Thursday, 24 February 2011

Genesis of a Dinosaur Revolutionary


This is Deinonychus antirrhopus and is one of the most iconic and enduring dinosaur images of all time. It was the work of Robert T Bakker in 1969 for John Ostroms’ ground breaking monograph of the same animal. Incredibly, that’s forty two years ago now, but for me, this is one of the most powerful and inspiring images in the history of dinosaur palaeontology.

I was recently looking through the literature that was amassed on my bookshelves for some information on the cranial morphology of hadrosaurs – specifically Edmontosaurus. I was trying to identify a recently arrived bone labeled as “unknown dinosaurian element” which, although was clearly of an unusual form, stood out to me almost immediately as being a cranial element, specifically part of a braincase but I was unsure what species.

Since the bone came from the Hell Creek Formation in Carter County, Montana I felt sure that the element was probably from Edmontosaurus since, at this particular site, this hadrosaurs’ remains are dominant. Sure enough, the first cranial diagram I arrived at confirmed my initial thoughts and it appeared to be the basisphenoid situated ventrally on the braincase, although this would need to be confirmed once the bone had been properly prepared.

Feeling rather pleased with myself, I placed the volume back on the shelf and took a step back and let my eyes peruse over the displayed books and papers. At this point I began to reminisce about how I got into palaeontology and dinosaurs in the first place. What were my influences? What books really made the difference? And what else was it that contributed to my creation as a dino-geek?


Like so many of you, it all began with childhood. As a child of the sixties, I grew up with TV science fiction and those wonderful B-movies from the fifties. I loved all of it and dinosaurs, pterosaurs and marine reptiles, in particular, were a large part of it but with one exception – they were real. These huge, stomping spectacular creatures had once existed and it fascinated me.

I started to write my own books and keep my own records. In reality, these were exercise books that I filled up with details from books borrowed from the library and I also copied diagrams from these books to produce pictures of the animals. I remember that my favourite diagrams were geological time scales – I was always doing them. I amassed over thirteen volumes doing this over the years. It was never enough though.

The books that I could get hold of at this time offered very general information but that was fine and they worked for me by providing me with a fundamental knowledge of the basics. For example, I certainly knew and understood what was saurischian and what was ornithischian and got to grips with some very basic skeletal anatomy. And then in the early seventies I got hold of Edwin H.Colbert’s Men and Dinosaurs and Dinosaurs: Their Discovery and Their World. These two volumes were a revelation and hugely influential. I loved them and because of them I got hold of a copy of A.S. Romers Vertebrate Paleontology -my new bible. I was well and truly on my way.


In these days there was very little television produced with palaeontology in mind and you have to remember there were only three television channels in the UK at this time. This was about to change in the seventies. At this point I decided it was to time to write a “best of” volume of all the material I had amassed over the years and started to create my tome. I would work on this to the extent of all other things – school work came second every time. In retrospect, this was obviously a silly thing to do but such was my passion for the subject that, at that time, everything else came second.

1975 was THE watershed year. So much happened all at once that even by todays standards of instant communications and news, it was indeed a revolutionary year. Firstly, the BBC broadcast a series based solely on paleontology, the first of its kind. Before the Ark was presented by Alan Charig and brought the scientists I’d only read about until then onto the screen so that I could see them and hear them for the first time. This was the only series that treated the viewer as someone who did indeed understand some science and let the scientists explain their theories without somebody either narrating or patronizing the viewer. Even today, Before the Ark is the only serious television series about palaeontology, in my opinion, to do this.


One episode stood out – Rise of the Dinosaurs – for this was the first time I had heard of the concept of hot blooded dinosaurs and the name Robert Bakker. I was hooked and made sure that I got hold of the book that accompanied the series. Then, in the same year, another programme, Horizon, also broadcast a one hour special on the warm bloods. The opening shots set in Dinosaur Provincial Park set the tone for the programme and this was the first time I’d seen and heard Bakker. I had a new Messiah. He explained everything so simply, so clearly that I was convinced he was right. I saw dinosaurs in a complete new light and became a full dinosaur revolutionary.

