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1.
The distribution of Spatulodinium (= Gymnodinium) pseudonoctiluca (Pouchet) J. Cachon & M. Cachon has been investigated for eight years (1998-2005) in the northeastern English Channel, type locality of the species and its immature stages. The species can be found after the spring diatom bloom from late May to October. The highest abundance was found in June 2004 after the Phaeocystis bloom. Exceptionally, the Phaeocystis bloom was absent in 2005 and only several specimens of S. pseudonoctiluca were observed. The immature and mature stages of Spatulodinium nearly always co-occurred. No other kofoidiniaceans such as Kofoidinium or Pomatodinium were observed. The first stages of the development of Spatulodinium can easily confuse with gymnodiniaceans. The transformation of the stage 'D', which has been described as Gymnodinium lebouriae (= G. fulgens) or Gymnodinium conicum (= G. viridis), into the mature stage, is illustrated. The stage 'D' originates from a cluster of pairs of smaller cells joined by an elongate episome. In the boreal Atlantic Ocean, Spatulodinium pseudonoctiluca, a single species whose life stages are often reported as separate species, is especially adapted to a strongly fluctuant environment.  相似文献   

2.
Larsen K 《ZooKeys》2011,(87):19-41
Three new species of are described from the manganese nodule province between the Clarion and the Clipperton Fracture Zone of the equatorial North Pacific Ocean, and collected during the Nodinaut expedition on board the r/v l′Atalante in the summer of 2004. The new species belongs to three genera as: Collettea (Collettea longisetosa), Robustochelia (Robustochelia pacifica), and Tumidochelia (Tumidochelia tuberculata). A key to the genus Tumidochelia is presented and the validity of the genera Robustochelia and Collettea is discussed.  相似文献   

3.
4.
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   

5.
The distribution and morphology of the dinoflagellate Erythropsidinium (=Erythropsis) was studied in the vicinity of the Kuroshio and Oyashio Currents, the Philippine, Celebes, Sulu and South China Seas, western and central equatorial and southeast Pacific Ocean. Ninety-four specimens were observed, most of them collected from depths of less than 90m. The highest abundance (15cellsL(-1)) was recorded in the north Philippine Sea in May (32 degrees N, 138 degrees E, 30-m depth). Twenty-four specimens were found in a station in the offshore Perú-Chile Current (31 degrees 52'S, 91 degrees 24'W). The transition regions between open warm waters and productive currents or upwellings seem to favour the abundance of Erythropsidinium. Specimens with duplicate pistons, with two protuberant ocelloids, and specimens with a piston that attains up to 20 times the body length are illustrated for the first time. All the specimens have been ascribed to the type species, Erythropsidinium agile, until stable taxonomical criteria are established for the species diagnosis. Despite the complexity of its organelles, the ocelloid and piston, the competitiveness of Erythropsidinium in the pelagic ecosystem seems to be low.  相似文献   

6.
Extant bats of the genus Emballonura have a trans-Indian Ocean distribution, with two endemic species restricted to Madagascar, and eight species occurring in mainland southeast Asia and islands in the western Pacific Ocean. Ancestral Emballonura may have been more widespread on continental areas, but no fossil identified to this genus is known from the Old World. Emballonura belongs to the subfamily Emballonurinae, which occurs in the New and Old World. Relationships of all Old World genera of this subfamily, including Emballonura and members of the genera Coleura from Africa and western Indian Ocean islands and Mosia nigrescens from the western Pacific region, are previously unresolved. Using 1833 bp of nuclear and mitochondrial genes, we reconstructed the phylogenetic history of Old World emballonurine bats. We estimated that these lineages diverged around 30 million years ago into two monophyletic sister groups, one represented by the two taxa of Malagasy Emballonura, Coleura and possibly Mosia, and the other by a radiation of Indo-Pacific Emballonura, hence, rendering the genus Emballonura paraphyletic. The fossil record combined with these phylogenetic relationships suggest at least one long-distance dispersal event across the Indian Ocean, presumably of African origin, giving rise to all Indo-Pacific Emballonura species (and possibly Mosia). Cladogenesis of the extant Malagasy taxa took place during the Quaternary giving rise to two vicariant species, E. atrata in the humid east and E. tiavato in the dry west.  相似文献   

