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Figure 2.3 The medusoid phase of a living aequorian hydroid. Diameter approximately 1 cm. compaction, would have been greater. In chapter 5 we see how recognition of the convex-side-down aspect of Ediacaran medusoids was the precursor to Garden of Ediacara theory, the concept that these medu-soids were actually bowl-shaped solar collectors. Many Ediacaran medusoids are three-dimensional fossils filled with fine sediment. The Mexican specimen figure 2.1 is one of these, as is the Irish find. How...
Medusoids
The most common Ediacaran body fossils were the first type discovered at the classic site in the Ediacara Hills, South Australia. Circular or discoid Ediacarans are conventionally called medusoids, in an intentional comparison to the free-swimming medusa phase of the jellyfish life cycle. This is perhaps unfortunate because it is by no means certain that Ediacaran medusoids were related to the jellyfish medusa. However, the name has stuck.8 The term medusa refers to the tentacles of living...
Dorion Sagan
Virtually as soon as earth's crust cools enough to be hospitable to life, we find evidence of life on its surface. But we are latecomers, and just as we must be familiar with the beginning of a mystery novel to understand its end, we must scrutinize the often ignored early phase of evolution. Mark McMenamin's allusively named Garden of Ediacara hones in on some of the key events and players in life's early phase a time for the biosphere that, like the first three years of a human life, is not...