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1.
Three species of the arcto-boreal, large gastropod Neptunea , described by Linnaeus in 1758 and 1771, occur in large numbers over wide areas of the inshore North Atlantic and adjacent Arctic seas and are conspicuous among Pliocene and Pleistocene molluscs in the Icelandic, North Sea, and western Mediterranean basins. Selections of lectotypes for these species from shells in the collection of the Linnean Society of London, and designations of their type localities, establish the identity of Linnaeus' neptunes and more accurately determine their geographic and geologic distribution. The geographic range of Neptunea (Neptunea) antiqua (L.), the type species, now extends from southern Norway to the northern Biscay coast of France and from the westernmost Baltic Sea to southwestern Ireland; this species also occurs in Pliocene-Holocene marine deposits in West and East Germany, Sweden, the Netherlands, England and France. Its type locality is determined to be the North Sea. N. (Neptunea) despecta (L.) lives in the eastern Canadian Arctic, off southern Greenland, the Barents Sea, and North Atlantic as far south as Massachusetts and Portugal; it also occurs in Pliocene-Holocene strata of eastern Canada, east-central Greenland, Norway (including Svalbard), the Soviet Union, Sweden and England. Its type locality is determined to be the postglacial deposits at Uddevalla in southwestern Sweden. N. (Sulcosipho) contraria (L.) now extends from the southern Biscay coast of France to Cape Spartel, Morocco; this species also occurs in Pleistocene and lower Holocene sequences of the western Mediterranean. Its type locality is determined to be Vigo Bay, Spain. A closely related fossil species, N. (S.) angulata (S. V. Wood), occurs in Pliocene and Pleistocene deposits of the North Sea basin.  相似文献   

2.
Aim To analyse the phylogeographical history of intertidal tardigrades in the North Atlantic in order to improve our understanding of geographical differentiation in microscopic organisms, and to understand the potential importance of the Mid‐Atlantic Islands as stepping stones between the American and European coasts of the Atlantic Ocean. Location Twenty‐four localities from the Mid‐Atlantic Islands (Greenland, Iceland and the Faroe Islands) and both sides of the North Atlantic Ocean. Methods A mitochondrial marker (cytochrome c oxidase subunit I) was sequenced from individual tardigrades belonging to the genus Echiniscoides. The existence of cryptic species was detected using generalized mixed Yule coalescence analysis; lineage ages were estimated with relaxed clock methods; and the degree of geographical differentiation was analysed with samova analyses, haplotype networks and Mantel tests. Results Echiniscoides hoepneri, previously known only from Greenland, was recovered throughout the Mid‐Atlantic Islands. The Faroe Islands population was isolated from Greenland and Iceland, but overall genetic variation was low. The morphospecies Echiniscoides sigismundi had high genetic variation and consisted of at least two cryptic species. A northern and a southern species were both recovered on both sides of the Atlantic, but only the northern species was found on the Mid‐Atlantic Islands. The northern species showed signs of long‐term isolation between the Western and Eastern Atlantic, despite the potential of the Mid‐Atlantic islands to act as stepping‐stones. There was no sign of long‐term isolation in the southern species. The Mid‐Atlantic individuals of the northern species were of Eastern Atlantic origin, but Greenland and Iceland showed signs of long‐term isolation. The genetic pattern found in the southern species is not clearly geographical, and can probably be best explained by secondary contact between former isolated populations. Main conclusions North Atlantic intertidal tardigrades from the genus Echiniscoides showed strong geographical differentiation, and the Mid‐Atlantic Islands seemed unimportant as stepping stones across the Atlantic. The geographical variation of the northern species of E. sigismundi suggests post‐glacial recolonization from several refugia.  相似文献   

3.
New records of marine Tardigrada in the Mediterranean Sea   总被引:1,自引:0,他引:1  
Meiofauna from Chafarinas archipelago (western Mediterranean, N. Africa) were studied, and marine Tardigrada were identified to species level. A total of 15 species, belonging to families Stygarctidae, Halechiniscidac (Subfamilies Halechiniscinae, Florarctinae, Styraconyxinae and Tanarctinae), Batillipedidae, and Echiniscoididae, were found for the first time from the Alboran Sea and southwestern Mediterranean area. Four species and one subspecies are new records for the Mediterranean Sea: I'ioractus acer, F. asper, P. stellatus, Actinarctus doryphorus and Echiniscoides sigismundi hispaniensis. The male of Floractus stellatus , previously unknown to science, is described. Many species have been recorded for the first time in different sedimentary environments, such as midlittoral pools, very shallow gravels, pools in a mixed rocky environment or between Posidonia oceanica meadows, 'Amphioxus' gravels, and coastal detritic.  相似文献   

