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1.
Currently, three stocks of sei whales (Balaenoptera borealis) are defined in the North Atlantic; the Nova Scotian, Iceland-Denmark Strait and Eastern North Atlantic stocks, which are mainly based upon historical catch and sighting data. We analyzed mitochondrial control region DNA (mtDNA) sequences and genotypes from 7 to 11 microsatellite loci in 87 samples from three sites in the North Atlantic; Iceland, the Gulf of Maine and the Azores, and compared against the North Pacific using 489 previously published samples. No statistically significant deviations from homogeneity were detected among the North Atlantic samples at mtDNA or microsatellite loci. The genealogy estimated from the mtDNA sequences revealed a clear division of the haplotypes into a North Atlantic and a North Pacific clade, with the exception of one haplotype detected in a single sample from the Azores, which was included in the North Pacific clade. Significant genetic divergence between the North Atlantic and North Pacific Oceans was detected (mtDNA ΦST?=?0.72, microsatellite Weir and Cockerham’s ? = 0.20; p?<?0.001). The coalescent-based estimate of the population divergence time between the North Atlantic and North Pacific populations from the sequence variation among the mtDNA sequences was at 163,000 years ago. However, the inference was limited by an absence of samples from the Southern Hemisphere and uncertainty regarding mutation rates and generation times. The estimates of inter-oceanic migration rates were low (Nm at 0.007 into the North Pacific and at 0.248 in the opposite direction). Although estimates of genetic divergence among the current North Atlantic stocks were low and consistent with the extensive range of movement observed in satellite tagged sei whales, the high uncertainty of the genetic divergence estimates precludes rejection of multiple stocks in the North Atlantic.  相似文献   

2.
North Pacific Pseudoscopelus sagamianus (from the Kuroshio zone) are characterized morphologically in detail. The neotype is established. The North Pacific population and the group of populations from the Atlantic and Indian oceans are compared in detail, significant differences are found between them in coloration of the orobranchial cavity and in the pattern of photophores of series trf and prcf. In the author’s opinion, these differences are of the subspecies level. Potential areas of subspecies are discussed, and the area of the whole species is verified. A possibility of validity of the name P. pierbartus Spitz et al., 2007, for the group of populations from the Atlantic and Indian oceans is considered. Additions and changes to methods of investigations of Pseudoscopelus suggested by Melo et al. (2007) are critically discussed.  相似文献   

3.
A new microcotylid, Tinrovia mamaevi n. sp. (Monogenea: Polyopisthocotylea), is described from the gills of Notacanthus bonaparte Risso (Notacanthiformes: Notacanthidae), sampled in the Western Mediterranean and North East Atlantic. This species is allocated to the subfamily Syncoelicotylinae Mamaev & Zubchenko, 1978 due to the possession of a symmetrical haptor with two separate frills. The clamps in T. mamaevi n. sp. are of the “microcotylid” type, arranged in two distinct lateral haptoral frills; the genital atrium and the copulatory organ are armed and the vaginal pore is unarmed. The new species differs from the type- and only species of the genus, T. papiliocauda Mamaev, 1987, in having a shorter and narrower haptor with a smaller number of clamps. Clamps are also smaller in the new species, testes are more numerous, the genital atrium is smaller, divided into two lateral lobes (instead of five) with a smaller number of spines and the eggs have a short and a long filament (instead of two short filaments). The host species and locality of T. mamaevi n. sp. also differ as T. papiliocauda which was recorded in Notacanthus sexspinis Richardson from the South Pacific.  相似文献   

4.
Variability of microsatellite DNA loci Gmo3, Gmo34, and Gmo35 is studied in samples of Pacific cod Gadus macrocephalus and Atlantic cod G. morhua. The results show high values of identity of the samples within the North Pacific basin (0.9766–0.9924) and within the Northeast Atlantic basin (0.9580). Based on the pairwise assessment of genetic differentiation, the F ST values are significantly different in all variants between the samples of Pacific and Atlantic cod (F ST = 0.5235–0.6719, p < 0.001). Within the basins, the significant differences in the frequencies of main alleles are revealed in the loci Gmo3 and Gmo34 for the samples from the Pacific and Atlantic oceans, respectively.  相似文献   

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6.
Two species, M. danae Ebeling and M. pumilis Ebeling, belonging to the species group “M. simus” are described in the final part of the revision of oligo-raker species of the genus Melamphaes (Melamphaidae) (≤19 gill rakers on the first gill arch). The species M. danae is distributed in the Indian and Pacific oceans between 30° N and 30° S. In the Pacific Ocean, it is known up to 112° W. The species M. pumilis is distributed in the North Atlantic between 17° and 45° N, and the main catches have been conducted in the western part of the ocean. In the eastern part of the ocean, the catches are registered up to 28° W. A key for the identification of 21 oligo-raker species of the genus Melamphaes is presented.  相似文献   

