Fossils from forgotten time amaze

Rare fossil creatures from a mysterious time known as the Ediacaran are
amongst the most exquisite examples of the earliest complex life, experts
say.

The 560-575-million-year-old specimens from Canada, of marine organisms
called rangeomorphs, are preserved in three dimensions, Science magazine
reports.

The organisms appear to be somewhat plant-like, with "frondlets" - leafy
structures that branch from stems.

These were probably free-floating, elevated above the sea floor by a stalk.

Guy Narbonne, of Queen's University in Ontario, Canada, found the new
assemblage of fossils in an area called Spaniard's Bay in eastern
Newfoundland.

The rocks at nearby Mistaken Point on the island have also yielded Ediacaran
fossils, but these are squashed flat

Lighting the fuse

Dr Narbonne believes rangeomorphs are a single biological group, which can
neither be classified as animals nor as plants.

The Ediacaran Period occurs just before the "Cambrian explosion", an
evolutionary blossoming in which many important animal groups appeared for
the first time.

Professor Jim Ogg, secretary-general of the International Commission on
Stratigraphy (ICS), has speculated that the mysterious Ediacaran organisms
were probably "torn to shreds" by the predatory animals that became more
common in the Cambrian.

The soft-bodied rangeomorphs were probably buried in a mud-flow, which was
itself then covered over by ash from a nearby volcano.

This year, geologists accepted the Ediacaran into their official calendar of
Earth history - the first new period to be added in 120 years.

The organisms may have had an asexual, or vegetative, method of
reproduction.

The Ediacaran begins at the end of the last ice age of the "Snowball
Earth",
or Cryogenian Period, a term given to a series of glaciations that covered
most of our planet between 850-630 or 600 million years ago.

One theory proposes that these climate shocks triggered the evolution of
complex, multi-celled life.

>From BBC
http://news.bbc.co.uk/2/hi/science/nature/3898605.stm

Posted by
Robert Karl Stonjek.
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