550 mya Hard Shelled Fossil Found

[Richard W Travsky <rtravsky@uwyo.edu>]

http://news.bbc.co.uk/hi/english/sci/tech/newsid_2070000/2070564.stm

Scientists have glimpsed the earliest days of sophisticated life on Earth.

They have discovered the fossilised remains of a marine animal - perhaps a
sponge or coral - which they say lived nearly 550 million years ago.

The creature's hard, shelly parts are far more complex than anything else
found from this time. 
...
"This was a crucial time in evolution in terms of the fossil record," said
Dr Rachel Wood, from Schlumberger Cambridge Research, UK. "It is when the
light turned on, as it were. 
...
Dr Wood and colleagues report their findings in the journal Science. They
found their fossil organism in what remains of a giant reef in southern
Namibia.

The creature - classified as Namapoikia reitogensis - lived in the deep
fissures or cracks in the reef. It is comprised of a series of tubules,
each just a few millimetres in diameter.

These hard parts are fully biomineralised; they are not leathery like the
skeletons of other creatures from this time.

If it was a coral, each tube would have probably housed a polyp with
tentacles. If it was more like a sponge, its entire surface would have
been covered in a thin veneer of tissue; small canals would have acted as
a filtration unit to pull food out of the water.

The features displayed in fossil have until now only been seen in
specimens that are 15 million years younger.

The primitive nature of N. reitogensis means it is impossible to say
whether it is really a Poripheran (sponge) or Cnidarian (coral). 
...