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1.
《Geobios》2014,47(1-2):19-29
The genus Homotherium, while wide ranging in Eurasia, has only been considered a sporadic component of the British Pleistocene fauna. The Early Pleistocene Homotherium crenatidens and the Middle to Late Pleistocene Homotherium latidens have however held a prominent position in the annals of the 19th century British geology and the discussion of the antiquity of man. As many of the UK sites containing Homotherium were first investigated over a hundred years ago, the literature is quite confused on the question of what was found and where it was finally curated. An attempt has been made to track down all specimens of British Homotherium mentioned in the literature and to give their current location. As part of this study, I correctly identify for the first time all the Homotherium canines from Kent's Cavern pictured in the famous Plate F of MacEnery. Additionally, a single Homotherium incisor, found by MacEnery, is deduced from the study of his surviving writings and images.  相似文献   

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The food of foxes in suburban London was examined using stomach contents and den litter analysis. A great diversity of food was taken. Adult foxes killed nearer to the city centre were found to eat significantly fewer earthworms, domestic pets and wild mammals, but more scavenged food items, than foxes killed closer to the suburban fringe. Cubs killed closer to the city centre ate significantly fewer earthworms and insects, and more pet birds, pet mammals and scavenged food items than cubs killed nearer the periphery of the suburban area. Although seasonal trends in food selection were apparent, they were not as pronounced as those observed in studies of rural foxes. At no time of the year did a single food item predominate in the diet of adult foxes. Passeriformes were the most important single food item in the diet of young cubs, but there was no correlation between the number of Passeriformes eaten and their abundance, nor between annual changes in the abundance of small birds and mean fox birth litter size and productivity. Most foxes examined were in good body condition; there was no seasonal variation in body weight, although fat content did vary seasonally. A complementary survey in Bristol on losses of domestic pets to foxes revealed that 07% of pet cats and 80% of other pets kept outdoors were killed in a year. Damage to garden Crops was negligible.  相似文献   

4.
The systematics of subtribe Dendrobiinae, Dendrobium, and Australian dendrobiums in particular, are reviewed. Molecular approaches have delimited the subtribe, established Asian and Australasian clades and clarified relationships at some levels within them. At most lower taxonomic levels within Dendrobium s.l., resolution has been partial. Morphological and molecular phylogenetics indicate that Dendrocoryne, Rhizobium and some other sections are not monophyletic, with morphological analyses providing the greatest resolution into groups corresponding with biogeography. For most sections, sampling is too incomplete to determine relationships and monophyly. Distribution, pollination syndromes, breeding systems, fertility and specialized anatomical features contribute little to classification. Natural hybrids are more common than previously stated and may have played a role in the high level of homoplasy and evolution of Australian epiphytes. There is little support for splitting Dendrobium into many genera and species based on terminal clades. The evidence is interpreted as favouring recombination of Cadetia, Flickingeria and Diplocaulobium within the conserved broad genus Dendrobium. Nomenclatural stability is retained in continuing to use the long‐held subgeneric sectional classification, including many of the sections of Schlechter, and infraspecific ranks of subspecies and varieties. In Dendrocoryne, Thelychiton, Tropilis and Tetrabaculum are rejected, as is Dockrillia in Rhizobium. Proposals to elevate infraspecific taxa to species level for variable species complexes are not supported by current morphological or molecular data based on slowly evolving DNA regions. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166 , 105–126.  相似文献   

