Friday, 28 January 2011

Odds, Ends and a New Tyrannosaurid

A few snippets of information now. I can now confirm the final closure of Quarry 4 and that there has been a significant amount of machinery moved into and around the quarry preparing it for the floodwaters to come. Speaking to our liaison at the quarry, the scheduled work will take around ten weeks to complete which, at time of writing, takes us into mid-April before the main flooding takes place.

The Quarry 5 situation remains unclear just now. It has often been the case that we receive mixed messages regarding our access into the new quarry. It was all very upbeat only a few weeks ago and the signs were good, as it finally seemed we were to be granted similar access rights as we have had at Quarry 4, albeit under a much tighter control.

I made a courtesy call this week, just to say hello and to see how things were going. I wish I hadn’t as everything had changed yet again. There would be no access at all now – maybe once if we were lucky and it looked decidedly grim for any future any access into the quarry at all. I was very disappointed and made a point of being extremely polite and trying not to show how anxious I really was.

Later, when I was mulling it all over, it seemed unlikely that this was the case since our liaison, whilst absolutely essential to our even getting anywhere near the quarry, is prone to the “good day, bad day” syndrome. Ring him today and all’s well, ring him tomorrow and its all doom and gloom. I did ask why the situation had changed so much and what brought about this zero access policy? I never really got a straight answer so I asked again and still didn’t get one as I was told everything but the reason. I hope it was a bad day and nothing more. There are other options but we will be saving them up until absolutely necessary.


Moving on and I finally popped off the bone from the centrum of the pliosaur vertebra that I’m cleaning up just now. It wasn’t as clean a removal as I would have liked but it’s not too bad and it also uncovered the other nutritive foramen as I thought it would. It’s cleaning up a treat now.

Andy Farke’s description of Nedoceratops was published last week and is a delicious contradiction to Scanella and Horner’s work on synonymising Triceratops and Torosaurus. Although I am happy to remain within the Scanella/Horner camp just now, I have to congratulate Andy on his paper and the counter arguments produced and I will delve into the issue again at a later date.

What pleases me, and Andy has commented himself about this here, is the courtesy and decorum shown by both camps towards each other regarding each other’s work, even though their conclusions differ. It is an example that I hope others take notice of.

Announced only today is the super basal tyrannosaurine Teratophoneus curriei ("Currie's monster murderer"). What a great name! Here’s the abstract:

Carr, T.D., T.E. Williamson, B.B. Britt & K. Stadtman. in press. Evidence for high taxonomic and morphologic tyrannosauroid diversity in the Late Cretaceous (Late Campanian) of the American Southwest and a new short-skulled tyrannosaurid from the Kaiparowits formation of Utah.

Naturwissenschaften. Online First. DOI: 10.1007/s00114-011-0762-7


Abstract

The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico.

Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei.

Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth. Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes.


Yet more evidence, it would seem, for dinosaurian provincialism. This is just a small part of a wealth of information that is leading to this conclusion. I’m currently working my way through New Perspectives on Horned Dinosaurs (wonderful volume by the way – review coming soon) and there is even more compelling evidence for provincialism here as well. And, of course, another tyrannosaurid, so soon after Bistahieversor was announced – from the same authors. And new species of daspletosaurs to come as well......


Reproduced from Carr et al 2011


Wednesday, 26 January 2011

Winter Goes On

The next trip to Quarry 4 was even harder than the last. Winter was well and truly in the driving seat and continued to make conditions almost impossible. I highlighted this trip
here at the time but it is always interesting looking back in review.

I’ve added a few more images of this particular day in the quarry which demonstrates just how tough the conditions were. And yet it was strangely enjoyable because it was extreme and so different to what we were use to. 

Looking into the murk.

Getting ready........

Harsh conditions.

Where to start?



Thursday, 20 January 2011

Winter 2009/10

Quarry 4 - November 2009
The Winter of 2009 had proven to be one of the harshest for some years. A substantial fall of snow during October and a sustained spell of freezing temperatures hinted at what was to come and it came as quite a shock to a nation that had become use to mild, wet winters.