7.
Two new oceanic free-living heterotrophic Heterokonta species with picoplanktonic size (< 2 microm) are described. Symbiomonas scintillans Guillou et Chrétiennot-Dinet gen. et sp. nov. was isolated from samples collected both in the equatorial Pacific Ocean and the Mediterranean Sea. This new species possesses ultrastructural features of the bicosoecids, such as the absence of a helix in the flagellar transitional region (found in Cafeteria roenbergensis and in a few bicosoecids), and a flagellar root system very similar to that of C. roenbergensis, Acronema sippewissettensis, and Bicosoeca maris. This new species is characterized by a single flagellum with mastigonemes, the presence of endosymbiotic bacteria located close to the nucleus, the absence of a lorica and a R3 root composed of a 6+3+x microtubular structure. Phylogenetical analyses of nuclear-encoded SSU rDNA gene sequences indicate that this species is close to the bicosoecids C. roenbergensis and Siluania monomastiga. Picophagus flagellatus Guillou et Chrétiennot-Dinet gen. et sp. nov. was collected in the equatorial Pacific Ocean. Cells are naked and possess two flagella. This species is characterized by the lack of a transitional helix and lateral filaments on the flagellar tubular hairs, the absence of siliceous scales, two unequal flagella, R1 + R3 roots, and the absence of a rhizoplast. SSU rDNA analyses place this strain at the base of the Chrysophyceae/Synurophyceae lineages.  相似文献   

8.
A new genus, Pseudolessonia, is proposed for the kelp Lessonia laminarioides Postels et Ruprecht (Laminariales, Phaeophyceae), which occurs on the northwest side of the Sea of Okhotsk, in the northwest Pacific Ocean. Pseudolessonia is monotypic and differs from Lessonia in its short primary stipes and its corrugated, unilaterally arranged blades with entire margins. This species is transferred on the basis of morphology and plastid gene sequence comparisons. We determined psaA and rbcL gene sequences from 17 taxa of Pseudolessonia, Lessonia, and putative relatives. Analyses of individual and combined data sets resulted in congruent trees showing a clear separation of Pseudolessonia laminarioides from Lessonia, but suggesting its sister relationships with the clade of Nereocystis, Macrocystis, Pelagophycus, and Postelsia in the North Pacific Ocean. On the other hand, Lessonia species from the South Pacific Ocean formed a strongly supported clade. The results indicate that the basal splitting of the blade, which has been considered a diagnostic character for the family Lessoniaceae, is a result of convergent evolution.  相似文献   

9.
Park  Taisoo 《Hydrobiologia》1994,(1):317-332
The geographic distribution of the bathypelagic calanoid genus Paraeuchaeta was investigated by examining midwater trawl and plankton net samples collected mostly from depths exceeding 1000 m throughout the world's oceans. Of the 81 species referred to Paraeuchaeta, the geographic ranges of about 50 species could be defined with reasonable certainty. Contrary to early authors, the number of species having a worldwide distribution was surprisingly small (12 species or 15% of the 81 species of the genus) as compared to common species endemic to various geographic regions (34 species or 42% of the total of 81). Almost twice as many species were found in the Indo-Pacific Ocean as in either the Atlantic or the Southern Ocean. Faunistically, the northern Atlantic, mid-Atlantic, northern Pacific, East Pacific, Indo-West Pacific, and Southern Ocean were distinct in terms of endemic species. A number of species were found to be endemic to highly productive areas, where they were usually very abundant. Rare species, on the other hand, were generally found to be widely distributed, although some were too rare for their range to be determined with certainty. To explain these findings, the following hypothesis is proposed: Bathypelagic calanoids endemic to and abundant in eutrophic areas are those adapted to eutrophic conditions of their habitats and therefore cannot expand their ranges into contiguous oligotrophic waters even if the other environmental conditions are favorable. Other species, on the other hand, generally have extensive geographic ranges because of their survival ability in widely expanding oligotrophic conditions and the absence of physicochemical barriers at bathypelagic depths of the world's oceans.  相似文献   