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Pacific herring (Clupea pallasii) is divided into three subspecies: two in northeast Europe and one in the north Pacific Ocean. Genetic studies have indicated that the populations in northeast Europe have derived from the northwest Pacific herring recently, or during the last 10–15 kyr, and that they are distinct from the population in the northeast Pacific. In addition, hybridization between the Pacific herring and the Atlantic herring has been documented. Otolith variation has been considered to be largely affected by environmental variation, but here we evaluate whether the genetic differentiation is reflected in otolith shape differences. A clear difference in otolith shape was observed between the genetically differentiated herring species Clupea harengus from the Atlantic and C. pallasii. The otolith shape of C. p. suworowi in the Barents Sea was different from the shape of C. pallasii in northern Norway and C. p. pallasii from the Pacific. Populations of C. p. pallasii, sampled east and west of the Alaska Peninsula, which belong to two genetically different clades of the C. p. pallasii in the Pacific Ocean, show a clear difference in otolith shape. C. p. suworowi and the local C. pallasii peripheral population in Balsfjord in northern Norway are more similar to the northwest Pacific herring (C. p. pallasii) than to the northeast Pacific herring (C. p. pallasii), both genetically and in otolith shape. The Balsfjord population, known to be influenced by introgression of mtDNA from the Atlantic herring, does not show any sign of admixture in otolith shape between the two species. A revised classification, considering the observed genetic and morphological evidence, should rather group the northwest Pacific herring in the Bering Sea together with the European populations of C. pallasii than with the northeast Pacific herring in the Gulf of Alaska.  相似文献   

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A critical analysis of literature data on the distribution, morphology, and phylogeography of the Arctic lamprey (Lethenteron camtschaticum) and five species of marine and anadromous fish such as navaga (Eleginus navaga), pollock (Theragra chalcogramma), rainbow smelt (Osmerus mordax dentex), Pacific herring (Clupea pallasii), and pond smelt (Hypomesus olidus) has been performed. The results show that all these species have colonized Northern European seas, distributing along the Arctic coastline of Eurasia after the glacier retreat. The reasons that the dispersal of these species in the Atlantic Ocean may be impeded (preference for a cold environment, competition, and decrease of the evolutionary potential) are discussed.  相似文献   

11.
Results of comparative analysis of specific features of morphology of larval lanternfishes of the Indo-Pacific genus Triphoturus based on materials from the southeastern part of the Pacific Ocean, northwestern Pacific, South China Sea, and the western part of the Indian Ocean, as well as on published data, are provided. Noticeable differences are shown in specific features of pigmentation of larval T. nigrescens (sensu Hulley, 1986) from different parts of the vast range of this species, that may be accounted for by its individual and/or geographic variation and by the collective pattern of this taxon. It is stated that it is necessary to use genetic data for the verification of the taxonomic status of the representatives of the genus. Morphological evidence in favor of the species isolation of T. oculeum and T. microchir based on larval materials is presented. The presence of three morphologically different forms of larval Triphoturus from the eastern Pacific differing in the pattern of body pigmentation that are identified with three nominal species of the genus Triphoturus—T. nigrescens, T. mexicanus, and T. oculeum—is confirmed. The study of specific features of distribution of larvae of these species in southeastern waters of the Pacific Ocean based on our own and published materials revealed the presence of larval T. mexicanus and T. oculeum off Peru, which is supported by data on the presence of adult individuals of both species here.  相似文献   

12.
Three oligo-raker species (?19 rakers on the first gill arch) of the genus Melamphaes out of the “M. typhlops” group are considered. The validity of M. indicus Ebeling is restored. This species inhabits equatorial and tropical waters of the Indian Ocean and the western part of the Pacific Ocean. M. eurous sp. n., which is related to M. indicus, is described from equatorial waters of the eastern part of the Pacific Ocean. M. typhlops (Lowe) inhabiting the northern part of the Atlantic Ocean, from the equatorial zone about to 45° N, is redescribed.  相似文献   

13.
Species assigned to Porphyra sensu lato (Bangiales) make up one of the largest groups of red algae in the world. While the Bangiales are monophyletic, Porphyra is not, but the number of genera remains unresolved and a consensus needs to be reached on how to proceed. Here, it is proposed that a global taxonomy for the group would enable resolution and consensus. Using examples from our work on Porphyra in both the northern and southern hemispheres, including the North Atlantic, Mediterranean and Pacific, notably Chile, we have addressed the following questions: i) how many species are there, ii) how many species are there in different parts of the world, and iii) how do these species relate to those in different parts of the world? A cumulative total of species described in the North Atlantic and Mediterranean since 1800 indicates that there are still species to be added to the flora for these regions. Determination of intraspecific diversity or diversity within species complexes was examined using the mitochondrial cox1. The results split the species into two distinct groups, revealed differences between the British and Faroese floras and indicated a new species in the Faroes. Detection of species diversity in different geographical areas of the world and their relationship with the North Atlantic and southeast Pacific (Chile) was studied using the plastid Rubisco spacer and partial rDNA SSU data. While the Rubisco spacer was limited for global comparisons, it was useful for species identification adding five more species to the Atlantic flora. The partial rDNA SSU data, while its shortness made it unsuitable for generic interpretation, revealed the spread of taxa from different geographical areas throughout the tree. We have concluded that to achieve a global taxonomy standard molecular markers should be used and we propose that the rbcL and complete rDNA SSU would be suitable. We have also concluded that while a few regions of the world have been well studied, before a consensus on generic boundaries can be achieved detailed taxonomic studies are needed in many other parts of the world including circumpolar Arctic, mid and southwest Atlantic and southeast Asia.  相似文献   

