Evidence Trilobites Were Snacked On

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

with pictures.

http://news.bbc.co.uk/2/hi/science/nature/3622091.stm

Direct evidence has now been found to show that trilobites - among the
most diverse of fossil animal groups - were eaten by other ancient sea
creatures.

Scientists discovered cracked trilobite body parts in the gut of a
510-million-year-old fossil marine animal.

It was long suspected that the ubiquitous trilobites, which survived for
about 300 million years, were a major food source for larger creatures.

New research in Biology Letters offers the first firm evidence for this. 
...
US, French and Chinese researchers identified fragments of the hard outer
shell of trilobites in the fossilised gut contents of an unknown animal
from the Kaili Formation, a sequence of rocks from southern China dating
to Middle Cambrian times.

The broken up pieces of trilobite exoskeleton are each about 1mm in length
and are stacked on top of each other.

But by using a scanning electron microscope, the researchers were able to
identify features on the chewed-up shell fragments known as scrobicules,
pitting on the surface of the shell, that are typical of so-called
eodiscoid trilobites. 
...
"It's very interesting. It's about as direct evidence as you can get,
even better than having coprolites - fossilised faeces," Professor Simon
Conway Morris, a palaeobiologist at the University of Cambridge, UK, told
BBC News Online.
...
The researchers say the animal which ate the trilobites is unlikely to
have scavenged them because all the gut contents appear to belong to one
animal.

"We're fairly confident this specimen provides actual evidence of
predation," co-author Heyo Van Iten, associate professor of geology at
Hanover College in Indiana, US, told BBC News Online. 
...
They have also found dark-coloured nodules in the digestive canal of the
creature, which appear to contain spherical bacteria.

The team suggests these nodules are well-developed digestive glands, which
are present in other Cambrian arthropods with presumed predatory habits.

The gut contents belong to an arthropod which has some similarities to the
creature Fuxianhuia, known from early Cambrian rocks in Chengjiang, China.
But not enough of the creature remains for it to be named. 
...