Invasions of ecosystems by exotic species are increasing and they may often act as a significant driver of the homogenization of the Earth’s biota, resulting in global biodiversity loss. Moreover, the addition of exotic species may have dramatic effects on ecosystem structure and functioning which may result in the extirpation of indigenous species. In 2004, a large population of an unknown lymnaeid was found in the Amatikulu Hatchery, northern KwaZulu-Natal, South Africa, and was subsequently found in few garden fish ponds in Durban. In 2007, it was identified using molecular techniques as Radix rubiginosa (Michelin, 1831) – a species widespread in southeast Asia. An invasion by R. rubiginosa is however likely to go unnoticed because its shell morphology resembles some forms of the highly variable and widely distributed indigenous lymnaeid, Lymnaea natalensis Krauss, 1848. Accurate and “easy” species identifications would permit the ready assessment of introduction histories and distributions, but in the present case identification was difficult due to unclear and contradicting accounts of the indigenous L. natalensis in the literature. A redescription of L. natalensis with emphasis on conchological and anatomical characteristics was therefore presented. This will help to distinguish variation between R. rubiginosa and L. natalensis and also assist those carrying out rapid bioassessment (SASS) surveys in South African rivers in recognising R. rubiginosa should it spread. For this, shells of R. rubiginosa and L. natalensis from both the UKZN Pond and the Greyville Pond were selected into either size class 1 (shell length < 10 mm) or size class 2 (shell length ≥ 10 mm). Six shell characters, shell length (height), shell width, aperture length (height), aperture width, length of last body whorl and spire height for each specimen was measured and analysed using principal component analysis (PCA) and The invasive potential of the freshwater snail Radix rubiginosa recently introduced into South Africa discriminant functions analysis (DFA). The most useful discriminant conchological characters were shell length, length of the last body whorl and aperture width. Use of these shell characters provided simple yet effective criteria for the separation of R. rubiginosa and L. natalensis. For both size classes R. rubiginosa had larger, more broadly ovate shells with longer (higher) body whorls than either of the two populations of L. natalensis that exhibited smaller, elongated shells with shorter (lower) body whorls. Also, R. rubiginosa had a narrower aperture width compared to the larger, wider aperture of the UKZN Pond L. natalensis population. The Greyville L. natalensis population was found to have narrower apertures than both R. rubiginosa and L. natalensis (UKZN Pond). The morphology of the radula and the reproductive anatomy of R. rubiginosa and L. natalensis from both the UKZN and Greyville Ponds showed little variation. The species did however vary in the relative numbers of radula teeth in each field and this serves as an additional useful diagnostic character. Both L. natalensis populations had similar mantle pigmentation patterns but that of R. rubiginosa was different. The mantle surface of R. rubiginosa was mottled black with patches of pale white to yellow. There were also large unpigmented fields and stripes that were not observed in L. natalensis. Having found characters to conveniently separate the alien R. rubiginosa from the indigenous L. natalensis, it became increasingly important to assess the potential invasiveness of this introduced species and its likely impact. The potential invasiveness of R. rubiginosa was assessed in relation to the already invasive North American Physidae Physa acuta Draparnaud, 1805 and the indigenous L. natalensis. This was particularly important in view of the success of P. acuta as an invader in South Africa. The hatching success, frequency of egg abnormalities, embryonic development, growth, survivorship, fecundity and life history parameters (GRR, Ro, rm, T and λ) for the four snail populations were assessed at three experimental temperatures (20oC, 25oC and 30oC). The invasive potential of the freshwater snail Radix rubiginosa recently introduced into South Africa The results showed that R. rubiginosa and P. acuta had a higher growth coefficient (K), longer survivorship, higher fecundity (higher hatching success, fewer egg abnormalities, longer duration of oviposition), shorter incubation period, greater life history parameters (GRR, Ro, rm and λ) and wider temperature tolerances than the two L. natalensis populations tested. The high adaptability of P. acuta to changing environmental factors such as temperature, is in agreement with the fact that it is now more widespread in South Africa than the indigenous species L. natalensis. This has important implications for R. rubiginosa, since this species displayed reproductive attributes and a temperature tolerance that were similar and in certain cases even exceeded the performance of the invasive P. acuta. This therefore implies that R. rubiginosa has the potential to colonize a wider geographical and altitudinal range than L. natalensis, and perhaps even P. acuta. Also, the superior reproductive ability of R. rubiginosa over L. natalensis is likely to present a situation that allows for its rapid spread as well as a possible impact on the indigenous L. natalensis that might render it vulnerable. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.

