davegodfrey: Coelacanth (Science)
Other than the first one, (in March 2009) where I discussed the deeply awesome Dorothy Hodgkin, I've utterly failed to do anything about Ada Lovelace Day. Mostly because at least initially it tended towards the technology, engineering, and computing side, and I'm a blue-skies scientist type.

When I was growing up there were two people presenting programmes about astronomy on the TV (somehow I managed to miss out on Carl Sagan)- Patrick Moore, and Heather Couper.

So I'd like to raise a glass to Carolin Crawford. Gresham Professor of Astronomy, (a post Heather Couper once held) and a regular on the BBC's In Our Time, which you can download for free. (Such as this episode on asteroids, with Monica Grady).

Being the Gresham Professor of Astronomy, she presents public lectures, such as this one about Saturn-

davegodfrey: Coelacanth (Science)
As usual the world has shown its knack for horrific timing. A day after the death of Caroline John who played one of the few Doctor Who companions who could match him in a battle of wits, and who I'm sure did much to inspire many women scientists (and indeed women generally) who saw that yes, you can be whatever you put your mind to even if you're "just a woman" we have this from the EU.

Here's the teaser trailer.

Are you done with the vomit bucket yet?

To be fair, the profile videos are pretty good- here's Joanna Zmurko, a Polish student working for a PhD in Virology in Belgium:-

She makes a pretty good case for why science is so cool. "On Friday I didn't know what the function of a certain gene was, but on Monday I did". That one sentence will do more to inspire young women to go into science as a career, than any number of flashy ads with pouts, lipstick, high heels and short skirts.

Naturally enough twitter has completely exploded against this #sciencegirlsthing, and the alternative #realwomenscientists is doing very nicely. Rarely has the "can we make maths pink?" joke felt more like reality.

If you want to inspire women to be scientists tell them the story of Vera Rubin, who had to meet her prospective PhD supervisors in the departmental lobby because women weren't allowed inside the offices, and provided the evidence that convinced people that Dark Matter exists.

How about Cecilia Payne-Gaposchkin, who showed that the sun was made of hydrogen, and said:

"The reward of the young scientist is the emotional thrill of being the first person in the history of the world to see something or to understand something. ... The reward of the old scientist is the sense of having seen a vague sketch grow into a masterly landscape."

You want inspirational women scientists- Caroline Herschel, sister of the more famous William (who discovered Uranus), was a first-rate astronomer, and was the first woman awarded the Royal Astronomical Society's Gold Medal (the second? Vera Rubin). Or Margaret Burbidge, coauthor of the B2FH theory, that still explains how the elements up to iron are made, and is an ardent feminist who turned down the Annie Jump Cannon (another female astronomer) Prize because it was only given to women.

And that's just four of the astronomers I could name off the top of my head. You want biologists? Barbara Hastings, Dorothea Bate, Miriam Rothschild, Mary Lyon. We have Florence Nightingale to thank for the pie chart- I'd argue that was a far more important contribution to medicine than being "the lady with the lamp".

But no. We have high heels, lipstick, and pouting. Its enough to make you give up and become a hairdresser...
davegodfrey: Coelacanth (Science)
Readers may have noticed that I have a bit of a thing for science communication. When its done well its beautiful to watch. Some scientists have a real flair for presentation (admittedly some don't- being an educator is hard.) But I haven't met a scientist yet who hasn't enjoyed talking to people about the research they do and why they do it.

Its one of the reasons I love UCL's "Lunch Hour Lectures" series (available on YouTube), the NHM's "Nature Live" programme of short talks,(which sadly aren't made available on the web these days), and the RI Christmas Lectures for the younger viewers.

The Vega Science Trust has put a whole load of science videos up on the web. There's lectures from the RI by Jocelyn Bell-Burnell, about how weird pulsars are (complete with the sort of demonstrations I recall from the RI Christmas Lectures of my youth), Richard Feynmann giving the Douglas Robb Lectures at the University of Auckland, and interviews with all sorts of Nobel Laureates and other scientists.

TV? Who needs one.
davegodfrey: South Park Me. (Default)
When I was a lad I read every dinosaur book I could get my hands on. And this being 20+ years ago much of what I read then is now out of date. Pterosaurs are now always shown as furry, when then there were somewhat brief dismissive mentions of this "Hairy Devil" from the USSR. Sauropods have been rescued from near-certain death by suffocation from snorkeling about in lakes. (The pressure from water at this depth would have crushed their lungs and irreparably damaged their hearts had they tried this. The German physiologist Robert Stigler tried breathing through a six-foot tube and suffered heart damage as a result.)

But one thing was almost universal. Sauropods weren't doing very much in the Cretaceous other than dying out. From their heyday in the Late Jurassic, when Diplodocus Apatosaurus and Brachiosaurus stumped about the place, by the Late Cretaceous the world was full of horned dinosaurs, flamboyantly crested hadrosaurs, spiky club-tailed ankylosaurs and the like. Occasionally you'd find mention of Alamosaurus, a 21 metre 30 tonne sauropod from New Mexico. But it was usually in the "A-Z" type books and tended to get three lines if that.

Now it turns out that a fair bit of this is the result of historical bias. The USA and Canada were the scene of some very intensive collecting during the 19th and early 20th centuries, followed by Roy Chapman Andrews expedition to Mongolia. The rest of the world didn't get much of a look-in. Which is a shame, because in the rest of the world there doesn't seem to have been much of a change. Hadrosaurs and ceratopsians were largely an Asian and American specialisation, and in North America the sauropods seem to have died out completely for 30 million years before Alamosaurus turns up to see out the Cretaceous. But in South America, for example, the sauropods thrived, and grew to even bigger sizes than the Jurassic Morrison Formation ones that everyone knows (Brachiosaurus, and its African cousin Giraffatitan)- despite being relatively poorly known (and in some cases poorly measured) Futalognkosaurus, Argentinosaurus and Puertasaurus were among the largest dinosaurs known, dwarfed only by the semi-mythical Amphicoelias fragillimus.

The impression that I got all those years ago was that this dinosaur was small (relatively), and not exactly common. Which is utterly and completely wrong. Alamosaurus crops up all over the place, and is a very common dinosaur. And while the size estimates might not have got much of a mention (we are talking about the era when Brachiosaurus was supposedly weighing in at 80 tonnes- roughly double the modern estimate), Alamosaurus was still the biggest dinosaur in the USA at the time. And yet faced with all the crazy horned, crested, spiky chaps it still doesn't get much of a look in.

But with a bit of luck this might change, and poor ignored Alamosaurus might get back into the kids books. Denver Fowler and Robert Sullivan would like to introduce you to SMP VP-1625, SMP VP-1850, and SMP-2104. A portion of the femur, a neck vertebra and a tail vertebra respectively. They're big. Really big. Argentinosaurus-sized big.

