonomic specialists (85 marine) from 18 countries have been engaged in a project to review New Zealand's entire biodiversity. The above-mentioned marine information sources, published literature, and reports were scrutinized to give the results summarized here for the first time (current to 2010), including data on endemism and invasive species. There are 17,135 living species in the EEZ. This diversity includes 4,315 known undescribed species in collections. Species diversity for the most intensively studied phylum-level taxa (Porifera, Cnidaria, Mollusca, Brachiopoda, Bryozoa, Kinorhyncha, Echinodermata, Chordata) is more or less equivalent to that in the ERMS (European Register of Marine Species) region, which is 5.5 times larger in area than the New Zealand EEZ. The implication is that, when all other New Zealand phyla are equally well studied, total marine diversity in the EEZ may be expected to equal that in the ERMS region. This equivalence invites testable hypotheses to explain it. There are 177 naturalized alien species in New Zealand coastal waters, mostly in ports and harbours. Marine-taxonomic expertise in New Zealand covers a broad number of taxa but is, proportionately, at or near its lowest level since the Second World War. Nevertheless, collections are well supported by funding and are continually added to. Threats and protection measures concerning New Zealand's marine biodiversity are commented on, along with potential and priorities for future research.

Marine Biodiversity of Aotearoa New Zealand

PubMed Central

Gordon, Dennis P.; Beaumont, Jennifer; MacDiarmid, Alison; Robertson, Donald A.; Ahyong, Shane T.

2010-01-01

The marine-biodiversity assessment of New Zealand (Aotearoa as known to Māori) is confined to the 200 nautical-mile boundary of the Exclusive Economic Zone, which, at 4.2 million km2, is one of the largest in the world. It spans 30° of latitude and includes a high diversity of seafloor relief, including a trench 10 km deep. Much of this region remains unexplored biologically, especially the 50% of the EEZ deeper than 2,000 m. Knowledge of the marine biota is based on more than 200 years of marine exploration in the region. The major oceanographic data repository is the National Institute of Water and Atmospheric Research (NIWA), which is involved in several Census of Marine Life field projects and is the location of the Southwestern Pacific Regional OBIS Node; NIWA is also data manager and custodian for fisheries research data owned by the Ministry of Fisheries. Related data sources cover alien species, environmental measures, and historical information. Museum collections in New Zealand hold more than 800,000 registered lots representing several million specimens. During the past decade, 220 taxonomic specialists (85 marine) from 18 countries have been engaged in a project to review New Zealand's entire biodiversity. The above-mentioned marine information sources, published literature, and reports were scrutinized to give the results summarized here for the first time (current to 2010), including data on endemism and invasive species. There are 17,135 living species in the EEZ. This diversity includes 4,315 known undescribed species in collections. Species diversity for the most intensively studied phylum-level taxa (Porifera, Cnidaria, Mollusca, Brachiopoda, Bryozoa, Kinorhyncha, Echinodermata, Chordata) is more or less equivalent to that in the ERMS (European Register of Marine Species) region, which is 5.5 times larger in area than the New Zealand EEZ. The implication is that, when all other New Zealand phyla are equally well studied, total marine diversity in the EEZ may be expected to equal that in the ERMS region. This equivalence invites testable hypotheses to explain it. There are 177 naturalized alien species in New Zealand coastal waters, mostly in ports and harbours. Marine-taxonomic expertise in New Zealand covers a broad number of taxa but is, proportionately, at or near its lowest level since the Second World War. Nevertheless, collections are well supported by funding and are continually added to. Threats and protection measures concerning New Zealand's marine biodiversity are commented on, along with potential and priorities for future research. PMID:20689846

Matrotrophy and placentation in invertebrates: a new paradigm.

