Sunday, June 27, 2010

Catholic Church Angry at not Getting Special Treatment

Cardinal Tarcisio Bertone, the Vatican Secretary of State, is annoyed.

Belgian authorities have seized around 500 files, searched church property, and held priests for questioning, over allegations of child sex abuse committed by a certain number of Church figures. The Belgian Catholic Church has previously apologised for it's silence on past sex abuse.

Cardinal Tarcisio Bertone, doesn't like it. He has called the detention of priests "serious and unbelievable". He said that "there are no precedents, not even under the old communist regimes".

He's right, there is no precedent for the church to be subject to the rule of law.

Cardinal Bertone also complained that bishops were kept in church during a search of church premises.

The Catholic Church not given special treatment? Shocking!

Saturday, June 26, 2010

What Does a GOP Apology Cost

By now everyone has heard of Joe Barton, ranking republican on the Congressional Committee on Energy and Commerce and his apology to BP.

However this allows us to calculate a handy base line.

Barton has received a total of $1,447,880 from oil and gas companies, and his apology consisted of 326 words.

The price of an apology from the ranking Republican on a Congressional Committee = $4440.00 per word.

Saturday, June 12, 2010

Palaeoporn 15

You spin my head right round, right round, . . .

Carrying on the theme of Palaeoporn 14, namely moulting in trilobites, here’s one to make your head spin.


The trilobite at the top of the post is a big Redlichia takooensis (around 12-14 cm in length), common in the Lower Cambrian Emu Bay Shale, except that it's head is on backwards and inside out!

First a little background. The trilobite exoskeleton is rigid, and so to grow they need to shed this outer covering, expand, and mineralize another exoskeleton around the expanded body (crabs do this today, with soft crabs – those that have shed their exoskeleton and are awaiting the new exoskeleton to harden - prized as bait.)

Since the exoskeleton is rigid, there needs to be an exit strategy so that the body can get out of the old exoskeleton. This is usually achieved in trilobites by having lines of weakness – or sutures – at strategic places on the body, which preferentially break. These are usually placed on the head and around the eyes, and separate the central part of the head - or fixigena - from the outer part of the head - or librigena - which is also called the free cheeks 'cos they represent the cheeks of the head and they get freed up during moulting.

When the trilobite starts moulting, usually the suture lines break, the exoskeleton around the head separates into fragments (fixigena and librigena), allowing the body to exit through the head, leaving the exoskeleton intact, and the head fragments to fall back into place.


Sometimes it doesn’t go to plan.

The free cheeks can be displaced, but that is usually the trilobite being careless on the way out. But sometimes things go wrong.

For comparison here is a proper R. takooensis (right, trilobite length 5 cm without spine) with its head on straight, fixigena and librigena all facing front and orientated correctly, even if the free cheeks are slightly displaced indicating that it is a moult.

So what happened to our backward friend up front?

Well, I'm pretty sure it wasn't born that way (no offense Jake), so it looks like a moulting accident.

Also the librigena isn't.

Liberated that is.

Although we don't have the whole body, the portion of the head outside of the eye (the librigena) is still in place indicating that the suture did not split.

What probably happened was that once the facial sutures failed to split, the exoskeleton broke behind the head. The animal then exited the old exoskeleton, pushing the head exoskeleton into the vertical and then beyond, which forced the head exoskeleton upside down and the front margin to point backwards.

In other words, imagine the head is an upside down bowl as in the diagram below, where F = front of the head, and B = back of the head.

Instead of splitting along the sutures, the whole head exoskeleton comes detached from the body exoskeleton. The trilobite then pushes its way out by forcing the head exoskeleton to tip 90 degrees onto the front margin, and then 180 degrees to lie upside down, with the front margin now pointing backwards and exposing the internal surface of the head exoskeleton.

The trilobite then escapes the old exoskeleton and is free to go.

Scary stuff perhaps, but not the worst example.

Next time - "Ultimate Moulting - when moulting REALLY goes bad"

Monday, June 7, 2010

Disco Tute Sows. Reaps.

Looks like someone has had enough of the Disco 'tute's butchering of the truth.

The problem for the Disco 'tute is that Steve Matheson not only knows the science, but also is a Christian (not so easy to claim he's an atheistic materialist).

Having had a run in with the Disco 'tute's Steve Meyer and having been beaten around the head and face by what can only be described as a completely-out-of-his-depth Richard Sternberg wealding a feather pillow (see also here and here), Steve Matheson has declared open season on the Disco 'tute.

In a letter to Steven Meyer, Matheson writes in part:

. . . I can't state this strongly enough: the Discovery Institute is a dangerous cancer on the Christian intellect, both because of its unyielding commitment to dishonesty and because of its creepy mission to undermine science itself. I'd like to see you do better, but I have no such hope for your institute. It needs to be destroyed, and I will do what I can to bring that about.

This should be interesting.

Read Steve's account of the discussion of Steve Meyer's book Signature of the Cell at Biola University part I, part II, and part III.

Thursday, June 3, 2010

Squid Wannabes in the Cambrian Another problematic Cambrian form finds a home. Once more the Burgess Shale comes up trumps, with the work of Martin Smith and Jean-Bernard Caron from the University of Toronto/Royal Ontario Museum shedding new light on Cambrian critters and the evolutionary things they get up to.

