Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

Intraspecific morphological variation of Agnostus pisiformis, a Cambrian Series 3 trilobite-like arthropod

  • Illiam Jackson
  • Graham Budd
Publishing year: 2017-03-15
Language: English
Pages: 467-485
Publication/Series: Lethaia
Volume: 50
Issue: 4
Document type: Journal article
Publisher: Taylor & Francis

Abstract english

The study of evolution in a palaeontological context is chiefly the study of change in shape and form. This requires data sets that quantify morphology and morphological variation. Historically morphology has been described using discrete characters or more recently using various morphometric approaches. Elliptical Fourier analysis (EFA) is an approach to quantifying morphology that results in the production of large data sets of elliptical Fourier descriptors (EFDs), which are highly suitable to multivariate analysis. EFA is used in this paper to quantify the shape and describe the ontogeny of Agnostus pisiformis (Wahlenberg 1818: Nova Acta Regiae Societatis Scientiarum Upsaliensis 8, 1), a trilobite-like arthropod of Cambrian Series 3, from three coeval localities in Sweden. An ontogenetic difference was detected between geographically distant populations from Västergötland and Skåne in Sweden. These differences are probably the result of environmental dysoxic stress leading to increasing phenotypic variation. These findings illustrate the utility of EFA applied to the study of fossil organisms; permitting studies of such high resolution that multiple assemblages of the same species can be comparatively studied to achieve a more detailed understanding of their morphological and ontogenetic variation.


  • Geology


  • ISSN: 0024-1164
Illiam Jackson
E-mail: illiam [dot] jackson [at] biol [dot] lu [dot] se

Postdoctoral fellow

Evolutionary ecology

+46 70 395 22 79