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1.
In this note the taxonomic position of the tiny eomyid genus Keramidomys (Hartenberger, 1967) from the Early/Middle Miocene boundary locality of Sandelzhausen in the Bavarian Upper Freshwater Molasse is reexamined. As the chronological dating of the Sandelzhausen fossil site has been modified in the past from formerly the Neogene mammal unit MN6 to now MN5 and thanks to new abundant material this rodent is compared with other European forms. It is shown that the Sandelzhausen eomyid must be called K. thaleri Hugueney & Mein, 1968 on the basis of several morphological dental differences from K. carpathicus Schaub & Zapfe, 1953. This rodent seems to be an immigrant from East Asia into Europe. Even if K. thaleri is known in many European localities, all correlated to MN5, it is always a rare element of European rodent faunas. Differentiation from K. carpathicus is not easy and requires a sufficiently large sample.   相似文献   

2.
Three genera of lagomorphs, Prolagus, Lagopsis, and “Amphilagus,” were identified during a revision of the lagomorph material from Sandelzhausen (MN5, Early/Middle Miocene boundary, southern Germany). Evidence of two morphological and dimensional classes were observed at some tooth positions in Prolagus (some p3 show an unmistakable P. oeningensis morphology, others closely resemble P. crusafonti), but not at other tooth positions (e.g., M1–2). Insufficient data from Sandelzhausen precludes identification of two different species of Prolagus from this locality, and to define the characteristics of the possible P. crusafonti-like species. Thus, all Prolagus specimens have been classified as P. aff. oeningensis. The genus Lagopsis is represented by L. cf. penai, whose presence is compatible with a MN5 age. The relative abundance of Lagopsis to Prolagus may indicate relatively cool and wet palaeoclimatic conditions. The largest primitive lagomorph species from continental Europe is present at Sandelzhausen. Morphological and dimensional comparisons with other European primitive lagomorphs exclude any affinity with the genera Eurolagus and Titanomys and with the species included in “Amphilagus ulmensis”. Some common features with “Amphilagus antiquus” were observed, although they are not sufficient for the attribution to this taxon. Until there is a general revision of European primitive lagomorphs, the Sandelzhausen giant lagomorph is classified as “Amphilagus” sp. Its origins, whether from evolution within Europe or migration from Asia, remain unknown.   相似文献   

3.
The fossil record of Araceae pollen beginning in the late Early Cretaceous and peaking in the Paleocene/Eocene is very sparse up to now, consisting of three highly distinctive types: zona-aperturate pollen of the Monstera or Gonatopus type (very similar to Proxapertites operculatus), an ulcerate-spiny type typical for Limnobiophyllum, and a polyplicate, omniaperturate pollen type (an ephedroid pollen with non-gnetalean affinities) which was recently reported from the late Early Cretaceous (Mayoa portugallica). An extensive literature search has shown that some distinctive Ephedripites forms (the Paleogene Ephedripites vanegensis, and the Late Cretaceous Ephedripites elsikii) are very similar to pollen of Spathiphyllum and both species are here transferred from Ephedripites to Spathiphyllum (as comb. nov.). We also add new fossil findings to the Araceae record. The new findings include a zona-aperturate, microperforate to microreticulate pollen type from the Palaeocene of Colombia, highly similar to extant Gonatopus or Zamioculcas or Monstera pollen (Araceae) and to fossil Proxapertites operculatus, which is currently seen as a fossil equivalent; and, an ulcerate, spiny pollen from the Eocene of Stolzenbach, Germany, extending the range of Limnobiophyllum (Pandaniidites), which is thought to be an extinct member of extant Araceae. The three pollen types add considerably to the reliable fossil record of the family that now contains more than 20 records of these three pollen types: with the zona-aperturate type recorded from the tropical or subtropical regions of Northern and Southern America, Central Africa, Southern and Central Europe, from the Indian subcontinent and the Malayan Archipelago; the ulcerate type occurring in North America and Europe; and the polyplicate type mainly occurring in South America and South-West Europe. Now we have good evidence that some of the aroid subfamilies were already in existence in the Cretaceous, increasing in diversity and worldwide distribution in the Paleogene. Dedicated to Prof. Dr. Stefan Vogel on the occasion of his 80th birthday.  相似文献   