As if all this wasn’t enough, Adrian J. Desmond published The Hot Blooded Dinosaurs, also in 1975. Although I initially borrowed it from the library, I realized that I had it on permanent loan and decided to buy a copy. I have no idea how many times I read this book but my head was spinning and my path had been set. For the foreseeable future, dinosaurs, palaeontology and I would be sharing the same path.

Bakkers’ The Dinosaur Heresies was published in 1986 followed by his disciple and champion, Greg Paul and his Predatory Dinosaurs of the World in 1988. Endothermic dinosaurs were here to stay. Although we are all aware that things are not as straightforward as they once seemed, I was lucky to be part of the dinosaur revolution and it was a great time to be there seeing it all take shape. Youngsters brought up on Jurassic Park don’t have any idea just how important a time this was and how much is owed to Ostrom, Bakker, Galton and others to make the study of dinosaurs the wonderful vibrant science that it is today.

I guess that I will always have the same fascination with dinosaurs and prehistoric life as I have always had. Even writing this blog is being part of it and electronic networking has made instant communication, for me, one of the most wonderful things in modern paleontology. You can be in the middle of the nowhere, photograph a specimen in situ and that image could be seen worldwide on the same day by all of us – truly amazing.

And yet I wouldn’t swap my experiences for anything. Learning by reading those early books and being part of the new order was truly a once in a lifetime experience in our continually evolving science.


Wednesday, 16 February 2011

Return to the Bluff


The summer of 2010 was a lean time for field trips. Gaining access into new quarries continued to be nigh on impossible and although Quarry 4 was visited every now and then, there was still nothing of note to be found. There was no doubt that times were getting hard.

September arrived and it was time to return to the Bluff. Yet again I knew that it would be tough but equally I felt it was important to go and keep my eye in, so to speak. The weather was absolutely spot on for prospecting. There had been a little rain earlier in the week and the temperature was comfortable with an overcast sky, sunny intervals and the odd chance of a shower.

Again, having signed in, I made my way to the quarry to begin prospecting almost immediately. The quarry continues to look bleak and not very inviting since there had obviously been no new excavations for a long time now. At least the lake had receded well after a fairly warm Summer and it was easier to get around the quarry.

First look, as always, was the reptile beds and I made my way along the flanks of the outcrop, carefully prospecting as I went. Eventually I came to a spot that keeps popping out the odd bone fragment every now and then and soon found yet another piece of bone. This was a little bigger than the norm and had a nice shiny patina but it was too scrappy to be diagnostic.

Interestingly, this bone was also of a brown colouration whereas the other material from this spot is normally jet black. This one small area, about 5 metres square, is the only area over the last two years that bone continues to appear. With no sign that the quarry is to reopen any time soon I decided to return to this spot a little later and do some scraping of my own to increase the possibility of more bone showing up.

It was at this point that I was introduced to David Brockhurst, an extremely knowledgeable and likeable man who is key to gaining access to a couple of extremely interesting quarrys known as Shawdon (name changed). The northern quarry demonstrates exposures of the Wadhurst Clay and is extremely prolific. I do not exaggerate when I say that Shawdon is probably the most productive mainland site for UK dinosaurs in the country.

I’ve seen some fantastic examples and both preservation and variety of taxa is impressive. Ornithischians include Iguanodon, Polacanthus and Hylaeosaurus. Theropods are represented by Baryonyx, allosauroids and dromaeosaurs. Additionally there are pterosaurs, crocodiles, turtles and a wealth of other vertebrate material and it all adds up to somewhere that’s just a bit special.


Associated Iguanodon caudals from Shawdon. Photo by Peter Holloway.


Dromaeosaurid tooth from Shawdon. Photo by Peter Holloway

Shawdon, however, is very heavily protected and rightly so. Visits to the site are strictly regulated and are few and far between and although I have been attempting to gain entry for a while now, these things cannot be rushed. Still it was good to meet Dave and I felt we hit it off alright so we will see how it goes.

Incidentally, Dave obviously new what he was doing because he soon uncovered a nice vertebral centrum and, not long after that, an extremely rare pterosaur phalanx.

Soon after I crossed over the road and continued the search at the same level. This particular zone has sporadically yielded crocodilian material and I was lucky enough to find another croc tooth. Although a little worse for wear and having the tip missing, it was a chunky tooth and quite heavily striated.

