Thursday, 23 December 2010

Dusty Dinosaurs


Although Christmas is upon us, I thought that I would have a little grumble this week. Not too much of a moan because I think that would be a bit unfair but it is something I’ve been observing for quite a while and, since last week, has almost become an embarrassment.

I’ve spent quite a bit of time at the Natural History Museum (NHM) in London over the last few years and I love the place. More often than not, it is for comparative study of fossil bones, to take digital images for the same purpose and also for this blog. I also go for the atmosphere that the building brings, and what a magnificent building it is – simply stunning.

Normally my first point of call is to go and look at the dinosaurs although, on this particular visit, it was to have a good look at the marine reptile gallery and examine a couple of specimens. So I arrived at the museum and, just like most visitors do, promptly headed for the Dinosaur Gallery and have yet another wander around.

On this occasion I walked in and straight away came upon the casts of Camarasaurus and Triceratops. As usual just their presence is enough to create that immediate sense of awe and wonderment and I got my camera out ready to start taking images.

I gazed at the scapulocoracoid of Camarasurus. At first in wonder at the size of these great shoulder blades and then, in amazement, at the amount of dust that was covering these cast bones. I looked up and around the great sauropod and, in the subdued museum lighting, I could see that the entire skeleton was caked in dust. Frankly, it looked awful and I quickly moved on to the Triceratops mount.

This cast was also in a filthy state but had an additional problem. Some of the exhibits are surrounded by toughened glass barriers which are obviously there to stop people from touching the bones or causing them damage. This makes sense but looking at the glass, you would be hard pressed to guess when it had been last cleaned. It was covered in fingerprints, misted over in many places and severely impaired ones view of the specimen. Truly disgusting.

A bit dark but you get the idea
I left the trike and climbed the stairs that were situated behind the camarasaur. I looked down on the sauropod and again was horrified at the amount of dirt on display. This was the pattern throughout the rest of my tour of the gallery. It didn’t matter where you looked, the overall condition of the specimens, the platforms where they were mounted, the glass barriers and displays was, frankly, shocking. I took quite a few images and later, when I downloaded them to the computer, the problem becomes even worse because of the flash.

Surely something needs to be addressed here. Keeping the museum and exhibits clean demonstrates a museum that has a sense of duty and cares for its collection. At the same time it also sends a valuable and positive message to the public, donors and supporters alike.
Like so many museums the NHM is centrally located in a city environment and there are a number of pollutants that cause problems. In this case, and one suspects that all museums have the same problem, dust is the number one issue. It permeates from the exterior, a combination of dirt, soot, soil and other nasties, and then combines with human skin and hair to settle throughout the interior and on the exhibits.

It continues to build up and become unsightly. Dust can also absorb moisture and create humidity which can damage specimens. It can also stain, attract pests and carry pollutants with it. It can even be abrasive when wiped off of delicate objects. Dust needs to be controlled.

I understand that in these times of austerity that the funds or indeed the inclination is not there to become proactive with regards to dust control or to even manage a simple cleaning regime. I don’t pretend to have all the answers either. I mean – how do you clean and dust a sauropod skeleton? With a vacuum cleaner and lots of extensions? Feather dusters? Will a scaffold be necessary? What are the health and safety implications? I do realise the problems. I do understand that only trained museum staff can do the job.

And yet something does need to be done. Surely regular cleaning in the museum is good management practice? The amount of dust on these specimens must amount to a few years of build up now and frankly it is unacceptable for the exhibits in a national museum to be in such a state and I hope something will be done soon to alleviate the problem.

That just leaves me to wish all of you who celebrate it, a very happy and peaceful Christmas.


Dusty dromaeosaurs!


Wednesday, 15 December 2010

Quarry 4 Produces


July arrived and I was due to head south again but the news that the Cuckoo’s Hole quarry was closed knocked the stuffing out of me a little bit and I was very disappointed not to able to visit. I could have visited the Bluff as well but, for me, it wasn’t time yet.

