Morphological and ontogenetic criteria for defining a trilobite species: The example of Siluro-Devonian Phacopidae

Catherine CRÔNIER, Arnaud BIGNON & Angela FRANÇOIS

en Comptes Rendus Palevol 10 (2-3) - Pages 143-153

Published on 30 April 2011

This article is a part of the thematic issue The species concept in palaeontology: Ontogeny, variability, evolution

The palaeontological species concept – a rather subjective concept – is based on morphological criteria and carries a notion of time. The delimitation of a species among trilobites does not break this rule and is based on morphological and ontogenetic features. Thus, among phacopid trilobites, characters such as the visual complex and the vincular furrow are diagnostic. Furthermore, quantitative studies of the morphological disparity and ontogenetic trajectories allow us better to define the species and its variability, and to identify the evolutionary patterns established in Phacopidae during 100 Ma of existence.


Trilobita, Phacopidae, Paleozoic, Disparity, Ontogeny, Phylogeny

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