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| Registros recuperados: 23 | |
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| Pinkster, Sjouk. |
| The morphological diversity within the species Echinogammarus berilloni (Catta, 1878), stressed by Spandl (1926), Margalef (1956) and Pinkster (1969) was a motive to sample systematically in drainage systems of the Iberian peninsula and of great parts of France. It became clear that E. berilloni in reality was the collective name for a group of at least 10 species, all of them with their own, restricted distribution area. Only one of these species, the real E. berilloni, inhabits a much larger area, including the major part of France, the Channel islands, Belgium, Luxembourg, the southern part of the Netherlands, and south-western Germany. In this study the characters of the E. berilloni-group are discussed and comparative descriptions are given of all... |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/504082 |
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| Platvoet, Dirk; Scheepmaker, Maarten; Pinkster, Sjouk. |
| During two and a half decades periodic survey programs have been carried out to follow the dispersal of Gammarus tigrinus. Since the last survey in the period 1985-1986 the species consolidated its position and showed a minor range extension in the southeastern part of the country. Gammarus specimens from the island Terschelling were electrophoretically investigated and compared with known G.tigrinus and G.zaddachi from the mainland. These experiments demonstrated the presence of G.tigrinus on this island. Crangonyx pseudogracilis which showed some range extension in the 1985-1986-survey, again was found outside its hitherto known distribution area. |
| Tipo: Article / Letter to the editor |
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| Ano: 1989 |
URL: http://www.repository.naturalis.nl/record/505504 |
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| Karaman, Gordan S.; Pinkster, Sjouk. |
| 1) This third part of the revision of the freshwater Gammarus species deals with the G. balcanicus-group. Members of this artificial group are characterized by poorly setose pereiopods 3 and 4 and uropod 3 and by the absence of dorsal carinae (processes) on the metasome segments. 2) The morphological characters used in this work are identical to those used in the first part, the revision of the Gammarus pulex-group (Karaman & Pinkster, 1977a). 3) The type material or topotypic material of all studied taxa was reexamined and compared with many (several hundreds) of newly collected samples and material from many European museums. 4) Complete descriptions and many illustrations are given of the males of all species from Europe and Asia Minor. The... |
| Tipo: Article / Letter to the editor |
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| Ano: 1987 |
URL: http://www.repository.naturalis.nl/record/504258 |
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| Pinkster, Sjouk. |
| Gammarus gauthieri (Karaman) was known from North Africa only. During systematic sampling, carried out in 1969 to 1970, it became clear, that the species is also widely distributed in the Iberian peninsula. Comparative descriptions of this species and of two other members of the Gammarus pulex-group, G. ibericus Margalef (new rank) from Spain, and G. acalceolatus nov. spec. from Morocco, are given. |
| Tipo: Article / Letter to the editor |
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| Ano: 1971 |
URL: http://www.repository.naturalis.nl/record/505531 |
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| Dieleman, Jan; Pinkster, Sjouk. |
| In the autumn of 1975 and in the spring of a new survey of the range of Gammarus tigrinus Sexton, 1939, was carried out, especially at the borders of the 1973 range. Considerable range extensions were found in the north-eastern parts of the province of Groningen, the Kampereiland (province of Overijssel), in the Deltaic Region and in some more or less isolated areas in the province of Zuid-Holland. In most of the newly invaded areas G. tigrinus has replaced the indigenous Gammarus species. Sampling along the Dutch-German border revealed that no invasion has taken place from any of the German populations. A fungus was found which appeared to be pathogenic for G. tigrinus. |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/505482 |
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| Scheepmaker, Maarten; Meer, Frits van der; Pinkster, Sjouk. |
| Populations of five related species belonging to the Gammarus pulex group from the Iberian Peninsula and southern France have been studied electrophoretically at 21 enzyme loci. Morphologically distinct forms from the same side of the Pyrenees proved to be genetically more similar than morphologically very similar forms from opposite sides of this barrier. With reference to published data, genetic differentiation between French and Iberian species was observed at the generic level. Inter-areal intraspecific genetic differentiation in Iberian species may warrant recognition of subspecies or sibling species. However, cross-breeding experiments performed did not assess levels of reproductive isolation of the forms involved. A dendrogram derived from genetic... |
| Tipo: Article / Letter to the editor |
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| Ano: 1988 |
URL: http://www.repository.naturalis.nl/record/504502 |
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| Pinkster, Sjouk. |
| La variabilité morphologique des Gammares du groupe pulex et la confusion concernant la position systématique des différentes formes de ce groupe, déjà démontrées par l’auteur en 1970, l’ont conduit à donner des descriptions de différentes formes du groupe et à discuter leur variabilité. Des expériences d’hybridation ont été faites entre des populations morphologiquement différentes, étroitement liées à, ou bien intermédiaires entre G. pulex et G. wautieri provenant de différentes localités d’Europe occidentale. Les résultats de ces expériences clarifient la position systématique de ces populations. Les données disponibles concernant l’écologie et la distribution des différentes espèces sont fournies. |
| Tipo: Article / Letter to the editor |
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| Ano: 1972 |
URL: http://www.repository.naturalis.nl/record/504267 |
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| Karaman, Gordon S.; Pinkster, Sjouk. |
| 2) These freshwater species can be classified in three artificial groups: (a) the G. pulex-group (species without dorsal carina and with dense setation on pereiopods 3 and 4 and uropod 3), (b) the G. balcanicus-group (species without dorsal carina and poorly setose pereiopods 3 and 4 and uropod 3) and (c) the G. roeseli-group (species with dorsal carina). These groups are merely artificial ones since transitive (intermediate) species do exist. Moreover, the origin of the species is not known, so that polyphyly is not excluded. 3) In the present work the Gammarus pulex-group is revised, based on rich material from Europe, North Africa, Asia minor and adjacent areas. 4) The taxonomic differences between the various species are usually small but distinct and... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/504622 |
