I am disappointed.
I have a soft spot for Kimberella, one of the few Precambrian animals that we can identify with reasonable precision. (Not to mention its pretty name! :D) Our love affair started before I became involved with biomineralisation, which might have contributed to the fact that I totally overlooked Ivantsov (2009).
(Image: Ivantsov’s Kimberella, rendered by the masterful hands of Nobu Tamura. From Wikipedia.)
The paper shows up on Kimberella‘s lovely Wikipedia page as a citation for the following:
The deformation observed in elongated and folded specimens illustrates that the shell was highly malleable; perhaps, rather than a single integument, it consisted of an aggregation of (mineralized?) sclerites.
These days when I’m >this< close to dreaming about biominerals at night, this jumped out at me like a giant neon sign. What? A mineralising animal that old? (I think this was also before I saw Coronacollina.) So I downloaded the paper, and eventually got round to reading it, and…
It’s an alright piece of scientific literature, and it’s got lots of lovely pictures of Kimberella fossils (though Fedonkin et al.  already had a ton of those). I would have been happy about it but for the fact that it totally flopped on the mineral thing. I thought that, you know, Ivantsov had some evidence to suggest that those bumps on the creature’s back were originally made of mineral stuff. And, indeed, his abstract quite confidently states not only that they were mineralised but also the specific mineral:
The fossil material shows that Kimberella had hard sclerites, probably of aragonite…
His reasoning? Let me quote…
The alternation of nodes and coarse folds in the central zone of the fossil may be explained by assuming that the nuclei of nodes were clumps of hard substance, which rapidly destroyed after the death of the animal. Aragonite, which obviously had no chances to be preserved in the terrigenous sediment, which, in addition, was saturated with hydrogen sulfide (Gehling, 2005), could have been such a substance.
I mean, really? They “could have been” made of aragonite because they disappeared? It’s like there is no other tough-ish material that can be destroyed after an animal dies. And he doesn’t go any deeper than that – no discussing/excluding other possibilities, nothing. He just leaves it there.
People, can you please not claim things in your abstracts that you then barely discuss, let alone demonstrate, in the paper?
Fedonkin MA et al. (2007) New data on Kimberella, the Vendian mollusc-like organism (White Sea region, Russia): palaeoecological and evolutionary implications. In: Vickers-Rich P & Komarower P (eds). The Rise and Fall of the Ediacaran Biota. Geological Society, London, Special Publications 286:157-179
Ivantsov YA (2009) New reconstruction of Kimberella, problematic Vendian metazoan. Paleontological Journal 43:601-611