4.
5.
The biological control program for saltcedar (Tamarix spp.) has led to open releases of a specialist beetle (Chrysomelidae: Diorhabda elongata) in several research locations, but the controversy over potential impacts to native, nontarget plants of the genus Frankenia remains unresolved. To assess the potential for nontarget impacts under field conditions, we installed cultivated Frankenia spp. (primarily two forms of Frankenia salina but also including Frankenia jamesii) at locations in Nevada and Wyoming where D. elongata densities and saltcedar defoliation were expected to be very high, so insects would be near starvation with high probability of attacking nontargets if these were suitable hosts. Subsequent insect abundance was high, and only minor impact (<4% foliar damage) was observed on both forms of F. salina under these ‘worst case’ conditions; there was no impact to F. jamesii. No oviposition nor larval development were observed on any plants, there was no dieback of damaged F. salina stems, and plants continued growing once insect populations subsided. These results under ‘natural’ field conditions contrast with caged host-range tests in which feeding, development and minor oviposition occurred on the nontarget plant. Other ecological factors, such as distance from target plants to natural Frankenia spp. populations, inhospitable conditions for agent survival in such sites, and intrinsic insect behavior that makes colonization and/or genetic adaptation highly unlikely, lead us to conclude that nontarget impacts following program implementation will be insignificant or absent. Host range testing of new agents, while necessary to ensure safety, must put greater attention on assessing the ecological context where agents will be establishing, and on balancing speculated risks against potential benefits of biological control.  相似文献   

6.
Several mollusc shells contain chitin, which is formed by a transmembrane myosin motor enzyme. This protein could be involved in sensing mechanical and structural changes of the forming, mineralizing extracellular matrix. Here we report the heterologous expression of the transmembrane myosin chitin synthase Ar-CS1 of the bivalve mollusc Atrina rigida (2286 amino acid residues, M.W. 264 kDa/monomer) in Dictyostelium discoideum, a model organism for myosin motor proteins. Confocal laser scanning immunofluorescence microscopy (CLSM), chitin binding GFP detection of chitin on cells and released to the cell culture medium, and a radiochemical activity assay of membrane extracts revealed expression and enzymatic activity of the mollusc chitin synthase in transgenic slime mold cells. First high-resolution atomic force microscopy (AFM) images of Ar-CS1 transformed cellulose synthase deficient D. discoideumdcsA cell lines are shown.  相似文献   

7.
The postglacial sediments of Kortowskie Lake contain well preserved chrysophycean cysts. Forty-six morphotypes were identified by scanning electron microscopy (SEM) and light microscopy (LM). Ten new morphotypes of fossil chrysophycean cysts are described. Some of the most abundant taxa show clear trends associated with the increase in lake trophic status. The cyst flora is divided into four groups: eutrophic forms (Cysta globata, C. cortoviensis, C. vermicularis); oligotrophic forms (Cysta curvicollis); cool-water forms (Cysta carinifera, C. crassicollis, C. microspinosa, C. modica and Cysta stellata), and indifferent forms (all other morphotypes which did not show a clear tendency). The percentage abundance of chrysophycean cysts wa related to climate changes, showing a considerable increase during the Subboreal period. Two factors, lake fertility and water level changes affected the abundance of the fossil cyst flora in the sediments of Kortowskie Lake.  相似文献   

8.
Manganese, Mn, is a naturally abundant metal in marine sediments. During hypoxic conditions the metal converts into a bioavailable state and can reach levels that have been shown immunotoxic to the crustacean Nephrops norvegicus. For this species it has previously been shown that exposure to 15 mg L−1 of Mn decreased the number of circulating haemocytes while it for the echinoderm Asterias rubens increased the number of coelomocytes. Here, we compared if five days of exposure to the same concentration of Mn affects the bactericidal capacity of these two species and the mollusc Mytilus edulis when inoculated with the bacterium Vibrio parahaemolyticus. Viable counts of the bacteria were investigated at a time-course post-injection in the blood and the digestive glands of Mn-exposed and un-exposed (controls) animals. Accumulation of Mn was also analyzed in these tissues. When exposed to Mn the haemocyte numbers were significantly reduced in M. edulis and it was shown that the bactericidal capacity was impaired in the mussels as well as in N. norvegicus. This was most obvious in the digestive glands. These two species also showed the highest accumulation of the metal. In A. rubens the bactericidal capacity was not affected and the metal concentration was similar to the exposure concentration. After a recovery period of three days the concentration of Mn was significantly reduced in all three species. However, in M. edulis and N. norvegicus it was still double that of A. rubens which could explain the remaining bactericidal suppression observed in N. norvegicus. This study pointed out that exposure to such Mn-levels that are realistic to find in nature could have effects on the whole organism level, in terms of susceptibility to infections. The effect seemed associated to the accumulated concentration of Mn which differed on species level.  相似文献   