5.
BACKGROUND AND AIMS: Based on molecular phylogenetic analysis, it has been suggested recently that the Cyperaceae comprises only two subfamilies: the Mapanioideae and the Cyperoideae. In most flowers of the Cyperoideae, the whorl of inner stamens is reduced, resulting in tetracyclic flowers. In the more primitive (scirpoid) genera within the Cyperoideae, the perianth consists of two polysymmetric whorls, whereas the perianth parts in the more derived genera have been subject to modifications and/or reduction. Comparative studies of the many silky hairs of Eriophorum and of the eight bristles of Dulichium have given rise to much discussion about their homology. METHODS: The spikelet and floral ontogeny in freshly collected inflorescences was investigated using scanning electron microscopy. KEY RESULTS: Complete floral ontogenies are presented for Scirpus sylvaticus L., Eriophorum latifolium Hoppe and Dulichium arundinaceum (L.) Britton, with special reference to the perianth. The results in S. sylvaticus confirm the trimerous monocot-like organization of the flower. It is used as a model for floral development in Cyperoideae. In the early developmental stages, the androecium of E. latifolium is surrounded by a massive perigonial primordium, from which the many hair-like bristles originate. Consequently, the stamens develop among the hair primordia, more or less simultaneously. The hairs are arranged in whorls, which develop centripetally. The development of the perianth in D. arundinaceum starts with the formation of three initial perianth primordia opposite the stamens. Subsequently, two more abaxial bristle primordia, alternating with the stamens, originate simultaneously with the appearance of three adaxial bristle primordia in the zone where an adaxial inner perianth primordium is expected. CONCLUSIONS: The floral development in E. latifolium and D. arundinaceum can be considered as variations upon the scirpoid floral ontogenetic theme.  相似文献   

6.
The Nuclear Body Appearance Rate in seventeen human prostatic cases was statistically analyzed according to three lesion areas--the hyperplastic nodule, non-nodule and atrophic--in the secretory epithelium and basal cells. It was meaningfully high in the secretory epithelium of the hyperplastic nodule, but not in the other two lesion areas. There was no meaningful result in basal cells. Though there is a wide variety of reported data on the human prostate, particular care must be taken in analysis at the electron microscopic level, keeping in mind that even in a single specimen this organ has a notable variety of tissue changes. The Nuclear Body Appearance Rate reflects cellular hyperactivity although it does not have a specific known function at present.  相似文献   

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Haustoria of Triphysaria pusilla and T. versicolor subsp. faucibarbata from a natural habitat were analyzed by light and electron microscopy. Secretory trichomes (root hairs) participate in securing the haustorium to the surface of the host root. The keel-shaped intrusive part of the secondary haustorium penetrates to the depth of the vascular tissue of the host. Some of the epidermal interface cells differentiate into xylem elements. A significant number of haustoria do not differentiate further, but in most haustoria one to five of the epidermal xylem elements terminate a similar number of xylem strands. The strands mostly consist of vessel members and they connect host xylem or occasionally host parenchyma to the plate xylem adjacent to the stele of the parasite root. Each strand of this xylem bridge is accompanied by highly protoplasmic parenchyma cells with supposed transfer cell function. Increased surface area of the plasmalemma occurs in these cells as it does in interface parenchyma cells. Graniferous tracheary elements are restricted to the haustorium and occur most frequently in the plate xylem. The plate xylem is also accompanied by highly protoplasmic parenchyma cells. Hyphae of mycorrhizal fungi of the host root occasionally penetrate into the distal part of the xylem bridge. We combine structural observations and physiological facts into a hypothesis for translocation of water and nutrients between host and parasite. Some evolutionary aspects related to endogeny/exogeny of haustoria are discussed, and it is argued that the Triphysaria haustorium represents a greatly advanced and/or reduced condition within Scrophulariaceae.  相似文献   

9.
The histochemistry of glycoconjugates in the nasolabial skin of the Japanese serow ( Capricornis crispus ) was studied by light microscopic histochemical methods, particularly lectin histochemistry. The eccrine glands present exhibited neutral and acidic glycoconjugates with different saccharide residues (alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine, alpha-D-galactose and N-acetyl-neuraminic acid) especially in the cells of the secretory acini, the free surface of the collecting duct cells also showed distinct positive reactions with most of the histochemical methods. The thick epidermis of the nasolabial skin contained smaller amounts of glycoproteins. The results obtained are discussed with regard to possible functions of the glandular secretions. This substance mixture may particularly improve water retention on the skin surface, and protect against physical damage as well as microbial contamination. There seem to be no basic differences of muzzle functions between wild and domesticated bovine species.  相似文献   