So, at short notice, I called Mark to see if he was up for a trip to Quarry 4 on the same day that I would have headed south. Luckily for me, he was and we met up on the Sunday morning at 9AM ready for the hunt. Yet again you could see that another big section of clay had been removed and we walked briskly, eager to start prospecting.

As we approached the back of the quarry, the shell/reptile beds were fully exposed and there were great masses of concretions that were showing on the surface. About thirty yards from the back of the quarry, a long spoil heap had been drawn up by the excavators and this, unusually, was not contaminated by old bricks and there was plenty of new clay to look over. I would save this section for later.

We both began with the ancient sea floor, carefully walking, looking at the nodules and every exposed sections of clay in between. There were two or three really big belemnites that had, unfortunately, been crushed by the excavators and a few Gryphaea of unusually large size fully exposed on the surface but these were ignored. Bigger prey was the order of the day.

After a while, Mark brought to my attention a nodule that had obviously had something entombed within. Careful scraping with picks and brushes revealed the remains of a fish in the block. We could clearly make some spines, presumably part of the dorsal fin, an operculum, a tooth and lots of other bits and pieces. Neither of us are heavily into fish and the exposed remains were obviously too fragmentary to even guess at identification.

Image courtesy of Mark Graham © 2010
But the block was certainly a prime candidate for preparation and it was obvious that the block contained a lot more unexposed bone and looked certain to be a good specimen. We decided to take the block out and first of all consolidated the exposed bone and then proceeded to remove the clay from around the block and leave the concretion sitting proud of the surface. We then attempted to split the block at an appropriate spot. Easier said than done.

For future reference, let me tell you that concretions are very aptly named and, despite the use of extreme force with a variety of chisels and hammers, could hardly make inroads into it. Time was obviously an issue and it became apparent that we were hardly well equipped for this sort of excavation. I think we both understood a little more now and the reasons why concretions with bones in are often taken out whole. There appears to be no other option.

Mark decided to call Cliff Nicklin and see if the museum would be interested in the fish. Cliff agreed to arrange an inspection of the block and then the matter would be taken from there. Satisfied that we had done all that we could, we decided to move on and continued to prospect.

We carefully moved on and arrived at the previously cleared bed. Again, despite our keenest attentions we were coming up short. We took a break for lunch and then headed back to area where the fish was. Mark continued to scour the area and I, reverting to type, started at the beginning of the spoil heap and slowly moved along, often sitting in the middle of the heap and looking very closely.

As I looked into the clay I saw what I thought was a dead slug and immediately thought it was strange to find a slug hundreds of yards away from any vegetation and in the middle of a barren clay quarry. I went to poke it to see if it was dead and was surprised that it was rock solid! As I lifted it up I could see that it was distinctly marked and as I cleaned it off realised that I had a crushing tooth from a hybodont shark.

It was big at over 50mm in length and I later identified it as Asteracanthus ornatissimus. This was a really rare tooth and big – I was absolutely delighted. The preservation and markings on the tooth were beautiful. After showing Mark my prize I carried on surveying this very same spoil for more fossils. I wasn’t to be disappointed.


Astonishing detail in this close-up

Cliff has always said to me that, because everything in sight is clay grey, you have to look for shapes and I have been trying to tune in for some time now. I also knew that a lot of my better finds over the years have been when I get on my hands and knees and look at the sediment really closely. This combination of shapes and close up work was about to pay dividends.

I worked my way along the spoil heap slowly but surely. After about 20 yards I virtually laid my head on the side of the spoil and looked along its length. About 5 yards away I made out a distinct concave shape in the spoil that was obviously out of place, and, as I approached it, I knew what I was seeing. Sure enough, standing proud in the middle of the spoil, was a huge vertebra. It even had a large proportion of the processes intact, despite being rolled about goodness knows how many times by the excavators.


Spot the vert!