10.
A new species of the macrourine genus Nezumia is described from specimens collected from the crest of Fieberling Guyot in the eastern North Pacific Ocean. The new species is distinguishable from all other Nezumia species chiefly on the basis of a high number of pelvic fin rays, a relatively high number of first dorsal fin soft rays, a steep blunt snout lacking scales ventrally, a relatively weak suborbital ridge, and a moderately long, thin barbel. Although possibly endemic to the Baja California Seamount Province, the new species appears to lack close relatives among the other Nezumia species of the eastern North Pacific Ocean. It might have arrived there either from a disjunct Tethyan distribution, thus retaining close relatives among the Atlantic Ocean species of Nezumia, or by way of stepping-stone dispersal from the Indo-west Pacific Ocean.  相似文献   

11.
Insects have invaded marine habitats only rarely and secondarily. Recently, we discovered a flightless dipteran species skating rapidly on the surface of seawater ponds at the Pacific coast of eastern China. Morphological analyses initially suggested an isolated position of the non‐biting midge, suggesting the erection of a new genus within Chironomini (Diptera: Chironomidae). However, an analysis of molecular data revealed that the marine species is in fact nested within the species‐rich genus Dicrotendipes. The apparent conflict between molecular and morphological data can be easily explained. It is likely that the new species has evolved a series of autapomorphic adaptations. These traits clearly distinguish the taxon from other species of the genus but do not justify the erection of a new supraspecific taxon, which would render Dicrotendipes paraphyletic. The switch to marine environments was likely a trigger for various morphological modifications resulting from increased selective pressure. Molecular data suggest that the potential speciation event occurred around 19–29 Ma, linked with a migration from freshwater to seawater ponds along the Pacific Ocean. Considering the results of our analysis, we place the flightless marine skater in the genus Dicrotendipes. All life stages of Dicrotendipes sinicus Qi & Lin sp. n. are described and illustrated, associated with larvae obtained by rearing or confirmed through association with DNA barcodes. The biology and ecology of the species are outlined based on collection data and in situ observations. Evolutionary patterns linked with repeated invasions of marine habitats are discussed.  相似文献   

12.
A new algal class, the Bolidophyceae (Heterokonta), is described from one genus, Bolidomonas, gen. nov., and two species, Bolidomonas pacifica, sp. nov and Bolidomonas mediterranea, sp. nov., isolated from the equatorial Pacific Ocean and the Mediterranean Sea, respectively. Both species are approximately 1.2 μm in diameter and have two unequal flagella; the longer flagellum bears tubular hairs, whereas the shorter is smooth. The flagellar basal apparatus is restricted to two basal bodies, and there is no transitional helix. Cells are naked, devoid of walls or siliceous structures. The internal cellular organization is simple with a single plastid containing a ring genophore and a girdle lamella, one mitochondrion with tubular cristae, and one Golgi apparatus close to the basal bodies. The Mediterranean and the Pacific species differ in the insertion angle between their flagella and their pattern of swimming, these differences possibly being linked to each other. Analyses of the SSU rDNA gene place the two strains as a sister group to the diatoms. Moreover, pigment analyses confirm this position, as fucoxanthin is found as the major carotenoid in both lineages. These data strongly suggest that the ancestral heterokont that gave rise to the diatom lineage was probably a biflagellated unicell.  相似文献   

13.
In the fourth part of the revision of the genus Melamphaes (Melamphaidae) multi-raker species (20 and more rakers at the first gill arch, rarely 19??in M. ebelingi) with eight soft rays in the ventral fin are considered. In this species, temporal spine is absent, there are 15 rays in the pectoral fin, and there are 11 to 12 abdominal vertebrae. M. ebelingi inhabits tropical and subtropical waters of the Atlantic Ocean. A new catch of this rare species in the northeastern part of the ocean is reported. The new species M. occlusus is described from one specimen from the subtropical part of the southwestern part of the Indian Ocean. Still another new species, M. nikolayi, is described from one specimen from the northwestern part of the Pacific Ocean (subtropical waters). A table for identification of 15 multi-raker species of the genus Melamphaes is provided.  相似文献   

14.
A new species of the genus Argyripnus is described from the underwater elevations of the Northwestern Pacific. The species is most similar to A. hulleyi from the western Indian Ocean, but it differs in a larger number of rays of the dorsal and pectoral fins, a slightly larger number of photophores in the ventral row, and several other characters. The type series of the species is the most northern record of the representatives of the genus in the Pacific Ocean.  相似文献   

