Exquisite Ediacaran Fossils

Researchers in the 16 July 2004 issue of the journal Science have discovered a new set of fossils, their three-dimensional features preserved in fine detail, of the mysterious Ediacaran animals from the Precambrian Period.

The Ediacaran fauna are thought to be the "fuse" of the Cambrian Explosion, in which many of the major animal groups appeared in a relatively brief period of time. Because the Ediacaran animals were soft-bodied, fossil evidence has been hard to come by and these organisms are still poorly understood.

The unusual Mistaken Point assemblage in Newfoundland contains an extensive array of Ediacaran fossils, although researchers have only found two-dimensional impressions there until now. Guy M. Narbonne describes a set of three-dimensional fossils from this assemblage found near Spaniard's Bay with preserved features as small as 30 micrometers.

Like other so-called "rangeomorph" fossils found at Mistaken Point, these organisms appear somewhat plant-like, with leafy structures called "frondlets" branching from stems. The frondlet structures were likely free-floating, elevated above the sea floor by a stalk. The fossils at Spaniard's Bay also reveal some new frondlet arrangements not previously seen.

There are no obvious analogs for rangeomorph structures among modern animals, according to Narbonne.

15 July 2004