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.
Three ciliate species from Australia and Norway were examined by silver impregnation, biometry, and scanning electron microscopy. Trochiliopsis australis n. sp. (order Nassulida, family Microthoracidae) differs from the single other known species of the genus, T. opaca, by its prominent ridges on the left side, the distinctly longer anterior segment of somatic kinety 2, and by the doubled total number of kinetosomes. Pelagohalteria n. g. (order Oligotrichida, family Halteriidae) differs from Halteria by the structure of the bristle complexes, which are composed of a vertically and a horizontally oriented row of kinetosomes. Two Halteria species belong to the new genus: P. viridis (Fromentel, 1876) n. comb., which is redescribed here, and P. cirrifera (Kahl, 1935) n. comb. Strobilidium lacustris n. sp. (order Oligotrichida, family Strobilidiidae) differs from its nearest relative, S. velox, by the smooth pellicle, the absence of symbiotic green algae, and by its larger size.  相似文献   

2.
Silicified achenes and some perigynia of four new sedges are described from the late middle or late Miocene Ash Hollow (Clarendonian or Hemphillian) and early middle Miocene Sheep Creek (Late Hemingfordian) Formations of Nebraska. Carex graceii, sp. n., Cyperocarpus terrestris, sp. n., and Cyperocarpus pulcherrima, sp. n., were collected from strata in Garden and Antelope Counties and Cyperocarpus eliasii, sp. n., was collected from strata in Sioux County. Certain of the newly discovered taxa exhibit considerable anatomical detail of the pericarp wall of the achene. In two taxa, Carex graceii and Cyperocarpus pulcherrima, the achene pericarp exhibits four topographic regions: a cuticle, an outer layer of pentagonally to hexagonally shaped epidermal cells containing silica bodies, a middle layer of sclerenchyma cells, and an inner layer of sclerenchyma cells whose long axes are perpendicular to the long axes of the cells of the middle layer. Similar pericarp anatomy was found in Cyperocarpus terrestris except that the inner layer was not observed. In the fourth taxon, Cyperocarpus eliasii, only an outer epidermal layer of elongate cells with small protuberances is preserved. The ultrastructure of the pericarp of the fossil taxa is similar to that of living forms. Associated flora and fauna indicate widespread savanna environments with significant riparian elements. This is the first systematic treatment of sedges from the Miocene of North America.  相似文献   

3.
4.
ABSTRACT The morphology of the hypotrichous ciliate, Holosticha corlissi n. sp., found in the moss Calliergonella cuspidata taken from the beech wood of Montejo de la Sierra (Madrid, Spain) is described. Some characteristics (organization of the mid-ventral, frontal and fronto-terminal cirri, presence of a buccal cirrus and the number of transverse cirri) are sufficiently different from the closely related species H. intermedia, H. sigmoidea and H. xanthichroma to suggest that it is a separate species, although its body shape, nucleus and buccal apparatus are very similar.  相似文献   

5.
Adult and fourth-stage larvae of Paracuaria hispanica n. sp., from the stomach of the Pyrenean desman Galemys pyrenaicus Geoffroy (Insectivora: Talpidae) in northern and central Spain, are described. The new species differs from the other members of the genus Paracuaria (P. adunca and P. soricis), among other morphological details, in its smaller body and spicule sizes, the presence of a cuticular ring around the tip of the female tail, and the existence of lateral alae running longitudinally along its body from the cervical region to the tail. In view of the latter feature, the genus Paracuaria is redefined. The fourth stage larva of the new species is distinguished from that of P. adunca by its monocuspid deirids. P. hispanica occurred in 45% of the 20 host specimens examined.  相似文献   

6.
In this study a new species of Neralsia is described, N. incompleta n. sp. The radial cell shape allows to distinguish it clearly from the rest of species of the genus. The distribution of Neralsia incompleta n. sp. is probably the entire American continent, having been collected from Canada to Paraguay. In spite of its abundance, the associated biology is unknown, although it should be related with parasitism of Diptera Cyclorrhapha.  相似文献   

7.
Margret H. Bayer 《Planta》1967,72(4):329-337
Summary Auxin and auxin-inhibitors from acidic ether extracts of normal Nicotiana stem tissues of N. glauca and N. langsdorffii and their tumor-producing 4n, 3n, and 2n-hybrids were separated by thin-layer chromatography. The growth substances were eluted and subjected to an Avena curvature test. A considerably higher amount of IAA was found in the tumor-forming 2n-hybrid (GL) than in the other plant material. The 4n-hybrid (GGLL) showed a small but significant increase in extractable IAA in comparison to its parents, whereas the 3n-hybrid (LLG) showed no difference from the langsdorffii parent. Inhibitory substances appeared at different Rf's but generally in low quantities. The inhibitor at Rf 0.5-0.6 (chromatography in n-butanol water-ammonia, 10: 10: 1, upper phase) seems to be identical with the inhibitor of Bennett-Clark and Kefford (1953). The results indicate that the potential for massive tumor production in the 2n- and 4n-hybrids of N. glauca x N. langsdorffii plants is coupled with increased IAA and inhibitor levels, whereas the 3n-hybrid, which forms tumors of much smaller size and in a later stage of development, does not differ considerably in its extractable IAA content from its N. langsdorffii parent.  相似文献   

