Thursday, July 13, 2006

Odontogriphus omalus and the Ediacarans

In this week’s nature there is a report on the Cambrian fossil Odontogriphus omalus (1). P.Z. has a nice write up at Pharyngula but I want to discuss the relationship between Odontogriphus and earlier Ediacaran fossils. It is mentioned in the article that Kimberella may be an ancestor of Odontogriphus but it seems that many of the bilaterian fossils of the Ediacaran have greater similarities particularly Dickinsonia type organisms (2). If that is the case Spriggina, Yorgia and Chondroplon may also have similarities to Odontogriphus although they are probabaly more distant relative than Dickinsonia. It certainly seems that many of the aspects of Odontogriphus morphology can illuminte the similarly squidgy Ediacarans. Anyway here are some pics for comparison:
Odontogriphus omalus from the supplementary material to (1)

Reconstruction of an unnamed dickinsoniid from (2)

The fossil on which the above reconstruction was based. Also from (2)

Following the research on Stromatoveris and Parvancorina it seems that the Ediacarans are finally finding their place on the evolutionary tree.


1) A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale p159
Jean-Bernard Caron, Amélie Scheltema, Christoffer Schander and David Rudkin
Nature 442, 159-163 (13 July 2006) doi:10.1038/nature04894

2) Anatomical Information Content in the Ediacaran Fossils and Their Possible Zoological Affinities
Integrative and Comparative Biology 2003 43(1):114-126; (free full text)
Jerzy Dzik

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