A little further on I came to a newly exposed area of clay and shales. It seems that some material has been excavated to enable access to the pumps and lines that keep the lake at a manageable depth. Despite the brickworks being mothballed, it was good to see that the staff were keeping the flood water under control – presumably so that the quarry could be worked immediately if required.

I looked through the newly scraped area but found nothing. This wasn’t too much of a surprise since it was in the lower beds and vertebrate material is seldom found here. After a while I decided to cross the quarry floor and head to the fish beds. There have been fish scales, verts and other bones found here over the years.

However, this area hasn’t been worked for many years and finds have declined recently – so much so that I found nothing at all earlier in the year. Unfortunately, this was the case again – not even a solitary scale could be found. It was at this point I thought it was time to take some proactive action and utilize a methodology that I had learnt from Quarry 4.

At Quarry 4 there is a small section of clay situated just above the Kellaways that yields many fine lepidotid scales. Once those that are exposed are collected, the exposure is lightly raked up and the surface broken to enable the rain to soak in and break up the matrix. This works a treat and on the next trip there are always more scales that have weathered out and are ready for collecting.

The grey fish shales - in the centre of this image.

So I spent some time breaking up the surface of the fish beds, especially those areas that have produced in the past. Quite a large area was prepared and it will be interesting to return in the spring to see if this produces or not. It certainly won’t hurt, that’s for sure.

Leaving the fish beds, I crossed over to the northern exposures and prospected there. As I approached another bone producing site, the weather deteriorated and started to rain but this wasn’t too bad and gave the clay and shales a dampening down which I find always helps to highlight fossils. But the north bank didn’t produce either. Finding material at the bluff continues to get harder and harder.

Eventually I moved back to the bone producing reptile beds in the south east of the quarry and decided to put to use the same Quarry 4 technique here as well and raked up the bone producing exposure, hoping to encourage more weathering for the following year. I was pleased with the effort put in and covered a decent area and am hopeful that this tactic may pay off.

I continued to prospect for a while afterward, carefully going over older ground before moving to the top of the quarry and checking out the old spoil heaps. Intriguingly, there had been some fresh movement of spoil for reasons unknown, and this gave me the opportunity to look at some new exposures but, alas, nothing turned up and I decided to call it a day.

It will be interesting to see if the prepared areas turn up any new material. Hopefully another winter may reveal some new bits and pieces and I hope that the crust of compacted clay may actually be broken up this time – I sure as hell hope it doesn’t get any worse!

Thursday, 10 February 2011

More on Tyrants

No furcula............
If you are into tyrannosaurs then Thomas Carr is a name you will be familiar with. If it isn’t then you have some serious reading and studying to catch up on. Indeed, Tom Holtz declared on the DML, not too long ago, that reading Carr’s work is more or less a prerequisite for any student of Tyrannosauroidea.

 And Carr is a busy man. Not content with announcing Bistahieversor sealeyi in 2010 (with long term colleague Thomas Williamson and others), he has also recently announced yet another tyrannosauroid, this time the wonderfully named Teratophoneus curriei.

Carr also gave a presentation at SVP last year regarding ontogenetic variation in Tyrannosaurus rex. Because of the boom in specimens recovered over the last twenty years, there are now examples of Tyrannosaurus that are beginning to fill the ontogenetic gap between the juvenile and adult stage.

This has now highlighted issues similar to those that have caused such debate amongst ceratopsians workers in recent times – namely that the differences between different growth stages can vary greatly and this has led to a number of taxa being mistakenly named.

Using an extraordinarily detailed cladistic analysis, utilising the details from twenty specimens, Carr was able to map out a growth stage of fifteen steps. The only gaps in the sequence were in the juvenile to sub-adult stage but this simply reflects the paucity of recovered specimens and the fact that these animals appear to put on a massive spurt of growth during this exact period of ontogeny. T.rex displays multiple ontogenetic stage variations throughout and appears to confirm that, indeed, there was only one species of Tyrannosaurus in the Maastrichtian.

Also at SVP, Mark Loewen et al presented their findings regarding tyrannosaurid evolution and regional endemism within the clade and took the opportunity to report on yet another new tyrannosaur – this time from the Wahweap Formation of Utah.

