Long Absence

Sorry I have been absent for so long. Life has been getting pretty busy, with grad school and a new baby on the way. But I hope to be back to blogging (at least once a week, if not more often) and Tangled Bank has given me the kick in the pants I need to get back to it! Visit us on August 15 to check Tangled Bank #86!

Fossil tracks suggest dinosaurs could swim

Ancient footprints have provided compelling evidence that some dinosaurs were able to swim. The 15m (50ft) trackway was discovered in the Cameros Basin in Spain, which, 125 million years ago, in the Early Cretaceous was a vast lake.

The unusual-shaped prints suggest the animal clawed at sediment on the lake bottom as it swam in about 3m (10ft) of water. Though it has been suggested that large sauropods occasionally waded through shallow waters, it is thought that these tracks were left by a large, bipedal, carnivorous dinosaur that was not wading, but rather was using the water to support its body.

Dr Loic Costeur, a palaeontologist at the University of Nantes, France, says "The Cameros Basin has thousands of walking footprints from diverse dinosaur fauna, but when we saw these it was obvious straightaway that this was a swimming dinosaur."

The underwater trackway is well-preserved in sandstone and is made up of 12 consecutive prints each consisting of two to three scratch marks. Ripple marks around the track suggest the dinosaur was swimming against a current, attempting to keep a straight path. Dr Costeur also stated that "The dinosaur swam with alternating movements of the two hind limbs: a pelvic paddle swimming motion."

I guess it was a sort of a prehistoric doggie paddle:)

Prehistoric Location, Location, Location

Human nature doesn’t change. Tour any archeological site and you will find necessities, desires and comforts of life common to all people. In particular this applies to the place we call home. A house buyer today views properties with a mental checklist of desired features and according to recent researchers, prehistoric cave-dwelling Britons did the same thousands of years ago.

A survey of over 400 caves in Northern England shows that people living in this area from 4,000 to 2,000 B.C. selected their homes based on five important features. Caves were favoured if they

*Were located at a higher altitude
*Had an east or west facing entrances
*Had large entrances
*Included deep passages
*Had a level area just outside of the entrance

Archaeologists discovered that the Peak District, a productive area for agriculture today, attracted more prehistoric cave users than the Yorkshire Dales. But caves were also used for more transitory purposes: sometimes caves were employed like roadside motels, where travellers would stop in for a few nights to rest before continuing their journeys

The benefits of this project include the discovery of many previously unexplored caves throughout Britain, a well-practiced methodology for surveying archeological sites, and an excellent compilation of data that will aid future researchers.

Why does a platypus lay eggs anyway?

Children are taught many ‘rules of thumb’ to help them identify animals, for example: mammals, are furry (or hairy), give birth to live young, make milk and take care of their children. So why does the furry platypus lay eggs? The discovery of this bizarre, egg-laying, duck-billed, web-footed mammal initially baffled naturalists, but now we understand them much better because we know much more about their special place in the tree of evolution.


All animals on Earth are related, even though these relationships aren’t always obvious. The reason these relationships are hard to figure out is that despite the diversity of animals we see, they represent a mere fraction of the life that has ever existed on this planet. In fact, one famous palaeontologist estimated that we know of less then 1% of the Earth’s diversity through time.

To understand the relationships between animals better, we have to look back in time, at the extinct ancestors of the animals alive today (animals living today are called ‘extant’).

This diagram (called a cladogram) shows how the five major groups of vertebrate animals are related:
-Fish gave rise to the first amphibians, which crawled on to land about 400 million years ago.
-Amphibians and reptiles share a common ancestor about 350 million years ago.
-Mammals and birds evolved from reptiles much later at different times during the Mesozoic Era.

Each of these major transitions was slow. It must be understood that a fish doesn’t become an amphibian overnight. There were many different species of animals that formed that transitory stages between these groups and possessed a unique set of characteristics, a sort of ‘mosaic’ between the two groups.

Now let’s look more closely at the evolution of mammals. Mammals evolved from mammal-like-reptiles, a very diverse groups of animals which are all (unfortunately) extinct. Through time three major groups of mammals evolved:
Prototherians - which lay eggs (eg. platypuses and echidnas)
Metatherians - which let young develop in pouches (marsupials such as kangaroos and koalas)
Eutherians – ‘modern mammals’ which give birth to well-developed offspring (this includes many familiar species such as rabbits, elephants, horses, and humans)

The platypus is a prototherian. This ancient group branched off of the mammal tree of life early on before the other two groups. There are many different prototherians in the fossil record but only platypuses and echidnas are still around. So the past there was a great diversity of egg-laying mammals, but sadly, all of those animals except for platypuses and echidnas) are now extinct.