8.
The microsporidium Nudispora biformis n. g., n. sp., a parasite of a larva of the damsel fly Coenagrion hastulatum in Sweden, is described based on light microscopic and ultrastructural characteristics. Merogonial stages and sporonts are diplokaryotic. Sporogony comprises meiotic and mitotic divisions, and finally eight monokaryotic sporoblasts are released from a lobed plasmodium. Sporophorous vesicles are not formed. The monokaryotic spores are oval, measuring 1.4–1.8 × 2.8–3.4 μm in living condition. The thick spore wall has a layered exospore, with a median double-layer. The polaroplast has two lamellar parts, with the closest packed lamellae anteriorly. The isofilar polar filament is arranged in 6 (to 7) coils in the posterior half of the spore. Laminar and tubular extracellular material of exospore construction is present in the proximity of sporogonial stages. In addition to normal spores teratological spores are produced. The microsporidium is compared to the microsporidia of the Odonata; its possible relations to the genus Pseudothelohania and to the Thelohania-like microsporidia are discussed. The new genus is provisionally included in the family Thelohaniidae.  相似文献   

9.
ABSTRACT. Trachelolophos gigas n. g., n. sp. and T. filum (Dragesco & Dragesco-Kernéis, 1986) n. comb. (basionym: Tracheloraphis filum) were discovered in the mesopsammon of the French Atlantic coast at Roscoff. Their morphology and infraciliature were studied in live and protargol impregnated specimens. The new genus, Trachelolophos, belongs to the family Trachelocercidae and is unique in having a conspicuous ciliary tuft, which is very likely a highly modified brosse, in the oral cavity. The two species investigated have a very similar infraciliature, differing only in morphometric characteristics and in the nuclear configuration. The entire somatic and oral infraciliature consists of dikinetids which have both basal bodies ciliated or only the anterior or posterior ones, depending on the region of the cell. The right side is densely and uniformly ciliated. Its kineties extend onto the left side to the glabrous stripe, where an anterior and posterior secant system are formed, reducing the number of kineties in the narrowed neck and tail region. The left side bears a narrow glabrous stripe bordered by slightly irregularly arranged dikinetids having rather stiff cilia (bristles), possibly forming an uninterrupted, prolate ellipsoidal (bristle) kinety as indicated by their ciliation. The bristle kinety commences subapically at the right margin of the glabrous stripe, extends posteriorly, then anteriorly at the left, to end up at the right margin again. The dikinetids of the right posterior portion of the bristle kinety have the posterior basal bodies ciliated, whereas the anterior basal bodies are ciliated in its left and right anterior portion. The ends of the bristle kinety meet distinctly subapically at the right margin of the glabrous stripe, as indicated by the diametrically opposed ciliation of the dikinetids. The anterior region (head) of the cell bears a distinct circumoral kinety composed of very regularly arranged dikinetids, associated with nematodesmata forming an oral basket together with the nematodesmal bundles originating from the oralized somatic dikinetids at the anterior end of the somatic kineties. The systematics of trachelocercid ciliates are briefly reviewed and discussed.  相似文献   

10.
Trypanosoma fallisi n. sp. is described from Bufo americanus in Ontario. The parasite was observed in 65 of 94 toads examined. The trypanosomes were pleomorphic with respect to the age of infections, being longer and broader in early infections (during spring and summer) and shorter and more slender during late summer and autumn. They ranged in size from 38–76 μm in body length and 3–8 μm in width, with a free flagellum 6–30 μm long. Epizootiological and experimental evidence suggests that this trypanosome is transmitted to the toads by the leech, Batracobdella picta. Trypanosoma fallisi is morphologically similar to T. bufophlebotomi described in Bufo boreas from California, but geographic isolation, host and vector differences as well as slight morphological differences indicate that speciation has occurred. Similar trypanosomes from Bufo americanus (which were identified as T. bufophlebotomi) in Michigan, are probably T. fallisi. This species shares many ultrastructual features with trypanosomes of other lower vertebrates and also of mammals.  相似文献   