4.
Nucella lapillus appears to be unique within the Muricidae, and indeed the Mollusca, in exhibiting a Robertsonian chromosomal polymorphism. The recorded diploid values range from 2 n  = 26 to 2 n  = 36, putatively brought about by fusion of smaller chromosomes to form five pairs of large metacentrics in the 2 n  = 26 form. In this study, the karyotypes of the numerically extreme forms (2 n  = 26 and 2 n  = 36) have been illustrated and described in detail, and a new scheme of nomenclature is proposed for the chromosomal rearrangements observed in N. lapillus . Chromosome numbers and karyotypes were recorded and analysed from 70 sites throughout its wide geographical range, mainly from around the UK coasts but also from sites in Norway, France, Spain, Portugal and the USA, showing remarkable variation in both diploid number and karyotypic configuration. The results provide new evidence that seven chromosomes in the 2 n  = 26 form can be involved in the Robertsonian rearrangements, but the maximum recorded diploid number remains 2 n  = 36. Inversions were confirmed in three chromosomes and one population was found to exhibit aneuploidy. Possible explanations for the geographical trends in karyotypic variation are discussed, but despite the advances in the karyology of N. lapillus , a simple solution to this enigmatic phenomenon remains elusive.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 195–210.  相似文献   

5.
6.
FERNANDEZ PRIETO, J. A., VERA, M. L., ALVAREZ MARTINEZ, M. J., DIAZ, T. E., FERNANDEZ CASADO, M. A., FERNANDEZ-CARVAJAL, M. C, GUTIERREZ VILLARIAS, M. I. & NAVA, H. S., 1993. Chromosome numbers and geographical distribution of Ulex europaeus subsp. europaeus (Leguminosae). Chromosome numbers are reported in Ulex europaeus subsp. europaeus (99 samples from northern Spain, France and Great Britain). Three levels of ploidy (diploid, tetraploid and hexaploid) have been detected; the diploid and tetraploid levels, hitherto unknown in this taxon, have been found exclusively in coastal areas of northern Spain and western France.  相似文献   

7.
A crab previously unknown in the European fauna was discovered in La Rochelle (France) in 1994. This shore crab was identified as Hemigrapsus penicillatus, a North-West Pacific species. It appears to be spreading rapidly. It has now been detected from Laredo, Spain (43 °25′N, 03 °20′W) to Fromentine, France (46°53′N, 02°09′W) in sheltered areas of the mid-littoral zone. It is locally abundant, with a density of up to 10–20 individuals per square metre. In its native area, its distribution ranges from a cold (northern Japan, south of the Pacific coast of Russia) to a tropical (Taiwan, Hong-Kong) habitat. Being tolerant to both high and low temperatures (even at freezing point), it will probably colonize most of the European and North-African coasts within a short period of time.  相似文献   

8.
9.
The two subspecies of Ulex europaeus L. (subsp. europaeus and subsp. latebracteatus) are easily differentiated by the shape and size of their bracteoles, and by their chromosome number. However, in the north-west of the Iberian Peninsula, the areas of both subspecies are not clearly delimited, the shape of the bracteoles is intermediate and the width is close to the diagnostic limit. Thus, allocation of some specimens to either subspecies is diffcult. Recendy, a controversy has arisen concerning the intrapopulational uniformity of the chromosome number in U. europaeus from west France and north Spain, and the usefulness of ploidy level and chromosome number as clear-cut indicators of the two subspecies. Thus, the merits of recognizing the subspecies as independent are re-analysed here. Our results for north-west Spain show that the chromosome number is uniform and stable within populations and is clearly related to the morphological characters. Correlation and discriminant analyses show that bracteoles and stomata sizes are highly correlated and are good predictors of ploidy level. Furthermore, the results support the maintenance of two subspecies in U. europaeus , which can be delimited by a combination of morphological characters, chromosome number and geographical distribution.  相似文献   

10.
FERNANDEZ PRIETO, J. A., NAVA, H. S., VERA, M. L., ALVAREZ MARTINEZ, M. J., DIAZ, T. E., FERNANDEZ CASADO, M. A., FERNANDEZ-CARVAJAL, M. C. & GUTIERREZ VILLARIAS, M. I., 1993. Chromosome numbers and geographic distribution of Ulex gallii and U. minor (Leguminosae). Chromosome numbers from 188 samples of the Ulex gr. gallii-minor from Portugal, Spain, France and Great Britain are reported. The gametic and somatic chromosome numbers are n = 16 and In = 32, respectively, in all samples of U. minor. Three levels of ploidy (diploid, tetraploid and hexaploid) have been detected in samples of U. galli, sensu lata from N Spain. In samples from Brittany and Great Britain, only the tetraploid level has been found. New data are compared with all previous reports for the species of this group of gorses.  相似文献   

