Zombie taxa

The dinosaurs all died out at the end of the Mesozoic, about 60 million years earlier.  Or did they...

Numerous dinosaur teeth have actually been found in much more recent rock formations, well into the Paeleogene. There are a number of explanations for this.

One explanation is that we are entirely wrong about the extinction of the dinosaurs. They did not go extinct at the end of the Cretaceous and persisted much longer, perhaps to the modern day! But for some mysterious reason their bones stopped being preserved and they just left teeth and claws.

An entirely different explanation, and dare I say a much more plausible one, is that in some taxa fossil structures may be eroded out of one layer and then re-deposited in a younger layer. Given that our fossil record of dinosaurs post-Cretaceous consists of just the sort of a structures (teeth) we'd expect to be washed out and re-preserved the evidence is consistent with this hypothesis.

This hypothesis also predicts that even today we would find structures like dinosaur teeth washed out of sediments and being preserved in brand new depositions. Yes, yes we do. Such taxa are known as zombie taxa.

Dilemma

The world’s largest set of shark jaws is going up for auction. The jaws, which once belonged to a megalodon, will be placed up for bid in Dallas, Texas in June at the Heritage Auction Galleries. The asking price is set at $625,000. The previous owner, the late Vito Bertucci, spent 16 years gathering the right shaped teeth to fit the jaw. So paleontologically this may be a specimen of many parts but realistically it is just awesome.

Magalodon is an extinct species of shark that lived roughly about 25 to 1.5 million years ago, during the Cenozoic Era.

It is thought that megalodon looked like a bigger version of the great white shark. Much bigger.

Furthermore a paper in 2008 suggested that Magalodon had the most powerful bite that has yet been discovered.

Personally I think this would look awesome placed around my front door. Assuming it doesn't go for much more than the asking price I guess I could sell my house and buy it but then I wouldn't have a front door... It's a pity CCS doesn't have a large slush fund or a generous benefactor because these jaws would also look great as the entrance to CCS. I'm not sure if they would send the right message but they'd look fantastic.

Walking with dinosaurs

Natasha's post below, and the topic of some forthcoming lectures, reminded me of the BBC's fondness for dinosaur simulations.

I think it all started with a show called 'Walking with dinosaurs' that was , at the time, the most expensive documentary ever made. Using computer simulation and animatronics to create a 'realistic' wildlife show - but one with dinosaurs. You should check these out if you haven't seen them. I think they are available on Netflix and Veoh online.

Then there's Prehistoric Park, made by the same company, which now includes a 'time portal' and a narrator. Wikipedia calls it 'docu-fiction'. I almost posted a clip from this earlier in the quarter because they have a nice segment with one of those giant Carboniferous arthropods - Arthropleura.


Finally, keep the time portal and the dinosaurs but add in ludicrous characters, creatures from the future and the stupidest plotlines you can imagine and you have Primeval. Check out episode two of the first series for Arthropleura in the London Underground.

Choose your own level of prehistoric incredulity.

Forbidden experiments

 Mothra's larval form destroying the Tokyo Tower in the movie Mothra from 1961.

In the Fantastic Four comics Dr Doom was expelled from Empire State University for carrying out 'Forbidden experiments'. The experiment in question involved contacting the dead so maybe that's not that surprising, but I was always amused by the notion that a University might have a big list of 'Forbidden experiments'. Ah yes, item number 147, 'Contacting the Dead', right after number 146 'Reanimating the Dead'.

Anyway, I was reminded of that when I took a quick look for some papers on insect gigantism and came across this recent review paper Atmospheric oxygen level and the evolution of insect body size, where they mention several experiments where people have selected for insect gigantism over many generations under high oxgyen conditions in the lab.

The effects of hyperoxia on growth and body size are less consistent and often nonlinear (Harrison et al. 2009). Body size increases in the giant mealworm, Z. morio (27% O₂; Harrison et al. 2009) and in the scarabaeid beetle C. texana (40% O₂; Harrison et al. 2009).

I'm pretty sure 'Creating Giant Insects' would also have been on empire State's list. Did Mothra not teach us anything?

But the answer to our question of what other giant insect (and other arthropod) fossils have been found is:

Among insects, gigantism in the Permo-Carboniferous has also been reported for Ephemeroptera, Diplura, Thysanura and the extinct order Paleodictyoptera (Briggs 1985; Kukalova-Peck 1985). Arthropleura, a group related to modern day millipedes, reached upwards of 2 m in length, almost six times the size of any extant millipede. 