10.
Abstract The pollen morphology of 11 species of the genus Glycyrrhiza L. with one from each of the genera Glycyrrhizopsis Boiss. & Bal. and Meristotropis Fisch. & C. A. Mey. was investigated by scanning electron microscopy. In pollen morphology, the main differences between Glycyrrhizopsis and Glycyrrhiza are: Glycyrrhizopsis—pollen grains 36.63 × 40.42 μm in size, oblate spheroidal in shape; and Glycyrrhiza—pollen grains 24.47–33.18 × 23.82–31.83 μm in size, prolate spheroidal in shape. Glycyrrhizopsis and Glycyrrhiza should be recognized as two distinct genera based on palynological and morphological characters. Meristotropis and Glycyrrhiza are similar in many important palynological and morphological characters, suggesting that the two should be merged. In Glycyrrhiza, two types of pollen grains, 3‐lobed‐circular or subtriangular in polar view, are found in different species, in accordance with morphological differences in the two groups, shedding light on the classification and evolution of the genus.  相似文献   

11.
  • Li X-Y.1992.Studies on germplasm of Glycyrrhiza by using different taxonomic methods.Advances in Plant Taxonomy in Northwest China 1:7-24.
  • Li X-Y.1993.A study of the system and new taxa of genus Glycyrrhiza L.Bulletin of Botanical Research 13(1):14-43.
  • Turrill WB.1937.Glycyrrhizopsis syriaca Turrill.Bulletin of Miscellaneous Information 2:79.
  • >>更多...  相似文献   


    12.
    The role of social behavior on the population regulation of the Japanese wood mouse, Apodemus speciosus, was studied in the Ashu Experimental Forest of Kyoto University by monthly trapping and direct observation on the social behavior at the artificial feeding site. The census was carried out from May to October in 1974 and 1975, and the direct observation in June, August and October, 1975. In the study area, the Japanese wood mouse has two breeding seasons in a year: in spring and in autumn. Minimum survival rate was high in the non-breeding season and low in the breeding season. It was negatively correlated to the number of sexually active adults in both sexes. Home ranges of females tended to be mutually exclusive, and female residents prevented the settlement of female immigrants. On the other hand, home ranges of males overlapped largely and males had a straight social hierarchy. Subordinate males tended to disappear more often than dominant males did, but male residents did not hinder the settlement of male immigrants. Males may regulate their number by driving out the subordinate males, while females by spacing behavior.  相似文献   

    13.
    The floral development of Phyllanthus chekiangensis has been studied by scanning electron microscopy. The perianth organs are initiated in two whorls, dimerous in male flowers and trimerous in female flowers, with a longer plastochron between whorls than between the organs within a whorl. Male flowers have two stamens. The prominent connective protrusions begin development simultaneously with the floral disk. The disk is two-lobed in male flowers but continuous in female flowers. In female flowers, the developing gynoecium remains open relatively long, so the developing ovules are visible from the outside for some time. The direction of the hemitropous ovules in the carpels is antitropous (epitropous). Two small obturators are formed per carpel, one above each ovule. The prominent nucellar beak extends far beyond the “micropyle”. A micropyle in the classical sense formed by integuments closing over the nucellus apex is not present at any stage of development. Thus, it is not correct to say that the nucellar beak “grows through the micropyle”. The exposed nucellar beak continues the curvature of the antitropous (epitropous) ovule and becomes contiguous with the obturator. The unusual length of the nucellar beak may be a potential synapomorphy of the enlarged Phyllanthus clade as inferred from molecular phylogenetics.  相似文献   

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    The arctic, marine, planktonic diatom Navicula pelagica Cleve (Bacillariophyceae) forms colonies slightly similar to those of Chaetoceros. The structures resembling setae are dislocated bands of the epithecae, attached by their ligula area to the central mucilage pad that keeps the cells together in colonies.  相似文献   

