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1.
Grateloupia doryphora (Montagne) Howe, originally described from Peru, has repeatedly been reported as an invasive species in Atlantic and Mediterranean waters. Various attempts to explain this species' route of introduction have been unsatisfactory. New evidence from comparative rbcL sequence analysis and morphology suggests that this adventive species in the NE and NW Atlantic corresponds with G. turuturu Yamada, originally described from Japan. This provenance follows a well-recognized trend of invasive marine organisms that have colonized the Atlantic Ocean and Mediterranean Sea from Pacific NE Asia.  相似文献   

2.
Simon  C.  Ar Gall  E.  Deslandes  E. 《Hydrobiologia》2001,443(1-3):23-29
Grateloupia doryphora (Montagne) Howe (Halymeniales, Halymeniaceae) has previously been reported for two locations along the Brittany coastline (France). Important ecological and morphological traits of the species in the breton populations are detailed here. Because of the impressive size it can reach, G. doryphora can be considered as the largest red alga in the world. G. doryphora has the tendency to dominate the algal flora once installed. At Lorient, in addition to the marginal extension of the population, a progressive colonisation of the whole intertidal zone has been noted for 2 years. The species actually preferentially develops in currents and pools where it is abundant between early winter and mid summer. An interesting development is the recent spreading from the mid and lower eulittoral towards the upper rocky pools. The seasonality of the life-cycle has also been studied over 2 years. In addition, this work reports on the first identification of G. doryphora near the Loire estuary in South Brittany, at Concarneau and in the Bay of Brest in western Brittany, and on the coasts of Normandy, at Granville and Cherbourg. The occurrence of attached specimens on ship hulls and pontoons suggests a distant transport of the species by navigation. Considering the rapid geographical propagation of G. doryphora, and its tendancy to proliferate in settling locations, the species can be regarded as potentially invasive on the north–west coasts of Europe.  相似文献   

3.
We report the invasion of the Gulf of Maine, in the northwest Atlantic Ocean, by the largest red seaweed in the world, the Asian Grateloupia turuturu. First detected in 1994 in Narragansett Bay, Rhode Island, south of Cape Cod, this alga had expanded its range in the following years only over to Long Island and into Long Island Sound. In July 2007 we found Grateloupia in the Cape Cod Canal and as far north (east) as Boston, Massachusetts, establishing its presence in the Gulf of Maine. Grateloupia can be invasive and may be capable of disrupting low intertidal and shallow subtidal seaweeds. The plant's broad physiological tolerances suggest that it will be able to expand possibly as far north as the Bay of Fundy. We predict its continued spread in North America and around the world, noting that its arrival in the major international port of Boston may now launch G. turuturu on to new global shipping corridors.  相似文献   

4.
Grateloupia doryphora (Montagne) M.Howe is an invasive foliose alga that was reported for the first time in Rhode Island, USA in 1997. The population has since increased in size and expanded in range. In this study, the genetic variation and potential sources of the Rhode Island G. doryphora population were examined using three types of molecular markers: randomly amplified polymorphic DNA (RAPD), nuclear internal transcribed spacer (ITS) sequences, and mitochondrial cox2–cox3 intergenic spacer (COX) sequences. No variation was detected in ITS or COX sequences among Rhode Island G. doryphora individuals. RAPDs, however, did reveal genetic variation, although banding patterns were similar, with RAPD genetic distances between individuals ranging from 0.00 to 0.17. The low level of genetic diversity observed within the Rhode Island population may be due to a small founder population or a founder population derived from a genetically uniform source. To identify possible sources of the Rhode Island invasion, individuals from nine geographically diverse populations of foliose Grateloupia were compared. Phylogenetic trees inferred from RAPD distances and ITS and COX sequences had similar topologies; thus there was phylogenetic congruence among these independent loci. The Rhode Island G. doryphora specimens were genetically similar to specimens from G. doryphora populations located in Portsmouth, England; Tholen Island, The Netherlands; and Brittany and Hérault, France. Interestingly, the G. doryphora population in each of these locations is itself due to an introduction event within the past 40 years.  相似文献   