So no, no Lepidoptera, you'll just have to make do with Mothra.

Hidden Leg of an Ancient Snake

No, not an unreleased Jim Morrison poem, but a headline on ScienceDaily today reporting on the latest imaging of a 95 million year old snake fossil published in the Feb. 8, 2011 issue of the Journal of Vertebrate Paleontology.

A novel X-ray imaging technology is helping scientists better understand how in the course of evolution snakes have lost their legs. The researchers hope the new data will help resolve a heated debate about the origin of snakes: whether they evolved from a terrestrial lizard or from one that lived in the oceans. New, detailed 3-D images reveal that the internal architecture of an ancient snake's leg bones strongly resembles that of modern terrestrial lizard legs.

Putting the dead to work

There's an interesting article in TREE (Trends in Ecology and Evolution) this month about the emerging science of conservation paleobiology.

There's a report at ScienceDaily: Putting the Dead to Work: Conservation Paleobiologists Dig Deep to Solve Today's Ecological, Evolutionary Questions, and the actual paper: Conservation paleobiology: putting the dead to work.

A new review of the research in this emerging field provides examples of how the fossil record can help assess environmental impacts, predict which species will be most vulnerable to environmental changes, and provide guidelines for restoration.

ScienceDaily is a good source for science news although it is almost always worth tracking down the original papers. They have got a lot better lately at including the full references at the end of their articles.

Oh the places you'll go

 In Ethiopia, Ellen Currano and Aaron Pan sample the shale for fossil plants.

Bruce passed along this article from the New York Times - A Fossil Hunt in Ethiopia’s Mush Valley.

Why is it important to know about the Ethiopian Plateau 22 million years ago? The Mush Valley preserves plants and animals from a time soon after a land connection was established between Afro-Arabia and Eurasia — a land connection that marked the end of Africa’s island status and that was used by animals to migrate between the two previously separated land masses. By looking at the fossil record from that period of time — before the Red Sea was formed — we can gain a clearer view of which species survived this great migration and which did not.

Aaron Pan was a CCS biology graduate about 10 years ago and is now curator of the Fort Worth Museum of Science and History.

Walking with Tetrapods

This week's Nature Video is also cool, and relevant to class.

The fossilized remains of 395-million-year-old footprints in Poland have turned back the clock on the evolution of four-legged creatures, or tetrapods. The finds, reported this week in Nature, are 18 million years older than the earliest confirmed tetrapod fossils.

Scientists are getting better at getting their stories out (or at least some journals are better at presenting stores to the media in digestible form)

Read the original Article, the accompanying News and Views, related news story and listen to the Nature Podcast.

Monkey-Man

Kathy pointed me to an interesting editorial in Nature today about the recent fossil primate discovery I mentioned here last week.

The article, entitled Media Frenzy, has the subhead:

A hyped-up fossil find highlights the potential dangers of publicity machines.

Take a look at the original paper in PLoS ONE, Nature's original report and today's editorial.

Do you agree with Nature's assertion that:
In principle, there is no reason why science should not be accompanied by highly proactive publicity machines. But in practice, such arrangements introduce conflicting incentives that can all too easily undermine the process of the assessment and communication of science.

Do you think the authors of the original paper did anything wrong?
Do you think the journalists who covered the story have been accurate in their reporting?

(The image above, which is from Nature's original report, is called 'monkey-man.jpg'. This is exactly the sort of misleading hype that Nature is railing against!)

Signs point to sponges

Just a few weeks ago there was a nature paper based on 'chemical fossils': Fossil steroids record the appearance of Demospongiae during the Cryogenian period.

MIT, where some of the researchers are based, had a press release: Signs point to sponges as earliest animal life 'Chemical fossils' provide evidence for first multicelled creatures.

The Cryogenian is that period in the Precambrian era when there was an extensive series of severe ice ages - often referred to as 'snowball earth'.

Soft-bodied animals such as sponges are very rarely preserved as fossils, so finding evidence of their early appearance required some clever detective work. The key turned out to be an examination of unusual chemicals: steroids of a particular type produced abundantly by sponges but virtually never by simpler organisms.

