The Nerineacea form a distinctive and significant component of shallow marine Mesozoic Tethyan macrofaunas. They occur in shelf sediments deposited in tropical regions during the Jurassic and Cretaceous. The group first appears in the early Jurassic and high diversity levels had developed by late Jurassic and early Cretaceous times. A major extinction episode occurred during the latter part of the Cenomanian and the Turonian, with the Nerineacea becoming finally extinct in the Maastrichtian. The heterostrophic nature of the ncrineacean protoconch (described here from Nerineidae and Nerinellidae species) indicates opisthobranch affinities. The Nerineacea is placed in the Entomotacniata, an independent order within the Opisthobranchia. The Entomotaeniata is considered to show greatest affinities with some members of the Acteonacea. The Pyramidcllacea are not included in the Entomotaeniata. The order contains the Ceritellidae, Nerineidae, Nerinellidae and ltieriidae. Early phylogenetic separation of the first three families is indicated. Within each family a limited number of "stable" internal fold patterns developed independently which reflected anatomical features of the abapical portion of the nerineid animal. The Nerineacea typically inhabited warm, clear, carbonate-dominated shallow marine environments on and around off-shore "highs", however, some genera lived in prelittoral or lagoonal situations. Only Ptygmatis shows any evidence of tolerance of abnormal salinities. Carbon and oxygen isotope analyses demonstrate that Nerinella and Simploptyxis specimens from Austrian Gosau deposits lived in water of normal marine salinity. Most Cretaceous nerineid genera were probably mobile epifaunal herbivores, although Nerinellidae species may have been infaunal. Cretaceous Nerineacea are taxonomically reviewed; the diagnoses of the subfamily Umboneinae; Diozoptyxis, Adiozoptyxis; Julesia and Phaneroptyxis are revised. Stratigraphic and palaeogeographic ranges indicate that certain species could potentially be used for correlation. Quantitative measurements of various parameters are included in specific descriptions; the value of these in specific resolution is tested in appropriate cases. An analysis of morphological range in one species (Diozoptyxis cochleaeformis) demonstrates wide continuous variation in overall shell shape and whorl concavity. However, external ornament and internal fold pattern do not show significant intraspecific variation; these features therefore provide reliable characters for species definition.

No description available.

published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy

The Early Jurassic was a time of rapidly rising sea-level associated with the extensive spread of anoxic bottom waters. Sea-level rise across the Pliensbachian - Toarcian boundary culminated in the falciferum Zone of the Toarcian and is one of the best authenticated eustatic events in the Jurassic. This major transgressive pulse was marked by deepw ater marine sequencesa nd was associatedw ith the deposition of organic-rich shales. The development of anoxia coincides with a notable period of mass extinction of the marine fauna. High resolution sampling and study of the microfaunast hrough sequencesin N. W. Europe confirm that benthic foraminiferal. faunas were similarly affected by an early Toarcianfalciferum Zone event. Samples were analysed from Pliensbachian - Toarcian mudstone,c lay and shale sequenceso f the south Dorset Coast,t he Midlands, the Yorkshire Coast, southern France and southwest Germany. The sections studied show distinct changes in assemblagesa cross the Pliensbachian - Toarcian boundary and in the basal zones of the Toarcian. Evidence for a foraminiferal extinction event in the Pliensbachian - Toarcian includes the elimination of the important Lower Jurassic Lingulina tenera, Frondicularia terquem! and Marginulina prima plexus groups, initiating a significant period of turnover of the microfauna. The foraminiferal extinction event recorded in the Lower Toarcian sections of north west Europe is only significant at species level. No extinctions at the family-level occurred. A marked changea lso occurred in the charactero f associatedn odosariid assemblagest:h e uniserial forms of Nodosaria, Frondicularia and Lingulina, dominating the Pliensbachian assemblagesw, ere largely replacedb y coiled Lenticulina in the early Toarcian. A reduction in test size and a decline in species diversity, compared with Hettangian to Sinemurian foraminiferal assemblagesr,e flect the developmento f low oxygen conditions followed by a subsequenrte newal of the microfauna in the Middle Toarcian. The foraminiferal data show no evidence of progressive displacement of older by younger faunas. Instead certain species only expanded their populations and diversity significantly after the extinction of similar niche-occupying species. The Pliensbachian - Toarcian (Lower Jurassic) sediments of the north Yorkshire coast contain highly organic-rich shales where the sequence stratigraphic significance is somewhat obscure. Benthic foraminiferal species distribution (as a function of organic flux and oxygenation) allowed palaeobathymetry to be determined on quantitative assemblage characteristics. In parallel with this methodology, a suite of trace elements (including Mn, Ca, Fe, and Al) have been analysed following nitric and hydrofluoric acid digestion. Maxima of Ca and Mn occur at the base of the falcifierum Subzone (falcifierum Zone). It is suggested that these maxima are an artefact of condensation of carbonate fossiliferous material due to sediment starvation and correspond to published estimates of a maximum flooding surface. Interpretations of the benthic foraminiferal assemblages surrounding this event provide further support for a transgressive event -associated with the development of low oxygen conditions and the deposition of organic-rich shales. Additional Lower Jurassic,H ettangiant o lower Pliensbachian,s equencesw ere investigated for the purposes of establishing their foraminiferal correlation potential as candidate Global Stratotype Sections and Points for the basal Sinemurian and basal Pliensbachian.

