Ediacaran fossils from Newfoundland

I told you I liked fossils, and here are some more that put yesterday's Junggarsuchus to shame in both age and weirdness. Everyone has heard of the Cambrian 'explosion', but there are also collections of pre-Cambrian fossil animals that have always been rather enigmatic—they just don't seem to correspond well to the morphology of Cambrian, or modern, forms.

Some new specimens from the pre-Cambrian have been described in a paper titled, "Modular construction of early Ediacaran complex life forms." They have been collected from 560 million year old rocks in Newfoundland, Canada. The focus of the paper is on patterns of organization: as the title says, these organisms appear to be modular in form, but it isn't the segmental modularity we see today. Instead, these pre-Cambrian animals were built on a fractal branching plan, repeated iterations of a structure called the "rangeomorph frondlet". The result was a creature that looked feathery or fern-like, and when described, it's hard to avoid using terms we usually associate with plants, like "stalk" and "leaf-like". But don't be confused, these are not plants, nor are they anything like modern animals, such as sea-pens, which have also adopted this kind of morphology.

Continue reading "Ediacaran fossils from Newfoundland" (on Pharyngula