So all those fantasies about T. rex versus the uber-sauropod just became scientifically viable. Woohoo!

Lehman, T.M. & Coulson, A.B. 2002. A juvenile specimen of the sauropod Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National Park, Texas. Journal of Paleontology 76(1): 156-172.

D’Emic, M., Wilson, J., & Thompson, R. (2010). The end of the sauropod dinosaur hiatus in North America Palaeogeography, Palaeoclimatology, Palaeoecology, 297 (2), 486-490 DOI: 10.1016/j.palaeo.2010.08.032

Denver W. Fowler and Robert M. Sullivan (2011) The first giant titanosaurian sauropod from the Upper Cretaceous of North America. Acta Palaeontologica Polonica in press available, online 07 Feb 2011 DOI:10.4202/app.2010.0105

After Man

Dec. 11th, 2010 01:02 pm
davegodfrey: Coelacanth (Science)
I am a massive fan of speculative zoology. I adore the whole "what if the dinosaurs hadn't died out" ideas, and like many people of my generation I owned lots of books about dinosaurs many of which were written by Dougal Dixon. Who, back in 1981 wrote "After Man: A Zoology of the Future". He also subsequently wrote "Man After Man", which is essentially full on Sci-Fi, though I have to say that Nemo Ramjet did the whole "the next 500 million years of human evolution" thing better in All Our Tomorrows" (seriously, read it, its freaking awesome, if not a little nightmarish in places). In 1988 "The New Dinosaurs", which I read before Jurassic Park came out. Sadly this is the one that doesn't stand up that well to the massive amount of stuff we've learnt about maniraptorans and the like since then. Specworld is a very good modern version.

But its After Man, which was the first, and I think still the best. Not all of the future animals are particularly practical- I agree with Tricia that tusks on a mole are just dumb. but the hypercarnivorous rats are a masterstroke.

But I mostly want to point out that Japan seems to have gone completely nuts for him. There was an hour-long program (sometime in the '80s by the looks of it) with some rather lovely stop-motion animals. I think it also talks a lot about other aspects of evolution, but I don't speak Japanese, so I have no idea exactly what they're talking about, but there's shots of the Galapagos and that kind of thing.

And if that wasn't enough, someone made a cartoon sequence with all these animals in it. Which would be perfectly sane if that happy dancing bipedal baboon wasn't supposed to be the size of a Tyrannosaurus

But what I most want is this the "After Man" model kit. (It looks like there was more than one "After Man" cartoon based on that too. And yes, the Nightstalker, a flightless, blind, bipedal, killer bat, from Hawaii, really was supposed to be five feet tall. Call Roger Corman, I've got an idea for a film...
davegodfrey: Coelacanth (Science)
Just quickly breaking radio silence to mention that "Inside Nature's Giants - The Giant Squid" will be shown on the 14th of October at 9pm on Channel 4. I don't know when it will make it over to "Foreign Parts" I'm afraid, nor if one can access Channel 4 On Demand from such places either.

But it looks freaking awesome. 75 minutes of squid dissection on prime-time TV! Suckers! Beaks! Gladii! Nidmental glands!
davegodfrey: Coelacanth (Science)
     Conservapaedia, that bastion of idiocy got its arse handed to it when trying to pick fights with scientists over the Long Term Evolutionary Experiment . This is a multi-million generation breeding experiment involving bacteria, that turned up all sorts of interesting things, including some novel characters of the sort the average creationist claims can't exist. Knowing where to pick its fights its gone after that well-known shaky theory, beloved of Liberals, Relativity.

Andrew Schafly & Co. vs. Physics. Fight! FIght! Fight!

I'm not a physicist, but even I can see most of this is bollocks, and if a physicist can point out to me where I'm going wrong I'd be very grateful.

"The theory of relativity is a mathematical system that allows no exceptions. It is heavily promoted by liberals who like its encouragement of relativism and its tendency to mislead people in how they view the world.[1] Here is a list of 29 counterexamples: any one of them shows that the theory is incorrect."

