This fossil is from the latest Precambrian (Vendian) of the Winter Coast
of the White Sea, in north Russia, just north of the city of Arkhangel'sk.
No one is entirely certain what it is. It was clearly soft-bodied in
life -- specimens are often found crinkled, folded, or even folded part way
over. It seems to have had a definite "head" end, but its body segments
alternate up the midline (like the fingers of two folded hands), and the
"head" is asymmetrical. Some specimens show light zigzag lines that are
probably muscles, and the specimens are often preserved in what look like
contracted or distorted positions, which further suggests that they had
some sort of muscles in life. The "head" contains unusual branching structures
that may have been some sort of digestive organ. At any rate, many arthropods
have similar finely branched extensions of the gut, branching off in the
head region and forming the digestive glands. But this fossil isn't an
arthropod. There's no sign of legs, and the asymmetrical segmentation
isn't like anything seen in typical arthropods.
In 1994, I found the first specimen of this oddball, preserved as an impression
on a loose block of fine sandstone that had slid down from some crumbling bluffs
on the White Sea coast, near the mouth of Yorga Creek. I remember coming back to
camp and saying to my Russian colleague, Andrei Ivantsov, "Nashól
trilobít!" (I found a trilobite!). . . and he got a little annoyed because he thought
I was teasing him. . . until he came to the site the next day, agreed that I had in fact
found something weird and noteworthy, and carefully chiseled the fossil off
the sandstone block.
The next year, Andrei found several more of these things at a new locality on
the White Sea coast. He described the thing in a paper pubished in 1999. It's not a
trilobite. . . But even so, Andrei did me the great honor of naming it after me. Yes,
this is the world-famous fossil Yorgia waggoneri. The fact that no one has
any idea what kind of organism Yorgia waggoneri is, I find to be
somehow deeply appropriate and satisfying.
See: Ivantsov, A. Yu. 1999. A new dickinsoniid from the Upper Vendian of the
White Sea Winter Coast (Russia, Arkhangelsk Region). Paleontological
Journal 33(3): 211-221. The specimen figured above is in the Paleontological
Institute (PIN) of the Russian Academy of Sciences, Moscow, specimen number
3993/5007.