5.
Robaina  R. R.  Garcia-Reina  G.  Luque  A. 《Hydrobiologia》1990,204(1):137-142
Explants of Gelidium versicolor, Grateloupia doryphora and Laurencia sp. were cultivated in Provasoli enriched seawater culture medium (PES) adjusted to several osmolalities (0.5, 0.7, 1.0 and 1.5 Os kg–1) and solidities (agar concentration = 3, 8 and 15 g L–1). Osmolality was adjusted by dilution of seawater with distilled water (50, 70 and 100% seawater) and by NaCl addition. Explants of Laurencia sp. and Grateloupia doryphora showed bud regeneration and callus formation. Explants of Gelidium versicolor only showed bud regeneration. Osmolalities of 0.5 and 1.05 Os kg–1. inhibited or drastically reduced bud regeneration and callus formation. The highest callus formation and bud regeneration were observed at 0.7 to 1.0 Os kg–1. An increase in the agar concentration of the culture medium was positively correlated with callus formation and negatively correlated with bud regeneration. An increase in the percentage of seawater increased the solidity of the culture medium and was positively correlated with callus formation. Glycerol was an effective carbon source for the vegetative propagation of axenic explants of Grateloupia doryphora, promoting growth and bud regeneration. An increase in glycerol concentration in the culture medium increased its osmolality, inhibiting the growth of the explants and their morphogenetic development.  相似文献   

6.
S. De Grave  D. Diaz 《Hydrobiologia》2001,449(1-3):179-186
A multivariate comparison of morphometric differences was undertaken on populations of Pontophilus norvegicus from four Atlantic and one Mediterranean locations. Multiple discriminant analysis revealed clear morphometric differences between Atlantic and Mediterranean populations, with the Atlantic populations exhibiting a low degree of separation. The underlying variables responsible for this discrimination are shown not to have any operational taxonomic utility and, hence, no sub-specific status is attached to the respective populations.  相似文献   

7.
This investigation was designed to compare the differential stress tolerance in young thalli of two similar intertidal red seaweeds, Grateloupia turuturu Yamada and Palmaria palmata Kuntze, and to identify whether the invasive alga G. turuturu was more stress tolerant than P. palmata to cope with adverse environmental conditions. To do so, we measured the production of reactive oxygen caused by methyl viologen (MV) by assessing the oxidation of dichlorohydrofluorescein (DCFH) to dichlorofluorescein (DCF), the activities of reactive oxygen scavenging enzymes and the changes of the optimal fluorescence quantum yield (Fv/Fm) when the thalli of the two species were exposed to oxidative stresses caused by the addition of MV, H2O2, 3(3, 4-dichlorophenyl)-1,1-dimethyl urea (DCMU), heavy metal, changes of salinities, heat and freezing. Results demonstrated that the activities of superoxide dismutase (SOD) and peroxidase (POD) in G. turuturu were much higher than in P. palmata. Fv/Fm in G. turuturu was less sensitive than that in P. palmata to MV, H2O2, DCMU, heavy metal, salinity and heat stress, indicating that G. turuturu could be better acclimatized to changing environments and thus had a higher threshold for oxidative stress than P. palmata. G. turuturu was shown to be more sensitive to freezing treatment (− 20 °C), which explained why the appearance of G. turuturu was rarely reported in colder water environments.  相似文献   

8.
The nostrils of the seabird Calonectris diomedea are endowed with a salt-excreting gland that could produce a suitable environment for the colonization of extreme halophilic prokaryotes. We have studied in this organ the presence of extreme halophiles by means of culturing techniques. We could easily cultivate members of haloarchaea, and all cultures studied were identified as members of one of the two species Halococcus morrhuae and Hcc. dombrowskii. In order to reveal the diversity of these colonizers, we undertook a taxonomic study. Altogether, the results indicated that members of the genus Halococcus may constitute a part of the natural epizootic microbiota of C. diomedea, and that they exhibit such an important degree of taxonomic variability that appeals for a pragmatic species definition. This seabird nests in the west Mediterranean coasts, but its migratory habits, reaching locations as distant from the Mediterranean as the South Atlantic, may help in the dispersal mechanisms of haloarchaea through the Earth’s surface.  相似文献   