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| Pinkster, Sjouk; Platvoet, Dirk. |
| Like in many previous years, the distribution pattern of G. tigrinus was followed. G. tigrinus proves to have recovered from its decline after the severe winter of 1978/1979. Likewise the distribution of C. pseudogracilis was checked, three year after its first discovery in the Netherlands. Some minor range extensions were found. In a monthly sampling program and in laboratory experiments information was collected on the biology so far unknown for this species. Its possible future interaction with local amphipod species is discussed. |
| Tipo: Article / Letter to the editor |
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| Ano: 1983 |
URL: http://www.repository.naturalis.nl/record/505403 |
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| Karaman, Gordan S.; Pinkster, Sjouk. |
| 1) This part of the revision of the freshwater Gammarus species deals with the G. roeseli-group. Members of this artificial group are characterized by the presence of dorsal processes (carinae) on the metasome segments. 2) A historical review is given from the first description of G. roeseli and the taxonomic confusion that followed, to the start of this study when 3 species and at least 15 subspecies were known. 3) Where possible, the type material of all these taxa is re-examined and compared with hundreds of newly collected samples and material from all major museums in Europe. 4) In this study the same morphological characters are used as in the revision of the G. pulex-group (Karaman & Pinkster, 1977). The variability of the various characters is... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/504157 |
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| Pinkster, Sjouk; Scholl, Adolf. |
| Until 1974 Gammarus ibericus was known only from the type-locality in Spain. In that year, Goedmakers recorded the species from many localities in the Massif Central, France. Indeed, these populations show a great morphological resemblance to the Spanish ones. These French populations were used in cross-breeding experiments with other populations from southern France, without result. Attempts to hybridize these populations with the G. ibericus from the type-locality also failed to produce any offspring. Electrophoretic studies showed that the French and Spanish populations are very different from a biochemical point of view; these differences are much greater than between any of the known freshwater species (or populations) from western Europe. It is... |
| Tipo: Article / Letter to the editor |
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| Ano: 1984 |
URL: http://www.repository.naturalis.nl/record/504359 |
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| Hautus, Tjeu; Pinkster, Sjouk. |
| Since its first discovery in the Netherlands in 1964, the dispersal of Gammarus tigrinus over inland waters is followed closely. In a survey carried out in 1985 and 1986 it appeared that G. tigrinus has extended its range in the southwestern and southeastern parts of our country. In the rest of the country the spreading has come to an apparent standstill. Apart from the mainland, G. tigrinus has been found for the first time on some Frisian isles: Texel, Terschelling and Ameland. During the present study the position of another alien amphipod, Crangonyx pseudogracilis, was investigated as well. For the first time some range extensions were found, since its initial discovery in 1979, in a limited area in the province of Groningen. Some remarks are made on... |
| Tipo: Article / Letter to the editor |
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| Ano: 1987 |
URL: http://www.repository.naturalis.nl/record/505332 |
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| Pinkster, Sjouk; Dieleman, Jan; Platvoet, Dirk. |
| Since its first discovery in the Netherlands in 1964, Gammarus tigrinus has rapidly spread over inland waters in the western and north-eastern parts of the Netherlands. It appeared that at the end of 1976, G. tigrinus had replaced the local Gammarus species in most of the newly invaded waters. Surveys carried out in 1978 and 1979 showed a different and rather confusing pattern i.e that G. tigrinus is still extending its range in the delta region of the Netherlands and in the province of Zuid-Holland but that its spreading has come to a stand still in the rest of the country. It has even disappeared from a great number of formerly inhabited waters. In some of these waters indigenous species like G. d. duebeni and G. p. pulex reappeared after an absence of... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/505333 |
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| Janssen, Hans; Scheepmaker, Maarten; Couwelaar, Matthijs van; Pinkster, Sjouk. |
| 1. Gammarus aequicauda (Martynov, 1931) and Gammarus insensibilis Stock, 1966 have been the subject of a quantitative ecological research project in the lagoon system of Bages-Sigean (France, dépt. Aude). From April 1976 till August 1977 samples have been taken at 31 different stations all over the lagoon at intervals of about 2 weeks. With the samples thus obtained we studied the biology and distribution of the two species in relation to environmental factors, the most important being chlorinity and temperature. 2. Both species reproduce throughout the year and have a regular reproductive pattern with maxima in spring and autumn. In G. aequicauda. as compared to the other species, this peak is earlier in spring and later in autumn. This is caused by a... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/504129 |
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| Pinkster, Sjouk. |
| In the Hercynian Massif, a geologically old area in Southern France, various morphologically distinct populations of the Gammarus pulex-group were found. When applying the morphological criteria postulated by Karaman & Pinkster (1977), at least three species can be distinguished. However, in hybridization experiments these populations proved to be interfertile, and thus conspecific. Likewise it was proved that this species cannot be identical with G. fossarum or G. ibericus, it is considered a new species: G. stupendus. Because of its polymorphic nature, it is difficult to describe the species and to find discriminating characters with G. fossarum and G. ibericus. The distribution of the new species and of G. ibericus are discussed. |
| Tipo: Article / Letter to the editor |
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| Ano: 1983 |
URL: http://www.repository.naturalis.nl/record/504939 |
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| Registros recuperados: 23 | |
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