I was absolutely delighted. After all the blank trips, all the miles I’d driven and the steep learning curve at Quarry 4, here was my reward. The vertebra was massive and obviously from a very large pliosaur. Not only were the processes preserved but a section of rib had become detached and stuck to the centrum during fossilisation. Again I called Mark to show him my prize and then I wrapped my prize carefully and carefully placed it into the rucksack. We both scoured the immediate surroundings to see if there were any more remains to be found but nothing turned up.

As the day approached its end, it was good that we were, at last, coming to terms with the quarry. We carried on prospecting in the general area of the spoil heap but to no avail. Nothing else was found but that was to be expected and, in the circumstances, I didn’t want to appear greedy!

As we left the quarry, I was to return a couple of times later in 2009 but nothing of note was recovered. We also received word at this time that Quarry 4 was finally going to be closed during 2010 and was to be flooded and turned into a nature sanctuary. This was sad but it did mean that Quarry 5 was finally going to be opened and, as Winter approached, machinery was slowly being transferred to the new site.

Preliminary excavations begun and many tons of glacial sands and gravels were removed but the drag lines soon reached the clays and excavation began in earnest. At this point there was still one drag line working Quarry 4, although we didn’t know why. The reason why became clear to us during the next few months.

2010 was approaching fast and there were changes ahead but we all looked forward to the New Year but first we had the ravages of one of the worst winters in years to contend with.

Wednesday, 8 December 2010

Complex Dinosaurs

Sauropods were a group of large plant eating saurischian dinosaurs found all over the world. For some time now I’ve always thought that when you could solve the biomechanics of sauropods, you could more or less solve the secrets of the dinosauria as a whole. Sauropods were amazing animals.

The functional morphology of sauropods has long come under intense scientific scrutiny. For example, how did sauropods eat enough food to maintain a constant metabolism and support their enormous body sizes? The size of a sauropods’ mouth appears, on the face of it, not large enough to eat sufficient plant matter. This is particularly fascinating when you consider the small size of the head in relation to the body and the relatively poor chewing mechanisms of some (but not all) sauropods (Christiansen 2000; Upchurch & Barrett 2000).

The long necks of sauropods are under continual scrutiny and have been since they were first discovered. There have been all sorts of theories regarding their posture, range, and movement and we are still unsure (Martin et al 1998; Stevens & Parrish 1999; Taylor et al 2009). Were their necks curved? Did they raise them vertically, hold them horizontally, were they sloping down?


Then how on earth did they pump enough blood to the brain and back again? The distances are enormous – in the case of Barosaurus, the neck is approximately 25 feet long, in Seismosaurus, even longer (Choy & Altman 1992; McIntosh 2005). Just how did they manage this? Obviously they did since the giraffe-like Brachiosaurus and Giraffatitan held their necks aloft and must have fed in the tree tops. The engineering required to achieve such blood flow defies belief. Theories are legion but none are universally agreed on.

The reason I mention the issues above is that I think we sometimes lose sight of what nature is capable of. We are all very astute in being able to say what is not physically or physiologically possible and yet we find it difficult to provide any suitable hypotheses or alternatives – at least any that can be agreed on. Totally understandable of course and yet this somehow misses the point.

These animals diversified and radiated for millions of years and were extremely successful. Sauropods did exist in vast numbers; they did eat enough to, not only survive, but proliferate. They did have a cardiovascular system more than capable of pumping blood around their bodies. These animals were truly natural wonders – these dinosaurs were complex creatures.

It was while studying the premaxillae of tyrannosaurs that it really occurred to me how complex they were – indeed how complex all theropods are, both avian and non-avian. If we concentrate on tyrannosaurs, however, we can see what has happened over the years. Certainly, despite vast amounts of data to the contrary, these animals are sometimes portrayed as slow scavengers who were not even capable of staying on their own two feet unless they stood still. This is just plain wrong.