Ok. This is neat, and a group that occurs in the Burgess Shale, the Emu Bay Shale, and Chengjiang. The Burgess Shale form Nectocaris pteryx, and the closely related forms Vetustovermis from the Lower Cambrian Emu Bay Shale,

and the now not-synonymous Petalilium from the Lower Cambrian Chengjiang fauna, has been re-interpreted as a stem group cephalopod.

The arguments in favour of the forms being stem group cephalopods is persuasive (stem group forms lack one or more features characteristic of the last common ancester of the crown group).

The forms have a number of characters that link them with molluscs, and closely with cephalopods. These include the presence of tentacles - albeit only one pair, an axial cavity containing gills (possibly homologous with the mantle cavity of crown group cephalopods), and a funnel

They are also rare – ninety-odd specimens from the Burgess Shale may seem a lot, but it isn’t really. The Emu Bay Shale form Vetustovermis is very rare. I didn’t find one decent specimen when I worked on the deposit. But rare is good if you are trying to push the mollusc line, because molluscs don’t moult. Arthropods do. And moulds can fossilise. In effect, this is like leaving numerous photocopies of yourself in the fossil record. One arthropod can leave numerous fossils behind. Molluscs can’t. So we would expect them to be rarer than arthropods, as is the case here.

The eyes are interesting. They are preserved differently that other eyes in the Burgess Shale. Usually, eyes are preserved as a carbon film coated by clay minerals. This is similar to body preservation and is taken to indicate that the eyes were compound (made of calcite crystals) and thus robust enough to preserve the same way as the body. In Nectocaris (as in the similar Chengjiang form Petalilium) the eyes are preserved as a carbon film that covers a thick layer of muscovite crystals. This is interpreted by the authors as indicating that the eyes were hollow in life, similar to cephalopod (and our) eyes today, rather than the compound eyes of arthropods.

Another nice feature is the serial repeated pairs of gills. Modern cephalopods have one gill, or set of gills, but the sequence of repeated pairs of gills in Nectocaris (and in Petalilium, and Vetustovermis) is exposing its common ancestry with segmented forms. In other words the common ancester of molluscs and arthropods was a metamerically segmented form (a form with a series of similar segments, like a trilobite or worm). Nectocaris, with its sequence of repeated pairs of gills, is therefore, a neat intermediary between the metamerically segmented ancestral form and the derived, more modern forms that have lost the segmentation. In mean, if you'd have asked a palaeontologist what a stem group cephalopod would look like, the answer would have been paired gills all the way down!

This group appears to lack a horny beak, a radula, a shell, and at least eight tentacles, which is why they are considered stem group forms. The last common ancester of the cephalopods is considered to have had all of these.

I have a few issues however.

First, have to say I’m not a fan of the paper’s title, Primative soft-bodied cephalopods from the Cambrian. “Primitive”! Oh dear, I had though we had stopped using that term – Early perhaps). And they are not strictly cephalopods (they are however, Conchifera). So, "Early Conchiferids from the Cambrian" perhaps (a bit dry I’d admit), or my personal choice, "Squid wannabes from the Cambrian".

Second, I am not a fan of the reconstruction either. Not the drawing itself – I’m a big fan of Marianne Collins’ work – but of the way it hovers with the funnel aimed downward like a Harrier Jump Jet or, as in Nature News and Views, the rocket underneath the Space Shuttle. Ugh!

It’s very unlikely that the funnel would have been used like that. One of the specimens has it in that position (figure “f” in first image) but it is unlikely to represent the life position. Burgess Shale fossils are found in all orientations, and numerous other specimens of Nectocaris have the funnel in various orientations. I think that figure “f” has a bad case of flacid funnel, probably post mortem.

The funnel was probably used to move forwards and backwards, but also maybe to blow fine sediment away from shallowly buried prey, or even blow them so that they tumbled which disorientated them, make them easier to catch. But what prey did they hunt? This is especially interesting given the jaws, or rather the lack of them! Which brings us to . . .

Third, where’s the jaws? It looks like they are absent in Nectocaris. This is strange, as the presence of teeth or radulas are well established in the Mollusca by the Middle Cambrian Burgess Shale time. Modern cephalapods have a beak, but the radula is reduced in octopus, and is absent (or extremely reduced) in Spirula, the Ram’s Horn Squid.

The authors say that the absence could be due to it not being preserved or that it is too small to preserve. I’m not buying that it didn’t preserve. Hard parts of other organisms preserve just fine in the Burgess Shale. But it could be that they were very small. Spirula is a small (around 4 cm) deep water squid that either has a very small or non-existant radula. Spirula feeds on plankton, so it could be that Nectocaris also fed on tiny plankton as well.

There is some vague feature which the authors claim could be mouth parts. If so it would suggest a diet of soft bodies organisms or very small organisms such as plankton.

So three Cambrian forms tidied up quite nicely, and a neat transitional form (gasp!) as well! Cambrian squid wannabes with a hangover from their metamerically segmented ancestry.

Smith, M., & Caron, J. (2010). Primitive soft-bodied cephalopods from the Cambrian Nature, 465 (7297), 469-472 DOI: 10.1038/nature09068

Smith, M., & Caron, J. (2010a). Primitive soft-bodied cephalopods from the Cambrian: Supplimentary Information Nature, 465 (7297), 469-472 DOI: 10.1038/nature09068

Chen, Jun-yuan; Huang, Di-ying; Bottjer, David J. (2005). "An Early Cambrian problematic fossil: Vetustovermis and its possible affinities.". Proceedings of the Royal Society, Part B 272 (1576): 2003–2007. doi:10.1098/rspb.2005.3159.