PubMed

Ostrovsky, Andrew N; Lidgard, Scott; Gordon, Dennis P; Schwaha, Thomas; Genikhovich, Grigory; Ereskovsky, Alexander V

2016-08-01

Matrotrophy, the continuous extra-vitelline supply of nutrients from the parent to the progeny during gestation, is one of the masterpieces of nature, contributing to offspring fitness and often correlated with evolutionary diversification. The most elaborate form of matrotrophy-placentotrophy-is well known for its broad occurrence among vertebrates, but the comparative distribution and structural diversity of matrotrophic expression among invertebrates is wanting. In the first comprehensive analysis of matrotrophy across the animal kingdom, we report that regardless of the degree of expression, it is established or inferred in at least 21 of 34 animal phyla, significantly exceeding previous accounts and changing the old paradigm that these phenomena are infrequent among invertebrates. In 10 phyla, matrotrophy is represented by only one or a few species, whereas in 11 it is either not uncommon or widespread and even pervasive. Among invertebrate phyla, Platyhelminthes, Arthropoda and Bryozoa dominate, with 162, 83 and 53 partly or wholly matrotrophic families, respectively. In comparison, Chordata has more than 220 families that include or consist entirely of matrotrophic species. We analysed the distribution of reproductive patterns among and within invertebrate phyla using recently published molecular phylogenies: matrotrophy has seemingly evolved at least 140 times in all major superclades: Parazoa and Eumetazoa, Radiata and Bilateria, Protostomia and Deuterostomia, Lophotrochozoa and Ecdysozoa. In Cycliophora and some Digenea, it may have evolved twice in the same life cycle. The provisioning of developing young is associated with almost all known types of incubation chambers, with matrotrophic viviparity more widespread (20 phyla) than brooding (10 phyla). In nine phyla, both matrotrophic incubation types are present. Matrotrophy is expressed in five nutritive modes, of which histotrophy and placentotrophy are most prevalent. Oophagy, embryophagy and histophagy are rarer, plausibly evolving through heterochronous development of the embryonic mouthparts and digestive system. During gestation, matrotrophic modes can shift, intergrade, and be performed simultaneously. Invertebrate matrotrophic adaptations are less complex structurally than in chordates, but they are more diverse, being formed either by a parent, embryo, or both. In a broad and still preliminary sense, there are indications of trends or grades of evolutionarily increasing complexity of nutritive structures: formation of (i) local zones of enhanced nutritional transport (placental analogues), including specialized parent-offspring cell complexes and various appendages increasing the entire secreting and absorbing surfaces as well as the contact surface between embryo and parent, (ii) compartmentalization of the common incubatory space into more compact and 'isolated' chambers with presumably more effective nutritional relationships, and (iii) internal secretory ('milk') glands. Some placental analogues in onychophorans and arthropods mimic the simplest placental variants in vertebrates, comprising striking examples of convergent evolution acting at all levels-positional, structural and physiological. © 2015 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.

Quantitative Analyse von Korallengemeinschaften des Sanganeb-Atolls (mittleres Rotes Meer). I. Die Besiedlungsstruktur hydrodynamisch unterschiedlich exponierter Außen- und Innenriffe

NASA Astrophysics Data System (ADS)

Mergner, H.; Schuhmacher, H.

1985-12-01

The Sanganeb-Atoll off Port Sudan is an elongate annular reef which rests on a probably raised block in the fracture zone along the Red Sea-graben. Its gross morphology was most likely formed by subaerial erosion during low sealevel conditions. Features of its topography and hydrography are described. The prevailing wind waves are from NE, Hence, the outer and inner reef slopes are exposed to different hydrodynamic conditions. The sessile benthos was analysed using the quadrat method. Four test quadrats (5×5 m each) were selected on the outer and inner slopes at a depth of 10 m along a SSW-NNE transect across the atoll. Cnidaria were by far the most dominating group; coralline algae, Porifera, Bryozoa and Ascidia, however, counted for just under 3 % living cover. Light and temperature intensities did not differ significantly at the sites studied; water movement, however, decreased in the following order: TQ IV (outer NE side of the reef ring) was exposed to strong swell and surf; TQ II (inner side of the SW-ring) was met by a strong longreef current; TQ I was situated on the outer lee of the SW-atoll ring and TQ III in the inner lee of the NE-side. This hydrodynamic gradient correlates with the composition of the coral communities from predominantly branching Scleractinia (staghorn-like and other Acropora species and Pocillopora) in TQ IV, through a Lobophyllia, Porites and Xenia-dominated community in TQ II, and a mixed community with an increasing percentage of xeniid and alcyoniid soft corals in TQ I, to a community in TQ III which is dominated by the soft corals Sinularia and Dendronephthya. The cnidarian cover ranged between 42.4 and 56.6 % whereby the two exposed test quadrats had a higher living coverage than the protected ones. In total, 2649 colonies comprising 124 species of stony, soft and hydrocorals were recorded by an elaborate method of accurate in-situ mapping. The 90 scleractinian species found include 3 species new to the Red Sea and 11 hitherto unknown species from its central part. Only 7 cnidarian species covered large areas, forming a Xenia macrospiculata-zone in TQ I, a Lobophyllia corymbosa-zone in TQ II, a Sinularia-Dendronephthya-zone in TQ III and an Acropora-Pocillopora verrucosa-zone in TQ IV. Hydrodynamic exposition and ratio of genus abundance Acropora: Montipora are closely correlated: on the windward side (TQ IV) it is 943:4, but on the leeward side (TQ I) 18:208. Apart from the taxonomic and quantitative distribution of species and colonies, types of growth form and categories of the dead substrate are given. Since soft corals do not contribute to the reef framework, the distribution of Scleractinia and Alcyonaria indicates that at Sanganeb-Atoll reef substance is mainly generated on the windward side.