When you look at the new taxon, my first thoughts are Teratophoneus. Both have extremely similar morphological patterns including a short robust maxilla and a reduced dental count. Both specimens are animals with powerful, short skulls that are broad and deep. Both specimens are Late Campanian and both appear to be basal tyrannosaurinae.

Running a phylogenetic analysis that tested relationships amongst tyrannosaurids, and to see how the new Wahweap taxon slotted into this group, revealed the apparent existence of a clade of tyrannosaurids in the south of the Western Interior corridor and Loewen et al interpret this data as suggesting a western North American origin for Tyrannosauridae.

Bistahieversor, Teratophoneus and the Wahweap taxon suggest, again, that there appears to be an unusually large quantity of taxa ranging from the south to the north of the Western Interior Basin. Maastrichtian tyrannosaurids Tyrannosaurus and Tarbosaurus settle into the southern clade, emphasising the split between themselves and Campanian tyrannosaurids from the north although where that leaves Daspletosaurus torosus, as a northern Campanian tyrannosaurine, appears unclear to me.

However, as I often allude, there are multiple daspletosaur taxa yet to be described in the literature, and these may demonstrate that both tyrannosaurine evolution and migration was extraordinarily rapid. Still, this work continues to highlight the wonderful uncertainty of tyrannosaurid research and emphasises the continual shifts in thought patterns and theory when it comes to the investigating the evolution of tyrannosaurids.

Also at SVP, there were a couple of tyrannosaur related posters of interest. Shychoski et al looked at how the arctometatarsus of tyrannosaurids enabled enhanced locomotive agility within the group. Using varied techniques including micrography, bone histology and computer aided tomography on a tyrannosaurid metatarsal three, revealed a complex arrangement of ligaments that both strengthened the foot and was capable of dispersing high torsion loads that may be incurred when actively hunting.


The arctometatarsalian condition

An analysis of the tyrannosaurid arctometatarsus which compared comparative agility within the group also confirmed that they could turn rapidly and brake hard making them extremely agile. Indeed, they were far more agile than other theropods with a similar body mass. By inference alone, this combination of high manoeuvrability and the specialised arctometatarsalian condition suggests, yet again, that tyrannosaurs were swift agile hunters which came to dominate the predatory niches within the Late Cretaceous.

Williams et al demonstrated how a new specimen of Tyrannosaurus from the Hell Creek Formation in Montana has provided evidence which demonstrates that the small forelimbs, so synonymous within Tyrannosauridae, were actually larger, and thus more useful, within juveniles. The specimen has a relatively complete forelimb with scapulocoracoid, humerus, ulna and unguals present – such an important find.

The humerus is long and slender in comparison to the adult animals and, coupled with extremely large unguals, demonstrates that the entire forelimb was considerably longer than in the adult morph and highlights that the reduction in forelimb size commenced throughout ontogeny. This confirms earlier work that assumed reduction in forelimb size occurred as the skull became bigger, deeper and more robust, thus emphasising the development of jaw power.

This also, interestingly enough, suggests that juvenile Tyrannosaurus may have had different prey requirements at this stage, perhaps a form of niche partitioning, and they may also have exhibited different behavioural patterns. The authors also highlight the similar trend, in a phylogenetic context, in basal tyrannosauroids such as Guanlong and Dilong which also displayed large forelimbs and manus and point out that rare intermediate specimens, such as Dryptosaurus, display a humerus that is reduced in size, thus indicating that the forelimb began to reduce in size at the proximal end first during tyrannosauroid evolution.


Finally, and back to Thomas Carr, Carthage College indicate that Dr.Carr is currently working on The Tyrant Lizards; The Reference Volume of Tyrannosauroidea. This textbook, aimed primarily at students and vertebrate palaeontologists, is extremely high on my wanted list and will probably be my new bible. You can count on the fact that I’ll be keeping a lookout for any news on publication and will relay any news as it becomes available.


References

Carr, T.D.,2010 Ontogenetic variation in Tyrannosaurus rex: results from a numerical cladistic analysis. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book, 2010, 70A.

Loewen, M, J. Sertich, R. Irmis, and S.D. Sampson 2010 Tyrannosaurid evolution and intracontinental endemism in Laramidia: New evidence from the Campanian Wahweap Formation. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book, 2010, 123A.

