species of the day: Vetustodermis planus

[eub]

http://news.bbc.co.uk/2/hi/science/nature/4156544.stm

The 5-10cm-long (2-4 inch) fossil, from Anning in China, had a flattened body and horizontal fins which, researchers think, could have been used to support it as it moved along the sea floor. It also had well developed senses, including a pair of eyes on stalks.
[...]
According to the latest study, the weird creature seems closest to molluscs, primarily because it had a snail or slug-like flat foot. However, the researchers say, it does not sit happily in this group.

"Phyla are defined by an organism having a set of features called characters, and currently there are no animals that we know of which contain the set of characters that Vetustodermis has," co-author David Bottjer, of the University of Southern California, US, told the BBC News website.

"The phylum with which it shares the most characters is the Mollusca, but squeezing Vetustodermis into the mollusca is a somewhat messy job."

Since Vetustodermis requires some "pushing and pulling" to force it into any known phylum, Professor Bottjer and his colleagues are tempted to speculate it belonged to a different group entirely; one which flourished and faded within the Cambrian.

Comments

[aquaeri.livejournal.com]

I just want to bang my head against a desk almost every time I read anything about classification of Cambrian organisms.

[eub.livejournal.com]

I don't know enough about Cambrian taxonomy to headbang, so it's classification of fungal anamorphs that does it to me.

[aquaeri.livejournal.com]

I don't technically know anything about Cambrian taxonomy either, not specifically. But the arguments seem to swing between "everything is part of an existing phylum, why are there no intermediate forms, there ought to be intermediate forms" and "we can't fit this sucker into an existing phylum, it's doesn't have the full suite of characters, let's create a new phylum" so fast it makes my head hurt.