This study investigated the physiological ecology, larval biology and population genetics of the nudibranch molluscs Adalaria proxima (A & H) and Onchidoris muricata (Müller). These two species are annual, simultaneous hermaphrodites and are ecologically very similar with the exception that A. proxima reproduces by means of pelagic lecithotrophic larvae whereas Omuricata has long-term planktotrophic larvae. The aim of the study was therefore to determine the selective pressures which resulted in the evolution of different larval types in these two species, and to ascertain the ecological and population genetic consequences thereof. Simple energy budgets comprising the major components (consumption, growth, respiration and reproduction) were constructed for laboratory populations of each species. In both A. proxima and O. muricata, feeding rate displayed an asymptotic increase with body size. Mean feeding rates of A. proxima were greater than those of comparable O. muricata individuals, and overall assimilation efficiency was higher in A. proxima than in O. muricata. This difference was reflected in the somatic growth rates which were correspondingly greater in A. proxima than in O. muricata. Net growth efficiencies were broadly comparable between the two species, however, growth of A. proxima was approximately linear over' time whilst that of O. muricata displayed a curvilinear, almost exponential, pattern. This is interpreted as demonstrating that some form of constraint (possibly feeding rate) operated on the growth rates of A. proxima but not on those of O. muricata. Respiration rates were found to be relatively constant within given animals, but significant differences were found between individuals. The allometry of respiration rate was not constant; Omuricata demonstrated a more rapid increase in respiration rate with increasing body size than did A. proxima. Individual variations in respiration rate did not reflect variations in the energy partitioned to either growth or reproduction. Reproductive patterns in the two species were dissimilar. A. proxima laid fewer spawn masses containing fewer, larger ova than those laid by O. muricata individuals. In addition, the spawning period of A. proxima was shorter than that of O. muricata (60 days and 105 days respectively). Both species exhibited a similar (proportional) degree of somatic catabolism over these periods. The consequently more rapid "degrowth" of A. proxima is interpreted as the necessary utilization of an energy resource (i. e. the soma) caused by an inability to meet the energy demands of reproduction through feeding alone. This was not the case in Oanuricata individuals which exhibited a much smaller maximum body size and were able to feed at a sufficiently rapid rate to maintain reproduction. In the latter case, the longer reproductive period served to maximise the total reproductive output. Several different measures of "Reproductive Effort" (RE) were calculated. These generally indicated that the RE of Omuricata was considerably greater than that of A. proxima. Although such differences have been used in the literature to classify the respective costs of different larval types or "reproductive strategies", the variability of the RE's obtained from the different measures used here has led to the suggestion that the general lack of association between RE and reproductive strategy which has been reported elsewhere may (partially) be attributable to the different measures of RE employed in different studies. Studies of the embryonic and larval period showed that the egg-to-juvenile period of O. muricata was approximately 50% longer than that of A. proxima. This difference was primarily attributable to the extended pelagic development of O. muricata larvae. Estimates of the degree of dispersal, and hence gene-flow, between populations of these species were tested by investigating the biochemical genetics of such populations. No data were available for O. muricata, but A. proxima populations proved to be more genetically heterogeneous than had been expected. It is therefore concluded that actual pelagic dispersal may be considerably abbreviated over that expected on the basis of larval culture data alone. A model is developed to explain the possible consequences of different egg-to-juvenile periods (which accrue from different larval types) on both the ecology of the benthic adult, and on overall energy partitioning to reproduction. However, although (probable) proximate causes and effects of the different reproductive traits exhibited by A. proxima and Oanuricata are shown, it has not been possible to determine the exact selective pressures which caused A. proxima to diverge from the ancestral "O. muricata" stock through the evolution of a pelagic lecithotrophic larva.

No description available.

Tez (Doktora) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Biyoloji Anabilim Dalı, 2007. / Bibliyografya var.

Diss. Naturwiss. Bern (kein Austausch).