    15.
    Summary Early spermatids of the crabUca tangeri consists of the nucleus of granular chromatin and the cytoplasm, which contains a proacrosomal vesicle in close association with membrane lamellae. In the mid spermatids an invagination of the acrosomal vesicle membrane gives rise to the formation of the perforatorium, a spindle-shaped tubule which encloses tubular membranous structures. The pair of centrioles located at the base of the acrosome is not directly involved in perforatorial differentiation. The acrosomal vesicle shows a heterogeneous content composed of the operculum, the thickened ring, and three layers of different materials concentrically arranged around the perforatorium. During the late spermatid stage the nuclear profile differentiates numerous slender arms and the chromatin arranges into fibers. Membranous tubules from the cytoplasm become incorporated into the tubular structures of the perforatorium. The mature spermatozoon has the typical structure of the branchyuran sperm, with a complex acrosome, cupped by the nucleus, and a thin cytoplasmic band intervening between the former main elements. The centrioles are degenerate. The nuclear arms are unusually numerous (more than 20) and lack microtubules or microtubular derivatives.  相似文献   

    16.
    Summary Observations on the nesting activities ofMicrothurge corumbae, carried out at the University Campus of Ribeirão Preto, São Paulo, Brazil, from 1977 to 1981, indicated that 61.9 % of nests were re-used by succeeding generations. Re-use by one generation was more frequent than by two generations, and re-use by a third was observed only once. Nests were re-used by one or several females. Single females were more frequently in the first re-use. In these cases nest re-use did not differ essentially from the solitary foundation of a new nest, except for the adoption of a pre-existing nest without excavation. In multifemale nests, analysis of relative age (wing wear), ovarian and spermathecal conditions of associated females and the content of nests at excavation indicated that the social pattern in such colonies is communal. There is some evidence that the associated females are relatives. The chalcidoid waspLeucospis was the principal nest parasite, and ants of the genusCrematogaster were nest predators. In multifemale nests, the rate of parasitism was significantly lower than in solitary nests, indicating that nest-sharing resulted in improved nest defense. On the other hand, the absence of predation on immatures of the first generation of M.commbae in multifemale nests suggests that such nests are also more resistant to attack by predators.  相似文献   

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    Using scanning electron microscopy, we studied the floral ontogeny of Sinojackia xylocarpa. There are 6–7 (–8) sepals. Sepal initiation is staggered; adaxial sepals arise later than abaxial and lateral ones. There are (5–) 6–7 (–8) petals, initiated simultaneously. Petals alternate with the sepals, and occasionally there are two petals instead of one between two sepals. The (10–) 12–14 (–16) stamens are initiated centripetally in two sets (whorls). These floral organ numbers deviate from those of the otherwise mostly pentamerous family Styracaceae. The ovary consists of three (rarely four) locules. In each of the locules, two rows of ovules are differentiated basipetally. Placentation is axile with (5–) 6 (–7) ovules in each locule. Ovules are unitegmic and are ascending with the micropyle directed downwards. Intra‐ovarian trichomes are present as in other representatives of Styracaceae and seem to be an apomorphic character of the family as they are absent in the closely related Symplocaceae and Diapensiaceae. Various levels of organ union occur in anthetic S. xylocarpa. The calyx is synsepalous and the ovary syncarpous. Possibly, the basal connation of petals and stamens is postgenital (and not congenital), but this needs further study. The outward curvature of the young anthers of the inner stamen whorl superficially simulates an obdiplostemonous androecium. However, the sequence of stamen initiation shows a diplostemonous pattern.  相似文献   

    19.
    In order to elucidate the species composition of free‐floating Ulva that cause green tide in several bays in Japan, and to clarify the generic status of Ulva and Enteromorpha (Ulvales, Ulvophyceae), the nuclear encoded internal transcribed spacer (ITS) region including the 5.8S gene and the plastid encoded large subunit of ribulose‐1, 5‐bisphosphate carboxylase/ oxgenase (rbcL) gene sequences for 15 species were determined. Both ITS and rbcL analyses indicate that free‐floating Ulva samples are divided into four different lineages that correspond to Ulva lactuca Linnaeus, U. pertusa Kjellman, U. armoricana Dion etal. and U. fasciata Delile. These four species are distinguished by cell morphology including the arrangement of cells, the shape and size of cells and the position of chloroplasts. Molecular data also indicated that Ulva and Enteromorpha are not separated as respective monophyletic groups within a large monophyletic clade and congeneric as shown by previous molecular studies using the ITS sequences alone. This strongly suggests that these genera are congeneric and Enteromorpha should be reduced to the synonym of Ulva.  相似文献   

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