Shychoski, L., E. Snively and M. Burns 2010 Manoeuvred out of a corner: ligament entheses of the arctometatarsus enhanced tyrannosaurid agility. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book, 2010, 165A.

Williams, S., S. Brusatte, J. Matthews and P. Currie 2010. A new juvenile Tyrannosaurus and a reassessment of ontogenetic and phylogenetic changes in tyrannosauroid forelimb proportions. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book, 2010, 187A.

Tuesday, 8 February 2011

"What Should Everyone Know About Paleontology?” by Dr.Tom Holtz


I normally try to avoid publishing the same details as my fellow palaeo-bloggers when a story goes public. However, there are always exceptions and I feel the need to join in and add this fascinating post on the DML by Dr.Tom Holtz in response to a question by Robert Takata. Awesome! A viral DML post – who would have thought? Well done everybody!

“What Should Everyone Know About Paleontology?”

Thomas R. Holtz, Jr.


The title question was recently asked by Roberto Takata on the Dinosaur Mailing List.

I think that is a good question. What really are the most important elements of paleontology that the general public should understand? I took a shot at coming up with a list of key concepts here and here, based on experiences with teaching paleontology and historical geology and with less-formally structured outreach to the public. I have offered this list (cross posted at the Superoceras and Archosaur Musing blogs) as a way for it to reach a wider audience. That this is Darwin Week makes it even more appropriate, as we should use this occasion to encourage a better understanding of the changes of Earth and Life through Time for the public at large.

Much as I might like to think otherwise, the specific details of the hindlimb function of Tyrannosaurus rex or the pneumatic features of brachiosaurid vertebrae really are not the most important elements of the field. Understanding and appreciating the nitty gritty details of the phylogeny and anatomy of any particular branch of the Tree of Life are not really necessary for everyone to know, any more than we would regard detailed knowledge of bacterial biochemistry or the partitioning of minerals in a magma chamber to be significant general knowledge. (Indeed, these latter two items are actually far more critical for human society than any specific aspect of paleontology, and so from a certain point of view really more important for people to know than the History of Life.)

That said, all human societies and many individuals have wondered about where we have come from and how the world came to be the way it is. This is, in my opinion, the greatest contribution of paleontology: it gives us the Story of Earth and Life, and especially our own story.

I have divided this list into two sections. The first is a list of general topics of paleontology, touching on the main elements of geology that someone would need to know for fossils to make any sense. The second is the more specific list of key points in the history of life.

(NOTE: as the idea of this list is that it should be aimed at the general public, I have tried to avoid technical terminology where possible.)

General

•That rocks are produced by various factors (erosion -> sedimentation; metamorphism; volcanic activity; etc.)

•That rocks did not form at a single moment in time, but instead have been and continue to be generated throughout the history of the planet.

•That fossils are remains of organisms or traces of their behavior recorded in those rocks.

•That rocks (and the organisms that made the fossils) can be thousands, millions, or even billions of years old.

•That the species discovered as fossils, and the communities of organisms at each place and time, are different from the same in the modern world and from each other.

•That despite these differences that there is continuity between life in the past and life in the present: this continuity is a record of the evolution of life.

•That we can use fossils, in conjunction with anatomical, molecular, and developmental data of living forms, to reconstruct the evolutionary pattern of life through time.

•That fossils are incomplete remains of once-living things, and that in order to reconstruct how the organisms that produced them actually lived, we can:

◦Document their anatomy (both gross external and with the use of CT scanning internal), and compare them to the anatomy of living creatures in order to estimate their function;

◦Examine their chemical composition, which can reveal aspects of their biochemistry;

◦Examine their microstructure to estimate patterns of growth;

◦Model their biomechanical functions using computers and other engineering techniques;

◦Investigate their footprints, burrows, and other traces to reveal the motion and other actions of the species while they were alive;

◦And collect information of the various species that lived together in order to reconstruct past communities.

•However, with all that, fossils are necessarily incomplete, and there will always be information about past life which we might very much want to know, but which has been forever lost. Accepting this is very important when working with paleontology.

•That environments of the past were different from the present.

•That there have been episodes of time when major fractions of the living world were extinguished in a very short period of time: such data could not be known without the fossil record.

