Vendobionts (Precambrian evolution)

Article By:

Seilacher, Adolf Institut für Geologie und Paläontologie, Germany.

Last reviewed:2003

DOI:https://doi.org/10.1036/1097-8542.YB030430

Vendobionta is a new taxonomic group based on a reinterpretation of the Ediacaran Fauna, vast fossil assemblages from the late Proterozoic age (600–543 million years ago) immediately preceding the end of the Precambrian Era. The Ediacaran Fauna were previously thought to contain only metazoan (multicellular) ancestors to numerous invertebrate groups. Because of their large sizes, segmentation, bilateral symmetry, and polarity, all the Ediacaran fossils were originally attributed to cnidarians (such as sea pens and jellyfish), annelid worms, and arthropods. However, a new interpretation has emerged for the majority of Ediacaran fossils, arising from functional incongruences which indicate that they were not related to these groups at all. Charniodiscus, for example, resembles modern sea pens in shape and erect attitude; but since its frond was a closed leaf, it would have been unsuited as a filter fan. Similarly, Dickinsonia may be compared to a segmented worm. Yet its pancake shape—nearly 100 cm (39 in.) long and 20 cm (8 in.) wide but only 2–3 mm (0.8–1.2 in.) thick—allowed neither the winding nor the peristaltic modes of locomotion characteristic for worms. Nor does the superficially trilobite-like shape of Spriggina indicate a relationship since, unlike trilobita, Spriggina lacked a carapace. Other vendobionts resemble nothing so much as the leaves of present-day land plants (Fig. 1).

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