Thesis (M. Phil.)--University of Hong Kong, 1978.

Thesis (M. Phil.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 152-169).

Orientador: Wagner Vilegas / Banca: Vanderlan da Silva Bolzani / Banca: Hosana Maria Debonsi / Banca: Luis Octavio Regasini / Banca: Letícia Veras Costa Lotufo / Resumo: A fauna acompanhante da pesca do camarão inclui uma série de invertebrados marinhos que são descartados por não ter valor comercial. A fim de tentar acrescentar algum valor a este material, foi analisada a composição química da estrela-do-mar Luidia senegalensis coletada na costa brasileira como consequência da aplicação da pesca de arrasto. A fim de avaliar sua composição química, foi utilizada uma combinação de extração em fase sólida (SPE) seguida de cromatografia líquida de ultra eficiência acoplada a espectrômetro de massas equipado com fonte de ionização por eletrosptray e analisador ion-trap linear (UPLCESI- IT-MSn). Luidia senegalensis contém asterosaponinas, que são esteroides glicosilados sulfatados contendo cinco e seis unidades de açúcar, além de poliidroxiesteroides. Este estudo mostrou a presença de compostos importantes e potencialmente bioativos em invertebrados associados à fauna acompanhante da pesca do camarão, usando um método rápido e eficiente. Normalmente descartada, a fauna acompanhante contém muitos invertebrados que podem hospedar uma grande variedade de gêneros de bactérias, algumas das quais com potencial de produzir produtos naturais bioativos com aplicações biotecnológicas. Assim, para utilizar um material normalmente descartado, foi explorado o potencial biotecnológico de bactérias cultiváveis de duas espécies de invertebrados abundantes na fauna acompanhante, o gastrópode Olivancillaria urceus e a estrela-do-mar Luidia senegalen... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The by-catch fauna of the shrimp fishery includes a number of marine invertebrates that are discarded because they do not have commercial value. In order to try to add some value to these materials, we analyzed the chemical composition of the starfish Luidia senegalensis collected in the Brazilian coast as a consequence of the trawling fishery method. In order to access their chemical composition, we used a combination of solid phase extraction (SPE) followed by ultra performance liquid chromatography coupled to electrospray ionization ion trap tandem mass spectrometry (UPLC-ESI-IT-MSn). Luidia senegalensis contains asterosaponins, which are sulphated glycosilated steroids, containing five and six sugar moieties, in addition to polyhydroxysteroids. This study helped us to support the presence of important and potentially bioactive compounds in invertebrates associated to the by-catch fauna of the shrimp fishery, using a fast and efficient method. Typically discarded, by-catch contains many invertebrates that may host a great variety of bacterial genera, some of which may produce bioactive natural products with biotechnological applications. Therefore, to utilize by-catch that is usually discarded we explored the biotechnological potential of culturable bacteria of two abundant by-catch invertebrate species, the snail Olivancillaria urceus and the sea star Luidia senegalensis. Sediment from the collection area was also investigated. Utilizing multiple isolation... (Complete abstract click electronic access below) / Doutor