•That entire branches of the tree of life have perished (sometimes in these mass extinction events, sometimes more gradually).

•That certain modes of life (reef formers, fast-swimming marine predators, large-bodied terrestrial browsers, etc.) have been occupied by very different groups of organisms at different periods of Earth History.

•That every living species, and every living individual, has a common ancestor with all other species and individuals at some point in the History of Life.

Specific

Honestly, despite the fact the specific issues about specific parts of the Tree of Life are the ones that paleontologists, the news media, the average citizen, etc., are more concerned with, they really are much less significant for the general public to know than the points above. Sadly, documentary companies and the like keep on forgetting that, and keep on forgetting that a lot of the public does not know the above points.

Really, in the big picture, the distinction between dinosaurs, pterosaurs, and crurotarsans are trivialities compared to a basic understanding that the fossil record is our document of Life’s history and Earth’s changes.

Summarizing the key points of the history of life over nearly 4 billion years of evolutionary history is a big task. After all, there is a tendency to focus on the spectacular and sensationalized rather than the ordinary and humdrum. As Stephen Jay Gould and others often remarked, from a purely objective external standpoint we have always lived in the Age of Bacteria, and the changing panoply of animals and plants during the last half-billion years have only been superficial changes.

But the question wasn’t “what should a dispassionate outsider regard as the modal aspect of the History of Life?”; it was “What should everyone know about paleontology?” Since we are terrestrial mammals of the latest Cenozoic, we have a natural interest in events on the land and during the most recent parts of Earth History. That is a fair bias: it does focus on who WE are and where WE come from.

That said, here is a list of key concepts in the history of life. Other researchers might pick other moments, and not include some that I have here. Still, I believe most such lists would have many of the same key points within them.


•Life first developed in the seas, and for nearly all of its history was confined there.

•For most of Life’s history, organisms were single-celled only. (And today, most of the diversity remains single-celled).

•The evolution of photosynthesis was a critical event in the history of Earth and Life; living things were able to affect the planet and its chemistry on a global scale.

•Multicellular life evolved independently several times.

•Early animals were all marine forms.

•The major groups of animals diverged from each other before they had the ability to make complex hard parts.

•About 540 million years ago, the ability to make hard parts became possible across a wide swath of the animal tree of life, and a much better fossil record happened.

•Plants colonized land in a series of stages and adaptations. This transformed the surface of the land, and allowed for animals of various groups to follow afterwards.

•For the first 100 million years or so of skeletonized animals, our own group (the vertebrates) were relatively rare and primarily suspension feeders. The evolution of jaws allowed our group to greatly diversify, and from that point onward vertebrates of some form or other have remained apex predators in most marine environments.

•Complex forests of plants (mostly related to small swampland plants of today’s world) covered wide regions of the lowlands of the Carboniferous.

•Burial of this vegetation before it could decay led to the formation of much of the coal that powered the Industrial Revolution and continues to power the modern world.

•While most of the coal swamp plants required a moist ground surface on which to propagate, one branch evolved a method of reproduction using a seed. This adaptation allowed them to colonize the interiors, and seed plants have long since become the dominant form of land plant.

•In the coal swamps, one group of arthropods (the insects) evolved the ability to fly. From this point onward insects were to be among the most common and diverse land animals.

•Early terrestrial vertebrates were often competent at moving around on land as adults, but typically had to go back to the water in order to reproduce. In the coal swamps one branch of these animals evolved a specialized egg that allowed them to reproduce on land, and thus avoid this “tadpole” stage.

•These new terrestrial vertebrates—the amniotes—diversified into many forms. Some included the ancestors of modern mammals; others the ancestors of today’s reptiles (including birds).

•A tremendous extinction event, the largest in the age of animals, devastated the world about 252 million years ago. Caused by the effects and side-effects of tremendous volcanoes, it radically altered the composition of both marine and terrestrial communities.

•In the time after this Permo-Triassic extinction, reptiles (and especially a branch that includes the ancestors of crocodilians and dinosaurs) diversified and became ecologically dominant in most medium- to large-sized niches.

•During the Triassic many of the distinctive lineages of the modern terrestrial world (including turtles, mammals, crocodile-like forms, lizard-like forms, etc.) appeared. Other groups that would be very important in the Mesozoic but would later disappear (such as pterosaurs and (in the seas) ichthyosaurs and plesiosaurs) evolved at this time.