As we entered February, the British Isles suffered a major fall of heavy snow that affected everyone. Roads were blocked, schools were closed and places of work were devoid of their employees. The snow and ice that followed, and the freezing temperatures, hung on for several days.

During this time, Mark and I had renewed our affiliation to Quarry 4 and were attempting to get down there since we had been informed that there would be significant movement of clay during the early part of the year.

The first day we selected was the first Saturday after the heavy snowfall that had fallen on the previous Monday. We felt there was a chance that we could make it OK but as the week wore on, the snow and ice returned and we decided that discretion was the better part of valour and cancelled.

This turned out to be the last big fall of snow and by the following Monday it had cleared and we tentatively opted to try again the following Saturday. With everything seemingly going to plan I loaded up the car and headed to Quarry 4.

As I got closer to the quarry it became very apparent that the thaw had not set in up here as well as it had down south although the distance from where I live to the quarry is only about 70 miles. I got more concerned on the final approach since the fields were now completely white.

I parked the car by the quarry, climbed the bank and surveyed the scene before me. The quarry had been worked on but it was the overall conditions that were interesting. Any sitting water, whether in trenches or floodwater, was solid ice. Indeed, where the permanent pools of water had flooded and spread across the floor of the quarry, the ice had made walking from one end of the quarry to other nigh on impossible. In fact it was downright dangerous.

Mark duly arrived and after getting rigged up with all our gear proceeded to walk around the top of the quarry and drop into it on the other side of the ice field. There was still some snow lying in the quarry but most of it had gone and we made our way to the newly excavated areas.

Suffice to say that conditions were harsh in the extreme. I’ve mentioned before about clay quarries being hard to negate in wet conditions but this was something else – you could hardly move.

When we got to the new excavations much of it was underwater and it was almost impossible to differentiate between anything at all. Mark did find, however, a nice twig and I managed a couple of big belemnites but that was it. The conditions were simply impossible.

So instead of spending a day at Quarry 4 we ended up leaving after only three hours – and that includid walking time! I was hopeful that new trenches would be dug to help drain some of the water away and this, in turn, would uncover some more fossils. I was expecting some decent finds in the not too distant future and, weather permitting, was hoping to return real soon.

Monday, 17 January 2011

The Final Sunset at Quarry 4


Over the weekend, I received the news that I had been expecting for some time now – namely that Quarry 4 was finally closed and that we were now not permitted to access the site with immediate effect.

This has been done primarily for safety concerns since, although the quarry is private and strictly off limits to the general public, access to the site is relatively easy and, in the current conditions, an accident could easily occur.

Since we were last there in December the quarry was slowly filling up with water and, without new trenches and pumps to keep the water level under control, it was getting harder to prospect for fossils and the areas free from water ingress were becoming extremely limited.

Another bad winter of snow, ice and, just recently, considerable amounts of rain have now completely flooded the back section of Quarry 4 and the waters continue to rise. This is particularly frustrating since there seemed to be a good chance of some Liopleurodon remains coming to light since a few big teeth had been recovered in a very tight area – a very unusual occurrence since these rare teeth are usually only found singularly.

We all wondered at the time if we would get the chance to return because of the flood waters and we were all keeping our fingers crossed we might get the chance. Time it seems was not on our side and it appears that this chance will be lost forever, although, to be fair, it was half expected.

What now for Quarry 4? Well we’ve know for almost two years now that the quarry was to be flooded and turned into a nature reserve and, now that nature has now taken a hand with some flooding of her own, contractors will move in at the end of this week and commence landscaping so that the main flooding of the quarry can take place. When the main flooding event occurs I hope to be there to take some video footage and stills.

When a site such as this is lost it inevitably brings with it a tinge of sadness. Quarry 4 has produced some wonderful specimens over the years and there is obviously more material to uncover. It’s weird to think that the ancient Jurassic sea bed is once again being covered over by water and any more fossils from this quarry will be lost forever.