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-06-14T18:27:09Z No. of bitstreams: 1 278478.pdf: 8521282 bytes, checksum: d3af1e302eb6e49c2a8b3eea361c4d9d (MD5) / Made available in DSpace on 2018-06-14T18:27:09Z (GMT). No. of bitstreams: 1 278478.pdf: 8521282 bytes, checksum: d3af1e302eb6e49c2a8b3eea361c4d9d (MD5) Previous issue date: 1997-09-26 / Foram estudadas espécies do gênero Astraea Röding, 1798, A. (Astralium) latispina (Philippi, 1844) e A. (Lithopoma) olfersii (Philippi, 1846), com base na concha, opérculo, morfologia externa das partes moles, cavidade palial, sistemas digestivo e urogenital, consideradas e discutidas as semelhanças e diferenças, apresentadas as respectivas listas sinonímicas. A conquiliologia comparada das espécies brasileiras com A. (Astralium) phoebia Röding, 1798 e A. (Lithopoma) americana (Gmelin, 1791) demonstrou a validade destas espécies considerando equivocadas as referências de ocorrência para o Brasil. As caracterizações gerais dos táxons supraespecíficos e as necessárias comparações do estudo das partes moles das espécies da superfamília foram realizados com base em dados bibliográficos apresentando as respectivas considerações e discussões. / The species of genus Astraea Röding, 1798, A. (Astralium) latispina (Philippi, 1844) and A. (Lithopoma) olfersii (Philippi, 1846), were study based on shell, opercula, external morphology of soft parts, mantle cavity, digestive and urogenital systems, similarities and diferences are regarded and discussed, the respective synonymies are given. The comparative conchology of the Brazilian species with A. (Astralium) phoebia Röding, 1798 and A. (Lithopoma) americana (Gmelin, 1791) showed that they are valid species but the references are regarding equivocated occurence for Brazil. The general features of supraspecific taxons and the necessary comparison on study of soft parts of the superfamily species realized based on bibliografic's information with respectives regardfulness and discussions.

Em 1982 o Brasil participa da Convenção das Nações Unidas para o Direito do Mar. Esta convenção dispõe sobre os usos dos espaços marítimos e oceânicos, buscando a utilização racional e a exploração dos recursos do mar. Devido ao escasso conhecimento da região da plataforma externa e talude continental, surge o programa Avaliação do Potencial Sustentável de Recursos Vivos da Zona Econômica Exclusiva – REVIZEE, tanto para a diversificação da exploração pesqueira quanto para a determinação dos limites sustentáveis de captura. Com base em material coletado em abril de 1998, durante campanha de Bentos concernente ao programa REVIZEE, são fornecidos resultados relativos a Gastropoda encontrados na radial 45, estações hidrográficas 6839 (32o55´70´´S - 50o34´60´´W), 6840 (33o01´45´´S - 50o12´75´´W), 6841 (33o00´16´´S - 50o22´84´´W) e 6842 (32o57´81´´S - 50o29´18´´W), localizadas ao largo de Rio Grande, Rio Grande do Sul, Brasil. Para a avaliação da diversidade bêntica foram utilizados três tipos de amostradores de fundo; Draga de arrasto, Box Corer e Van Veen. Molluscos foram separados dos demais grupos taxonômicos pela equipe do REVIZEE e recebidos pelo laboratório de malacologia da Universidade Federal do Rio Grande do Sul. O material foi triado sob lupa Zeiss Stemi 2000- C ou Wild M-38. O material foi identificado por comparação com os dados da bibliografia e/ou por comparação com exemplares depositados nas coleções do Museu Oceanográfico Eliézer de Carvalho Rios (MORG) e/ou com a coleção particular do Dr. José Carlos Tarasconi São identificados e caracterizados quanto a tamanho, esculturação e área de ocorrência 6.020 exemplares distribuídos em 36 famílias - 80 táxons em nível de espécie, 19 em nível de gênero e 2 em nível de família. A família Turridae é a que apresenta o maior número de táxons com 16 espécies. Turritella hookeri Reeve, 1849 é a espécie mais abundante, com 684 exemplares. Registra-se pela primeira vez para o Rio Grande do Sul as seguintes espécies: Brookula conica (Watson, 1886), Calliostoma echinatum Dall, 1881, Solariela carvalhoi Lopes & Cardoso, 1958, Caecum massambabensis Absalão, 1994, Turritella hookeri Reeve, 1849, Crepidula plana Say, 1822, Natica pusilla Say, 1822, Polinices lacteus (Guilding, 1833), Eulima mulata Rios & Absalão, 1990, Melanella aff. hypsela (Verrill & Bush, 1900), Trachipollia turricula (von Maltzan, 1884), Anachis sparsa Reeve, 1859, Dentimargo janeiroensis (E. A. Smith, 1915), Axelella brasiliensis Verhecken, 1991, Drilliola loprestiana (Calcara, 1841), Mitrolumna biplicata (Dall, 1889), Nannodiella vespuciana (Orbigny, 1842), Stenodrillia goundlachi (Dall & Simpson, 1901), Terebra brasiliensis E. A. Smith, 1873 e Mathilda aff. scitula Dall, 1889. Novos limites de profundidade são registrados para 29 espécies. Com base na lista de espécies encontradas, se discute sobre o limite das Províncias Caribenha e Patagônica e sobre a influência da Laguna dos Patos no Talude Continental ao largo de Rio Grande.