Now I'm no physicist, but at a cursory glance even I can tell half of this is just crap.
  • The Pioneer anomaly.
  • Anomalies in the locations of spacecraft that have flown by Earth ("flybys").[2]
And how large are these anomalies? I have no idea what caused this- but it could be something to do with the spacecraft itself, unobserved bodies, etc. Its interesting its not been seen with the other probes or indeed planets
  • Increasingly precise measurements of the advance of the perihelion of Mercury show a shift greater than predicted by relativity, well beyond the margin of error.[3]
  • The discontinuity in momentum as velocity approaches "c" for infinitesimal mass, compared to the momentum of light.
  • The logical problem of a force which is applied at a right angle to the velocity of a relativistic mass - does this act on the rest mass or the relativistic mass?
I've no idea. I was never very good at physics. Perhaps the physicists have worked this out? Have you asked them?
  • The observed lack of curvature in overall space.[4]
Space is really, really big. You won't believe how mindbogglingly big it is. I mean, you might think its a long way to the shops, but you can't see the curvature of the Earth at that scale, and that's peanuts compared to space.
  • The universe shortly after its creation, when quantum effects dominated and contradicted Relativity.
We know that QM and relativity don't mesh together. Just because at the very small it doesn't work doesn't mean its not a good theory. it explains lots of things at the very big.
  • The action-at-a-distance of quantum entanglement.[5]
  • The action-at-a-distance by Jesus, described in John 4:46-54.
1. This is another QM vs GR argument. 2. You're taking the word of a book that thinks locusts have four legs against that of mathematics?
  • The failure to discover gravitons, despite wasting hundreds of millions in taxpayer money in searching.
We can't find it therefore it doesn't exist. Gravitons are really had to see. Hell, gravitational waves are really hard to see- you need huge laser beams and supernovae to detect any sign of them. I'm not surprised they're elusive. And aren't gravitons a QM thing anyway? Does relativity require that they exist?
  • The inability of the theory to lead to other insights, contrary to every verified theory of physics.
Well, mainly the things it explains are really big, and really far away. Just because 20th Century physics got obsessed over atoms doesn't mean there aren't things being done with relativity. And are you seriously suggesting that "Not been helpful = Not true" Seriously?
  • The change in mass over time of standard kilograms preserved under ideal conditions.[6]
I think that has rather more to say about what the standard kilogram is made of than it does about black holes, etc, etc.
  • The uniformity in temperature throughout the universe.[7]
Isn't the CMB data a prediction of relativity? Isn't that why this was written?
  • "The snag is that in quantum mechanics, time retains its Newtonian aloofness, providing the stage against which matter dances but never being affected by its presence. These two [QM and Relativity] conceptions of time don’t gel."[8]
Either relativity is wrong or QM is wrong. Which would you rather. (I'm going to ask this question again later).
  • The theory predicts wormholes just as it predicts black holes, but wormholes violate causality and permit absurd time travel.[9]
Just because something is absurd, doesn't mean it isn't true. QM comes up with some ridiculous predictions. And we've seen them happen.
  • The theory predicts natural formation of highly ordered (and thus low entropy) black holes despite the increase in entropy required by the Second Law of Thermodynamics.[10]
2nd law only applies to closed systems. Black holes are not a closed system- stuff falls in, and Hawking Radiation means that stuff falls out. You've tried arguing this one with biologists against evolution. What makes you think physicists will roll over? When you lose to biologists about physics don't pick fights with physicists on the same turf...
  • Data from the PSR B1913+16 increasingly diverge from predictions of the General Theory of Relativity such that, despite a Nobel Prize in Physics being awarded for early work on this pulsar, no data at all have been released about it for over five years.
According to Wikipedia "In 2004, Taylor and Joel M. Weisburg published a new analysis of the experimental data to date, concluding that the 0.2% disparity between the data and the predicted results is due to poorly known galactic constants, and that tighter bounds will be difficult to attain with current knowledge of these figures." So perhaps because there are some things we haven't got nailed down quite so accurately as we'd like (including "g", the gravitational constant) the data doesn't fit the predictions. Predictions which are presumably based on constants which aren't as accurate as we'd like leading to... Predictions that don't quite fit the data perhaps?
  • The lack of useful devices developed based on any insights provided by the theory; no lives have been saved or helped, and the theory has not led to other useful theories and may have interfered with scientific progress.[11] This stands in stark contrast with every verified theory of science.
Really? What about GPS?  And how many peoples lives have been saved by heliocentrism?
  • Relativity requires different values for the inertia of a moving object: in its direction of motion, and perpendicular to that direction. This contradicts the logical principle that the laws of physics are the same in all directions.
  • Relativity requires that anything traveling at the speed of light must have mass zero, so it must have momentum zero. But the laws of electrodynamics require that light have nonzero momentum.
  • Unlike most well-tested fundamental physical theories, the theory of relativity violates conditions of a conservative field. Path independence, for example, is lacking under the theory of relativity, as in the "twin paradox" whereby the age of each twin under the theory is dependent on the path he traveled.[12]
  • The Ehrenfest Paradox: Consider a spinning hoop, where the tangential velocity is near the speed of light. In this case, the circumference (2πR) is length-contracted. However, since R is always perpendicular to the motion, it is not contracted. This leads to an apparent paradox: does the radius of the accelerating hoop equal R, or is it less than R?
I have no idea. But there's all kinds of weird stuff predicted by QM too. Though I'd be interested to see what explanation a physicist has for this. I'm sure there is one.
  • The Twin Paradox: Consider twins who are separated with one traveling at a very high speed such that his "clock" (age) slows down, so that when he returns he has a younger age than the twin; this violates Relativity because both twins should expect the other to be younger, if motion is relative. Einstein himself admitted that this contradicts Relativity.[13]
As I understood it the twin who travels very fast is the one who doesn't age. Time for him has slowed down relative to the other one. I could be wrong, but just because it makes your head hurt to think about it doesn't mean its wrong.
  • Based on Relativity, Einstein predicted in 1905 that clocks at the Earth's equator would be slower than clocks at the North Pole, due to different velocities; in fact, all clocks at sea level measure time at the same rate, and Relativists made new assumptions about the Earth's shape to justify this contradiction of the theory; they also make the implausible claim that relativistic effects from gravitation precisely offset the effects from differences in velocity.[14]
Do they? Do they really? And what shape is the Earth? Precisely?
  • Based on Relativity, Einstein claimed in 1909 that the aether does not exist, but in order to make subatomic physics work right, theorists had to introduce the aether-like concept of the Higgs field, which fills all of space and breaks symmetries.
Even I know that the aether was predicted to exist as something for light to travel through. Its not like the Higgs field. Which might not exist anyway. Not every model of QM needs a Higgs Boson.
  • Minkowski space is predicated on the idea of four-dimensional vectors of which one component is time. However, one of the properties of a vector space is that every vector have an inverse. Time cannot be a vector because it has no inverse.
I find it hard to believe that Minkowski would have got published if he couldn't account for this.
  • It is impossible to perform an experiment to determine whether Einstein's theory of relativity is correct, or the older Lorentz aether theory is correct. Believing one over the other is a matter of faith.
Michelson and Morely would disagree I think.
  • In Genesis 1:6-8, we are told that one of God's first creations was a firmament in the heavens. This likely refers to the creation of the luminiferous aether.
Does it now. Because as I understood it the Israelites believed that the heavesn were a dome and the stars were nailed on. Perhaps thats what the "Firmament" is?
  • Despite a century of wasting billions of dollars in work on the theory, "No one knows how to solve completely the equations of general relativity that describe gravity; they are simply beyond current understanding."[15}
No-one knows how to solve the Navier-Stokes equations. No-one knows if the Riemann Hypothesis is true. No-one knows if super-symmetry is correct. "There's stuff we don't know! It must be wrong!" This is, frankly anti-intellectualism and anti-knowledge at its most sickening.
Comments, especially welcome, as I've cobbled this together after a pint or three, and have, frankly no idea what I'm talking about. Although I have listened to more episodes of "In Our Time", so I'd like to think I had a layman's idea of roughly what these scientist fellows are talking about.
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davegodfrey: Coelacanth (Science)
When discussing the fact that Torosaurus never existed, I mentioned that something similar had happened with Iguanodon.

Iguandon is one of the world's most famous dinosaurs, and its famous for being one of the first discovered. Initially described from teeth, by Gideon Mantell, it was reconstructed first as a colossal lizard, and then as a rhino-like quadruped with a horn on its nose. Later finds near the town of Bernissart in Belgium allowed Louis Dollo to show that the animal's "horn" was a thumb-spike, and the arms were considerably shorter than the hind limbs, giving the characteristic Fonz-style pose that many people are familiar with. Later work by David Norman, showed that Dollo had dislocated large chunks of the tail and that in fact the animal was largely quadrupedal.

Iguanodon being initially based on relatively poor material, as is so often the case has ended up as something of a "wastebasket taxon", with lots of indeterminate bits and bobs ascribed to it, and several species all lumped together. At the last count there was Iguanodon anglicus / I. mantelli, described by Mantell based on his teeth and other material, the gracile, I atherfieldensis, the Belgian I. bernissartensis, the American species I. lakotaensis, the Mongolian species I. orientalis,  and several other species from the UK, I. hollingtoniensis, I. fittoni, I. dawsoni (named after the perpetrator of Piltdown, Charles Dawson), and I. hoggi, often referred to the related genus, Camptosaurus. And that's just the species known from good material, or that have stayed in Iguanodon for more than a few years. There are several other species that are either based on very poor material, that are either undiagnostic, were fairly rapidly shifted into other genera (Iguanodon prestwichi has been happily residing in Camptosaurus for over 100 years now), not from ornithopods, or aren't even dinosaurs.

