首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Two new, recent diatoms, Stephanodiscus suzukii Tuji et Kociolek and Stephanodiscus pseudosuzukii Tuji et Kociolek are described from Lake Biwa, Japan, where they had been identified previously as Stephanodiscus carconensis Grunow var. carconensis and S. carconensis var. pusillus Grunow, respectively. These forms are compared in terms of valve ultrastructure with populations of S. carconensis from North America. The Japanese species differ from the North American specimens in characteristics related to the central fultoportula and rimoportula.  相似文献   

2.
3.
Thalassiosira Cleve is one of the most species-rich marine diatom genera. Previous studies have mainly focused on polar and temperate areas, but recent studies on material from Asian waters suggested that a high and undescribed species diversity of Thalassiosira occurs in Asia. On the basis of plankton samples collected from the South China Sea, a new species, T. sinica sp. nov. Y. Li & Y. Q. Guo is described. The morphology of the cells was examined by light and scanning electron microscopy. The hypervariable region of the nuclear large-subunit ribosomal DNA and the relatively conserved region of the nuclear small-subunit ribosomal DNA were sequenced for information on phylogenetic relationships. The living cells are usually solitary and drum-shaped. The areolae on the valve are delicate, small and arranged in fascicles. In addition to a regular ring of marginal fultoportulae on the valve edge, T. sinica possesses one central fultoportula and a number of fultoportulae arranged into 2–3 irregular rings on the valve face. A rimoportula located inside the ring of marginal fultoportulae possesses a long and strong external tube. The valvocopula and the copulae have rows of pores, but the pores on the valvocopula are larger than those on the copulae. Thalassiosira sinica appears to be included in subgroup C sensu Gedde because of a rimoportula with a distinct external tube located on the valve face. The molecular phylogeny, inferred from both SSU and LSU sequences, does, however, not support the validity of subgroup C, as the closest allies of T. sinica here turned out to be T. diporocyclus and T. lundiana, species in which the rimoportulae are located on the valve margin.  相似文献   

4.
Thecadinium inclinatum Balech and four new marine sand‐dwelling species of the dinoflagellate genus Thecadinium are described from the sandy beaches along the coast of Shikoku, Japan. Thecadinium inclinatum is thecate, bilaterally flattened, elliptical in shape, non‐photosynthetic, and measures 55–75 μ in length and 43–59 μ in depth. The epi‐ and hypotheca theca are semielliptical and the thecal surface is smooth with small pores. The plate formula is Po (pore plate), 3′, 7″,?c,?s, 5″′1″′.Thecadinium ovatum sp. nov. is thecate, non‐photosynthetic, bilaterally flattened and almost oval in lateral view. The cell measures 40–50 μm in length and 33–40 μm in depth. The hypotheca has two or three strong antapical spines. The plate formula is 3′, 6″,6c, 5s?, 5″′, 1″′. Thecadinium striatum sp. nov. is thecate, non‐photosynthetic, bilaterally flattened and somewhat elliptical in lateral view. The cell is 33–41 μm long and 23–30 μm deep. Several striae are present on the hypotheca. The plate formula is 3′, 6″, 6c, 5s?, 5″′, 1″″. Thecadinium yashimaense sp. nov. is bilaterally flattened, photosynthetic and elliptical in ventral view. The cell is 44–65 μm long and 23–36 μm wide. The thecal surface is smooth with small pores. he cingulum forms a steep left–handed spiral. The plate formula is Po, 3′, la, 6″, 5c, 4s, 5″′, 1″′. Thecadinium arenarium sp. nov. is somewhat wedge‐shaped in ventral view, photosynthetic with brownish chloroplasts and almost rounded in cross section. The cingulum forms a steep left‐handed spiral. The cell measures 35–41 μm in length and 25–30 μm in width. The thecal surface is weakly reticulated with small pores. The hypotheca is conical. The plate formula is Po, 3′, la, 6″, 5c, 4s, 5″′, 1″″.  相似文献   