If you are interested in this topic I recommend visiting Date A Clade, which has an excellent (and more comprehensive) cladogram with detailed information on when major groups of animals split away from each other.

Tyrannosaurus Forelimbs Revisited

Earlier in the week, I posted some theories regarding the function of T. rex’s diminutive arms. I just thought I would add some recent research before I closed the topic:

Matt Smith (Museum of the Rockies) and Ken Carpenter (Denver Museum of Natural History) began examining the wrist, hand and finger bones of the T. rex forelimb and used wax to hold the bone joints together. This led them to figure out that the forelimb's two claws have an unusual feature: unlike the opposable human thumb and forefinger combo, which can grasp objects, the two dinosaur claws face away from each other like the barbs of a fishing hook.

What does this mean? Perhaps these claws embedded themselves into the prey’s flesh and immobilized it while T. rex used his jaws to finish the job. .

Matt Smith says, "People had been looking at [forelimb] function based on proportionate size. I don't think that's appropriate."

Scooped (or rather Bitten) again!

Once again, Brian Switek of Laelaps and Mike Ryan of Palaeoblog have beaten me to the punch on reporting on a recent publication that suggests the first tetrapods were able to bite their prey (rather then suck their food up).

Reference: Markey, M.J. and Marshall, C. R. 2007. Terrestrial-style feeding in a very early aquatic tetrapod is supported by evidence from experimental analysis of suture morphology Proceedings of the National Academy of Science. Early Edition on April 16 2007.

Evolution is only a theory...

As you may have heard, in 2006, the Kansas school board was campaigned to add required labels to textbooks that mention evolution. There have been many parodies on the “Warning, Evolution is only a theory” labels, these are my favourite:) campaigned to add required labels to textbooks that mention evolution. There have been many parodies on the “Warning, Evolution is only a theory” labels, these are my favourite:)

Shark Myths and Facts

Da-dum ... Da-dum ... Da-dum.. Da-dum.. Da-dum, Da-dum!

It has been 30 years now since the release of the blockbuster Jaws and these two notes still instill fear. Some would argue that great whites are not vengeful, man-eating killing machines but are in fact, intelligent, misunderstood ancient sea creatures. I would agree with this statement in that they do not target people and are intelligent animals, but their fundamental morphology has remained unchained for millions of years because they are perfectly adapted killing machines: keen senses, speed, agility and a mouth full of huge, serrated teeth backed by the most powerful jaws of the animal kingdom. Make no mistake, they are efficient and ferocious animals perfectly suited to their niche.

*The great white is about 6m (20ft) long and the largest predatory fish.

*It is actually grey on top with a white underbelly, camouflage for hunting. The colouration makes them difficult to see from above as they blend in with the rocks and the white belly makes them hard to see from below because they blend in with the sky.

*Sharks never run out of teeth. If they lose one another spins forward from rows and rows of backup teeth. A great white has hundreds of teeth in its jaws at any one time.

*Sharks prefer a high fat food source since fat stores more energy then muscle. Their favourite snack is a baby seal.

*Once a seal is caught, other sharks smell the blood in the water and show up for the meal. Great whites can smell one drop of blood in 100L of water. Since their prey has a lot of blood, nearby sharks are easily attracted to the kill and show up for a feeding frenzy.

*The meal is divided up based on interactions. The animal that splashes the most water gets the next bite. Despite eating together sharks do not hunt together.

*The great white can move through the water at 40 km/hour

*But though they are fierce predators, great whites don’t like the taste of humans; less then 6 people are killed by sharks every year.

Fish Finds Land-Legs

Evolution doesn’t happen all it once, it takes a few tries :)

BC creator dies while drawing last cartoon

Cartoonist Johnny Hart, who won awards for his comic strips, BC and The Wizard of Id, has died of a stroke at the age of 76.

BC, which depicted a world populated by cavemen and dinosaurs, first appeared in newspapers in 1958. The Wizard of Id was a political satire based in a run-down kingdom ruled by a diminutive and tyrannical monarch.

Johnny Hart’s comics reached over 100 million people. He died at his storyboard, doing what he loved best.

Palaeobarbius malibui

I have no idea if this letter, that was supposedly sent to the Smithsonian Institute, is real but regardless it is hilarious.