11.
The names of all 135 species-group taxa of Cerambycidae described by N. N. Plavilstshikov are listed. Types of all these taxa preserved in the Zoological Museum of the Moscow State University and in the Zoological Institute (St. Petersburg) are catalogued, with lectotypes and paralectotypes designated. New synonymies are proposed: Pseudosieversia rufa (Kraatz, 1879) = Macrorhabdium ruficollis Plavilstshikov, 1915, syn. n.; Pseudo sieversia Pic, 1902 = Macrorhabdium Plavilstshikov, 1915, syn. n.; Agapanthia angelicae Reitter, 1898 = A. jacobsoni Plavilstshikov, 1915, syn. n. Dorcadion arietinum phenax Jakovlev, 1900, stat. n. is a valid name of the taxon known before as D. arietinum strandi Plav. Alosterna tabacicolor subsp. tokatensis Pic, 1901 (= A. t. caucasica Plavilstshikov, 1936, syn. n.) is regarded as a valid name (nomen protectum), and A. chrysomeloides var. subvittata Reitter, 1885 is regarded a nomen oblitum, as well as Cortodera umbripennis var. pallidipes Pic, 1898, while C. ruthena Plavilstshikov, 1936 is nomen protectum. Vadonia bipunctata puchneri Holzschuh, 2007, stat. n. is widely distributed in southern Ukraine and southern Russia from Dnepropetrovsk to Rostov-on-Don, and in the North Caucasus; specimens of this subspecies, as also specimens of V. saucia (Mulsant et Godart, 1855), stat. rest., known from the southern Crimea, constitute a part of the type series of V. bipunctata mulsantiana (Plavilstshikov, 1936).  相似文献   

12.
Eoangiopteris goodii sp. n. is described from Upper Pennsylvanian coal balls from Ohio (Shade locality) containing isolated pecopterid pinnules approx. 7 × 9 mm that bear up to 20 linear synangia on the lower surface. The synangia extend at right angles from the midrib to the downturned pinnule margins and measure 2.0–3.5 mm in length. Individual synangia are compact and are composed of 10–19 sporangia that have their bases embedded in an elongate parenchymatous pad. In longitudinal section sporangia measure 0.4 × 2.0 mm and have acute elongate, curved apices. Spores average 70 μm in diam and are most similar to the dispersed spore genus Verrucosisporites. Eoangiopteris goodii differs from the generitype E. andrewsii Mamay in its greater size, pinnule histology, and spore type. Sporangium wall complexity and spore type of the two presently known species of Eoangiopteris are considered to be at about the same evolutionary level as the more primitive species of Scolecopteris. Construction of the synangia in Eoangiopteris is different from that of Scolecopteris and indicates that at least two evolutionary lines are recognizable within the Pennsylvanian Marattiales.  相似文献   

13.
A bacterium tentatively classified as Arthrobacter strain Py1 being capable to degrade pyrrole-2-carboxylate as only source of carbon, nitrogen, and energy was isolated from soil. In contrast to many other N-heterocyclic compounds, growth of the isolate on pyrrole-2-carboxylate was not affected by molybdate or its specific inhibitor tungstate, indicating a molybdoenzyme-independent breakdown. The latter was initiated by a hydroxylation reaction catalyzed by a pyrrole-2-carboxylate oxygenase, which also exhibited an NADH-cytochrome c reductase activity. The pyrrole-2-carboxylate oxygenase reaction as examined in cell extracts depended on NADH, FAD, and pyrrole-2-carboxylate; the apparent K m values were 44, 6, and 43 M, respectively. A degradation pathway for pyrrole-2-carboxylate is proposed which involves 5-hydroxy-pyrrole-2-carboxylate and 2-oxoglutarate.  相似文献   

14.

Neoalbionella Özdikmen, 2008 comprises 10 accepted species, which all infect sharks of Squaliformes and Carcharhiniformes. Adult females belonging to species of Neoalbionella, based on the maxillule palp armed with three setae and the maxilliped subchela claw with only one secondary denticle, were collected from sharks off the coast of South Africa. Neoalbionella izawai n. sp. collected from the anterodorsal part of the spiracle opening of Centrophorus moluccensis Bleeker differs from its congeners by having maxillae that are separated except at the tapering tips where they are fused and that are longer than the trunk, uropods originating from the pointed posterior margin of the trunk and that are well developed, and maxillipeds without an additional spine at the base of the subchela barb. Neoalbionella etmopteri (Yamaguti, 1939) is herein reported from two new hosts (Etmopterus spp.) off South Africa.

