Boffins ID freakish spine-smothered prehistoric critter: The claw gave it away

Old news

I'm pretty sure I read this a couple of years ago and stuffed the cutting into my copy of Stephen Goulds' Wonderful Life: The Burgess Shale and the Nature of History - but Hallucigenia always makes good copy.

And the book is still an excellent read even if some of the ideas have been shown to be incorrect - that's how science works.

Legs modified for chewing

“The peculiar claws of Hallucigenia are a smoking gun that solve a long and heated debate in evolutionary biology ... ” said Dr Smith.

Top notch boffinery!

'“An exciting outcome of this study is that it turns our current understanding of the evolutionary tree of arthropods – the group including spiders, insects and crustaceans – upside down,” said Dr Javier Ortega-Hernandez, the paper’s co-author.'

Much like the original renderings of this oceanic nightmare beast. Turned upside down that is.

Tardigrades

Wonderful critters - can survive vacuum, freezing to almost 0K, radiation, dehydration.

And they look cute for microscopic animals.

The excellent Attenborough series Life on Earth has the Hallucigenia upside down. It's still a great series though.

says:

I first saw Hallucigenia in an old coffee table book "The Rise of Life" by John Reader (yes, I still have it.)

My first thought on seeing the picture is "surely they have it upside down". The spindly little spine legs would sink into the sea bottom ooze. The waggly other protruberances would certainly make a better method of propulsion, whether walking or swimming. I deferred to the paleontologists who discovered the thing, but it is nice to be right.

Link to the actual paper

Presumably as a result of strict anti-drug laws forbidding references to hallucigenia, the identity of the actual paper in question was censored from the story. Never fear, here it is:

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13576.html

The Charge of the Light Brigade?

Sounds like a lot of excellent old-style paleontological analysis. But, then there's this:

"Most gene-based studies suggest that arthropods and velvet worms are closely related to each other; however, our results indicate that arthropods are actually closer to water bears, or tardigrades, ..."

Their results use "cladistic analysis", which is basically creating a family tree by counting up matching features, then putting individuals with the most shared features closest together. The problem with this is, of course, that it's the human analyst who decides what's a feature and what's not. One analyst may count all hair on an organism as a single feature, while her compatriot counts scalp hair, facial hair, leg hair, nose hair, and ear hair(!) each as a separate feature. Since there's no objective *amount* of difference between features, the analysis is skewed by the choice of features.

The introduction of DNA analysis for use in creating evolutionary family trees has largely overcome this problem. Not only is DNA the actual genetic material specifying the creature's features, but one can often identify similarities between organisms' DNA that don't show in the physical animal (e.g. mutated genes that no longer can produce a gene product), or see that a feature that seems to be present in two animals is in fact encoded by unrelated genes in each, and thus is not an indicator of evolutionary relatedness (e.g. eyes that came about via completely different evolutionary routes).

Of course, if one compares only a tiny portion of the genomes of two animals (perhaps even just one or two genes), the chances of making an error in the evolutionary ordering are greatly increased. I hope that's the situation the paper's author is referring to here, rather than claiming to have overturned a robust DNA-based evolutionary tree.

New ! Amazing ! Wrongco Proxy Crock !

In the mid seventies biologists were confronted with a single celled life form that was SO DIFFERENT from other 'known' lifeforms that they split all life into three categories, Bacterium, Phylum and Archaea. The Archaea live in the most extreme environments imaginable, including sea floor volcanic vents and the two mile ice capped Lake Vostok. These life forms live on Carbon that is independent of atmospheric C14 ratios, and being at the base of the food chain, cause anomalies in the life forms that feed on them. Fresh killed seal and penguins in Antarctica show a Carbon-14 date of 3000 years old, explained in the "Wrongco Proxy Crock" article in archive at Canada Free Press and under Satire at Faux Science Slayer site, where there is a range of subjects on the current false paradigm reality.

They get a

Tardy grade: 2.7