Naturally enough, mention tyrannosaurs and it is Tyrannosaurus that comes to the fore and rightly so. For me this has to be the single most impressive land predator ever and it is understandable that huge amounts of study are devoted to this species. After all, the amount of material recovered in the last twenty years is astounding – over forty known specimens and the numbers are rising (Larson 2008).

Back to tyrannosaurid premaxillae then. Tyrannosaurus is continually portrayed as a huge bone shattering, crunching set of jaws that was able to consume vast amounts of flesh and bone in huge gulps. Perfectly reasonable – there are even coprolites full of pulverised bone (Chin et al 1998). Except that tyrannosaurs also had an arcade of eight premaxillary teeth (Holtz 2004). What were they for?

A typical D-shaped tyrannosaurid premaxillary tooth.

Maybe they were used for grooming, intraspecific communication or, as seems to be the general consensus, these teeth were used for selective feeding (Hone & Watabe 2010), stripping flesh from the bone and nibbling bits of flesh off, maybe, to even feed their young . Either way, this immediately does away with the common depiction of Tyrannosaurus as a simplistic bone-mashing-eat-everything carnivore. If Tyrannosaurus just fed like this then why have a premaxillary? The premaxillary suggests complex behavioural patterns – otherwise why bother with it?

And then when you start to look at tyrannosaurs in more detail, their general biomechanics, just like sauropods, are astounding. The overall combination of good eyesight, superb sense of smell and hearing is generally accepted and the brain was relatively large to process all the details (Witmer & Ridgely 2009). These are adaption’s, not only for hunting and scavenging, but for intraspecific communication and environmental awareness.

Another adaption to consider is bipedalism – the general body plan for all theropods is more or less the same, pot-bellied therizinosaurs not withstanding. High running speed in tyrannosaurs has come under intense scrutiny over recent years and whilst it is generally accepted that a top speed of 40mph is somewhat exaggerated, a 40 foot long, 7 ton tyrannosaur running at 15 mph is not exactly hanging about and was more than adequate to run down its contemporaries (Farlow et al 1995b; Paul 1998).

However, even a tyrannosaur briskly walking has come in for some tough scrutiny. It has been suggested that a tyrannosaur would hardly dare break into a trot just in case it tripped or fell. I mean what would a theropod do if it broke a leg or, as has been suggested, couldn’t even get back to its feet and remained grounded?

Whilst this may have an element of mechanical soundness about it, the truth actually stares us in the face. Let’s take a couple of steps back and think about it. An entire clade of dinosaurs, the theropoda, evolved into bipedal animals that walked on their toes and endured for around 150 million years – considerably more if you include aves. These animals ranged in size from critters the size of a chicken to huge multi-tonne mega-carnivores. If these animals were continually falling over, breaking bones, and not able to get up then evolution would have demanded a change in their way of moving around the terrain or theropods would have probably become extinct within a very short time span. After all, ostriches don’t worry too much about whether they will trip and fall when it is time to outrun a predator – albeit an ostrich doesn’t weigh a few tons.

I’m being a little simplistic here but the point is essentially correct. Theropods did not worry about falling over and did not hesitate to put their foot on the gas when food was required. And again the ability to combine agility, judgement and hunting skills is indicative of complex animals.

Finally, a look at the tail of a tyrannosaur. The tail was a massive part of the animal, held proud from the ground, heavily muscled and not only acted as a counter balance for the large head of the animal, but was also the driving force that propelled the animal forward at speed and would have been vital in maintaining equilibrium when the animal moved. And, indeed, while writing this post, a newly published paper (Persons & Currie 2010) makes a point of this very issue and puts some substance behind the theory.

This combination of characters, from the massive head through to the tail, and all of the specialised traits in between suggests a level of complexity comparable with any extant mammal of today. Behavioural inference can only be that – inferred but that still leaves an enormous amount of physical evidence that is totally indicative of complexity within species.

Dinosaurs were complex animals of the highest order. Of that there is and should be no doubt.


