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| Registros recuperados: 16 | |
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| Boogaard, M. van den; Kuhry, B.. |
| Extensive frequency data are used for a reconstruction of Devonian cunodont apparatuses. Correspondence analysis and a related clustering method are selected as statistical tools, and are used as informal methods for testing a priori hypotheses rather than as search mechanisms. In our view, the Palmatolepis apparatus consists of palmatolepan P elements, tripodellan or nothognathellan O elements, palmatodellan and smithiform N elements, and a symmetry transition consisting of falcodontan A1 elements, asymmetrical scutulan A2 elements, and symmetrical scutulan A3 elements. A peculiar phenomenon, already described by other authors, is the numerical dominance of the P elements, which are on the average 15 times as frequent as corresponding O and N elements. It... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.20. |
| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/317498 |
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| Hinte, J.E. van; Ruffman, A.; Boogaard, M. van den; Jansonius, J.; Kempen, T.M.G. van; Melchin, M.J.; Miller, T.H.. |
| Orphan Knoll is an isolated, drowned continental fragment 550 km northeast of Newfoundland. The top of Orphan Knoll stands at 1800 to 2000 m and is marked by a series of protruding mounds. Dredging at the base of one of the mounds in 1971 obtained a suite of fossiliferous limestone pebbles that are interpreted to reflect nearby bedrock. The shallow marine limestone facies include mudstone, wackestone, packstone, and grainstone. The pebbles yielded Late Ordovician, Silurian and Devonian conodonts, as well as Ordovician/Silurian scolecodonts, chitinozoans and graptolites. Similarly, sponge spicules suggest the presence of Late Ordovician as well as Middle Devonian material including a Silicunculus-type of hexactinellid anchoring basalia and an octactine... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.20. |
| Ano: 1995 |
URL: http://www.repository.naturalis.nl/record/317524 |
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| Boogaard, M. van den. |
| The conodont fauna extracted from a boulder in the Lorentz River (southern Irian Jaya) is described. Arguments are put forward that the elements of Distomodus dubius (Rhodes, 1953) sensu Jeppsson, 1972 are part of the apparatus of species of Coryssognathus Link & Druce, 1972, a genus that ontogenetically acquires an apparatus of multidenticulate elements on account of the phenomenon that one coniform element of each of the several (curvature-transition ?) series successively incorporates its - to that time independently growing - coniform neighbours within its lamellae. Attention is called to the fact that probably also the apparatus of Distomodus kentuckyensis Branson & Branson, 1947 - as described by Cooper (1975) had a similar ontogeny and that... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.22. |
| Ano: 1990 |
URL: http://www.repository.naturalis.nl/record/317481 |
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| Boogaard, M. van den. |
| An investigation of some faunas rich in Milaculum Müller, 1973 lead to the conclusion that the Milaculum animal was - at least partly - covered by plates of different morphology. Several specimens of Milaculum were encountered with adhering smaller platelets showing that the epidermal tissue of this animal consisted of a mosaic of larger and smaller plates. The characteristics of the material encountered are suggestive of an agnathan affinity of Milaculum. Two new species are described, Milaculum balticum from the Upper Ordovician of Estonia and M. longmyndium from the Lower Silurian of the Welsh Borderland. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.20. |
| Ano: 1988 |
URL: http://www.repository.naturalis.nl/record/317535 |
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| Boogaard, M. van den. |
| The conodont faunas from the Viséan and lower Namurian limestone succession in the Cantabrian Mts are mainly characterised by abundant Gnathodus spp. and minor amounts of Lochriea spp. However, Gnathodus and Lochriea are four times largely or almost completely replaced by Vogelgnathus campbelli, every time during a relatively short interval. Apart from being present in moderate quantities in basal Viséan faunas, V. campbelli is lacking in most of the Gnathodus-dominaled faunas from the Cantabrian Mts. These invasions by V. campbelli are supposed to have occurred during a rise of sea level enabling this - presumably more offshore - species to enter the region while at the same time the habitat of Gnathodus c.s. was partly or almost completely drowned. These... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.22. |
| Ano: 1992 |
URL: http://www.repository.naturalis.nl/record/317455 |
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| Germeraad, J.H.; Freudenthal, M.; Boogaard, M. van den; Arps, C.E.S.. |
| The new computer-based registration system, a project of the National Museum of Geology and Mineralogy in the Netherlands, will considerably increase the accessibility of the Museum collection. This greater access is realized by computerisation of the data in great detail, so that an almost unlimited number of operations to select and sort the data is possible. A flexible design of annotating information, mainly in plain words, saves considerable time. The fast mechanical data processing permits the efficient preparation of catalogues which contain selected information about the geological collection; as an additional benefit labels may be produced at low costs. The RGM system disposes of the burden of classical registration books and card-indexes, without... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.03. |
| Ano: 1972 |
URL: http://www.repository.naturalis.nl/record/317543 |
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| Registros recuperados: 16 | |
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