The beginning of a solution to this mess was in 2000, when the ICZN (International Commission of Zoological Nomenclature) designated Iguanodon bernissartensis as the type species of Iguanodon, primarily because this species is known from 37-odd individuals, many of which are complete, whereas I. anglicus was based on several teeth  One specimen of I. bernissartensis appeared to be rather more gracile than the others, and was later referred to I. atherfieldensis.

This already sounds confusing, but in practise what tended to happen was that specimens were either referred to I. atherfieldensis if they were relatively slender, and I. bernissartensis for the chunky guys, regardless of how old the specimen was. This is clearly unsatisfactory. Especially as these animals start looking rather different when you look closely and start including the other species in the mix.

In 2006 Gregory Paul separated Iguanodon atherfieldensis into the separate genus Mantellisaurus, in honour of Gideon Mantell. A year later he erected a new genus and species for the Belgian I. atherfieldensis specimen, calling it Dollodon bampingi. Iguanodon lakotaensis was also separated into a new genus (Dakotadon), and I. orientalis regarded as a "Nomen Dubium". He did not attempt to redescribe I. hoggi, I. dawsoni, or I. fittoni and I. hollingtonensis, regarding them as "Iguanodontidae" of uncertain affinity- and possibly not even not particularly close to Iguanodon at all. This was for two reasons, one, they were clearly morphologically distict from each other, and also of a significantly different age. Warm-blooded species tend not to last more than 2 million years, but Iguanodon would have had a range of over 40 million years, spanning most of the northern hemisphere. Which seems unlikely to say the least. Lumping everything together like this masks diversity and evolutionary trends and generally makes it much harder to work out what's really going on. He didn't entirely approve of the ICZN's decision to have I. bernissartensis as the type species, but there isn't a better option, and I agree that its prefereable to have the well known dinosaur from Dollo's iconic reconstruction that is familiar to public and professionals alike for such a historically important genus.

In 2010 David Norman looked at some of the other species that hadn't been officially removed from the genus, "tacitly accepting" Paul's erection of the genus Mantellisaurus, but disagreeing with the separation of Dollodon and Dakotadon, for reasons that he didn't elaborate on other that to say "wait for the paper". "Iguanodon" hollingtonensis and "Iguanodon" fittoni were synonimised into the new genus Hypselospinus fittoni, meaning "high spine" named for the shape of the vertebrae. "Iguanodon" dawsoni was renamed Barilium dawsoni "heavy flank" because, well its got a big arse.

So "Iguanodon" turns out to be far more diverse than you'd first think there's room for at least four, if not six or more genera in there, spanning the gap between the Jurassic camptosaurs to the familiar duck-billed hadrosaurs with their dental batteries, and flamboyant crests. And of course there's the promise of more research to follow, and an interesting (if somewhat esoteric) debate about haow different species have to be before you start putting them in different genera.
davegodfrey: Coelacanth (Science)
About a month ago John Scannella and Jack Horner published an article "Torosaurus Marsh, 1891, is Triceratops Marsh, 1889 (Ceratopsidae: Chasmosaurinae): synonymy through ontogeny" in the Journal of Paleontology*

*Note. Ceratopsidae are the "horned dinosaurs", including Styracosaurus, Triceratops/Torosaurus, Chasmosaurus, and Pachyrhinosaurus to name but a few. The Chasmosaurines are a subgroup which had long brow horns, short nasal horns, and big frills, (Chasmosaurus and Triceratops/Torosaurus are fairly typical.) The other group (the Centrosaurinae) had short, or absent brow horns, a long nasal horn, and a relatively short frill (Styracosaurus and Pachyrhinosaurus are good examples of this group).

What this paper attempts (and I think succeeds) to show is that the fossils attributed to Triceratops are all juveniles, and the fossils attributed to Torosaurus are all adults. They looked at all the skulls they could get their hands on, and looked at what was happening to the bones, and they are fairly confident that they've identified a growth sequence between Triceratops and Torosaurus.

As it grew Triceratops first developed the long brow horns, and a short solid frill. When it reached maturity then holes in the frill opened as bone was absorbed, and the frill itself then grew significantly longer. There are one or two Triceratops specimens that show that the bones in the frill were starting to thin as this happened.

So all in all, a reasonably convincing study. So why the hoo-ha?

Because journalists (and the sub-editors responsible for their headlines) can't read, and then the internet gets hold of their shoddy penmanship, and before you know it people are clutching their pearls and comparing this to "Pluto not being a planet anymore". (Breaking Daily News are particularly precious, I really can't see how this could delight creationists at all.)

Anyway. The ICZN (International Commission of Zoological Nomenclature) has some pretty strict rules about how you go about naming things. Generally the first name given has priority. Its why Brontosaurus was renamed Apatosaurus (Apatosaurus was published first). Its why Laelaps had to be renamed Dryptosaurus (a mite had already been given the name). Its generally a very sensible rule, and only causes problems when you discover that another name was previously published for the same species, but completely ignored, or if the type species, or the specimen on which the name was originally based turn out to be fairly poor for identifying, well anything.

When this happens you appeal to the ICZN and they think about it, ask for comments and make a decision. Often they'll agree with you. If no-one's used a name for ages there's no point in keeping it if everyone else uses something different. There's a application currently going through the ICZN< to replace Cetiosaurus medius with Cetiosaurus oxoniensis as the type species of the sauropod Cetiosaurus, primarily because the material of C. medius is crap, and everyone uses C. oxoniensis when talking about Cetiosaurus. Something similar happened to Iguanodon a little while ago, and there was a paper recently that made everything really confusing. Some day I'll write about it.

Anyway, in this case strict priority is going to rule. Torosaurus was described three years after Triceratops. The species included in Torosaurus will be reclassified as species of Triceratops. Scannella and Horner don't go so far as to synonymise the individual species however, so Triceratops gets several new species and a new look for the adults.
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davegodfrey: Coelacanth (Science)
Apparently this bunch of clowns has won a Quality Badge for "Learning Outside The Classroom". Except, as noted by several people, its got a somewhat questionable attitude to science. Its a creationist zoo. You have to dig fairly deep to get to the creationist stuff, and its probably something they aren't allowed to mention too much in their school visits, the worksheet on "Adaptation" doesn't mention evolution, but at KS2 (7-12 year olds) you wouldn't really expect it to. However there's no mention of evolution or classification as subjects in either the GCSE (15-16 year olds) or AS/A-Level (17-18) workshops. Animal welfare, conservation, genetics and farming all get mentioned, but not evolution or biodiversity. I wonder why.