•Dinosaurs were initially a minor component of these Triassic communities. Only the tall, long-necked sauropodomorphs were ecologically diverse during this time among the various dinosaur branches. However, a mass extinction event at the end of the Triassic (essentially the Permo-Triassic extinction in miniature) allowed for the dinosaurs to diversify as their competitors had vanished.

•During the Jurassic, dinosaurs diversified. Some grew to tremendous size; some evolved spectacular armor; some become the largest carnivorous land animals the world had seen by this point. Among smaller carnivorous dinosaurs, an insulating covering of feathers had evolved to cover the body (possibly from a more ancient form shared by all dinosaurs). Among the feathered dinosaurs were the ancestors of the birds.

•Other terrestrial groups such as pterosaurs, crocodile-ancestors, mammals, and insects continued to diversify into new habits.

•During the Jurassic and (especially) the Cretaceous, a major transformation of marine life occurred. Green-algae phytoplankton were displaced by red-algae phytoplankton (which continue to dominate modern marine ecosystems). A wide variety of new predators—advanced sharks and rays, teleost fish, predatory snails, crustaceans with powerful claws, specialized echinoids, etc.—appeared, and the sessile surface-dwelling suspension feeders that dominated the shallow marine communities since the Ordovician became far rarer. Instead, more mobile, swimming, or burrowing forms became more common.

•During the Cretaceous one group of land-plants evolved flowers and fruit and thus tied their reproduction very closely with animals. Although not immediately ecologically dominant, this type of plants would eventually come to be the major land plant group.

•The impact of a giant asteroid—coupled with other major on-going environmental changes—brought an end to the Mesozoic. Most large-bodied groups on land and sea, and many smaller bodied forms, disappeared. The only surviving dinosaurs were toothless birds.

•The beginning of the Cenozoic saw the establishment of mammals as the dominant group of large-bodied terrestrial vertebrates. Early on mammals colonized both the sea and the air as well.

•During its beginning the Cenozoic world was warm and wet, much like the Cretaceous. However, a number of changes of the position of the continents and the rise of mountain ranges caused the climates to cool and dry.

•As the world cooled and dried, great grasslands developed (first in South America, and later nearly all other continents).

•Various groups of animals adapted to the new grassland conditions. Herbivorous mammals became swift runners with deep-crowned teeth, often living in herds for protection. Mammalian predators became swifter as well, some becoming pack hunters.

•Other new plant communities evolved, and new animal communities which inhabited them. The rise of modern meadows (dominated by daisy-related plants and grasses) saw the diversification of mouse-and-rat type rodents, many frogs and toads, advanced snakes, songbirds, etc.

•A group of arboreal mammals with very big brains, complex social communities, and gripping hands—the primates—produced many forms. In Africa one branch of these evolved to live at mixed forest-grassland margins, and from this branch evolved some who became fully upright and moved out into the grasslands.

•This group of primates retained and advanced the ability to use stone tools that its forest-dwelling ancestors already had. Many branches evolved, and some developed even larger brains and more complex tools. It is from among these that the ancestors of modern humans and other close relatives evolved, and eventually spread out from Africa to other regions of the planet.

•About 2.6 million years ago a number of factors led to ice age conditions, where glaciers advanced and retreated. Various groups of animals evolved adaptations for these new cold climates.

•The early humans managed to colonize much of the planet; shortly after their arrival into new worlds, nearly all the large-bodied native species disappeared.

•At some point before the common ancestor of all modern humans spread across the planet, the ability to have very complex symbolic language evolved. This led to many, many technological and cultural diversifications which changed much faster than the biology of the humans themselves.

•In western Asia and northern Africa (and eventually in other regions), modern humans developed techniques to grow food under controlled circumstances, leading to true agriculture. (Other cultures are known to have independently evolved proto-agricultural techniques).

•This Neolithic revolution allowed for the development of more settled communities, specialization of individual skills within a community (including soldiers, metallurgists, potters, priests, rulers, and with the rise of writing, scribes).