9.
Grateloupia filicina (C. Agardh) Lamouroux, originally described from the Mediterranean Sea, has long been considered a textbook example of a marine red alga with a cosmopolitan distribution. An rbcL‐based molecular phylogeny, encompassing samples covering the entire geographic distribution of the species, revealed a plethora of “cryptic” species, whereby the presence of genuine G. filicina is limited to the Mediterranean basin. The phylogeny revealed a strong biogeographic imprint, with specimens from temperate regions resolved in clades composed of species inhabiting the same geographic region. Presence of widely divergent morphologies in the temperate clades indicated that several lineages have converged independently to a G. filicina‐type morphology. Tropical representatives are resolved in a single clade with very uniform G. filicina‐type morphology and pairwise sequence divergences that are lower than the average divergence observed in temperate lineages. This, combined with a lack of clear geographic structure among the tropical lineages, may indicate a more recent divergence with long‐range dispersal capacities. Violations to the biogeographic signal in temperate lineages seemed to be due to either inadequate taxonomy or recent introductions. Grateloupia minima P. & H. Crouan, a taxon placed in synonymy under G. filicina, is reinstated as a separate species distributed in the northeast Atlantic Ocean. Grateloupia capensis sp. nov. is described to accommodate specimens from South Africa with a G. filicina‐type morphology, and G. filicina var. luxurians is elevated to species status. Morphological and anatomical characters were put forward that support the distinctiveness of these three distinct species.  相似文献   

10.
A newly abundant Gracilaria species in the sounds of southeastern North Carolina has become a problem for commercial fishing and industries drawing water from the lower Cape Fear River. DNA sequence analyses have shown that this species is Gracilaria vermiculophylla, a taxon originally described from East Asia. Surveys for G. vermiculophylla have shown that it has a discontinuous distribution in the sounds of southeastern North Carolina, and suggest that it is spreading. Gracilaria vermiculophylla meets 6 of the 10 criteria used to help identify invasive species in that it has only recently appeared in southeastern North Carolina; is associated with human mechanisms of dispersal; has a restricted distribution; has disjunct populations in isolated oceans; no means of active dispersal, and an exotic evolutionary origin. The species may also meet two additional criteria as its local range is believed to be expanding, and it is filling a previously unoccupied seasonal niche. These factors taken together strongly suggest that G. vermiculophylla is an invasive species in southeastern North Carolina.  相似文献   

11.
Mediterranean reports of Gracilariaceae species, in particular those assigned to the G. verrucosa complex, were re-examined with the use of molecular tools, in order to verify their systematic position and better understand their distribution. Within this complex, we recognized four distinct taxa: Gracilariopsis longissima, Gracilaria gracilis, Gracilaria longa and a possible new species. The rbcL gene sequences, together with those of other terete Mediterranean entities, were included in a broad molecular phylogeny of the family. The reproductive characters of the studied taxa do not fit completely with published hypothesis on the generic and intrageneric relationships, suggesting that the anatomy of some subgroups should be better characterized.  相似文献   

12.
Distinguishing natural versus anthropogenic dispersal of organisms is essential for determining the native range of a species and implementing an effective conservation strategy. For cryptogenic species with limited historical records, molecular data can help to identify introductions. Nematostella vectensis is a small, burrowing estuarine sea anemone found in tidally restricted salt marsh pools. This species’ current distribution extends over three coast lines: (i) the Atlantic coast of North America from Nova Scotia to Georgia, (ii) the Pacific coast of North America from Washington to central California, and (iii) the southeast coast of England. The 1996 IUCN Red List designates N. vectensis as “vulnerable” in England. Amplified fragment length polymorphism (AFLP) fingerprinting of 516 individuals from 24 N. vectensis populations throughout its range and mtDNA sequencing of a subsample of these individuals strongly suggest that anthropogenic dispersal has played a significant role in its current distribution. Certain western Atlantic populations of N. vectensis exhibit greater genetic similarity to Pacific populations or English populations than to other western Atlantic populations. At the same time, F-statistics showing high degrees of genetic differentiation between geographically proximate populations support a low likelihood for natural dispersal between salt marshes. Furthermore, the western Atlantic harbors greater genetic diversity than either England or the eastern Pacific. Collectively, these data clearly imply that N. vectensis is native to the Atlantic coast of North America and that populations along the Pacific coast and in England are cases of successful introduction.  相似文献   

