Evolutionary Relationships within the Avalonian Ediacara Biota: New Insights from Laser Analysis  

This talk will focus on new high resolution scanning of the type material for the earliest, complex Ediacaran genera Charnia, Charniodiscus, Bradgatia and Ivesheadia from Charnwood, UK, and compare these with the recently described Beothukis mistakensis, Charnia wardi,  C. antecedens and Fractofusus spp. from broadly coeval strata in Newfoundland.  We use laser and other techniques to both map and discuss the similarities and differences in morphology between these Ediacaran forms.  Key features can now be seen to include the number of growth axes, the number and placement of growth tips, the presence of radiating or sub-parallel axes for the first and smaller order branches; the extent of displayed or undisplayed leaf-like architecture; and the extent of furling of the margins of these leaf-like elements.  We use these origami-like features to suggest homologies between the major taxa, leading to a preliminary phylogenetic hypothesis for the evolution of the Avalonian Ediacara biota.