Of course by the time you've got to this section you'll have noticed the red section marked "Evolution and Creation". Guess which side of the fence they sit on. Taking their stance on the difference between reptiles and mammals we can see that they're both factually incorrect, and creationist (I know, I know, hardly unusual), but they wouldn't be demanding that mammals and reptiles were so radically different if they weren't trying to push their agenda. SO I'll push mine back a little.

1. Reptiles have horny or scaly skin. Mammals have fur or hair.

True. Fur is one of the defining features of mammals. But fur and scales are both made from keratin. (Alpha and Beta keratin in the case of reptiles. Alpha keratin only in the case of mammals)

2. Mammals have a single type of skin cell for colour. Reptiles have 3 types of skin cell for colour.

Well, given that they have different skin structures- reptiles having scales and mammals a glandular skin I'm not surprised. But these are modern mammals, and modern reptiles we're talking about here. The last common ancestor between the two groups would have been about 300 million years ago. (Although Noah's Ark don't accept this dating methodology).

3. Reptiles have low metabolism and require less energy. Mammals have high metabolism.

4. The body temperature of reptiles varies according to their environment (they are 'cold-blooded'). Mammals are able to maintain a constant temperature (they are 'warm-blooded').

Birds also have a high metabolism. And beta keratin. And not all reptiles are cold-blooded. Leatherback turtles can maintain a body temperature above that of their environment. So do Tuna and Great White Sharks. There was a nice paper in Science that showed that the mosasaurs, plesiosaurs and pliosaurs were very probably warm-blooded.

5. Reptiles (but not tortoise/turtles, snakes or crocodilians) have a "third eye", known as a parietal or pineal eye. It has a cornea, lens and photoreceptors. Mammals have only a parietal gland, used for endocrine production.

So that's the Tuatara, and the lizards that aren't snakes then. If its been lost in crocs, turtles and snakes why not mammals? Lineages lose features through evolution all the time. Whales don't have external back legs. Stellar's Sea Cow didn't have any fingers. So what?

6. Reptiles have small, relatively even teeth with single roots; they are replaced often. Mammals have different types of teeth with multiple roots - incisors, canines, premolars and molars - and replace their teeth only once.

And we have a sequence of fossils that show how this feature was acquired. And while reptiles don't have quite the variety of tooth morphology in their jaws that mammals do there's still a fair amount going on. Look at a T. rex jaw, there are big teeth and little teeth, and they're in different parts of the jaw doing different things. But the main reason this is important is because mammals, and their more reptilian ancestors evolved chewing. Most reptiles don't chew. And you need to have your teeth occluding properly to be able to chew effectively. To do that you can't be replacing teeth continuously, you'd have gaps all over the place. So continuous replacement doesn't become an option, but diversification of tooth morphology is suddenly a very real proposition.

7. Reptiles have 3 bones in the lower jaw: the dentary (holding the teeth), the quadrate and the articular. Mammals have only one lower jaw bone.

8. Reptiles' ears have only one bone, the stapes. Mammals have 3 bones, (stapes, malleus, incus), and the very complicated organ of Corti.

These two are again closely related. The malleus and the incus are the quadrate and the articular. Again there's a whole series of fossils that you can follow showing how the jaw joint became involved in hearing and the dentary enlarged and a new jaw joint evolved. One lovely name for an early mammaliaform (now sunk into synonomy more's the pity) was Diarthrognathus or "Two Jointed Jaw", because that's exactly what it had, a quadrate/articular joint and a dentary/squamosal one.

9. The reproductive system of male reptiles includes a hemi- penis. This consists of two penises, which are used singly and repeatedly to fertilise several of a female's eggs.

And most birds don't have penises at all (ducks are an occasionally quite frightening exception). Penises come and go, grow bones and lose them, are co-opted from all sorts of different tissues and structures.

10. Most reptiles lay eggs. Mammals do not.

ALERT! ALERT! TAXONOMY FAIL! One word. Monotremes. Platypuses and Echidnas lay eggs.

11. Reptiles do not usually guard their eggs or care for their young. Mammals all have milk glands and suckle their young.

Again milk production is one of the defining features of mammals. Its in the name! Sadly we can't see how it appeared, because the tissues don't fossilise. I don't see how its a problem. Birds have feathers.But they're still vertebrates.

12. The sex of the unborn young of reptiles is determined by external temperature. Hot temperatures result in more females.

Only in some reptiles. In others it is determined by genes. And in birds its a gene. Interestingly there are some similarities between the sex determining genes of birds and monotremes. Evidence (along with the egg thing) of shared ancestry between the two groups.

13. Mammals breathe by way of a diaphragm in their chest (the thorax). Reptiles have no diaphragm and breathe very differently, with their cheeks and mouth.

And in the case of alligators and crocodiles with a through-flow system like that of birds.

14. Reptiles have a 3-chambered heart, except crocodilians which, like mammals, have a 4-chambered heart. Since their hearts cannot pump blood far upwards, reptiles move close to the ground (they 'creep').

Eh? I wouldn't describe a Komodo Dragon as "creeping". But as reptiles don't have a high metabolism they don't need so much oxygen, so they don't need to separate the two halves of the heart (and very little mixing of oxygenated and deoxygenated blood actually goes on thanks to complex valves). Even with their more inefficient hearts reptiles can be pretty active when they want to be.

15. The legs of reptile are splayed out from the body. The legs of mammals are positioned under the body.

Except for dinosaurs (including birds), lots of early crocodiles, modern crocs in a hurry. Oh, and Platypuses and Echidnas. They have a sprawling gait too. But aren't they mammals?

I've actually been trying to work out what kind of creationists the Noah's Ark Zoo people are. They don't seem to accept that the world is 6,000 years old, like AiG do. But they certainly don't like the answer radiometric dating gives. And most bizarre of all is their take on the fossil record- it records the recolonisation of the world after the flood with animals and plants, and as each group became abundant enough to fossilise that's when it turned up in the rock record, despite always having been there. Its a hideous fudge that isn't obviously your typical YEC stuff, and as such means I'm sure these guys are vilified by the AiG crowd. And yet its also at odds with reality. As someone on Pharyngula said "halfway between right and wrong is still wrong".

Oh and that cool new paper on hot-blooded mosasaurs? Your reference is:

Bernard, A. et al. (2010) Regulation of Body Temperature by Some Mesozoic Marine Reptiles. Science, 328, 1379 - 1382

Oh, and you know what really sticks in my craw? The Horniman Museum doesn't have a badge. Bastards.
davegodfrey: South Park Me. (Default)
Day 22 A Website

I've already mentioned Mike Everhart's Oceans Of Kansas website elsewhere, so I'll point you somewhere else instead.