The relationship between shellbed type and sequence architecture: examples from Japan and New Zealand

NASA Astrophysics Data System (ADS)

Kondo, Yasuo; Abbott, Stephen T.; Kitamura, Akihisa; Kamp, Peter J. J.; Naish, Tim R.; Kamataki, Takanobu; Saul, Gordon S.

1998-12-01

Examples of lithology, fossil content and taphonomic features of shellbeds and intervening less fossiliferous intervals are presented from four Plio-Pleistocene successions (Shimosa Group, Boso Peninsula, Omma Formation, Hokuriku area, Japan, and Okehu, Kai-iwi, and Shakespeare groups in Wanganui, and the Rangitikei Group along the Rangitikei River in New Zealand). As for pre-Pliocene 3rd- and 4th-order depositional sequences, Plio-Pleistocene 5th- to 7th-order depositional sequences contain a variety of shellbeds which are often associated with surfaces or intervals that are characterized by sedimentary condensation, omission or erosion (e.g. sequence boundaries, ravinement surfaces, downlap surfaces and condensed sections). Stratigraphic patterns of shellbed type tend to be similar and repetitive within a basin and a locality. This demonstrates that a specific palaeogeography played an important role in determining the nature of shellbeds. For example, shellbeds formed in the context of toplap are common only in the Shimosa Group, which was deposited in a moderately sheltered sea, the palaeo-Tokyo Bay. Toplap shellbeds are rare in other sequences formed in more open conditions. Despite the variability resulting from such basin characteristics, common styles of shellbeds can be recognized that formed under conditions of marine onlap, backlap, downlap and toplap. Each type of shellbed has a characteristic fossil composition and taphonomy. Onlap and toplap shellbeds contain low-diversity macrobenthic associations including Glycymeris, Mercenaria, Paphies or other bivalves having robust shells, which are often abraded or fragmented. Backlap shellbeds, which are equivalent to the condensed section formed at the maximum transgression, are characterized by dominance of epifaunal macrobenthos such as bryozoa, brachiopoda, pectinid and ostreid bivalves, preserved in a slightly cemented, glauconitic muddy matrix. In contrast to fossils in such condensed sections, the shell density and species diversity of downlap shellbed associations are rather low, and in a few examples the macrobenthic association was buried rapidly in a lower unit of the highstand systems tract (HST) stratigraphically located above the condensed sections. Variations in the stratigraphic distribution of shellbed types are reflected in symmetrical and asymmetrical sequence architectures. Symmetrical sequences have roughly the same thickness of transgressive systems tracts (TST) and highstand systems tracts (HST), and have well segregated shellbeds that were formed during marine onlap and backlap. Asymmetrical cycles have very thin TSTs and much thicker HSTs, and are characterized by the amalgamation of condensed onlap and backlap shellbeds. Such contrasting cycle architectures are interpreted to reflect inner (symmetrical) and outer (asymmetrical) shelf palaeodepositional settings. The amalgamated onlap/backlap shellbeds appear to be common in Plio-Pleistocene sequences. Owing to the short duration of glacio-eustatic sea-level changes with dominant frequencies of 20,000, 40,000 or 100,000 years, shellbeds in the Plio-Pleistocene are relatively simple and thin compared to those formed in ordinary third-order depositional sequences. Infauna-dominated benthic associations are generally more common than in third-order cycles, and epifaunal associations facilitated by taphonomic feedback on sediment-starved shell-gravel substrates occur only in the condensed section corresponding to maximum transgression in most Plio-Pleistocene sequences.