Em 1982 o Brasil participa da Convenção das Nações Unidas para o Direito do Mar. Esta convenção dispõe sobre os usos dos espaços marítimos e oceânicos, buscando a utilização racional e a exploração dos recursos do mar. Devido ao escasso conhecimento da região da plataforma externa e talude continental, surge o programa Avaliação do Potencial Sustentável de Recursos Vivos da Zona Econômica Exclusiva – REVIZEE, tanto para a diversificação da exploração pesqueira quanto para a determinação dos limites sustentáveis de captura. Com base em material coletado em abril de 1998, durante campanha de Bentos concernente ao programa REVIZEE, são fornecidos resultados relativos a Gastropoda encontrados na radial 45, estações hidrográficas 6839 (32o55´70´´S - 50o34´60´´W), 6840 (33o01´45´´S - 50o12´75´´W), 6841 (33o00´16´´S - 50o22´84´´W) e 6842 (32o57´81´´S - 50o29´18´´W), localizadas ao largo de Rio Grande, Rio Grande do Sul, Brasil. Para a avaliação da diversidade bêntica foram utilizados três tipos de amostradores de fundo; Draga de arrasto, Box Corer e Van Veen. Molluscos foram separados dos demais grupos taxonômicos pela equipe do REVIZEE e recebidos pelo laboratório de malacologia da Universidade Federal do Rio Grande do Sul. O material foi triado sob lupa Zeiss Stemi 2000- C ou Wild M-38. O material foi identificado por comparação com os dados da bibliografia e/ou por comparação com exemplares depositados nas coleções do Museu Oceanográfico Eliézer de Carvalho Rios (MORG) e/ou com a coleção particular do Dr. José Carlos Tarasconi São identificados e caracterizados quanto a tamanho, esculturação e área de ocorrência 6.020 exemplares distribuídos em 36 famílias - 80 táxons em nível de espécie, 19 em nível de gênero e 2 em nível de família. A família Turridae é a que apresenta o maior número de táxons com 16 espécies. Turritella hookeri Reeve, 1849 é a espécie mais abundante, com 684 exemplares. Registra-se pela primeira vez para o Rio Grande do Sul as seguintes espécies: Brookula conica (Watson, 1886), Calliostoma echinatum Dall, 1881, Solariela carvalhoi Lopes & Cardoso, 1958, Caecum massambabensis Absalão, 1994, Turritella hookeri Reeve, 1849, Crepidula plana Say, 1822, Natica pusilla Say, 1822, Polinices lacteus (Guilding, 1833), Eulima mulata Rios & Absalão, 1990, Melanella aff. hypsela (Verrill & Bush, 1900), Trachipollia turricula (von Maltzan, 1884), Anachis sparsa Reeve, 1859, Dentimargo janeiroensis (E. A. Smith, 1915), Axelella brasiliensis Verhecken, 1991, Drilliola loprestiana (Calcara, 1841), Mitrolumna biplicata (Dall, 1889), Nannodiella vespuciana (Orbigny, 1842), Stenodrillia goundlachi (Dall & Simpson, 1901), Terebra brasiliensis E. A. Smith, 1873 e Mathilda aff. scitula Dall, 1889. Novos limites de profundidade são registrados para 29 espécies. Com base na lista de espécies encontradas, se discute sobre o limite das Províncias Caribenha e Patagônica e sobre a influência da Laguna dos Patos no Talude Continental ao largo de Rio Grande.