Palaeos is one of the greatest websites I have ever found. It discusses pretty much the whole of palaeontology, covering thousands of taxa, providing primers on cladistics, morphology, biogeography, etc, etc. And its just been wikified, so if you think you can help then jump aboard.

I think probably my favourite essay on there, and its hard to choose there are so many, is the essay "What Is A Tetrapod?"
davegodfrey: Coelacanth (Science)
A Non-Fictional Book

Just the one? But there are so many more books that are real than ones that aren't. Um. I'm going to take this to mean "Non-Fiction book", I'm going to recommend Mike Everhart's Oceans of Kansas, a book that owes much to his website of the same name. There are lots of lovely photos of specimens, the spectacularly weird pterosaur Nyctosaurus, which has no fingers- and just look at that crest, mosasaurs that were clearly eaten by sharks, Sabre toothed "herring",
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"birds with teeth", and one of the largest turtles ever.

Each chapter begins with a little fictional vignette of life in the Kansas Seaway, describing moments in the life (and death) of its inhabitants, and several are backed up with fossil evidence (the famous fish-within-a-fish fossil for instance) Its wonderfully illustrated by Dan Varner, and I recommend it to everyone with an interest in fossils. More importantly its not a technical book, so everyone can enjoy it.
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Deep Time.

Feb. 1st, 2010 11:18 pm
davegodfrey: Coelacanth (Science)
I shall preface this by stating here and now I have never had much truck with the "think of the history of life as a year" or "reduce the age of the Earth to a day". Humans are always described as appearing at half past eleven on December 31st, or in the last seconds before midnight. But that's the whole of human history there. Its almost as hard to imagine 200 thousand years as it is 200 million. They still don't mesh with the human experience.

Breath in. Now breathe out.
In the time it took you to do that (I'm going to guess and say about one and a half seconds many things can happen. We see the moon as it was 1.5 seconds ago. A  male Ruby-Throated Hummingbird can beat his wings 300 times during that period. Now compress things the other way. Shrink the traditional Three Score Years and Ten to that length of time. What of human history then? What of the history of the planet.

One and a half seconds ago the Second World War raged across Europe. Three seconds and we are back to the height of the Victorians, Six seconds takes us to the Restoration, the plague and the foundation of the Royal Society. Fifteen seconds takes you back before the Renaissance to the early 14th Century. Thirty seconds and Islam is founded. A minute and the Olmecs are building pyramids in America in 790BC. Two minutes takes us back to before the Egyptians were building there, another minute and there are no metal tools, but agriculture is already developed.

Breath in. Breathe out.

After an hour we are deep into the Ice Age. Mammoths roam across much of Europe, Asia and North America. Two hours and the people we see no longer look so familiar. The earliest records of Homo sapiens go back 250,000 years or so. After six hours at work you'll be looking forward to going home. And yet at the speed we travel back in time we have only gone back one million years. At this rate one day is equal to four million years. 65 million years ago dinosaurs (apart from birds) became extinct. That's roughly 16 days in our comparison. Mammals go from small and insignificant to dominating the ecosystems we see today.

Breathe in. Breathe out.

63 days after beginning this journey we reach what some have termed the "Great Dying". 250 million years ago 83% of all genera were wiped out in the Permian Mass Extinction. After 100 days we find the first tetrapods. Insects have already colonised the land, and the first forests are well established. Four and a half months takes you back to the Cambrian explosion and the first trilobites, 525 million years ago.

Breathe in. Breathe out.

One hundred and seventy five days. Nearly six months. The Cryogenian, 700 million years ago and the "Snowball Earth". The earliest complex multicellular organism is from 1200 million years ago. Ten months. Two years, four and a half months and we have the first fossil evidence of life on earth. Just over three months later and we find the first geochemical evidence of life.

Breathe in. Breathe out.

If you lived your life in the time it takes to do that, then the oldest minerals on Earth are three years old. Time enough for life to unfold all the precxious things it has.
davegodfrey: Coelacanth (Science)
There's a new paper on the origin of primates. Now I've not looked into primate evolution much (other than criticising the hype around some recent discoveries). But this seemed interesting. In a "Yer what?" way.

Michael Heads has calibrated the origin of the various primate groups to several tectonic events involved in the breakup of Pangaea.

New and Old World Monkeys diverged 120 million years ago when the Atlantic opened. Lemurs diverged from their closest relatives when the Mozambique Channel opened 160 million years ago, and the deepest split in the primate tree, between the haplorhines (monkey, apes, and tarsiers) and strepsirrhines (lemurs and lorises) is 180 million years ago in the Early Jurassic.

This is a problem. The earliest known primate fossil is Purgatorius from the Upper Cretaceous of the USA. (Well maybe. A recent paper in Nature indicates that it isn't a primate but the sister group to placentals as a whole.) Other than that the earliest primates turn up in the Eocene, about 56 million years ago. Molecular divergence times however put the split between primates and their closest living relatives the Dermopterans (the Colugos or "flying lemurs") at about 80 million years.

He is right in pointing out that the previously accepted dates are indeed the minimum dates. Any new fossil discovery could shift them by several million years. Just a week or so ago some tetrapod footprints were found that indicated that tetrapod evolution occurred about 10-20 million years earlier than we thought, creating "ghost lineages", spans of time where no fossils are known, but are expected.

If Heads' model of primate evolution is correct then it creates ghost lineages of 100 million years. This, to me, seems rather excessive. Defending this he points out that several groups do not have a fossil record, yet must be very old, while other modern groups are only known from a few very early fossils (he mentions proscopiid grasshoppers from 110 million years ago). Fair enough, but the molecular dates indicate a ghost lineage of about 25-30 million years from the earliest fossils to the latest divergence times. Increasing this by four times really needs rather more support than he gives it. A new fossil would be enough to make people think.

He is correct in his statements that molecular dates (however they are calibrated) are generally minimum dates, but he repeatedly states that they are "transmogrified" into maximum dates. I can't find any detailed criticism from this paper as to how this is done (do the authors just swap words around? Or are there mathematical tricks that can get you this result?)

Moreover where Heads' paper also falls down is in his refusal to accept that rafting can play a part in evolution and dispersal. It is generally accepted that chameleons originated on Madagascar and then spread. Frogs have made it to Madagascar from Indonesia, and this week a paper was published in Nature showing how ocean currents in the Eocene would have allowed lemurs to raft across the Mozambique Channel, but would prevent them doing so today. He also fails to take into account that the separation of continents is not a simple matter. The North Atlantic began to appear in the Cretaceous, but there were extensive connections between Europe and North America throughout the Eocene, allowing animals to island hop across. I see no reason why South America and Africa would be different.