5.
During a survey of the coral reef diatoms of Moorea Island (Society Archipelago, South Pacific) a small‐sized member of the order Achnanthales was studied using a light microscope (LM) and a scanning electron microscope (SEM). This marine taxon has: a raphe valve (RV) with a non‐crenulate edge; a high cingulum; a sternum valve (SV) often irregularly striated and areolae with concave hymenate pore occlusion; a thick and plain SV valvocopula (SVVC), ring‐shaped, composed of large fused fimbriae, with a central elliptic foramen bordered by the peg‐like edge of the fimbriae. On abvalvar side, the SVVC bears radiate concave and robust transapical ribs, interlinking with short elevated transverse ribs of the RV valvocopula (RVVC). Large marginal fenestrae of the RVVC give access to pseudoloculi. One oblong, unique and striated papilla is located on each RVVC rib. Given this unique set of features, we describe Xenococconeis opunohusiensis gen. et sp. nov. as a new taxon belonging to the Achnanthales. The characteristics of the new taxon are compared with Campyloneis Grunow and Cocconeis Ehrenberg. From New Caledonia, Cocconeis neocaledonica Maillard ex Lange‐Bertalot et Steindorf, a freshwater diatom, was described with two internal septa with marginal pseudoloculi. Based on subsequent SEM illustrations and remarks, we propose the transfer of C. neocaledonica to the new genus, and compare it to the type species, Xenococconeis opunohusiensis.  相似文献   

6.
A new fossil diatom, Stephanodiscus kusuensis sp. nov., is described from a diatomite deposit from the Kusu Basin, Oita Prefecture Japan. Radiometric age estimates of the strata in which the taxon occurs are 400–500 kyr. The new species is distinct from all other known species of Stephanodiscus because it possesses a highly pronounced double concentric undulation and two distinct arrangements of central strutted processes. Cladistic analysis is used to identify the phylogenetic position of this taxon with respect to other Stephanodiscus species.  相似文献   

7.
Two novel strains C4III282T and C4III291 were isolated from seawater collected a site off the Taketomi coral reef. Phylogenetic analysis based on the 16S rRNA sequences revealed that the two strains belong to the genus Vibrio. MLSA using eight protein-coding genes (ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA, and topA) showed that C4III282T and C4III291 are closely related to the members of the Ponticus clade, namely Vibrio panuliri JCM 19500T, Vibrio ponticus DSM 16217T, and “Vibrio rhodolitus” G98. ANI and in silico DDH values with members of the Ponticus clade were 77.6-78.7% and 22.2-23.1, respectively. The name Vibrio taketomensis sp. nov. is proposed with C4III282T (CAIM 1928T = DSM 106943T = JCM 33434T) as the type strain.  相似文献   

8.
Pseudokeronopsis rubra (Ehrenberg, 1836), type species of Pseudokeronopsis, is a widely reported but taxonomically confused species with most available sequences either misidentified or dubious. Based on the Yellow Sea population, of which the molecular data have been analyzed in a previous work, we redescribe P. rubra and try to clarify the identifications of the populations designated as P. rubra or those allocated to this species. Nonetheless, there is still a need of integrated investigation of the species combing both morphological and molecular data based on specimens from its type locality. Recent molecular analyses indicate a Yellow Sea population of Pseudokeronopsis (marked as P. cf. songi) likely represents a new species. Here we describe it as P. parasongi sp. nov. based on the specimens from the same population. The new species possesses a yellow-brownish body with both pigmented cortical granules and colorless blood cell-shaped structures underneath the body surface, invariably one contractile vacuole at 66% of body length and occasionally a second one at 25%, and the midventral complex terminating 2–23 μm ahead of 2–4 transverse cirri. It differs from closely related species by its yellow-brownish body color and separates from them in the ITS1-5.8S-ITS2 and COI genetic distances.  相似文献   

9.
Two new diatom species, Haslea salstonica and Haslea pseudostrearia are described in light and electron microscopy and compared with two well-known members of Haslea. Scanning electron microscope observations confirm that the new species belong to the genus Haslea. This study extends previous observations on the genus, particularly with respect to the development of a pseudostauros. The characteristic features of the genus are discussed briefly.  相似文献   

10.
Thalassiocyclus pankensis sp. nov. is described from Panke Swamp (Panke-numa) located in Horonobe Town, Hokkaido, northern Japan. The species is characterized by a strong transversely undulate central area of the valve face with one to three fultoportulae on the elevated part and one fultoportula on the depressed part. The external valve face has costate radial interfascicles and very wide fascicles on the marginal area. Thickened openings of mantle fultoportulae are located at the end of interfascicles with roofed board spines. The cingulum consists of five bands. The new species is compared to the only other species belonging to genus Thalassiocyclus , T. lucens (Hustedt) Håkansson & Mahood. Thalassiocyclus pankensis is the second species in the genus Thalassiocyclus and also the first report of a Thalassiocyclus species in Japan.  相似文献   