•From this point we begin to get a written record, and so the historians can take up the story…

This list is obviously not comprehensive, and there are many elements that I had to ignore to keep it relatively short. Still, I hope this overview helps put where we as a species fit into the larger perspective of Life’s long voyage, a voyage that could only have been traced by the study of fossils.

Wednesday, 2 February 2011

Tough Going at the Bluff

A moody Bluff

Spring 2010 loomed large and about time too I thought. The winter had been horrendous, our second hard winter on the trot. Sub-zero temperatures for weeks on end, snow, ice and rain had made the dark months miserable and it was hard to see any positives about the period. Indeed, large gas and electricity bills made it very painful indeed.

However, winter slowly passed but was still hanging on and just wouldn’t quite give up. But it was a new field trip season and first up, as usual, was the Bluff. I hadn’t been to the Bluff for a year since the last field trip clashed with SVP at Bristol and there was no way I was missing that! I’d kept up to date with the news from the quarry and knew that very little had been recovered. That wasn’t a surprise since the brick works was still mothballed and this was the third year of no new scrapings.

However, I did believe that the harsh winter would be of some benefit and that the continual erosion over winter would help in uncovering some new material or, at the very least provide a few tentative clues. I was to be sorely disappointed.

I arrived early as normal although I wasn’t the first there. One of those there was a woman that had visited the quarry many times before and was also at Bristol. I also recognised a couple of the others and, after signing in, I quickly made my way to the Bluff hoping to gain an advantage from the stolen minutes gained ahead of everyone else but this time I had only been in for a matter of minutes before a few of the others turned up.

As usual, I started on the reptile beds on the south east side of the quarry – the fabled Baryonyx beds. And, to be fair, it started off reasonably well and found a piece of bone exactly where I expected to find some. But again, the mother lode remained elusive and I spent a long time trying to find any other piece of bone that would identify the bone bearing bed. But nothing else materialised.

I move on to another bed in the same formation that had provided several teeth and some crocodile scutes in the past but all that was found was a lepdotid scale, albeit an extremely nice example. After scouring this bed I decided to prospect the northern beds but to get there I had to circumnavigate the very large lake that had now formed in the bottom of the quarry.


In all my years of visiting this quarry, I had never seen the lake so big but this was yet another result of the quarry not being worked. When the site is active, there are always pumps in place to keep the water down but because the site is closed this has not been done. In time they will have to do it and before next winter I imagined otherwise, if the quarry was to be reopened, they would have to wait weeks before any clay could be extracted.

I made my way around the perimeter of the quarry and arrived at the northern beds, and it was here that I realised how much the clay had become compacted during the Winter. On first inspection, the clay and the shales looked much as they had done at any other time but I came to realise that the vast majority of the quarry had a crust of compressed clay covering the strata below. It was obvious that weeks and weeks of ice and snow had compacted the surface to an immense degree. After the ice and snow had melted, even further deluges of rain didn’t break it up and the water simply ran off. No wonder there was no new material of any substance to be found.

Wealden badlands

Never the less, undaunted, I continued to prospect for whatever could be found but to no avail. It was apparent that nobody else had found much either – one croc tooth and a minute fish jaw albeit with some teeth in place – but that was it. I made my way to the fish beds hoping to recover more scales and fish bones and but even here there was nothing and this was always the banker layer, the place where, if all else failed, you could find something. It was now that I began to appreciate how necessary it was for a new scraping of the clay but when this will be, nobody knows.

I made my way back to the south east side of the quarry and continued the search but only a few badly preserved scales were found. Even the continually worked theropod track way, uncovered over the last couple of years, failed to produce a single new track. The Bluff was proving to be an even harder prospect than ever.

It is fairly certain now that very little will be found at this quarry now until the brickworks reopens. I’ve no doubt that in time it will but this is, of course, highly dependant on the current economic climate in the country improving and, at time of writing, this still seems some way off.

On the positive side, there is still 100 years of clay in the Bluff and the site is fortunate in as much that there was a multi-million pound investment of new machinery shortly before the world-wide recession hit. This (fortunately?) led to the plant being mothballed as opposed to being closed, like so many different sites across the country, although the local job losses were very unfortunate.

Despite these obstacles, I will continue to return and keep prospecting since the Bluff almost certainly has other significant new discoveries to come and I, for one, cannot wait to see what turns up.