Ancient Backboned Creature fossil 

 “The discovery of a 1.5-inch vertebrate fossil in Precambrian rocks has pushed back the date of the earliest vertebrates by millions of years. This specimen, found in Ediacaran rocks in Australia, looks like a tadpole with clear muscle segments and a vertebrate body plan. Many scientists are skeptical of its features due to the early rocks it is found in, but it is no surprise to creationists. The evolutionary story of the origin of multicellular life is further confounded by this discovery.” Evolution Exposed, Second Ed., Oldest vertebrate fossil discovered, dsc.discovery.com/news/afp/20031020/vertebrate.html

Response to comment [from a Catholic]:  "...earliest known vertebrate..."

How did colonial organisms get the information required to code for all of the proteins and hormones needed to form different types of cells?

Response to comment [from an atheist]:  "I'd have thought anything found to be more than 10,000 years old would come as a surprise to YECs..."

To some.  They tend to stick between 6,000-10,000 years.

How did colonial organisms share genetic information so that a single cell could develop into many cells that perform different functions?  Has this ever been replicated in the lab?

Response to comment [from a Catholic]:  "...intermediate..."

Does the ability of some new trait ("evolutionary milestones") to give an advantage, like bilateral symmetry, make it likely to evolve?  Does evolution offer predictable claims about what advantages are expected to enhance survival?   If we don't know when it has occurred?

Ancient Backboned Creature fossil