15.
Previous records of dinoflagellate Scaphodinium mirabile Margalef (Leptodiscaceae, Noctilucales) were restricted to the Mediterranean‐Black Sea and Eastern Atlantic Ocean. Nine and 34 specimens were observed in the upper 100 m layer in May and July, respectively, in a cross‐section in the vicinity of the Kuroshio Current (NW Pacific Ocean). Nearly all the Lugol‐fixed specimens appeared folded over themselves, an appearance that differs from the view reported in the scarce literature available.  相似文献   

16.
17.
The bathyal genus Bassogigas (Teleostei: Ophidiidae) is revised based on 25 specimens, 18 from the west Atlantic Ocean and seven from the Indo-west Pacific Ocean. One specimen, from off Guam, west Pacific Ocean, represents a new species, Walker's cusk eel Bassogigas walkeri. The other 24 specimens all belong to the type species, Gills cusk eel Bassogigas gillii. A comparison between the Atlantic and the Indo-west Pacific Ocean specimens of B. gillii showed no differences in meristic and morphometric characters, but in two of the Indo-west Pacific Ocean specimens the sagittal otolith varied somewhat from the remaining specimens. The two Bassogigas species differ in the length of the lateral line, the number of scales in the midline of the body, the form of the median basibranchial tooth patches and in the thickness of the otolith.  相似文献   

18.
Twenty-five species of chromodorid nudibranchs from the Indo-West Pacific are described including nine which are new to science. There are six new species of Chromodoris , two of Nounea and a new species which forms the type of a new monotypic genus. Of the other species discussed in this paper, ten are species of Chromodoris , five Risbecia and one Digidentis. Species with the following colour patterns are discussed: white with orange or yellow spots; white with yellow (or orange) and purple spots; white with purple spots or patches and mantle border; white with a sinuous submarginal brown band. A full review of the relevant literature is included as is a discussion on Indian Ocean and West Pacific species pairs.  相似文献   

19.
Parapharyngodon kenyaensis n. sp. and Thelandros samburuensis n. sp. (Nematoda: Pharyngodonidae) from the large intestine of the agamid lizard (Agama caudospina) are described and illustrated. Parapharyngodon kenyaensis n. sp. is the 41st species assigned to the genus, and it differs from other species in that genus by possessing 3 pairs of caudal papillae, cloacal lip adornment, and spicules of 112-120 microm in length. Thelandros samburuensis n. sp. is the 31st species assigned to the genus, and it differs from other species in that genus by possessing swollen posterior annulations, 6 caudal papillae, a smooth anterior cloacal lip, and spicules of 43-52 microm in length. In addition to the 2 new nematode species, Abbreviata ortleppi (Nematoda: Physalopteridae) and Strongyluris ornata (Nematoda: Heterakidae) were found.  相似文献   

20.
研究旨在利用传统形态学与DNA条形码技术相结合的方法, 进一步探讨中国布氏鲾属Eubleekeria Fowler 1904鱼类的分类与鉴定问题。2014—2016年从广东湛江和广西北海、防城港和东兴近海采集了153尾鲾科鱼类样品, 经形态学鉴定为布氏鲾属种类: 琼斯氏布氏鲾Eubleekeria jonesi (James, 1971)。该种主要鉴别特征为: 眼位于口裂的水平线之上, 颊部无鳞, 两臀鳍之间区域裸露无鳞, 颈部有半圆形裸露无鳞区域, 背鳍上黑斑色淡, 略呈灰色。将其鉴别特征与相关文献记录比较, 表明之前中国大陆记录的黑边布氏鲾Eubleekeria splendens (Cuvier, 1829)可能为琼斯氏布氏鲾。基于线粒体COⅠ基因片段结合GenBank中布氏鲾属鱼类的同源序列, 采用邻接法构建的分子系统树显示, 此研究中采集自中国大陆的布氏鲾属鱼类标本与中国台湾记录的黑边布氏鲾Eubleekeria splendens (Cuvier, 1829)明显地分为两支。基于Kimura双参数模型(K2P)计算, 支系间遗传距离为0.130, 远大于支系内平均遗传距离(0.005和0.006), 支持将二者作为独立物种的观点, 与此研究传统形态学方法的结果一致。  相似文献   

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