title: How and why to achieve greater objectivity in taxonomy, exemplified by a fossil ostracod (Amplocypris abscissa) from the Miocene Lake Pannon.
abstract: A project on fossil ostracods from Hennersdorf (Vienna Basin, Middle Pannonian "E" stage) documents the non-marine ostracodAmplocypris abscissa(Reuss 1850) as a polymorphic taxon. The high morphological variability of the valves belonging to this species and its geographic distribution in the Lake Pannon point to a widely spread fossil taxon. This traditional view emerges from the fact that A. abscissa displays few homologous "landmarks" (morphological reference points) which makes it difficult to compare morphotypes within and among populations. The present contribution offers arguments for the need of objective criteria when describing ostracods with few visible morphological traits. It is demonstrated that using a composite algorithmic approach which combines information implemented in the computer programme MORPHOMATICA for different variables, measured on interval and ratio scales, is able to define morphological traits objectively. The data analysed with multivariate statistics are further used for diagnostic profiles of clearly delineated morphotypes. The potential taxonomic value of three morphotypes here identified forAmplocypris abscissais discussed. It is argued that this taxon represents a phylogenetic lineage within which a cluster of species with discrete morphological traits exists. Finally, it is proposed to apply similar algorithms for the necessary revision of the whole group ofAmplocyprisspecies from Lake Pannon.
authors.affiliation: Commission for the Stratigraphical and Palaeontological Research of Austria, Austrian Academy of Sciences, c/o Institute of Earth Sciences (Department of Geology & Palaeontology), Karl-Franzens University of Graz, Heinrichstrasse 26, A-8010 Graz, Austria.
authors.forename: Dan L
authors.initials: DL
authors.lastname: Danielopol
authors.affiliation: Universalmuseum Joanneum, Department for Geology & Palaeontology, Weinzöttlstrasse 16, A-8045 Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Gross
authors.affiliation: Natural History Museum Vienna, Geological-Palaeontological Department, Burgring 7, A-1010 Vienna, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Harzhauser
authors.affiliation: Institute of Earth Sciences, Department of Geology & Palaeontology, Karl-Franzens University of Graz, Heinrichstrasse 26, A-8010 Graz, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Minati
authors.affiliation: Institute of Earth Sciences, Department of Geology & Palaeontology, Karl-Franzens University of Graz, Heinrichstrasse 26, A-8010 Graz, Austria.
authors.forename: Werner E
authors.initials: WE
authors.lastname: Piller
keywords: Comparative Morphology; Fossil Ostracoda; Geometric Morphometrics; Lake Pannon; Late Miocene; Taxonomy