Evolution in Foraminifera
نویسندگان
چکیده
منابع مشابه
The evolution of early Foraminifera.
Fossil Foraminifera appear in the Early Cambrian, at about the same time as the first skeletonized metazoans. However, due to the inadequate preservation of early unilocular (single-chambered) foraminiferal tests and difficulties in their identification, the evolution of early foraminifers is poorly understood. By using molecular data from a wide range of extant naked and testate unilocular spe...
متن کاملIterative evolution of digitate planktonic foraminifera
—Digitate shell morphologies have evolved repeatedly in planktonic foraminifera throughout the Cretaceous and Cenozoic. Digitate species are usually rare in fossil and modern assemblages but show increased abundance and diversity at times during the Cretaceous and middle Eocene. In this paper we discuss the morphology and stratigraphic distribution of digitate planktonic foraminifera and establ...
متن کاملMolecular versus taxonomic rates of evolution in planktonic foraminifera.
Neogene planktonic foraminifera are among the most widely used microfossils in the study of tempo and mode of evolution. Comparisons of taxonomic rates between the two major clades in this group have shown that the nonspinose globorotaliids have undergone a significantly more rapid evolutionary turnover than the spinose globigerinids (S. M. Stanley et al., 1988, Paleobiology 14, 235-249). In or...
متن کاملActin Phylogeny of Foraminifera
Molecular phylogenies of foraminifera are commonly inferred from the small subunit rRNA (SSU) genes, which can easily be obtained from single cells isolated from environmental samples. The SSU phylogenies, however, are often biased by heterogeneity of substitution rates, and their resolution of higher level relationships is often very low. The sequences of protein-coding genes provide an import...
متن کاملBa incorporation in benthic foraminifera
Barium (Ba) incorporated in the calcite of many foraminiferal species is proportional to the concentration of Ba in seawater. Since the open ocean concentration of Ba closely follows seawater alkalinity, foraminiferal Ba /Ca can be used to reconstruct the latter. Alternatively, Ba /Ca from foraminiferal shells can also be used to reconstruct salinity in coastal settings in which seawater Ba con...
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ژورنال
عنوان ژورنال: Nature
سال: 1963
ISSN: 0028-0836,1476-4687
DOI: 10.1038/2001034a0