NCB Naturalis

Leiden, Netherlands

NCB Naturalis

Leiden, Netherlands

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Wesselingh F.P.,NCB Naturalis | Alcicek H.,Pamukkale University
Palaeontology | Year: 2010

Abstract: We present the first record of the cardiid genus Monodacna from the Pliocene of Anatolia, Turkey. Monodacna imrei sp. nov. was found in the Pliocene Killik Formation from the western margin of the Baklan Basin, in very marginal brackish to freshwater lacustrine deposits. The new record extends the stratigraphic range of the modern Ponto-Caspian genus back into the Pliocene and adds to earlier evidence that modern Ponto-Caspian taxa originated in the Pliocene of south-western Turkey. © The Palaeontological Association.


M. indraneil spec. nov. is described from locations in Sarawak, Malaysian Borneo. Both sexes of M. arthuri Fraser are re-described based on recent material. Records of M. amoena Ris from Borneo in fact refer to M. indraneil; there is no evidence that M. amoena occurs on Borneo. Relationships between Argiocnemis, Agriocnemis and Mortonagrion are discussed. Copyright © 2011, Magnolia Press.


Donovan S.K.,NCB Naturalis
Lethaia | Year: 2011

Artistic licence is kept under firm control when restoring fossil tetrapods and their natural environments, but the same care is not always applied to reconstructions of ancient invertebrates. Selected renderings of fossil crinoids illustrate grossly inaccurate skeletal geometry and outmoded ideas of palaeoautecology. Together, these combine to give the public an incorrect impression of what a fossil crinoid looked like and how it lived, in some instances inferior to what was possible in the 19th century. The reason why crinoids receive such poor service from artists is, in part, probably due to their being exotic; humans and other tetrapods are a common part of our experience, whereas stalked crinoids, although extant, can only be seen in life with the aid of a research submersible in deep water (>100m). Crinoids also have a complex endoskeleton that requires care in illustration. They are unusual creatures in an alien environment even at the present day. But echinoderm palaeontologists need to be more energetic in promoting the correct depiction of ancient species. □Crinoidea, illustration, morphology, palaeoenvironments, reconstruction. © 2011 The Author, Lethaia © 2011 The Lethaia Foundation.


Somaclonal variation of some 124 specially selected cultivars of Hosta Tratt. (Hostaceae) was investigated. Nuclear DNA contents (2C-value) were measured by flow cytometry of leaves and roots of L1, L2 and L3 layers derived from apical meristems. These values were then converted to inferred ploidies by comparing the measured 2C-values and ploidy with those of the parent plant. During tissue-culture propagation, on occasion diploid (L1-L2-L3=2-2-2) hostas give rise to polyploids, such as fully tetraploids (4-4-4), and periclinal chimeras, such as partial tetraploids (4-2-2). Continual propagation can result in partial tetraploidsbecoming full tetraploids. Nuclear DNA of some diploids increased with incomplete chromosome sets resulting in fully aneuploids, such as hostas with a DNA ploidy of L1-L2-L3=2.5-2.5-2.5 and 3.7-3.7-3.7, and even in aneuploid periclinal chimeras, such as L1-L2-L3=2.5-2-2 and 3.8-2-2. The polyploidy of L1, irrespective of the ploidy of L2 and L3, is found to mainly determine the thickness of leaves. Also the higher the ploidy of L1, the wider and more intense in color is the leaf margin. The measurements of Hosta cultivars and their lineages of sports show that chromosome losses or gains are an important source of new cultivars. The complexity of chromosomal distribution in lineages of several Hosta cultivars is discussed. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.


Donovan S.K.,NCB Naturalis
Proceedings of the Geologists' Association | Year: 2013

'Localism' occurs when geologists are most influenced by data with which they are familiar, applying it to new, but not necessarily appropriate, areas of study. Jamaica has been particularly prone to localist interpretations. Henry T. De la Beche (1796-1855) mapped eastern Jamaica in 1823-1824, and made lithostratigraphic comparisons between Jamaica and Europe that were the first attempt at intercontinental correlation. He correlated the Jamaican succession on the basis of lithological similarity to rocks in Europe. Charles A. Matley (1866-1947) is best remembered for his mapping in North Wales. He was geologist to the second geological survey of Jamaica in 1921 and developed the Basal Complex hypothesis which envisaged a geological structure analogous to that of North Wales, where the deformed Mona Complex underlies the Lower Palaeozoic succession. Matley thus provided a 'factual' basis for theories that the Antillean islands were the peaks of a foundered continent. Charles T. Trechmann (1885-1964) was the principal opponent of the Basal Complex hypothesis, not recognising evidence for old basement in Jamaica. His 'answer' was the Theory of Mountain Uplift, based on gravitational tectonics, but Trechmann's theory was comparable to the earlier fixist theories of tectonics that he learnt as a student. © 2012 The Geologists' Association.