published_or_final_version / Zoology / Master / Master of Philosophy

Artificial reefs are being built in most parts of the world for a wide variety of purposes. Divingtourism is a common motivator for the construction of many reefs, particularly in the tropics,although the most widely used purpose is to improve or reconstruct hard bottom habitats andincrease the yield from fisheries. There are two main reasons for why aquatic life is attracted toartificial reefs. They provide excellent protection by often being hollow or filled with crevicesand cavities and increasing opportunities for improved foraging through accumulating biomassand extending the foraging range of an organism by acting like stepping stones. Sweden is acoastal country with few artificial reefs. In this study, two reefs were constructed in the sea offthe coast of Halmstad, Sweden to test small scale artificial reef production, marine organismcolonisation of the reefs during the first year, and to increase the local marine life diversity.Many marine organisms that would not normally occur in the sites where the reefs wereconstructed were observed, such as Symphodus melops and Anguilla anguilla. The reefs alsoprovided a new “clean slate” substrate for the settling of sessile organisms such as Urticina felinaor partially sessile organisms (i.e. during a certain stage of their life-cycle) such as some speciesof Cnidaria polyps. The tested method to construct these reefs was relatively cost effective for itspurpose. However a few minor but vital improvements, such as better binding materials, areneeded. Local marine life in the area has become more diverse during the experiment and thatalone is enough reason to motivate construction of similar reefs along the Swedish coast. / Artificiella rev anläggs runt om i världen med en mängd olika syften. Det är vanligt att dykturism används som anledning för att bygga artificiella rev, speciellt i tropikerna. Restaurering av hårdbottenrev och mål att öka kommersiella fiskebestånd är dock de största motiveringarna. Det finns två huvudsakliga orsaker till varför akvatiskt liv attraheras av konstgjorda rev. De erbjuder utmärkt skydd i form av håligheter och sprickor, samt att de ökar möjligheterna för födosök genom att ackumulera biomassa och fungera som ”stepping stones”, det vill säga utöka födosökningsområdet. Sverige är ett kustland med få artificiella rev. Två rev anlades i Laholmsbukten, Kattegatt, just utanför Tjuvahålan i Halmstad med syftet att undersöka effektiviteten och nyttan av småskaliga rev, att studera marina organismers kolonisering av reven och att öka den lokala biodiversiteten. Många marina organismer som inte borde förkommit i området där reven anlagts tidigare observerades. Ett par exempel är Symphodus melops) och (Anguilla anguilla). Reven fungerade även som rena underlag för sessila organismer att fästa på. Djur som till exempel havsros (Urticina felina) och Cnidariapolyper noterades. Metoden för att konstruera reven visade sig vara kostnadseffektiv i förhållande till syftet, men några viktiga steg, bland annat fästmaterialet, behöver förbättras. Den lokala artmångfalden ökade efter anläggningen av reven och borde vara nog motivering för att fortsätta bygga liknande rev längs den svenska kusten.

Confronted with a diverse sandflat community of interacting organisms and a spectrum of physical forces, a meaningful community analysis should begin with a description of physical characteristics and faunal distributions over time. The functional importance of certain species in the community should then be investigated by using both field and laboratory experiments. Consequently, the purpose of this research was twofold: (1) to apply the methods of similarity and gradient analysis to describe the faunal gradation on an intertidal sandflat and; (2) use these data to design a predator exclusion field experiment aimed at assessing the effects of shorebird, crab and fish predation on certain infaunal and epifaunal invertebrates.