Collision of the Tacheng block with the Mayile-Barleik-Tangbale accretionary complex in Western Junggar, NW China: Implication for Early-Middle Paleozoic architecture of the western Altaids

NASA Astrophysics Data System (ADS)

Zhang, Ji'en; Xiao, Wenjiao; Luo, Jun; Chen, Yichao; Windley, Brian F.; Song, Dongfang; Han, Chunming; Safonova, Inna

2018-06-01

Western Junggar in NW China, located to the southeast of the Boshchekul-Chingiz (BC) Range and to the north of the Chu-Balkhash-Yili microcontinent (CBY), played a key role in the architectural development of the western Altaids. However, the mutual tectonic relationships have been poorly constrained. In this paper, we present detailed mapping, field structural geology, and geochemical data from the Barleik-Mayile-Tangbale Complex (BMTC) in Western Junggar. The Complex is divisible into Zones I, II and III, which are mainly composed of Cambrian-Silurian rocks. Zone I contains pillow lava, siliceous shale, chert, coral-bearing limestone, sandstone and purple mudstone. Zone II consists of basaltic lava, siliceous shale, chert, sandstone and mudstone. Zone III is characterized by basalt, chert, sandstone and mudstone. These rocks represent imbricated ocean plate stratigraphy, which have been either tectonically juxtaposed by thrusting or form a mélange with a block-in-matrix structure. All these relationships suggest that the BMTC is an Early-Middle Paleozoic accretionary complex in the eastern extension of the BC Range. These Early Paleozoic oceanic rocks were thrust onto Silurian sediments forming imbricate thrust stacks that are unconformably overlain by Devonian limestone, conglomerate and sandstone containing fossils of brachiopoda, crinoidea, bryozoa, and plant stems and leaves. The tectonic vergence of overturned folds in cherts, drag-related curved cleavages and σ-type structures on the main thrust surface suggests top-to-the-NW transport. Moreover, the positive εNd(t) values of volcanic rocks from the Tacan-1 drill-core, and the positive εHf(t) values and post-Cambrian ages of detrital zircons from Silurian and Devonian strata to the south of the Tacheng block indicate that its basement is a depleted and juvenile lithosphere. And there was a radial outward transition from coral-bearing shallow marine (shelf) to deep ocean (pelagic) environments, and from OIB/E-MORB to N-MORB lava geochemistry away from the Tacheng block. Comparisons with published data suggest that these positive isotopic values, stratigraphic, structural and geochemical relationships can be best understood as an analogue of the relationships between the Ontong Java oceanic plateau and the Pacific oceanic crust. Therefore we propose that the basement of the Tacheng block was an Early Paleozoic oceanic plateau. The southern part of the Tacheng block was an accretionary complex and the northern part was an oceanic basin in the Early Paleozoic, the configuration of which is similar to that of the present Ontong Java oceanic plateau situated on the Pacific oceanic crust, and its accretion into the Solomon accretionary complex. The presence of Ordovician SSZ-type ophiolites, early Paleozoic blueschist and Silurian SSZ-type intrusions in the BMTC, and Early-Middle Paleozoic continental arc-related intrusive rocks in the northern margin of the CBY provide further corroboration of a former subduction zone between the southern West Junggar and the northern margin of the CBY. Furthermore, consideration of the fact that the Kokchetav-North Tianshan range was collaged to the southern margin of the CBY in the Ordovician-Devonian indicates that both ranges were amalgamated synchronously with the CBY constructing the Early-Middle Paleozoic architecture of western Altaids.

