Credneria
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| Credneria | ||||||||||||
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Imprint of a leaf from Credneria triacuminata in the Dresden Botanical Garden |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous to Paleocene | ||||||||||||
| 100.5 to 56 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Credneria | ||||||||||||
| Zenker , 1833 |
Credneria is a fossil genus of the leaves of plane trees from the Upper Cretaceous and the Paleocene of the northern hemisphere.
etymology
These sheets were formally described for the first time by Jonathan Carl Zenker in 1833, who also gave them their name. The corresponding “ petrefacts ” were known beforehand. The name of the genus honors the German theologian Karl August Credner (1797–1857), the brother of the geologist Heinrich Credner , who had given Zenker several such specimens for investigation.
Locations
Most of the pieces have so far been found in Central Germany. For example, pieces of Credneria triacuminata ( Santonium ) that were found in Magdeburg are in the collection of palaeobotany at the University of Münster . Find sites in northern Germany are particularly well-known, for example on the Teufelsmauer , an elongated cliff line off the northern edge of the Harz Mountains. Many impressions of Cretaceous leaves have been and are still found there. Others are in Saxony and Bohemia .
Appearance
The leaves are oval in shape and heart-shaped and petiolate at the base. They have different types of arteries and teeth .
meaning
For a long time, Credneria represented the geologically oldest fossil hardwood plant in Germany. The corresponding fossils are very similar to the foliage of plane trees , which is why the genus is often placed in the family Platanaceae . Their appearance in the fossil record shows the increase in number and diversity in the angiosperms that rose during the Cretaceous .
It is particularly noteworthy that in Blankenburg, for example, Credneria are never found in layers, but only individually in the otherwise fossil-free sandstone . In addition, the leaves of the Blankenburg quarry are mostly rolled up like a bag at the edge or entirely. This gave rise to the assumption that they were warped by drying out and then embedded in sand dunes.
Known species
- Credneria triacuminata
- Credneria cuneifolia
- Credneria bohémica
- Credneria denticulata (Serrated Crednerie, Zenker 1833)
- Credneria subtriloba (almost three-lobed cedneria, Zenker 1833)
- Credneria integerrima (Whole-margined Crednerie, Zenker 1833)
- Credneria biloba (two-lobed crednerie, Zenker 1833)
literature
- Jonathan Carl Zenker: Contributions to the natural history of the primeval world. Organic remnants (petrefacts) from the Altenburg lignite formation, the Blankenburg ashlar sandstone, Jena colored sandstone and the Bohemian transition mountains. Friedrich Mauke, Jena 1833, pp. 15–22 (archive.org).
Web links
- Credneria in the Paleobiology Database
Individual evidence
- ↑ Zenker (1833), p. 16 (archive.org)
- ↑ a b c d Richard Pott: General Geobotany. Biogeosystems and Biodiversity. Springer, 2005, ISBN 3-540-23058-0 , p. 76 f. (GoogleBooks)
- ↑ Heinrich Georg Bronn: Lethaea Geognostica, or illustrations and descriptions of the most characteristic fossils for the mountain formations. 3. Edition. Second volume. E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart 1851–52, p. 55 (e-rara.ch).