Zur Biologie, Taxonomie und Chronologie der Conodonten

The actual state of knowledge concerning the conodont animal is critically reviewed. All soft tissue documented by the specimens of the conodont animal were interpreted by the British collectors as Craniota (Vertebrata) features. Opinions on the precise affinities, however, remain controverse: The alleged chorda could have been a gut, bilateral symmetry, myomery, apatitic biomineralisation occur also in Invertebrata, caudal fins do in Chaetognatha. Even the lobes in the capital area interpreted as sensory organs could have served as aiding organs for food intake. Therefore, the originally sensational findings are reduced to the core issue that the conodont animal had an eel-like body and at the blunt end of it, behind peculiar lobes, the mineralized conodont elements were arranged. As a consequence, a relationship to the Protochordata cannot be excluded. A systematic position of the conodont animal as possible Vertebrata is likely only if organized below the Ostracodermata which is particularly so because conodonts occur so early in the Cambrian. In the second part of the article conodonts are discussed as guide fossils. The comprehensive, empirically grown taxonomy of the single elements is the prerequisite for recognizing outstanding, high resolution stratigraphy. In comparison, a multielement taxonomy remains as long problematical, as it is based on assumed, mostly statistically reconstructed rather than on natural multielement apparatuses. Taxonomical and nomenclatorial operations built on assumed apparatus affinity can bear heavily on nomenclature and stratigraphy of platform elements. It can be shown at the example of the Devonian that the platform elements have provided particularly in the pelagic facies a Standard Conodont Zonation that covers time almost without any gaps. The basis for this is that platform single element species and their phylogenetic development are extra-well known. In a special paragraph, history and applicability of the Standard Zonation is discussed in details. Different conodont biofacies are developed between the pelagic realm where the Standard Zonation originated, and the coastal areas so that conodonts can indicate temporal and bathymetric relationships of the mother rocks. In addition alternative conodont zonations were introduced mainly for the shallow water. Because of their conspicuous stratigraphic significance in the Devonian, conodonts were employed by International Committees to redefine Series and Stage Boundaries. For the boundary selection species were utilized from phylognetic lineages as only from tight evolution their point of origination could be well identified and recognized in worldwide correlation. The GSSPs (Global Stratotype Section and Point) within the Devonian are discussed in detail. In recent times, attempts are made at calibrating the duration of conodont zones on the basis of their well known rate of evolution and high temporal resolution. These analyses have to be continued in order to demonstrate the absolute time relationship of condont zones in more and continuous detail. Currently the phyletically controlled Standard Conodont Zonation is the authoritative stratigraphic method in the Devonian. It has provided together with the GSSPs precise and valuable fix points for a Global Time Scale (GTS). In combination with additional stratigraphie methods the Standard Conodont Zonation may provide further refinements in the future.