He doesn't address the issue of why we have a nice transitional sequence of various primate groups in the Eocene, but that isn't necessarily a problem- the footprint paper in Nature gave us the same problem to deal with. However the footprints are evidence for the existence of tetrapods at a particular time period. Heads has not presented any physical evidence to back up his claims, rather he's taken the current distribution of primate groups as evidence that they always lived in these areas, and matched them up with past events. Would he have got the same results if he had used a different group? And if not what does that say about his methods?

Finally, other than ascribing a date of 185 million years to the split at the base of the Archonta (the larger group uniting Primates, Tree Shrews, and Colugos) he says nothing about what this data means for the diversification of other placentals, marsupials or indeed the origin of mammals as a whole. Without running the mathematics I can't help get the feeling that were this paper correct it would push the origin of mammals somewhere into the Permian. Which seems, shall we say, extremely unlikely given the fossil record we have there.

As they say, extraordinary claims require extraordinary evidence.

Michael Heads: Evolution and biogeography of primates: a new model based on molecular phylogenetics, vicariance and plate tectonics, Zoologica Scripta, Published Online: Nov 10 2009 4:44AM DOI: 10.1111/j.1463-6409.2009.00411.

J. R. Wible, G. W. Rougier, M. J. Novacek & R. J. Asher: Cretaceous eutherians and Laurasian origin for placental mammals near the K/T boundary, Nature 447, 1003 - 1006 (21 June 2007)
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davegodfrey: Coelacanth (Science)
Does anyone have access to November' 2009's Zoologica Scripta? I'd like a copy of the following paper please.

Michael Heads. Evolution and biogeography of primates: a new model based on molecular phylogenetics, vicariance and plate tectonics. Zoologica Scripta, 2009.

It suggests that lemurs and lorises diverged from the new and old-world monkeys about 180 million years ago, (the early Jurassic). I'd like to post a criticism of it, but I'd rather wait until I've read the paper. After all, he might have included some important data that hasn't made it into the press reports that explains why placentals should be found in the Permian, or that he's produced a ghost lineage based on no fossil evidence whatsoever that's about 100 million years long. Like I say. I don't want to be prejudiced.
davegodfrey: Coelacanth (Science)
So  having had a look at the paper, and watched the video courtesy of Nature I thought I'd see how the various newspapers reported this new and interesting discovery.

As far as I can see The Daily Express doesn't cover it at all. But as their astrologer is writing a guide to getting fit in 2010 I think they might have given up on being a newspaper these days.

The Mail throws the "Missing Link" phrase around in the first paragraph. Which is a shame, because I've not seen it mentioned anywhere in the reporting or the press release. If anything this is something that would have been largely ignored if it was contemporaneous with the body fossils- "Oh neat, tetrapod trackways. Oh they're marine. That's interesting, virtually everything else is freshwater" would have been the response. However the rest of the article is not bad- the quote from Ahlberg reads like the abstract, and they've lifted some quotes from Phillipe Janvier's "News and Views" article accompanying the Nature paper. I think they fumbled it a bit, but made a decent recovery. Just don't look at the comments.

The Guardian is pretty good actually. Doesn't use the "missing link" phrase, which I think is a win. Quotes Janvier (who made the important point that the sequence of fossils probably hasn't changed, its just that the timing of the actual transition is way off). It also quotes Ahlberg and Jenny Clack (though it initially spelt her name wrong- but this is the Guardian, so that's to be expected). Where I think it does best is online, where there's the blog by Adam Rutherford providing more information I mentioned last time.

The Indy is generally very good, and provides more information about the circumstances leading up to the find- they were thought to be dinosaurs until they had another look at the fossils in the surrounding rocks to work out how old they really were. It probably explains why the article says "They occurred in a rock formation several metres beneath a younger rock formation." because otherwise that's a totally pointless statement- there's no information about why this younger formation is important. Did it contain the conodonts that they used to work out how old the rocks were? Was it just a pretty colour? What? Enquiring minds wish to know.

The Times however seems to be making stuff up. It describes the creature that made the tracks as looking like a stout crocodile, which is not an inaccurate description of the typical early tetrapod. However it says that; "However, unlike the modern-day crocodile, the ancient creature appears to have held its body up from the ground as there is no trace of it being dragged along. It may have been closer to a dog in terms of posture." No. Seriously. Just No. Crocs have legs that stick out from the side less than that of lizards or salamanders, giving them a semi-erect gait that raises their bodies off the ground. Dogs have a very different gait, their legs are directly under their bodies like dinosaurs, and mammals. All the early tetrapods have sprawling gaits- we don't see body or tail trails because the animal was supported by water in the intertidal zone, and because it had a sacrum which allowed it to support its tail with the hind limbs. Dogs don't enter into this anywhere.

Its also not true that the rocks "teemed with marine fossils". Tracks are common, but body fossils are extremely rare, and this is not uncommon. There seems to be something about environments that are good for preserving tracks, but lousy for preserving the organisms that made them. I think however they may have redeemed themselves by solving the question of why they were thought to be dinosaur tracks- the man who first discovered them didn't know how old the rocks were.

The red-tops seem to have completely ignored it, which is not surprising- Metro gave it a sentence or two, and I can't find it on the intertubes.

So not a bad showing for the papers this time round. Shame the creationists turn up with their "how can you know so much from a footprint?" crap. Well dear, lots. There's a whole science out there that you're completely ignorant of called ichnology.


Jan. 7th, 2010 12:34 am
davegodfrey: Coelacanth (Science)
Scientists in changing mind based on new data shocker!

Grzegorz Niedźwiedzki, Piotr Szrek, Katarzyna Narkiewicz, Marek Narkiewicz, and Per Ahlberg (late of the NHM, now firmly ensconced in Sweden) appear to have thrown a cat among the pigeons. Actually what they've done is thrown a tetrapod among the fishes.

Until last tonight we thought we'd got a handle on tetrapod evolution. First you get things like Eusthenopteron, often cited as the standard Devonian "Lobe-Finned Fish". While clearly a fish it has rather limb-like fins. A little while later (385 million years ago to be precise) a group called the Elpistostegids turn up, the most famous of these is probably Tiktaalik which did the rounds couple of years back. These are much more tetrapod-like. The heads have a long snout, the front fins are even more limb-like, with the beginnings of a shoulder and wrist, but the back legs are relatively small, and while Tiktaalik could probably do push-ups, it certainly couldn't walk anywhere.