But of course time moves on and Quarry 5 is well advanced now and is being excavated regularly and I am extremely lucky to know that we have at last gained access to the new quarry in spring although we hope to have an exploratory trip sooner than that. However, access will be heavily regulated and impossible for most. Like I said, I take nothing for granted and consider myself extremely fortunate.

There are a few more posts in the works about Quarry 4 still to come and these will include the discovery of the Liopleurodon teeth that I mentioned earlier, as well as some other interesting specimens.

Wednesday, 12 January 2011

Tail Fins for Plesiosaurs

Photo by LadyofHats

One of the most interesting presentations at SVP last year was Benjamin Wilhelms’ talk on osteological evidence that supports the existence of a tail fin in cryptocleidoid plesiosaurs. I often wondered if they had a tail fin or a similar fluke since, on the face of it, it seemed that evolution was missing a trick here, especially if cryptocleidoids were fairly active hunters and needed a boost of speed to intercept their prey.

The hypothesis that plesiosaurs had tail fins is not new. Wilhelm points out that Richard Owen in 1865 suggested that plesiosaurs may have had a tail fin due to lateral compression in the last ten caudal vertebrae of one specimen. I was particularly intrigued by the specimen referred to Dames (1895) as the holotype of Seeleysaurus guilelmiimperatoris, which clearly showed a dark outline in the caudal region attributable to a tail fin or similar, although this cannot be confirmed.

Working in the Oxford Clay, it occurred to me that I had never heard of any skin, fin or body impressions found with the multitude of specimens of marine reptile that had been recovered, although I’m sure there must have been examples. Fish, on the other hand, I know of a few examples and, the most recent, was a large (two metres) Asthenocormus sp. from Quarry 4 which was exceptional due to preservation of skin and fin impressions and a wonderfully preserved outline of the tail

Comparing two recently recovered specimens of plesiosaur, tentatively referred to Pantosaurus striatus from the Sundance Formation in Wyoming, with specimens of Cryptoclidus oxoniensis and Muraenosaurus leedsi, both from the Oxford Clay in England, Wilhelm has unearthed some pretty good comparative evidence that at least cryptocleidoid plesiosaurs did possess a tail fin.

These include variable morphology of the neural spines in some caudal vertebrae including increased height and distal ends which demonstrate increased length and that are more flared to increase attachment for cartilage which would have provided strength and stiffness to a tail fin.

Fascinatingly, some neural spines change direction and increase articulation which provides even more surface area for a larger cartilage attachment which tends to be situated below what appears to be the tallest part of the fin and would, again, have provided strength and support.

Toward the distal end of the tail, the caudal vertebrae gradually become laterally compressed as the centra reduce in width, as do the caudal ribs. This is also thought to demonstrate the presence of a tail fin.

Comparisons with extant taxa such as cetaceans, scombroid fishes and lamnid sharks suggest the tail fin could produce thrust, downward force and some ruddering capability for the plesiosaur and was almost certainly capable of independant movement.

So it does seem likely that cryptocleidoid plesiosaurs did have a tail fin. Whether this applies to all plesiosaurs is uncertain and this work does have some ramifications, particularly for elasmosaurids and, as Wilhelm points out, there is still much more research to do.

This is really solid work and I’m very impressed by it. If you want to learn more and to get the in depth detail, a copy of Wilhelm’s work is freely available here.

References

Dames, W. 1895. Die plesiosaurier der S├╝ddeutschen Liasformation. Abhandlungen der K├Âniglich Preussischen Akademie der Wissenschaften zu Berlin 1895:1–81.

Owen, R. 1865. A monograph on the fossil Reptilia of the Liassic Formations. Part 3. Sauropterygia. Monograph of the Palaeontographical Society 17: 1-40.

Wilhelm, B.C. 2010. Novel anatomy of cryptoclidid plesiosaurs with comments on axial locomotion. Ph.D thesis, Marshall University, Huntington, WV. USA

Wilhelm, B.C., O’Keefe, F. 2010. A new partial skeleton of Pantosaurus striatus, a cryptocleidoid Plesiosaur from the Upper Jurassic Sundance Formation of Wyoming. Journal of Vertebrate Paleontology, 30:1736–1742.