  相似文献   

15.
16.
The morphologies of two novel ciliates, Arcanisutura chongmingensis n. gen., n. sp. and Naxella paralucida n. sp., collected from Shanghai, China, have been investigated using live observation and silver staining methods. Arcanisutura n. gen. can be easily distinguished from related genera by its inconspicuous, oblique anterior suture. Arcanisutura chongmingensis n. sp. is mainly recognized by its elongated body with a tail‐like posterior end, 25–33 somatic kineties, and 4–11 excretory pores. Naxella paralucida n. sp. can be distinguished from its congeners based on its two short nassulid organelles, fusiform trichocysts, 37–49 somatic kineties, and 16 nematodesmal rods. The small‐subunit (SSU) rRNA gene sequences of these two species are presented, revealing the phylogenetic positions of Arcanisutura and Naxella. Phylogenetic analyses show that Arcanisutura forms a sister clade to other synhymeniid genera, namely, Chilodontopsis, Orthodonella, and Zosterodasys; Naxella is most closely related to Nassula spp. and is located within the monophyletic clade of the family Nassulidae.  相似文献   

17.
ABSTRACT. Lagenophrys anticthos n. sp. resembles L. aegleae Mouchet-Bennati; however, the two species are distinguished from one another by differences in the structure of the lorica aperture. Similarities in the shape of the lorica and macronucleus indicate a close phylogenetic relationship between L. anticthos and L. aegleae. The size of L. anticthos varies greatly within a population, and it is unclear whether this can be attributed to genetic differences or to environmental factors. In L. anticthos, variation in the form of the lips of the lorica aperture is correlated with variation in size. The brown, iron-rich incrustations observed around the loricae of L. aegleae by an earlier worker were not seen, indicating that the incrustations do not play a role in the symbiosis between L. aegleae and its host as was previously thought.  相似文献   

18.
Patterns of organelle inheritance were examined among fertile somatic hybrids between allotetraploid Nicotiana tabacum L. (2n=4x=48) and a diploid wild relative N. glutinosa L. (2n=2x=24). Seventy somatic hybrids resistant to methotrexate and kanamycin were recovered following fusion of leaf mesophyll protoplasts of transgenic methotrexate-resistant N. tabacum and kanamycin-resistant N. glutinosa. Evidence for hybridization of nuclear genomes was obtained by analysis of glutamate oxaloacetate transaminase and peroxidase isoenzymes and by restriction fragment length polymorphism (RFLP) analysis using a heterologous nuclear ribosomal DNA probe. Analysis of chloroplast genomes in a population of 41 hybrids revealed a random segregation of chloroplasts since 25 possessed N. glutinosa chloroplasts and 16 possessed N. tabacum chloroplasts. This contrasts with the markedly non-random segregation of plastids in N. tabacum (+)N. rustica and N. tabacum (+) N. debneyi somatic hybrids which we described previously and which were recovered using the same conditions for fusion and selection. The organization of the mitochondrial DNA (mtDNA) in 40 individuals was examined by RFLP analysis with a heterologous cytochrome B gene. Thirty-eight somatic hybrids possessed mitochondrial genomes which were rearranged with respect to the parental genomes, two carried mtDNA similar to N. tabacum, while none had mtDNA identical to N. glutinosa. The somatic hybrids were self-fertile and fertile in backcrosses with the tobacco parent.Contribution No. 1487 Plant Research Centre  相似文献   

19.
Immunoelectrophoretic studies of the seed proteins of material provisionally referred to B. secalinus var. or f. hirsutus have revealed that it is serologically distinct from B. secalinus. The plant has many of the characters of B. secalinus fitting that species to life as a contaminant of cereal fields, but the floret and seed sizes are much smaller, and the sheaths are normally hairy. In Britain the plant appears to contaminate small-seeded pasture grasses which are sown on roadsides. The chromosome number of this plant is 2n = 14, unlike typical B. secalinus which has 2n = 28. The plant seems to be introduced in Britain, but its native distribution is not known. In view of its distinctive morphology and its serological difference from B. secalinus and other bromes, it is proposed to name it as a new species: Bromus pseudosecalinus P. SMITH sp. nov.  相似文献   

20.
Nitzschia sublinearis Hustedt and N. pura Hustedt are common oligosaprobic freshwater diatom species that frequently occur in diatom inventories, thus being important in water quality studies. Both are considered as species with overlapping diagnostic criteria in several floras, which is typical of the whole genus Nitzschia. The type material of Hustedt of N. sublinearis and N. pura was examined using LM and EM in order to document the range of variation within the type populations and to compare it with populations occurring in different European rivers. Detailed observations allowed recognition of two new freshwater diatom species: N. alicae sp. nov., occurring in mesotrophic up to eutrophic conditions, and N. puriformis sp. nov., mostly occurring in oligotrophic habitats, both in rivers and streams at middle and high altitudes. The most reliable taxonomic features that separate both new species from the most similar taxa are the density of fibulae and striae, valve shape, and valve width as well as the shape of areolae. Morphological examination of different populations indicates that N. puriformis is relatively common in European rivers and has been overlooked to date and confounded with N. pura by several researchers. By contrast, N. alicae has, to date, been collected only in Slovakia and Northern Italy, but with a high frequency of occurrence and sometimes in high abundance at sites.  相似文献   

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