Donovan S.K.,NCB Naturalis
Proceedings of the Yorkshire Geological Society | Year: 2012

Fossil echinoderms derived from the Chalk occur rarely as clasts eroded from erratic rafts on the beaches of north Norfolk and are almost invariably represented by the holasteroid echinoid Echinocorys scutata (Leske). A small collection of other echinoderms from the Overstrand to Cromer coast includes the crinoid Austinocrinus bicoronatus (von Hagenow), and the echinoids Temnocidaris (Stereocidaris) sp., phymosomatid sp. and Galerites sp. Most preserve at least some evidence of corrasion and/or bioerosion. The echinoids are preserved either as steinkerns or are otherwise protected by flint; the crinoid columnal had lost much of its surface detail due to corrasion. The known stratigraphic ranges of these species suggest that they are derived from the local part of the Norfolk Chalk, spanning the upper Campanian to lower Maastrichtian interval.


Donovan S.K.,NCB Naturalis
Proceedings of the Yorkshire Geological Society | Year: 2012

A slab of Wenlock sandstone from the valley of the River Rawthey in the Howgill Fells, Cumbria, northern England, preserves a monospecific association of long, parallel to sub-parallel crinoid pluricolumnals. No crowns or attachment structures are associated; this is either an artefact of cut effect or an indication that the columns had been autotomized in response to adverse environmental conditions. The accumulation is allochthonous, but may represent a life assemblage. Current direction corresponded to the long axes of the pluricolumnals, as indicated by an example of a 'train crash' crinoid pluricolumnal.


Donovan S.K.,NCB Naturalis
Proceedings of the Yorkshire Geological Society | Year: 2012

Lower Devonian crinoids are poorly known from the British Isles. The British Geological Survey, Geological Survey Museum collection of Lower Devonian crinoids, mainly made by amateur collectors in the 19th century, is described for the first time. Taxa include Hexacrinites sp. A, Hexacrinites sp. B, Floricrinus (col.) priscus (Goldfuss) (probably Middle Devonian) and Bystrowicrinus (col.) sp. sensu lato; some nautiloids were misidentified as crinoids. Hexacrinites is moderately speciose in the Middle Devonian of SW England; columnals described herein extend this record into the Lower Devonian (Emsian). Pentacrinus priscus Goldfuss, erroneously included in a Mesozoic genus for over 180 years ago, is reclassified within the Devonian morphogenus Floricrinus (col.) Stukalina. Both F. (col.) priscus and Bystrowicrinus (col.) sp. represent columnal morphologies similar to some crinoids locally common in the Upper Ordovician, but unknown from the Silurian of the British Isles.


Zonneveld B.J.M.,NCB Naturalis
Nordic Journal of Botany | Year: 2012

Nuclear genome size of conifers as measured by flow cytometry with propidium iodide was investigated, striving to collect at least a single species from each genus. 64 out of 67 genera and 172 species were measured. Of the 67 genera, 21 are reported here for the first time and the same is true for 76 species. This nearly doubles the number of measured genera and adds 50% to the number of analyzed species. Conifers have chromosome numbers in the range of n = (7)10-12(19). However, the nuclear DNA content (2C-value) is shown here to range from 8.3 to 71.6 picogram. The largest genome contains roughly 6 × 10 10 more base pairs than the smallest genome. Genome sizes are evaluated and compared with available taxonomic treatments. For the mainly (sub)tropical Podocarpaceae small genome sizes were found with a 2C-value of only 8-28 pg, with 13.5 pg on average. For the Taxaceae 2C-values from 23-60 pg were determined. Not surprisingly, the genus Pinus with 97 species (39 species measured here) has a broad range with 2C =38-72 pg. A factor of 2 difference is also found in the Cupressaceae (136 species) with nuclear DNA contents in the range 18-35 pg. Apart from the allohexaploid Sequoia, ploidy plays a role only in Juniperus and some new polyploids are found. The data on genome size support conclusions on phylogenetic relationships obtained by DNA sequencing. Flow cytometry is applicable even to young plants or seeds for the monitoring of trade in endangered species. © 2012 The Authors. Nordic Journal of Botany © 2012 Nordic Society Oikos.


Kalkman V.J.,NCB Naturalis | Orr A.G.,Griffith University
Hydrobiologia | Year: 2012

Recent studies show a remarkable scarcity of faunal exchange events between Australia and New Guinea in the Pleistocene despite the presence of a broad land connection for long periods. This is attributed to unfavourable conditions in the connecting area associated with the long established northern Australian Monsoon Climate. This would be expected to have impacted strongly on freshwater faunas with the following results: (1) limited overlap in species, (2) most higher taxonomic groups present in both areas sharing no species or even genera and (3) shared species dominated by lentic species with high dispersal capacity. Testing these predictions for dragonflies showed the turnover in the family, genus and species composition between Australia and New Guinea to be higher than anywhere in the world with only 50% of families and subfamilies, 33% of the genera and 8% of the species being shared. Only one of the 53 shared species favors lotic waters compared with 64% of the 652 combined Australian-New Guinean species. These results agree with our predictions and indicate that the dragonfly fauna of Australia and New Guinea have effectively been separated during the Pleistocene probably due to the prolonged unfavourable climatic conditions in the intervening areas. © 2012 Springer Science+Business Media B.V.

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