9.
The genus Metaschizotherium is a Miocene member of the Schizotheriinae (Chalicotheriidae, Perissodactyla) and appears in the MN 5 of Southern Germany with the species M. bavaricum. The Chalicotheriidae have mostly been reconstructed as browsers. In this study, the mesowear method is applied to 11 upper premolars and molars of M. bavaricum from the Upper Freshwater Molasse locality of Sandelzhausen (MN 5). With this method the amount of abrasive and attritive dental wear is investigated and thus it provides a time-averaged signature of food abrasiveness of ungulates. Principal components analysis is performed on mesowear variables of M. bavaricum. This species is found to classify closest to extant mixed feeding ruminants. This indicates that the diet of M. bavaricum essentially included nonabrasive browse but also a certain amount of abrasive plant material. The composition of the diet of extant reference species indicates that this abrasiveness was most likely imposed by bark and whole branches. In the palaeoecological context of Sandelzhausen M. bavaricum occupied the dietary niche of a mixed feeder or an abrasion-dominated browser. A high degree of similarity is recognised between the mesowear patterns of M. bavaricum from Sandelzhausen and M. fraasi from the MN 6 of the Franconian Alb. This is interpreted as reflecting a similar dietary niche of the two species.   相似文献   

10.
Archival research reveals that it is highly probably that the first discovery of a fossil ape was made by Hugh Falconer and his associates in the 1830s during surveys of Neogene deposits in the Siwalik hills of British Colonial India. However, priority is commonly awarded to Edouard Lartet who, in 1837, brought to light a fossil primate specimen from the Miocene beds at Sansan in France to which Paul Gervais gave the namePliopithecus. Falconer's letters and scientific papers announcing the find of a fossil primate group from the Siwalik Hills were antecedent to Lartet's report to the French Academy of Sciences, Paris. The circumstances surrounding this misconception over priority of discovery of fossil apes are reviewed with attention to the historic significance of the Siwalik fossil primates and with respect to the development of paleoanthropology in South Asia.  相似文献   

11.
Within the fossil collection from the Sandelzhausen Lagerstätte in the Upper Freshwater Molasse near Mainburg, Germany, are remains of the schizotheriine chalicothere Metaschizotherium bavaricum, von Koenigswald, 1932. This new material includes elements from a large part of the body, and allows the dentition and postcranial skeleton of Metaschizotherium to be described in detail for the first time. At approximately 16 Ma (MN5), M. bavaricum is now the best-known Early and Middle Miocene European schizotheriine and is important for comparative studies. It differs to some degree from earlier Miocene (MN2–MN4) European material attributed to Moropus sp. or Metaschizotherium wetzleri (Kowalewsky, 1873) and to a larger degree from the Late Miocene species Ancylotherium pentelicum (Gaudry and Lartet, 1856). At Sandelzhausen, M. bavaricum apparently lived in a moist forested environment, where it probably fed on leaves, fruit, and seeds. Members of the Chalicotheriinae, such as Anisodon and Chalicotherium, are not found at Sandelzhausen and may not have been present in Europe at this time. M. bavaricum, like other Schizotheriinae, did not have the bizarre gorilla-like proportions of the Chalicotheriinae. Instead, its general body proportions resemble those of contemporary schizotheriine chalicotheres on other continents, for example, Moropus from North America. M. bavaricum is slightly smaller than the type species of Metaschizotherium, M. fraasi von Koenigswald, 1932 (MN6–MN7) and differs from it in small ways that are still being explored as variation within and differences between these species are clarified. The schizotheriine chalicothere from La Grive St.-Alban (France) referred to M. fraasi by von Koenigswald (Palaeontographica, Beitrage zur Naturgeschichte der Vorzeit 8:1–24, 1932) and Viret (Nouvelles Archives Musée d’Histoire Naturelle de Lyon 6:53–81, 1961) should be restudied and referred to a different taxon.  相似文献   