Paleoanthropology Division
Smithsonian Institute
207 Pennsylvania Avenue
Washington, DC 20078

Dear Sir:

Thank you for your latest submission, labeled "93211-D, layer seven, next to the clothesline post...Hominid skull." We have given this specimen a careful and detailed examination, and regret to inform you that we disagree with your theory that it represents conclusive proof of the presence of Early Man in Charleston County two million years ago. Rather, it appears that what you have found is the head of a Barbie doll, of the variety that one of our staff, who has small children, believes to be "Malibu Barbie." It is evident that you have given a great deal of thought to the analysis of this specimen, and you may be quite certain that those of us who are familiar with your prior work in the field were loathe to come to contradiction with your findings. However, we do feel that there are a number of physical attributes of the specimen which might have tipped you off to its modern origin:

1. The material is molded plastic. Ancient hominid remains are typically fossilized bone.

2. The cranial capacity of the specimen is approximately 9 cubic centimeters, well below the threshold of even the earliest identified proto-homonids.

3. The dentition pattern evident on the skull is more consistent with the common domesticated dog than it is with the ravenous man-eating Pliocene Clams you speculate roamed the wetlands during that time.

This latter finding is certainly one of the most intriguing hypotheses you have submitted in your history with this institution, but the evidence seems to weigh rather heavily against it. Without going into too much detail, let us say that: A. The specimen looks like the head of a Barbie doll that a dog has chewed on. B. Clams don't have teeth. It is with feelings tinged with melancholy that we must deny your request to have the specimen carbon-dated. This is partially due to the heavy load our lab must bear in its normal operation, and partly due to carbon-dating's notorious inaccuracy in fossils of recent geologic record. To the best of our knowledge, no Barbie dolls were produced prior to 1956 AD, and carbon-dating is likely to produce wildly inaccurate results. Sadly, we must also deny your request that we approach the National Science Foundation Phylogeny Department with the concept of assigning your specimen the scientific name Australopithecus spiff-arino. Speaking personally, I, for one, fought tenaciously for the acceptance of your proposed taxonomy, but was ultimately voted down because the species name you selected was hyphenated, and didn't really sound like it might be Latin. However, we gladly accept your generous donation of this fascinating specimen to the museum. While it is undoubtedly not a Hominid fossil, it is, nonetheless, yet another riveting example of the great body of work you seem to accumulate here so effortlessly. You should know that our Director has reserved a special shelf in his own office for the display of the specimens you have previously submitted to the Institution, and the entire staff speculates daily on what you will happen upon next in your digs at the site you have discovered in your Newport back yard. We eagerly anticipate your trip to our nation's capital that you proposed in your last letter, and several of us are pressing the Director to pay for it. We are particularly interested in hearing you expand on your theories surrounding the trans-positating fillifitation of ferrous ions in a structural matrix that makes the excellent juvenile Tyrannosaurus rex femur you recently discovered take on the deceptive appearance of a rusty 9 mm Sears Craftsman automotive crescent wrench.

Yours in Science,

Harvey Rowe
Curator, Antiquities

Darwin Fish Contest

Here is your chance to come up with your own parody of the fish emblem! Ring of Fire is holding a contest to come up with a new fish, they will manufacture and sell the winner's design. Click here to read more and check out my submission (below), which to be honest is a big large and probably won’t be practical for manufacturing:) The contest closes on 16 April.

Evolution Videos

Laelaps has a compilation of hilarious evolution videos worth checking out on his blog. Highlights include The Flanders visiting the Hall of Man at the Springfield museum, The Family Guy’s version of the big bang / evolution and a great montage of Bush or Chimp set to an anti-evolution song sang by a lovely school choir. Click here and Enjoy!

In the News: Ancient Humans, Great Pyramids and an Antarctic Amphibian

Mystery of the great pyramids solved
Original Publication: Dassault Systems
Popular News site: CBC

Ancient human fossil from China collides with ‘Out of Africa' theory
Original Publication: PNAS
Popular News site: BBC

Antarctic amphibian
Original Publication: JVP
A synopsis of the original article will be published on this blog later today.

Happy St. Patrick's Day!

This is one of my favourite videos of all time, particularly because of the cute mudskippers featured at the end. As is obvious by the title of my blog, I find the idea of fish with feet fascinating. So before you get to the video, a little indulgence:

Mudskippers are a group of marine fishes that are unique in that they have adapted a suite of characteristics to suit an amphibious lifestyle:

* Weight bearing limb structure
* Cutaneous air breathing (breathing through skin, mouth and throat)
* Ability to dig burrows for protection (from predators and for their nurseries)

All of these characteristics as well as their widespread sub tropical to tropical distribution means mudskippers have a lot in common with the first tetrapods. However unlike the first tetrapods, mudskippers are small: about 15cm long (the first tetrapods were large, some as big as 150cm) long and mudskippers eat crabs and insects (not fish).