Finally at about 370mya tetrapods which actually have proper legs with fingers and everything turn up. Animals like Acanthostega, Ichthyostega, and friends. None of these was ideally suited to life on land- Acanthostega was still dependant on gills, and would have died if you'd taken it out of the water. Ichthyostega would have fared better, but wasn't going to go anywhere terribly quickly. The most recent reconstructions indicate it was rather seal-like. Around about this time the elpistostegids disappear, so we have a nice rough evolutionary sequence, with all the usual (or indeed unusual) branching and diversification that entails- Livoniana's seven rows of teeth are my favourite example.

Or rather "did", now the nice Polish scientists have borked it all up. They've just found the earliest tetrapod footprints and trackways. And they're 397 million years old. Over 10 million years older than the elpistostegids and 18 million older than the "proper" tetrapods. Oh dear. Actually, no. Not "oh dear" "How awesome is that?" They went looking for fossils and trackways where no-one expected to find evidence of tetrapods, and they found it anyway. Adam Rutherford justly celebrates the fact that it was pure research with no applications- and Per notes that not even the guys who's job it is to give money for just those sort of projects would have forked out.

The individual prints are clearly from a tetrapod, and preserve digits. (6 in the case of the photos I've seen. This sounds odd but was expected- Acanthostega had eight fingers, and Ichthyostega seven). The trackways aren't so well preserved, but indicate that the animal would have had a side-to-side gait like that of a salamander. This is decidedly weird- Tiktaalik and Panderichthys shouldn't produce those sorts of trackways. And "walking" seems a bit too advanced for Acanthostega- it couldn't place its feet flat on the ground if it tried. The more I think about it the more important this find gets.

What's going on then? Obviously the biggest problem we have is the spottiness of the fossil record. There's a similar problem with all the lovely Chinese dinobirds. They're mostly from the Early Cretaceous, but the "first bird" is from the Jurassic, and significantly older. My guess is that the changeover is an artefact of the fossil record. Somewhere out there are earlier "fishapods"
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, and as for why Tiktaalik and co hung around for so long after they should have got out of the way for these shiny real tetrapods I shall defer to Grzegorz Niedźwiedzki, who suggests that the elpistostegids were the first to colonise the environments where we've been lucky enough to find their bones. Ichthyostega's great grandmother seems to have been happy to have frolicked around the stromatolite studded tidal flats leaving her footprints, but little else behind.

As always the sciencebloggers have excellent commentary. Ed Yong has talked to Shubin and Daeschler who described Tiktaalik, as well as Jenny Clack, Laelaps, discusses it with reference to work done by Owen in the 19th century, and is very excited by all the new questions that this work raises.

Or you could watch the video, which discusses the environment the fossils were found in, and new ideas for why tetrapods might have started out on land (warning, hot field-trip action depicted)

(There's also really nice shot of the fuzzy Dilophosaurus model Darren Naish blogged about a little while ago in the intro)

Hopefully I'll get a post up in the next couple of days about how the press have reported mangled the reports.

Grzegorz Niedźwiedzki, Piotr Szrek, Katarzyna Narkiewicz, Marek Narkiewicz & Per E. Ahlberg
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 Tetrapod trackways from the early Middle Devonian period of Poland: Nature 463, 43-48 (7 January 2010)
davegodfrey: Coelacanth (Science)
Today is the 75th birthday of one of the greatest popularisers of science we have seen. Sadly he died in 1996 and is not around to share it with us. Presenting the seminal TV show Cosmos in the 1980s Sagan made this moving statement about our place in the universe, how tiny and insignificant we are on the cosmic stage, how petty our squabbles, and therefore how important it is that we look after the only home we have ever known, and the other humans we share it with.

davegodfrey: Coelacanth (Science)
Remember Ida? (or Darwinius massillae to give her full name)? Remember how six months ago she was unveiled to the world in a whirlwind of hype? Remember how the blogging community despaired of this, while noting what a lovely fossil she was?

This week more research has been published, after the discovery of Afradapis, a related species from the Late Eocene of Egypt. Not nearly as nice as Ida its a jaw and teeth. This is not unusual- most of our ideas about mammalian evolution were based on teeth until genetics came along and morphology had to play catch-up. And when dealing with extinct groups such as adapids its the best thing we have going- teeth are the most robust parts of your body, and withstand the processes of decay and weathering the best. The fossils shows some features present in the catarrhine primates (the group that include apes and Old-World monkeys). Which is very interesting. However...

...all is not as it seems. The team did a phylogenetic analysis, of 117 living and extinct species, using 360 characters. This is only about 3 characters per taxa, and I'm sure more would be nice- but you can guarantee that not all characters will be preserved in each group (its rather hard to say what features are present in the ankle of a genus only known from its teeth for example), and its the first phylogenetic analysis I'm aware of that includes Darwinius which is a very Good Thing. Sadly for most people, its published in Nature, which means anyone who doesn't have a subscription only gets the abstract and whatever mangling the newspapers put this and the press release through.

This analysis shows that Ida, Afradapis and the other Adapoids are not stem anthropoids, and are not even haplorhines (the group that includes monkeys [and apes] and tarsiers). In fact they fall out as the sister group to the living strepsirrhines (lemurs, lorises, and bushbabies). To me thats far more interesting than if the adapids were on the line to humans, because it means the features they share with us either evolved twice (once in anthropoids and once in adapids- the position the paper's authors take) or are primitive to a wider group of primates. Without having read the paper I can't say why the author's favour one over the other.

ETA: Brian Switek over on Laelaps has a very nice post, (with a lovely drawing of Afradapis' jaw). The features that link adapids and anthropoids (but are not present in the earliest anthropoids) are details of the mandibular symphysis (the joint between the two halves of the lower jaw) and the loss of the second premolar. Neither of these features are likely to be lost and re-evolved, when evolution discards things they tend to stay discarded, and when they come back, they're usually subtley different.

Before we start questioning how effective the analysis was- and believe me scientists will, plugging more species in, pulling others out, re-examining specimens, poking holes everywhere they can to see how good this tree really is, taking the analysis at face value raises a whole series of interesting questions. If we're seeing convergence between anthropoids and adapids, then what were these two different groups doing that was similar, and if the features we are seeing are primitive, then why did lemurs and other groups lose them.

And this to me is the beauty of science. When scientists are wrong it is very often for interesting reasons- lack of data, working within a theory that could not account for new observations, etc. And when they are shown to be wrong, a whole vista of new questions open up, new ways to be interestingly wrong, but at the same time inch closer to a greater understanding of the universe. And people wonder why I love science so damn much.

Seiffert, E., Perry, J., Simons, E., & Boyer, D. (2009). Convergent evolution of anthropoid-like adaptations in Eocene adapiform primates Nature, 461 (7267), 1118-1121

I recommend reading this interview with Seiffert.

davegodfrey: South Park Me. (Default)

H/T to Pharyngula, as always...


davegodfrey: South Park Me. (Default)
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