12.
The physical characteristics and environmental versatility of the alga Halopteris scoparia (Phaeophyta, Sphacelariales) make it a suitable substrate for development of epiphytic communities. Spatial variation of the epifauna on this alga in Algeciras Bay (southern Spain) in response to different environmental conditions is investigated. There is a clear difference in community composition between external and internal areas of the bay, with an important group of species present in only one of the areas (e.g., in outer areas crustaceans such as Tanais dulongii or Amphilochus neapolitanus or the polychaete Nicolea venustula; and species from inner areas such as the crustacean Jassa marmorata and the mollusc Alvania montagui or Rissoa similis). The external zone shows high hydrodynamics and low sedimentation rates, whereas in the internal one, there is a high sedimentation rate (as a result of two main rivers, a less strong current regime, and the presence of urban and industrial wastes). The conditions prevailing in the internal zone of the bay are unfavourable for most of the epifaunal species in the external bay areas.  相似文献   

13.
A fossil trimerous flower from the Turonian (ca. 90 MYBP, Upper Cretaceous) of New Jersey is described as a new genus in the familyLauraceae. The fossil flower is charcoalified and preserved in exceptional detail. This fossil specimen is particularly remarkable in that several pollen grains have been preserved; pollen grains ofLauraceae generally have very thin exine and are rarely preserved in the fossil record. Although the specimen is incomplete and lacks anthers, there are sufficient structural details preserved to permit an assignment to theLauraceae, as well as comparisons with the tribePerseeae. This new genus provides an important addition to our knowledge of systematic and structural diversity in CretaceousLauraceae.  相似文献   

14.
The cytoplasmic hemoglobin III from the gill of the symbiont-harboring clamLucina pectinata consists of 152 amino acid residues, has a calculated Mm of 18,068, including heme, and has N-acetyl-serine as the N-terminal residue. Based on the alignment of its sequence with other vertebrate and nonvertebrate globins, it retains the invariant residues Phe45 at position CD1 and His98 at the proximal position F8, as well as the highly conserved Trp16 and Pro39 at positions A12 and C2, respectively. The most likely candidate for the distal residue at position E7 is Gln66.Lucina hemoglobin III shares 95 identical residues with hemoglobin II (J. D. Hockenhull-Johnsonet al., J. Prot. Chem. 10, 609–622, 1991), including Tyr at position B10, which has been shown to be capable of entering the distal heme cavity and placing its hydroxyl group within a 2.8 Å of the water molecule occupying the distal ligand position, by modeling the hemoglobin II sequence using the crystal structure of sperm whale metmyoglobin. The amino acid sequences of the twoLucina globins are compared in detail with the known sequences of mollusc globins, including seven cytoplasmic and 11 intracellular globins. Relative to 75% homology between the twoLucina globins (counting identical and conserved residues), both sequences have percent homology scores ranging from 36–49% when compared to the two groups of mollusc globins. The highest homology appears to exist between theLucina globins and the cytoplasmic hemoglobin ofBusycon canaliculatum.  相似文献   

15.
Clearance rates of Limnoperna fortunei (Bivalvia) were investigated in laboratory experiments using monocultures of the alga Chlorella vulgaris. Experimental conditions included two mollusc sizes (15 and 23 mm), and three water temperatures (15, 20 and 25 °C) covering the normal seasonal range in the lower Paraná river and Río de la Plata estuary. Filtration rates obtained were, for the larger mussels: 9.9, 13.1 and 17.7 ml mg tissue dry weight–1 h–1 at 15, 20 and 25 °C, respectively; and for the smaller ones: 17.7, 20.8 and 29.5 ml mg–1 h–1. Differences between sizes and between temperatures (except 15 vs. 20 °C) were statistically significant. In absolute terms larger animals have higher clearance rates, but as a function of body mass smaller individuals feed more actively. Within the range of experimental values used, filtration rates were positively associated with water temperature. These clearance rates (125–350 ml individual–1 h–1) are among the highest reported for suspension feeding bivalves, including the invasive species Dreissena polymorpha, D. bugensis and Corbicula fluminea. High filtration rates, associated with the very high densities of this mollusc in the Paraná watershed (up to over 200,000 ind m–2) suggest that its environmental impact may be swiftly changing ecological conditions in the areas colonized.  相似文献   

