Detection of ecophenotypic variation in fossils and its application to a Jurassic scallop

Abstract

Johnson, Andrew L. A. 1981 12 15: Detection of ecophenotypic variation in fossils and an application to a Jurassic scallop. Lethaia, Vol. 14, pp. 277–285. Oslo. ISSN 0024–1164. It is possible that variation in fossils might often be ecophenotypic. and for sy tematic purposes a method is needed to distinguish ‘environmental’ from ‘genetic’ variation. Baaed on recognition of the fact that ecophenotypes are almost always a product of developmental flexibility, a method is developed to facilitate their recognition in at least certain types of fossil. It ia predicted that ecophenotypically varying organisma should be characterised by an ontogenetic reduction in variation and (between samples derived from different environments) an ontogenetic divergence in mean form. An attempt is made to determine whether variation in some Jurassic scallops. suspected of being ecophenotypic, is indeed so. The attempt is a failure, but on the basis of analogy with a living species it is strongly suspected that the paradoxical results obtained are the result of insufficiently localised sampling of a Species which reacted to environmental differences within the apace of a few metres. Invalidity of the basic method is not necessarily implied. *Phenohpic variation. genotypic variotivn. Pelercypoda, Pectinidar, Propeamussiidae. Jurassic, methodology.