Coronacollina aside: great discovery + science communication fail = grumpy Mammal.
Now that we’ve drunk a few metaphorical beverages of choice to the melodiously named little sponge, allow me a rantish tangent on the terribly written press release that accompanies the paper. It makes me roll my eyes right off the bat by saying that “life” exploded in the Cambrian. No, no, no. Animals did. Plenty of other life forms didn’t, far as I know.
This, especially the part I bolded, just seems to come out of nowhere: “The finding provides insight into the evolution of life — particularly, early life — on the planet, why animals go extinct, and how organisms respond to environmental changes. The discovery also can help scientists recognize life elsewhere in the universe.” Excuse me, but where the fuck did that come from? Needless to say there’s not a word about extraterrestrial life in the entire paper, and not much about extinction or environmental change, either.
Then the article goes on to, well, not so much “suggest” as outright claim that no Precambrian animals with hard skeletons were known before this discovery: “’Up until the Cambrian, it was understood that animals were soft bodied and had no hard parts,’ said Mary Droser, a professor of geology at the University of California, Riverside, whose research team made the discovery in South Australia. ‘But we now have an organism with individual skeletal body parts that appears before the Cambrian.’” Cloudina and Namacalathus beg to differ, and I would bet money that Mary Droser knows this. In fact, Cloudina is referenced in the paper as an example of Precambrian hard parts. I’m undecided on what’s worse, if Droser fibbed about the fossil record, or if whoever edited her comments was clueless. And this is a fairly important piece of information, as the truth makes the significance of poor Coronacollina slightly less obvious. (Hmm…)
The next “highlight” (lowlight???) is where it says Coronacollina was constructed like Cambrian sponges. No, it was constructed like a Cambrian sponge, and an unusual one at that. There were many other Cambrian sponges that looked nothing like these prickly cones, see an assortment from the Burgess Shale here.
Then comes this characterisation: “[C. acula was s]haped like a thimble to which at least four 20-40-centimeter-long needle-like “spicules” were attached…” Um, someone didn’t read the paper here. It’s at most four in the known specimens, although the authors do speculate that there could’ve been more in life. And the lower end of their lengths has one fewer zero…
The crowning misreading near the end: “Droser explained that the spicules had to have been mineralized because the casts show they are ruler-straight. Moreover, they broke.” Dear article writer, I don’t know what she “explained” in person, but the paper describes the spicules (bolding mine) as “straight, rigid structures that were most commonly broken once disarticulated. Some spicules display a slight deviation from ruler-straight, implying either a composition of chitin that was plastic during life, or a mineralized composition of biogenic silica or calcium carbonate preserved deformed due to plastic behavior postburial” Newsflash: chitin is not a mineral. Granted, later in the paper they reason that some sort of mineral is most likely due to the apparent brittleness of the spicules, but they clearly don’t rule out a mainly organic composition.
Grah. I hate how press releases often get so many things wrong, and this one isn’t even a decent piece of writing. Disappointing doesn’t even begin to describe it.