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-02-07T23:36:45Z No. of bitstreams: 1 414931.pdf: 16359662 bytes, checksum: a3df833c2a842e9418e3aa8e01fff4c5 (MD5) / Made available in DSpace on 2018-02-07T23:36:45Z (GMT). No. of bitstreams: 1 414931.pdf: 16359662 bytes, checksum: a3df833c2a842e9418e3aa8e01fff4c5 (MD5) Previous issue date: 1999-10-20 / CAPES / Todas as espécies do gênero Turbonilla Risso, 1826 previamente reportadas para o litoral brasileiro são revisadas em nível conquiliológico a partir de comparações com suas séries-tipo. T. abrupta Bush, 1899; T. arnoldoi Jong & Coomans, 1988; T atypha Bush, 1899; T. brasiliensis Clessin, 1900; T coomansi Aartsen, 1994; T. dispar Pilsbry, 1897; T fasciata ( d'Orbigny, 1840); T. multicostata (C. B. Adams, 1850); T protracta Dall, 1892; T. puncta (C. B. Adams, 1850); T. rushii Bush, 1899; T. turris (d'Orbigny, 1840); e T. uruguayensis Pilsbry, 1897 são confirmadas como espécies válidas e com ocorrência no litoral do Brasil. T. puncturata Martens, in Clessin, 1900 e T. haycocki Dall & Bartsch, 1911 são consideradas como sinônimos júnior de T. rushii e T. puncta, respectivamente... / The species of the genus Turbonilla Risso, 1826 previously recorded to the Brazilian coast are reviewed on a conchological basis after comparisons against their type-series. T. abrupta Bush, 1899; T. amoldoi Jong & Coomans, 1988; T. atypha Bush, 1899; T. brasiliensis Clessin, 1900; T. coomansi Aartsen, 1994; T. dispar Pilsbry, 1897; T. fasciata ( d'Orbigny, 1840); T. multicostata (C. B. Adams, 1850); T. protracta Dall, 1892; T. puncta (C. B. Adams, 1850); T. rushii Bush, 1899; T. turris (d'Orbigny, 1840); and T. uruguayensis Pilsbry, 1897 are confirmed as valid species, with occurrence in the Brazilian coast. T. puncturata Martens, in Clessin, 1900 and T. haycocki Dall & Bartsch, 1911 are placed in synonymy with T. rushii and T. puncta, respectively...

Em 1982 o Brasil participa da Convenção das Nações Unidas para o Direito do Mar. Esta convenção dispõe sobre os usos dos espaços marítimos e oceânicos, buscando a utilização racional e a exploração dos recursos do mar. Devido ao escasso conhecimento da região da plataforma externa e talude continental, surge o programa Avaliação do Potencial Sustentável de Recursos Vivos da Zona Econômica Exclusiva – REVIZEE, tanto para a diversificação da exploração pesqueira quanto para a determinação dos limites sustentáveis de captura. Com base em material coletado em abril de 1998, durante campanha de Bentos concernente ao programa REVIZEE, são fornecidos resultados relativos a Gastropoda encontrados na radial 45, estações hidrográficas 6839 (32o55´70´´S - 50o34´60´´W), 6840 (33o01´45´´S - 50o12´75´´W), 6841 (33o00´16´´S - 50o22´84´´W) e 6842 (32o57´81´´S - 50o29´18´´W), localizadas ao largo de Rio Grande, Rio Grande do Sul, Brasil. Para a avaliação da diversidade bêntica foram utilizados três tipos de amostradores de fundo; Draga de arrasto, Box Corer e Van Veen. Molluscos foram separados dos demais grupos taxonômicos pela equipe do REVIZEE e recebidos pelo laboratório de malacologia da Universidade Federal do Rio Grande do Sul. O material foi triado sob lupa Zeiss Stemi 2000- C ou Wild M-38. O material foi identificado por comparação com os dados da bibliografia e/ou por comparação com exemplares depositados nas coleções do Museu Oceanográfico Eliézer de Carvalho Rios (MORG) e/ou com a coleção particular do Dr. José Carlos Tarasconi São identificados e caracterizados quanto a tamanho, esculturação e área de ocorrência 6.020 exemplares distribuídos em 36 famílias - 80 táxons em nível de espécie, 19 em nível de gênero e 2 em nível de família. A família Turridae é a que apresenta o maior número de táxons com 16 espécies. Turritella hookeri Reeve, 1849 é a espécie mais abundante, com 684 exemplares. Registra-se pela primeira vez para o Rio Grande do Sul as seguintes espécies: Brookula conica (Watson, 1886), Calliostoma echinatum Dall, 1881, Solariela carvalhoi Lopes & Cardoso, 1958, Caecum massambabensis Absalão, 1994, Turritella hookeri Reeve, 1849, Crepidula plana Say, 1822, Natica pusilla Say, 1822, Polinices lacteus (Guilding, 1833), Eulima mulata Rios & Absalão, 1990, Melanella aff. hypsela (Verrill & Bush, 1900), Trachipollia turricula (von Maltzan, 1884), Anachis sparsa Reeve, 1859, Dentimargo janeiroensis (E. A. Smith, 1915), Axelella brasiliensis Verhecken, 1991, Drilliola loprestiana (Calcara, 1841), Mitrolumna biplicata (Dall, 1889), Nannodiella vespuciana (Orbigny, 1842), Stenodrillia goundlachi (Dall & Simpson, 1901), Terebra brasiliensis E. A. Smith, 1873 e Mathilda aff. scitula Dall, 1889. Novos limites de profundidade são registrados para 29 espécies. Com base na lista de espécies encontradas, se discute sobre o limite das Províncias Caribenha e Patagônica e sobre a influência da Laguna dos Patos no Talude Continental ao largo de Rio Grande.