Taxonomy Including Morphology

The taxonomy section of the database covers data on the actual state of classification and morphological characteristics. They are stored in special records of the families, genera, species, and specimens in open nomenclature. The relational character of the databases allows the user to switch easily from the taxa database to the databases with the Geographic data or the Literature. The records of most families and genera contain extended descriptions with the current state of their diagnosis and definition. Synonymy lists of all taxa are stored in the note attached with each record.

But what do we really observe? Certainly not genera: nobody knows the extension of a genus; there is no generally accepted definition. The species concept provides the basic information about the diagnosis in which at least one character or one combination of characters is described as unique in this unit. But we do not know very much about the variability of the species under consideration unless we have a sufficient number of individuals. As can be seen in GONIAT, a large number

Fig. 4.1 Main window and part of the table view of the Taxa database.

of species are based just on a single specimen, the holotype, without any paratype. Because we have normally only conchs of the animal, we do not know if there are several species using the same conch shape. Ontogenetic investigations are rather rare. What we only have in reality are the characteristics of the shell. With respect to mass extinction, we must keep in mind that we are speaking only of characters that disappear or come up later in times of recovery. GONIAT is especially designed for investigation of the qualitative or morphologic changeover of the ammonoids. It concentrates on the duration of morphologic characteristics as expressed in the data on first appearance, last appearance, general frequency, and extant taxa. Two different databases, one for the early and middle stages of ontogeny (if known), the other for the adult conch shape, provide information on the ontogeny of the species.

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