13.
The entire sequence of the mitochondrial cytochrome b gene and 2 partial sequences of the ribosomal RNA12S and 16S genes have been used to study the molecular phylogeny in 10 species of soles belonging to the genera Solea, Monochirus, Microchirus, Dicologlossa, and Synaptura from the Atlantic waters of the Gulf of Cádiz (Spain). The results obtained by means of different phylogenetic analyses (maximum likelihood, maximum parsimony, and neighbor-joining) were quite similar, supporting the monophyly of the Solea species. Nevertheless, they favor the differentiation of Dicologlossa cuneata and Dicologlossa hexophthalma in 2 distinct genera, since the most closely related species to the last one is Microchirus azevia. The fact that M. azevia is also more closely linked to Monochirus hispidus than to its congeneric Microchirus boscanion argues in favor of a taxonomic reorganization of these genera.  相似文献   

14.
The crab genus Brachynotus de Haan, 1833 is restricted to the intertidal and shallow subtidal of the Mediterranean and northeastern Atlantic. It is presently recognized to consist of four species, of which three (B. foresti, B. gemmellari and B. sexdentatus) are endemic to the Mediterranean. The fourth species, B. atlanticus, is found along the Atlantic coasts of northern Africa and southern Europe, but also extends into the western Mediterranean. This high level of endemism suggests that speciation within Brachynotus is strongly correlated with the geography and geology of the Mediterranean Sea. A molecular phylogeny based on the mitochondrial large subunit (16S) rRNA gene indicates that the four species of Brachynotus form a monophyletic group within Atlantic Varunidae. The DNA sequence data also show that the genus Brachynotus can be subdivided into two species groups, one comprising B. atlanticus and B. foresti, and the other one B. gemmellari and B. sexdentatus. While B. atlanticus and B. foresti are clearly genetically distinct, B. gemmellari and B. sexdentatus are identical in the studied region of the 16S rRNA gene, suggesting a recent separation or continuing gene flow.  相似文献   

15.
The mtDNA Cyt b gene was sequenced partially for Variola louti of Serranidae, Epinephelinae and seven endemic species of groupers—Epinephelus awoara, E. brunneus, E. coioides, E. longispinis, E. sexfasciatus, E. spilotoceps and E. tauvina in China. The seven endemic species and other seven foreign species of groupers—E. aeneus, E. caninus, E. drummondhayi, E. haifensis, E. labriformis, E. marginatus and E. multinotatus from the GenBank were combined and analysed as ingroup, while Variola louti was used as outgroup. We compared the 420 bp sequences of Cyt b among the 15 species and constructed two types of molecular phylogenetic trees with maximum parsimony method (MP) and neighbor-joining method (NJ) respectively. The results were as follows: (1) As to the base composition of mtDNA Cyt b sequence (402 bp) of 14 species of Epinephelus, the content of (A + T) was 53.6%, higher than that of (G + C) (46.4%). The transition/transversion ratio was 4.78 with no mutation saturation. (2) The cluster relationships between E. awoara and E. sexfasciatus, E. coioides and E. tauvina, E. longispinis and E. spilotoceps were consistent with phenotypes in taxonomy. (3) In the phylogenetic tree, the species in the Atlantic Ocean were associated closely with those in the Pacific Ocean, which suggested that the Cyt b sequences of Epinephelus were highly conserved. This may be attributed to the coordinate evolution. (4) In wel1-bred mating or heredity management, mating Epinephelus of the same branch should be avoided. It is likely to be an effective way to mate the species of the Atlantic Ocean with those of the Pacific Ocean to improve the inheritance species. __________ Translated from Acta Hydrobiologica Sinica, 2006, 30(4): 432–438 [译自: 水生生物学报]  相似文献   