Referances

Chin, K., Tokaryk, T.T., Erickson, G.M., Calk, L.C., 1998. A king-sized theropod coprolite. Nature 393, 680–682.

Choy, D. S. J. & Altman, P. 1992 The cardiovascular system of Barosaurus: an educated guess. Lancet 340, 534-536.

Christiansen, P. 2000. Feeding mechanisms of the sauropod dinosaurs Brachiosaurus,Camarasaurus, Diplodocus and Dicraeosaurus. Historical Biology 14, 137–152.

Farlow, J. O, M. B. Smith, and J. M. Robinson. 1995b. Body mass, bone “strength indicator,” and cursorial potential of Tyrannosaurus rex. Journal of Vertebrate Paleontology, 15:713–725.

Holtz, T. R., Jr. 2004. Tyrannosauroidea; pp. 111–136 in D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria, second edition. University of California Press, Berkeley, California.

Hone, D.W.E., and Watabe, M. 2010. New information on scavenging and selective feeding behaviour of tyrannosaurs. Acta Palaeontologica Polonica 55 (4) 627-634.

Larson, N 2008. One Hundred Years of Tyrannosaurus rex: The skeletons: pp. 1-55 in P. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King, Indiana University Press, Bloomington, Indiana

Martin, J., Martin−Rolland, V., and Frey, E. 1998. Not cranes or masts, but beams: the biomechanics of sauropod necks. Oryctos 1: 113–120.

McIntosh, J. S. 2005. The genus Barosaurus Marsh (Sauropoda, Diplodocidae). In Tidwell, V. & Carpenter, K. (eds) Thunder-Lizards: The Sauropodomorph Dinosaurs. Indiana University Press (Bloomington & Indianapolis), pp. 38-77.

Paul, G.S.1998. Limb design, function and running performance in ostrich-mimics and tyrannosaurs. Gaia 15:257–270.

W. Scott Persons, Philip J. Currie 2010. The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non-Avian Theropods. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 2010.

Stevens, K. A. & Parrish, J. M. 1999 Neck posture and feeding habits of two Jurassic sauropod dinosaurs. Science 284, 798-800.

Taylor, M. P., Wedel, M. J. & Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica 54, 213-220

Upchurch, P. and Barrett, P. M. 2000. The evolution of sauropod feeding mechanisms. pp. 79–122 in Sues, H.D. (ed.): The evolution of herbivory in terrestrial vertebrates. Perspectives from the fossil record. Cambridge University Press.

Witmer, L.M. and R.C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record 292:1266–1296.

Wednesday, 1 December 2010

The Ammonite Macrocephalites



This is the Middle Jurassic ammonite Macrocephalites – from the Early Callovian of Lincolnshire and collected at the end of the 19th century. I was given the specimen by a friend of mine, Maria, who was given a private collection from a client of hers (Maria is a hair stylist).

The clients’ mother had recently died and, during the house clearance, there was a coal scuttle that was filled with fossils and minerals. Knowing that Maria had a liking for curios, she gave the collection to her and Maria asked me to pop around one evening and help identify some of the pieces.

The collection is delightful – somebody’s very personal accumulation of finds over the years and, although there was not too much that was either very well preserved or of any significance, there were some interesting pieces.

There were ammonites, belemnites, brachiopods, sponges, corals, echinoids and some plant fossils, as well as few bits that were, although organic, hard to identify. The minerals I couldn’t particularly help with (not my field I’m afraid). There was also a couple of deer antlers, probably Pleistocene in origin, and the most unusual piece was a section of swordfish rostrum, but this was not fossilised and was obviously contemporary.

Maria gave me the ammonite as a thank you, which was nice of her, and said that the collection would be donated to a local school or museum which is just great. The label in the second picture is delightfully written and says, if you can’t make it out, “Ammonite, from Swinstead, Lincolnshire, July 1897”. It’ll take a little prep work to clean it up but it is a really nice example and, considering the collection date, a historical piece. Thanks Maria!