16.
The differentiation of foliar epidermis structures, cuticles, stomata, and indumentum of most of the extant Euro-Mediterranean taxa ofQuercus have been studied by light and scanning electron microscopy, and compared with other genera and fossil material. Results allow the recognition of the subgg.Sclerophyllodrys, Cerris andQuercus, and of various sections and even individual species. The cyclocytic stomata type, regarded as plesiomorphic, is found in the geologically oldest representatives of the familiy (Dryophyllum, resp.Eotrigonobalanus) and in the relatively old, evergreen to semi-evergreen species ofQuercus subgg.Sclerophyllodrys andCerris. These taxa also have relatively thick and smooth cuticles. Anomocytic stomata, thinner cuticles and the presence of crystalline wax flakes are regarded as apomorphic features and characterize the deciduous taxa of subg.Quercus. These changes are interpreted as ecological adaptations to the changing climates from the Tertiary to the present. An analysis of the various character combinations found in macrofossils and the often poor species separation inQuercus suggest that hybridization has played a major role in the evolution of the Euro-Mediterranean oaks.  相似文献   

17.
Neonates are highly sensitive to infections because they are biased to develop Th2 immune responses. When exposed to certain agents, such as DNA vaccines or CpG DNA motifs, neonates are capable to mount adult-like Th1 protective responses. This study investigates the capacity of Candida albicans (C. albicans) dsDNA to induce host resistance in newborn mice against gastrointestinal C. albicans infection. The protective properties of dsDNA are related to an increased number of spleen CD4+ T cells secreting IFN-γ. In infected DNA-treated mice, an enhanced production of IFN-γ by Peyer’s patch cells was observed together with reduced colonization and histopathological changes in the stomach. Our results indicated that C. albicans dsDNA administration in neonates elicited the protective immune response against gastrointestinal Candida infection.  相似文献   

18.
Buccal microwear patterns on teeth are good indicators of the abrasiveness of foodstuffs and have been used to trace the dietary habits of fossil species, including primates and hominids. However, few studies have addressed the variability of this microwear. The abrasiveness of dietary components depends not only on the hardness of the particles ingested, but also on the presence of dust and other exogenous elements introduced during food processing. These elements are responsible for the microwear typology observed on the enamel surfaces of primate teeth. Here we analyzed the variability of buccal microwear patterns in African Great Apes (Gorilla gorilla and Pan troglodytes), using tooth molds obtained from the original specimens held in several osteological collections. Our results suggest that ecological adaptations at subspecies or population level account for differences in microwear patterns, which are attributed to habitat and ecological conditions within populations rather than differences between species. The findings from studies on the variability of buccal dental microwear in extant species will contribute to a better understanding of extinct hominids’ diet and ecology.  相似文献   

19.
Phytosociological characteristics and a rate of endangerment of the salt marsh vegetation in central and southern parts of the east Adriatic coast were studied. A total of 73 vegetation relevés were made and elaborated according to the standard procedures of the Braun-Blanquet method. Numerical analysis of the relevés and life forms was performed. Two associations of the class Arthrocnemetea-Puccinellio festuciformis-Arthrocnemetum fruticosi and Limonio-Artemisietum coerulescentis were recorded, together with the association Juncetum maritimo-acuti of the class Juncetea maritimi. These associations show no significant differentiation with regard to their floristic composition, but only in terms of particular species cover and frequency rates, as well as by life forms and microecological habitat conditions. These are specific habitats, rarely found in the studied area, and highly threatened by human activity (tourism, agriculture).  相似文献   

20.
Linuparus White, 1847 comprises three extant species, Linuparus trigonus (Von Siebold, 1824), L. sordidusBruce, 1965, and L. somniosusBerry and George, 1972, as well as 32 fossil species. Most fossil records are from North America and Europe, but the extant species are all confined to the Indo-West Pacific. Different colour forms in L. trigonus and L. sordidus have been noted, with Northern Hemisphere specimens generally darker in colour for both species. The phylogenetic relationships of the extant Linuparus species, including the colour forms, were investigated using mitochondrial 12S rRNA and COI gene sequence analysis. We found no genetic evidence to differentiate the colour morphs of L. sordidus, but the two colour forms of L. trigonus were clearly distinct at the species level. This is supported morphologically by a consistent difference in the shape of the thoracic sternum between the two forms. The paler coloured Southern Hemisphere form is described as a new species, L. meridionalis. Phylogenetic analysis shows that L. trigonus and L. meridionalis sp. nov. are derived sister taxa, while L. somniosus is basal within the genus. Thus the present results support the previous hypothesis that Linuparus was originated in shallow water.  相似文献   

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