Rangeomorph

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Rangeomorphs are an extinct, basal kingdom of soft-bodied creatures, neither animals nor plants that appeared 575 million years ago at the beginning of the Ediacaran period. They survived about 30 million years, forming 80% of the fossils found from that period, until the Cambrian explosion of modern species after which they rapidly declined.

In 2004 extremely well-preserved fossils discovered in Newfoundland, Canada revealed some details of rangeomorph structure. They consist of branching "frond" elements each a few centimeters long, each of which is itself composed of many smaller branching tubes held up by a semi-rigid organic skeleton. This self-similar fractal-like structure could have been formed using fairly simple developmental patterns.

Rangeomorphs were unable to move and had no reproductive organs, perhaps reproducing by dropping off new fronds. Rangeomorph communities are most similar to those of modern, suspension-feeding animals, but it is difficult to relate their morphology to any modern animals. They may represent an extinct stem-group near the base of animal evolution.