11.
A new stalk-forming diatom was observed at high relative abundances on periphytic samples collected in the Rio Negro hydrographic basin (Brazilian Amazon) and is here described using light and scanning electron microscopy. We also present ecological preferences of the new species. Eunotia amazonica sp. nov. co-dominated periphytic samples collected during the rainy seasons of 2013 and 2014 near the city of Manaus (Amazonas, Brazil). The main diagnostic feature of the new species is the stalk-forming growth form (‘Cymbella-like’) illustrated here for the first time in the genus Eunotia Ehrenberg. Previous reports on growth forms in common European databases for this genus included colonial (‘ribbon-like’) but also ‘mobile’, ‘fixed by pads’ or ‘without structures of fixation’. We demonstrated that the three dominant Eunotia species in periphytic samples from the Rio Negro all exhibited distinct ‘growth forms’ or habits: Eunotia amazonica sp. nov. (stalked), Eunotia intricans Metzeltin & Lange-Bertalot (ribbon-like) and Eunotia rabenhorstiana (Grunow) Hustedt (branched-arborescent). The high diversity of species, many of which are unknown to science, as well as the poorly known life-forms and habits of the Eunotiaceae in the region, partially prevent the use of metrics based on life-form to assess ecological changes. Generic assumptions based on robust statistical methods may obscure reality and lead to biased conclusions of diatom community changes in poorly explored regions such as Neotropical freshwater rivers, where the Eunotiaceae are largely dominant, particularly in the Amazon basin.  相似文献   

12.
Two new species, Rhus neoglutinosa M. Gilbert (Anacardiaceae) and Teclea borenensis M. Gilbert (Rutaceae) are described in preparation for the forthcoming Flora of Ethiopia.  相似文献   

13.
Astragalus ansinii A. Uzun, Terzioğlu & S. Palabaş-Uzun, a new species from northeast Anatolia is described and illustrated. It belongs to Astragalus sect. Hypoglottis Bunge, but the characters in combination do not match completely with this section because the legumes, leaves and calyces are glabrous. This local endemic is known from two adjacent localities with several individuals. Astragalus ansinii is morphologically most similar to A. viridissimus but differs mainly by indumentum, numbers of pairs of leaflets and seed shape together with metric data related to calyx, standard and peduncle. Nuclear ITS was analysed in both species and was found to be highly similar. In addition, the seed morphology, distribution, conservation status and ecology of both species are discussed.  相似文献   

14.
Diospyros korupensis Gosline is described as a new species endemic to the Korup National Park in Cameroon and neighbouring areas on the slopes of Mt Cameroon. Diospyros onanae Gosline is described as a new species from the South and Southwest Regions of Cameroon allied to the poorly known D. soyauxii Gürke & K. Schum. ex. Gürke.  相似文献   

15.
16.
17.
Five strains of bifidobacteria were isolated from faeces of a common marmoset (Callithrix jacchus) and a red-handed tamarin (Saguinus midas). The five isolates clustered inside the phylogenetic group of the genus Bifidobacterium but did not show high sequence similarities between the isolates and to known species in the genus by phylogenetic analysis based on 16S rRNA gene sequences. Sequence analyses of dnaJ1 and hsp60 also indicated their independent phylogenetic positions to each other in the Bifidobacterium cluster. DNA G+C contents of the species ranged from 57.3 to 66.3 mol%, which is within the values recorded for Bifidobacterium species. All isolates showed fructose-6-phosphate phosphoketolase activity. Based on the data provided, the five isolates represent five novel species, for which the names Bifidobacterium reuteri sp. nov. (type strain: AFB22-1(T) = JCM 17295(T) = DSM 23975(T)), Bifidobacterium callitrichos sp. nov. (type strain: AFB22-5(T) = JCM 17296(T) = DSM 23973(T)), Bifidobacterium saguini sp. nov. (type strain: AFB23-1(T) = JCM 17297(T) = DSM 23967(T)), Bifidobacterium stellenboschense sp. nov. (type strain: AFB23-3(T) = JCM 17298(T) = DSM 23968(T)) and Bifidobacterium biavatii sp. nov. (type strain: AFB23-4(T) = JCM 17299(T) = DSM 23969(T)) are proposed.  相似文献   

18.
19.
Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and not indicative of a true planktonic mode of life.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号