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The oldest representative of a modern deep-sea ophiacanthid brittle-star clade from Jurassic shallow-water coral reef sediments

100%

Thuy B., Schulz H.

Acta Palaeontologica Polonica

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2013

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tom 58

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nr 3

Ophiurites crinitus is a fossil brittle−star species which passed largely unnoticed since its original description. In this paper, we redescribe the type material of O. crinitus with the aim to put it into the context of modern ophiuroid systematics, and propose the new genus name Ophiosternle to replace the invalid Ophiurites. The re−assessed species is shown to be a member of the extant deep−sea family Ophiacanthidae, articulated fossils of which are extremely rare. It presents greatest affinities with members of the Ophioplinthaca–Ophiocamax–Ophiomitra clade, of which it most probably represents the oldest known fossil species. The depositional environment of the strata, which yielded the described specimens is interpreted as shallow, storm−influenced marine setting in the immediate vicinity of coral reefs. This contrasts with the distribution pattern of extant species of the Ophioplinthaca–Ophiocamax–Ophiomitra clade, which almost exclusively occur at depths exceeding the shelf break.

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Red Devonian trilobites with green eyes from Morocco and the silicification of the trilobite exoskeleton

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Klug C., Schulz H., De Baets K.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 1

117-123

Latest Emsian (Early Devonian) sediments at the famous mud−moundand trilobite−locality Hamar Laghdad (Tafilalt, Morocco) yielded some red−coloured remains of phacopid trilobites. Closer examination revealed that the eyes of these phacopids are often greenish in colour. EDX−analyses showed that the lenses retained their original calcitic composition, possibly greenish due to Feand Mn−impurities, while most of the exoskeleton was silicified. The silicified parts contain elevated concentrations of iron which causes the red colour. This phenomenon is explained by the porosity of the exoskeleton in contrast to the homogeneous and massive construction of the lenses and their Mg−content. These incompletely silicified trilobites enabled a reconstruction of the silicification process in trilobites. Their diagenetic alteration probably occurred as a result of events associated with the Cretaceous transgression.

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Estimation of minor components in caraway, fennel and carrots by NIRs - comparison of results from dispersive and fourier-transform instruments

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Schulz H., Quilitzsch R., Drews H. H., Kruger H.

International Agrophysics

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2000

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tom 14

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nr 2

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 International Agrophysics

3 Schulz H.

1 De Baets K.

1 Drews H. H.

1 Klug C.

1 Kruger H.

1 Quilitzsch R.

1 Thuy B.

1 2013

1 2009

1 2000

The oldest representative of a modern deep-sea ophiacanthid brittle-star clade from Jurassic shallow-water coral reef sediments

Red Devonian trilobites with green eyes from Morocco and the silicification of the trilobite exoskeleton

Estimation of minor components in caraway, fennel and carrots by NIRs - comparison of results from dispersive and fourier-transform instruments