11.
12.
Fish tagged as kelts at a number of Irish stations have been recaptured outside Irish waters along the coasts of Great Britain, Norway and West Greenland. Salmon tagged as smolts in three Irish rivers have been recaptured off the coast of West Greenland and one off the Faroes. Sixteen fish tagged as smolts in Denmark, Great Britain and Sweden were recaptured in Irish rivers or on the coastline of Ireland. Clean salmon tagged in the open sea have travelled to the coasts of Great Britain and a single fish travelled to southern Sweden. Feeding salmon tagged off West Greenland, in the Labrador sea and off the Faroes have been recaptured in Irish waters.  相似文献   

13.
Section Sideritis is an extremely diversified group which is formed mainly by species growing at low altitude. The group of high altitude taxa of this section is polyphyletic and has been taxonomically divided in different subsections in which these taxa appear normally associated with low-lying planitiary ones, the latter being the probable ancestors. The subsections comprising high altitude taxa are: subsect. Gymnocarpae , subsect. Fruticulosae; subsect. Hyssopifoliae , subsect. Luridae; subsect. Boigiae and subsect. Aranensis . Most of the high altitude taxa of section Sideritis are endemics with small distribution areas; they are incompletely known and threatened with extinction. The upper altitude limit of this section is attained at over 3000 m in Sierra Nevada (Spain) by Sideritis glacialis Boiss., which has been included in subsect. Fruticulosae Obón and D. Rivera. The taxonomy of this complex group of high altitude endemic taxa of Sideritis subsection Fruticuhsae is discussed on the basis of macro-morphological and micro-morphological characters. These are used in identification keys and for analysis of dissimilarity. The different habitats, allied species and plant communities are described. The following taxa are recognized: Sideritis glacialis subsp. glacialis, S. glacialis subsp. vestita, S. glacialis subsp. virens and S. glacialis subsp. fontquerii .  相似文献   

14.
Erwinia carotovora subsp. atroseptica is a pathogen of potatoes in Europe because of its ability to induce blackleg symptoms early in the growing season. However, E. carotovora subsp. carotovora is not able to produce such severe symptoms under the same conditions. On the basis of the technique described by Straus and Ausubel (Proc. Natl. Acad. Sci. USA 87:1889-1893, 1990), we isolated DNA sequences of E. carotovora subsp. atroseptica 86.20 that were absent from the genomic DNA of E. carotovora subsp. carotovora CH26. Six DNA fragments ranging from ca. 180 to 400 bp were isolated, cloned, and sequenced. Each fragment was further hybridized with 130 microorganisms including 87 E. carotovora strains. One probe was specific for typical E. carotovora subsp. atroseptica strains, two probes hybridized with all E. carotovora subsp. atroseptica strains and with a few E. carotovora subsp. carotovora strains, and two probes recognized only a subset of E. carotovora subsp. atroseptica strains. The last probe was absent from the genomic DNA of E. carotovora subsp. carotovora CH26 but was present in the genomes of many strains, including those of other species and genera. This probe is homologous to the putP gene of Escherichia coli, which encodes a proline carrier. Further use of the probes is discussed.  相似文献   

15.
We investigated the geographical distribution of genetic variation in 67 individuals of Triglochin maritima from 38 localities across Europe using AFLP markers. Analysis of genetic variation resulted in the recognition of two major genetic groups. Apart from few geographical outliers, these are distributed (1) along the Atlantic coasts of Portugal, Spain and France and (2) in the North Sea area, the Baltic Sea area, at central European inland localities, the northern Adriatic Sea coast and the Mediterranean coast of southwest France. Considering possible range shifts of T. maritima in reaction to Quaternary climatic changes as deduced from the present-day northern temperature limit of the species, Quaternary changes of coastline in the North Sea area and the very recent origin of the Baltic Sea, we conclude that the coastal populations of T. maritima in the North Sea and Baltic Sea areas originated from inland populations.  相似文献   

16.
Véra Eisenmann 《Geobios》1979,12(6):863-886
Biometrical study of the metapodials of modern wild species (E. grevyi, E. burchelli boehmi, E. zebra hartmannae, E. africanus, E. hemionus and E. przewalskii) and some fossil forms (E. stenonis vireti and cf. vireti from the Villafranchian of France and Spain; E. tabeti and E. mauritanicus from the Lower and Middle Pleistocene of Northern Africa; E. mosbachensis from the Middle Pleistocene of Germany). Classical functional and evolutive interpretations of some characters are discussed: development of the distal keel, of the distal supra-articular and articular widths, of the proximal widths and antero-posterior diameters.  相似文献   