Reproduced from Wilhelm 2010.


Monday, 3 January 2011

Pliosaur Vertebra - Some Facts & Figures

Note the nutritive foramen.
One of my correspondents, Paul, has shown some interest in this pliosaur vertebra and rightly so. It is extremely rare to find a vertebra this well preserved and uncrushed from the Oxford Clay. It seems to be from either Simolestes or Liopleurodon although, due to its size, we feel that it is almost certainly Liopleurodon since the same area has produced a few big Liopleurodon teeth toward the back end of 2010. There may be more material to collect but it is all underwater at the moment and inaccessible.

The centrum is 85mm long in a straight line and extremely concave. Both cranial and caudal articular surfaces are almost circular and slightly convex, 100mm in length mediolaterally and 110mm dorsoventrally on the cranial face and less caudally although this surface has suffered some damage. Ventrally there is a keel and there is one foramen exposed on the right lateral side of the centrum about 35mm up from the aforementioned keel. The other foramen is below the attached rib? on the left lateral surface.

Another pointer to Liopleurodon is the fact that connecting area between centrum and neural arch is extremely long - almost the whole length of the centrum. The processes themselves I've kept plugged with matrix while I've been prepping the centrum - for added support. But it is evident that both neural spine and the transverse processes were thick and robust. The overall height of the vertebra from keel to the uppermost neural process is 210mm.

Preparation has been fairly straight forward although I have spent quite a bit of time on the right lateral side of the centrum carefully teasing off matrix off what is left of the surface patina of the bone. The processes represent quite a challenge but the neural canal is there and intact. I'll keep you informed as the vertebra develops.

In cranial view.

In caudal view.

The float may be rib or process - not too sure just now.

Saturday, 1 January 2011

Right then - 2011........

What with family commitments and the holiday season, it has obviously been hard to find the time to blog as per normal but that should sort itself out over the next week. I've been away for only a few days and already there have been more new titanosaurs and ceratopsians announced, although Titanoceratops is causing a bit of a stink over on the DML.

As I've been alluding to for some time, lumping and splitting is now becoming something of a millstone around the neck of dinosaur palaeontologists' - so much so now that there is the first rumblings of a a severe split within the community although it should never come to that. That would be ridiculous and completely nonsensical. However. this debate will rumble on throughout 2011 and I hope that it will be a debate and not a shouting match since that will serve nobody.

But, just because I can, let me just say that there is yet another centrosaurine taxon to be announced which is another very cool animal and it will be a very satisfying day for a friend of mine when it is published. Will 2011 be yet another year for the ceratopsians? Maybe but then it depends whether you are a lumper or a splitter - and yes I am joking!

The picture above shows a ray tooth collected from Bracklesham Bay on New Year's Eve. Now I know that a few of our better known fossil hunting websites rate this bay very highly for shark and ray teeth. What they don't tell you about is the amount of collectors there! I called in for a brief visit at low tide since I thought it would nice to find a shark tooth at the end of the year - in with the old, if you like. I liked the dichotomy.

When I arrived I surveyed the scene and saw at least twenty collectors, some of them armed with sieves and loads of other paraphernalia. I still had a look but apart from mollusc's, of which there are plenty, all I found was this little ray tooth. The beaches had been heavily scoured and nothing remained. So I'm not saying don't go to Bracklesham but be prepared to struggle and work hard for your finds - it just isn't as easy as it once probably was.

Enough for now but I thank those of you who visit these pages from time to time and a big thank you to my nine followers (it really makes a difference knowing you're there). Special mentions in dispatches for Dave Orr over at Love in the Time of Chasmosaurs. Dave has been very generous in featuring this blog in a few of his posts and my traffic has increased because of it. Thanks Dave! And thanks to the rest of my colleagues in the paleo-blogosphere - its been fun!

Happy new year everybody and I hope you all visit in 2011.