Studying an unusually well preserved long sequence of strata found in Oman, the research team was able to extract these "chemical fossils" from a large number of samples spanning a range of tens of millions of years -- before, during and after the Ediacarian period. This provided clear evidence that sponges must have evolved long before the great variety of multicellular organisms that proliferated at the dawn of that period.

At that time in geological history, the Earth was just coming out of the last of its "snowball Earth" phases, when the entire planet was shrouded in ice. Since the new findings show that complex life seems to have begun tens of millions of years before that, that means these organisms were able to survive through that extreme episode of glaciation, something that many scientists had thought was impossible. This provides new evidence that the freezing was not absolute, but instead left some open patches of water.

"There's plenty of evidence in these rocks that there were places on Earth where life was flourishing" during this snowball episode, known as the Cryogenian, Summons says. "There must have been some refugia. Life certainly didn't shut down."

Fossil Fish Brain

The structure of the skull (foreground) of a 300-million-year-old iniopterygian fish from Kansas remotely related to living ratfish is elucidated thanks to holotomography, a technique based on synchrotron X-ray phase contrast imaging (background), and yields the first hint at an exceptional mineralization of the brain (orange). (Credit: PNAS/Philippe Janvier (CNRS, Museum National d'Histoire Naturelle))

I think this must be the 300 million year old fish brain that was mentioned on Tuesday. Although it is the first time that the soft tissue of such an old fossil brain has ever been found it sounds like it is also one of the first times people have used sophisticated imaging techniques to look inside the fossil skull.

(S)cientists used the technique of absorption microtomography to study different samples. One sample, stemming from Kansas (US), revealed a peculiar structure: it was denser than the surrounding matrix that fills the braincase, and which is made of crystalline calcite. In order to elucidate its structure in detail, they decided to use a second technique, X-ray holotomography. Surprisingly, the results showed a symmetrical and elongated object placed in the same position as a brain would have been.

Snake longer than school bus

Researchers have unveiled fossils of the world's largest snake, a 42-foot-long relative of the boa constrictor.

Reported at Cryptomundo (which has the best headline), Science News, and many more, details are in this week's Nature. Apart from the fact a giant snake is inherently cool, the discovery also sheds light on the paleoclimate.

The maximum body size that a snake species can reach is related to the average annual temperature of the environment in which it lives. So, average annual temperature in Titanoboa’s rainforest probably measured between 32° and 33° Celsius, about 6 degrees C higher than the average temperature in the region today, the team reports.

Researchers knew the temperature was higher 60 million years ago than it is today, but the new finding could help scientists better calibrate models of ancient climate.

I guess Titanoboa is kind of a cool name but I still prefer Beelzebuffo. Beelzebuffo had a better picture too. Am I the only person who thinks the artists reconstruction above would be greatly improved by the addition of a schoolbus?

Bone Wars

Today's featured article on Wikipedia is 'Bone Wars' -

...the name given to a period of intense fossil speculation and discovery during the late 1800's marked by a heated rivalry between Edward Drinker Cope and Othniel Charles Marsh. Each of the two paleontologists used underhanded methods to out-compete the other in the field, resorting to bribery, theft, and destruction of bones. The scientists also attacked each other in scientific publications, attempting to ruin the other's credibility and cut off his funding.

Cope and Marsh were financially and socially ruined by their attempts to disgrace each other, but their contributions to science and the field of paleontology were significant, and it provided substantial material for further work—both scientists left behind many unopened boxes of fossils after their deaths. The efforts of the two men led to over 142 new species of dinosaurs being discovered and described. The products of the Bone Wars resulted in an increase in knowledge of ancient life, and sparked the public's interest in dinosaurs, leading to continued fossil excavation in North America in the decades to follow.

Blast from the past:
High-performing males have underachieving daughters

Protobird

In the news today, yet more fabulous fossil finds from China. A fossil of a primitive feathered dinosaur uncovered in China is helping scientists create a better model of how dinosaurs evolved into modern birds. The protobird is "very close to the point of divergence" at which a new branch of winged dinosaurs first took flight.

Giant bird feces

I confess I was attracted to this article mainly by the heading. But the reconstruction of paleoenvironments is a topic we will touch on a couple of times so I think this is relevant

Giant Bird Feces Record Pre-human New Zealand.

A treasure trove of information about pre-human New Zealand has been found in feces from giant extinct birds, buried beneath the floor of caves and rock shelters for thousands of years.