17.
Abstract.  Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a major cause of traumatic myiasis in livestock in Central and Eastern Europe and in countries bordering the Mediterranean. The present study explored the utility of external body characters, genitalia characters and mitochondrial DNA characters for identification of this and related species in the subfamily Paramacronychiinae. Sequence analyses of the 3' terminal 273 bp of the mitochondrial cytochrome b gene revealed two lineages of W. magnifica , one from Spain and France and the other from the rest of Eurasia, differing by only two base pairs. Phylogenetic analysis of cytochrome b showed that W. magnifica and Wohlfahrtia vigil Walker were sister species; this conclusion was not contradicted by a phylogenetic analysis of the morphological characters. Based on cytochrome b , the genetic distance between specimens of W. vigil from Europe and North America was sufficiently large to justify the recognition of more than one species. A new species, Wohlfahrtia monegrosensis , from northern Spain, was described, based on morphology and cytochrome b . A unique combination of external body characters of males or females were diagnostic for W. magnifica , the W. vigil group and Wohlfahrtia bella , but only the genitalia characters were diagnostic for all nine species studied.  相似文献   

18.
A fossil flora from the Late Paleocene-Early Eocene Thyra Ø Formation of eastern North Greenland (paleolatitude 77° N) has yielded monocotyledon leaf impressions with characters seen only in the closely related modem species in the families of Heliconiaceae, Musaceae, and Strelitziaceae. The combination of large costae widths and parallel, nonanastomosing, lateral veins that depart at right angles from the costae in the fossil material are features present only in leaves of extant species from these families. Three basic venation patterns also are recognized in the modem species of these families, but except for the genera Strelitzia and Phenakospermum, none of these patterns are present exclusively in any one family. Musopsis n. gen. is created for the fossil material from Greenland, but it is considered a form genus due to the lack of gross morphological features that can be used for separating leaves of the modem genera in Heliconiaceae, Musaceae, and Strelitiziaceae. It is the first known Arctic occurrence of fossil leaf material resembling this modem group of taxa.  相似文献   

19.
Quaternary glaciations have played a major role in shaping the genetic diversity and distribution of plant species. Strong palaeoecological and genetic evidence supports a postglacial recolonization of most plant species to northern Europe from southern, eastern and even western glacial refugia. Although highly controversial, the existence of small in situ glacial refugia in northern Europe has recently gained molecular support. We used genomic analyses to examine the phylogeography of a species that is critical in this debate. Carex scirpoidea Michx subsp. scirpoidea is a dioecious, amphi‐Atlantic arctic–alpine sedge that is widely distributed in North America, but absent from most of Eurasia, apart from three extremely disjunct populations in Norway, all well within the limits of the Weichselian ice sheet. Range‐wide population sampling and variation at 5,307 single nucleotide polymorphisms show that the three Norwegian populations comprise unique evolutionary lineages divergent from Greenland with high between‐population divergence. The Norwegian populations have low within‐population genetic diversity consistent with having experienced genetic bottlenecks in glacial refugia, and host private alleles that probably accumulated in long‐term isolated populations. Demographic analyses support a single, pre‐Weichselian colonization into Norway from East Greenland, and subsequent divergence of the three populations in separate refugia. Other refugial areas are identified in North‐east Greenland, Minnesota/Michigan, Colorado and Alaska. Admixed populations in British Columbia and West Greenland indicate postglacial contact. Taken together, evidence from this study strongly indicates in situ glacial survival in Scandinavia.  相似文献   

20.
Phylogenetic relationships among chain-forming Cochlodinium species, including the harmful red tide forming dinoflagellate Cochlodinium polykrikoides, were investigated using specimens collected from coastal waters of Canada, Hong Kong, Japan, Korea, Malaysia, México, Philippines, Puerto Rico, and USA. The phylogenetic tree inferred from partial (D1–D6 regions) large subunit ribosomal RNA gene (LSU rDNA) sequences clearly differentiated between C. polykrikoides and a recently described species, Cochlodinium fulvescens. Two samples collected from the Pacific coasts of North America (British Columbia, Canada and California, USA) having typical morphological characters of C. fulvescens such as the sulcus located in the intermediate region of the cingulum, were closely related to C. fulvescens from western Japan in the phylogenetic tree. Cochlodinium polykrikoides formed a monophyletic group positioned as a sister group of the C. fulvescens clade with three well-supported sub-clades. These three clades were composed of (1) East Asian, including specimens collected from Hong Kong, western Japan, and southern Korea, (2) Philippines, from Manila Bay, Philippines and Omura Bay, Japan, and (3) American/Malaysian, from the Atlantic coasts of USA, the Pacific coast of México, Puerto Rico, and Borneo Island, Malaysia. Each of these clades is considered to be a so-called “ribotype” representing the population inhabiting each region, which is distinguished based on ribosomal RNA gene sequences in the species despite similarities in their morphological characters.  相似文献   

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