14.
The frequency of occurrence of the COI gene of mitochondrial DNA in the Pacific flatnose Antimora microlepis and blue antimora Antimora rostrata (Moridae, Gadiformes) was analyzed in samples collected in different areas of the World Ocean. The revealed maximum haplotype diversity of COI in the blue antimora in the North Atlantics may indicate that this species emerged in this region, from which it widely distributed in the World Ocean. The Pacific flatnose Antimora microlepis originated from Antimora rostrata. Antimora might penetrate into the North Pacific by several routes: through the Panama Strait, along the coast of Antarctica, or through the Indian Ocean along the coast of Australia.  相似文献   

15.
Scirpus hattorianus is a possible alien species in Japan, and a clarification of its unclear taxonomy is required to reveal its origin. It is not known whether the plants initially described from Japan represent the same species distributed in North America. To clarify the origin of the species, we attempted to sequence old specimens collected about 80 years ago using newly designed primer pairs specific for short sequences, including the variable sites. Chloroplast sequences of ndhF were compared among Japanese and North American S. hattorianus, and the closely related species, S. atrovirens, S. flaccidifolius, and S. georgianus. We succeeded in sequencing all samples, and two haplotypes were detected in S. hattorianus: one was unique to the species and the other, detected from specimens potentially collected from the same population as the types, was shared by both North American S. hattorianus and two closely related species, S. atrovirens and S. flaccidifolius. Our results suggest that Japanese S. hattorianus is an alien species that was introduced from North America at least twice.  相似文献   

16.
A new fungicolous species, Cosmospora inonoticola, is described and illustrated based on a specimen collected from northeast China. It is characterized by the occurrence of fruitbodies of Inonotus sp.; perithecia nonstromatic, subglobose to pyriform, not collapsing when dry; clavate asci containing (3–)6(?8) spores; ascospores ellipsoidal to broadly ellipsoidal, pale brown, finely warted, bicellular, conspicuously constricted at septum; and producing a verticillium-like asexual state. A multi-locus analysis of the combined ITS, rpb1 and tub sequences confirmed its taxonomic position, and revealed the distinction from its morphologically similar species including the type species, C. coccinea, which occurs also on Inonotus. A specimen with sexual state of C. lavitskiae is reported for the first time, and a reference specimen is indicated.  相似文献   

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Four European Hodophilus species with an odour similar to naphthalene, a strong unpleasant odour similar to that of mothballs, are recognized based on sequence and/or morphological data. The traditional concept defines Ho. foetens as the only Hodophilus species with a naphthalene odour in Europe. This name is now assigned to one of the studied species based on morphological examination of the holotype specimen. A recently collected specimen is proposed as the epitype. The other three species with a naphthalene odour are described here as new: Ho. pallidus, Ho. subfoetens and Ho. tenuicystidiatus. They are distinguishable in the field based on a combination of lamellae number and colour of basidiomata. All four species are grouped in the Ho. foetens superclade, one of two superclades, together with the Ho. micaceus superclade, in the genus Hodophilus. All are different species from North American taxa with a naphthalene-like odour recognised in a previous study. The Ho. foetens superclade also includes one species identified as Ho. atropunctus that does not have a distinctive odour. The type collection of Ho. albofloccipes, a recently described European species with a naphthalene odour, is placed together with some collections without a distinctive odour in the Ho. micaceus superclade.  相似文献   

20.
The marine benthic fauna in Arctic shallow-water is reported to be a relatively young assemblage by species of either Pacific or Atlantic affinity. Whether current deep-sea Pacific species are included in the affinity or not is unknown. Combining morphological comparisons and genetic analyses, a new deep-sea hydroid to science, Sertularia xuelongi sp. nov. (Cnidaria: Hydrozoa: Sertulariidae), is described from the northern margin of the Bering Sea Basin at depths of 800–1570 m collected in 2010. It is characterized by slender and zigzag-shaped hydrocauli, alternately arranged hydrothecae and the absence of distal-lateral horns in fully matured female gonothecae. Its distribution, currently known only from Bering Sea Basin, suggests that it could not be an Arctic species with Pacific affinity. However, phylogenetic analyses based on the mitochondrial 16S rRNA gene show that it is clustered into a distinctive clade with four closely related species recorded from shallow-water of Northwest France, Iceland, Chukchi Sea and/or Bering Sea. In addition, its sequence similarity is highly relevant to these four species: Sertularia argentea (98.6 %), S. cupressina (98.8 %), S. plumosa (98.8 %) and S. robusta (99.4 %). All these provide a new insight into the relevance of North Pacific deep-sea species to the benthic fauna in Arctic and adjacent shallow-water. The taxonomic restriction of the genus Sertularia and the re-validation of the genus Polyserias are discussed. Future researches on more deep-sea species from Pacific and/or Atlantic are required to understand the evolution and speciation pattern involved in polar relevance.  相似文献   

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