Composite biostratigraphy and microfacies analysis of the Upper Jurassic - Lower Cretaceous carbonate platform to slope successions in Sivrihisar (Eskişehir) region (NW Turkey, Pontides): Remarks on the palaeogeographic evolution of the Western Sakarya Zo

NASA Astrophysics Data System (ADS)

Atasoy, Serdar G.; Altıner, Demir; Okay, Aral I.

2017-04-01

Two stratigraphical sections were measured along the Upper Jurassic - Lower Cretaceous carbonate successions exposed in a tectonic klippe of the Sakarya Zone (Pontides), north of Sivrihisar. According to the biozonation and microfacies types, two coeval but dissimiliar rock successions, separated by a thrust fault, have been detected. These successions belong to different depositional belts of the Edremit-Bursa-Bilecik Carbonate Platform (EBBCP), western Sakarya Zone. The lower succession displays a slope to basin facies and consists of the Kimmeridgian - Berriasian Yosunlukbayırı Formation and the overlying Valanginian Soǧukçam Limestone. Within these deposits the following biozones were defined: Globuligerina oxfordiana - Mohlerina basiliensis Zone (Kimmeridgian), Saccocoma Zone (Lower Tithonian), Protopeneroplis ultragranulata Zone (Upper Tithonian), Crassicollaria (massutiana subzone) Zone (uppermost Tithonian), Calpionella (alpina, Remaniella, elliptica subzones) Zone (Lower Berriasian), Calpionellopsis (simplex, oblonga subzones) Zone (Upper Berriasian) and Calpionellites (darderi subzone) Zone (Lower Valanginian). This succession is overthrusted from north to south by another distinct succession characterized by the shallow marine carbonate facies of the Kimmeridgian Günören Formation. Within this unit Labyrinthina mirabilis - Protopeneroplis striata (Kimmeridgian) Zone is recognized. A facies model is proposed for the Sivrihisar transect of the EBBCP for Kimmeridgian - Valanginian interval, based on the distribution of microfacies types. The toe-of-slope facies are characterized by peloidal-bioclastic packstone, mudstone-wackestone and calpionellid/ radiolarian wackestone-packstone comprising pelagic taxa (calpionellids, radiolaria, Globochaete sp., Pithonella sp., Saccocoma sp., calcareous dinocysts, aptychi, very rare planktonic foraminifera and nannoconids) and rare fossil groups transported from the carbonate platform (benthic foraminifera, microencrusters, worm tubes, bivalve, crinoid and echinoid fragments). These deposits represent the background pelagic deposition on the slope. The slope facies are mainly composed of bioclastic-peloidal/ bioclastic-intraclastic packstone, rudstone-grainstone, bioclastic-lithoclastic floatstone-rudstone and reflect generally the increase in the amount of platform derived material (benthic foraminifera, microencrusters, worm tubes, corals, sponges, bryozoa). The matrix of these coarse grained deposits also contains pelagic taxa (calpionellids, radiolaria, Saccocoma sp., Globochaete sp., Pithonella sp., aptyhci). The slope facies are sometimes intercalataed with the toe-of-slope type facies indicating quiescence periods. The shallow marine carbonate platform deposits are characterized by peloidal-intraclastic poorly washed grainstone with bioclasts, bioclastic mudstone-wackestone, intraclastic packstone-rudstone and contain several shallow marine fossils (benthic foraminifera, encrustres and rare echnoid, bivalve and coral fragments) without any pelagic taxa. These carbonates are interpreted as back-reef platform deposits that should not be far away from the platform margin due to the co-occurence of Protopeneroplis striata and Mohlerina basiliensis, abundant in the shelf edge and reefal areas with the complex benthic foraminifera, Labyrinthina mirabilis common in lagoonal areas. If the position of the studied sections with respect to the EBBCP is considered, the studied basin and slope facies should represent the southern platform margin and slope environments of this carbonate platform that faced an ocean to the south during the Jurassic-Cretaceous. The slope and basinal facies overthrusted by the shallow marine deposits in a region situated to the south of the main İzmir-Ankara-Erzincan (İAE) suture suggests an important disruption and shortening of the EBBCP margin and slope deposits related to the closure of the İAE ocean.