16.
Phenotypic variation of lionfish supraocular tentacles   总被引:1,自引:0,他引:1  
A previous observation suggested that a novel phenotype of lionfish supraocular tentacle is evolving rapidly in the Red Sea and Indian Ocean. We confirm the existence of this phenotype in high prevalence in invasive populations of lionfish in the Western North Atlantic. Observations of individual lionfish from the Atlantic populations indicate that supraocular tentacles are more prevalent on juvenile and young adult lionfish suggesting this characteristic is size specific and is not associated with a genetic lineage. The high prevalence of this novel phenotype in the Atlantic may be a founder effect rather than continued selection. Genetic analysis further supports this conclusion as this phenotype is present in two Pterois species found in the Atlantic.  相似文献   

17.
Italian representatives of the Cardamine pratensis group were investigated using morphometric, karyological, and molecular (AFLP-fingerprinting) analyses. Focus was on resolving the taxonomic and evolutionary position of C. granulosa from Piemonte (NW Italy) and of populations from central Italy, previously included in C. granulosa or C. pratensis s. str. Results show that C. granulosa is a morphologically and genetically well defined diploid species, but is extremely rare and restricted to a small area in Piemonte. Central Italian populations differ from both C. granulosa and C. pratensis s. str., and, although the morphological differentiation is not strongly pronounced, they show marked molecular divergence, suggesting recognition as a new species, Cardamine apennina. Because of their restricted distribution and diploid chromosomal level, C. apennina and C. granulosa may represent basal and quite isolated lineages, whereas reticulation on diploid and polyploid level has affected remaining lineages of the C. pratensis group. Both Italian endemics are endangered due to rarity and habitat loss. A key for identification of the Italian taxa of the C. pratensis group is also provided.  相似文献   

18.
Over the last decade, the non-native, filter-feeding crab Petrolisthes armatus invaded oyster reefs of the South Atlantic Bight at densities of thousands m−2. Mesocosm and field experiments demonstrated that P. armatus at ∼10–75% of mean summer densities: (1) suppressed growth of small oysters, biomass of benthic microalgae, and recruitment of native mud crabs, (2) enhanced oyster, mussel, and total bivalve recruitment, macroalgal cover, and survivorship of predatory oyster drills, but (3) did not affect native taxonomic richness. Laboratory feeding assays, field tethering experiments, and population changes in field and mesocosm experiments suggest that P. armatus is a preferred prey for native mud crabs and other consumers, thus relieving predation on native species and enhancing recruitment or survival of bivalves and oyster drills. In contrast, the invasive crab can consume crustacean larvae and via this feeding may suppress recruitment of native mud crabs. Our findings should be conservative given the low densities of P. armatus seeded into experimental plots and our inability to run longer-term experiments due to controls rapidly being colonized by non-native crabs recruiting from the plankton. Invasive crabs commonly impact native communities via predation, but community impacts of this invasive crab may be as much due to its role as a preferred prey of native consumers as to its predation on native prey. Given that oysters are foundation species for shallow reefs in the South Atlantic Bight, the long-term effects of this invasion could be considerable.  相似文献   

19.
An unsual sulfoxide amino acid (4-methanesulfinyl-2-methylamino butyric acid) was isolated from the red macroalgae Grateloupia doryphora. Its structure was elucidated on the basis of analyses by NMR and Mass sepctroscopies.  相似文献   

20.
The common potato, tetraploid Solanum tuberosum spp. tuberosum L. (tbr), has a narrow genetic base but a large number of related tuber-bearing species that harbor genetic diversity for agronomic characters. The taxonomic status of Solanum ruiz-lealii Brücher (rzl), a diploid species endemic to Mendoza province, Argentina, is controversial. It has been described as a new species of non-hybrid origin and as a natural hybrid between S. kurtzianum Bitt. & Wittm. (ktz) and S. chacoense Bitt. (chc). The hypothesis of the hybrid origin of rzl is examined systematically for the first time by phenetic analyses of morphological and molecular (SSR markers) data, and cytological analyses of interspecific hybrids. The morphological, cytological and molecular data are congruent, and suggest that rzl is not a recent natural hybrid between the ktz and the chc populations studied but has probably originated by divergence of chc, or by hybridization between chc and another taxon.  相似文献   

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