Dinosaur Tracks Close to Washington D.C.
Plans to display Dinosaur Trackways in Washington D.C.
When asked to comment on dinosaur discoveries in the United States most experts may cite discoveries in the Badlands of Montana or the Cleveland-Lloyd Dinosaur quarry in Utah. Certainly, it is true to say that they are many fantastic Mesozoic fossil sites in the west of the USA but the eastern part of the United States, although perhaps a little under-represented in terms of fossil evidence, can still spring a few surprises.
Now a new study of fossil trackways in Maryland, north-eastern USA has provided a glimpse into a thriving dinosaur based eco-system. Many of the trackways, have been found just a few miles drive out of Washington D.C. Trackways and footprints are called trace fossils. Trace fossils preserve evidence of the activity of animals such as their trackways, borings or burrows. The problem with most sets of footprints, even the very best preserved ones, is that, unless the animal is found fossilised at the end of the trackway, scientists can never be 100% certain as to the species or genus that actually left the prints. Trace fossils such as footprints do have a significant advantage over other types of fossil such as fossil bones, most are direct in situ evidence of the environment at the time and place the organism was living.
A total of over 900 fossilised footprints from a variety of dinosaurs all dated from the mid Cretaceous have been identified from the area. Theropods, Ankylosaurs (Nodosauridae), Sauropods and Ornithopods are represented by the prints. Palaeontologists have estimated that the trackways were made between 121 and 98 million years ago. Trace fossils of other animals have also been preserved in the this part of the USA, one trackway has been identified as a flying reptile, perhaps a Pterosaur flew down to get a drink and its trail was preserved in the soft sediment. Mammal tracks have also been found, indeed one trackway indicates that some mammals were quite large, tracks of a quadrupedal mammal about the size of a large dog have been recorded.
“Based on the trace fossils, over two dozen species of dinosaurs were living in Maryland at that time,” co-author of the study, Ray Stanford commented. Ray specialises in studying fossil trackways, he began to discover tracks in the area whilst out looking for native Indian artifacts, in the stream-beds that criss cross the area.
He explained that as water and human development erode such beds, “floats” can result. These are pieces of track-bearing substrate that hydrodynamically dislodge from their natural stratigraphic context during stream bank flooding.
“This is one instance where building booms and storms can benefit science,” he said.
All of the discoveries were made either in Prince George’s county, near the capital, Washington D.C. or at the White Marsh Run area of Baltimore county.
The picture shows a number of footprint specimens, the peculiar, almost flower-shaped five-toed print in the foreground was most probably made by a Nodosaur. Nodosaurs are members of the Ankylosauria, heavily built, slow-moving, plant-eaters with body armour and horns – a model of Nodosaur can be seen at the top of the picture.
Ray Stanford in conjunction with a Johns Hopkins University palaeontologist called Davide Weishampel hope to publish a journal paper on this new genus of Nodosaur. The Nodosaur print in the foreground is much smaller than the cast print in the very centre of the image (the print which the model Nodosaur is facing), this indicates that some of the trackways may have been made by young, immature animals. This area may have provided a Cretaceous nursery for many species, a popular nesting and breeding ground for a variety of dinosaurs. The scientists state that they may even have uncovered trackway evidence showing youngsters following adults, a possible insight into animal’s behavioural and social relationships.
Analysis of the region’s geology indicates that during that dinosaur era, fresh water sources and plant life would have been plentiful. Stanford has excavated fossilised pollen for ancient plants, along with fossilised wood for a large, now-extinct fern tree similar to today’s cycads.
The Smithsonian Museum of Natural History in Washington D.C. is investigating the possibility of putting some of the tracks on display in a special exhibition. There are certain obstacles to overcome, such as how best to present the casts so that their fine detail can be seen, but such an exhibit be popular with museum visitors. After all, it would give the residents of Washington D.C. an opportunity to learn more about some of the previous residents in the neighbourhood.
At Everything Dinosaur we get asked to source various dinosaur and prehistoric animal models for customers. As we know the Wild Safari Dinosaurs model range (Safari Ltd) quite well, it proved helpful when asked to supply a Dodo model with some dinosaur toys.
Finding dinosaur models and dinosaur toys for young palaeontologists or for keen collectors of prehistoric animal models and replicas is all in a day’s work for our team members. Updating our model collections and trying to allocate the right products into the right category on line is quite a task these days as our product range grows and grows.
At shortly before 1am this morning (GMT) an earthquake with a magnitude of 5.2 struck the United Kingdom. The epicentre (the point on the Earth’s surface directly above the centre of the earthquake), was 4 kilometres north of the town of Market Rasen, Lincolnshire.
There is one report of an injury, the British Geological Society (BGS) had by 7am received over 1,400 reports from members of the public, the media and the emergency services. Some structural damage has been caused, chimneys falling off, walls collapsing close to the epicentral area, but this tremor was felt across a large part of the UK. Many residents in English and Wales towns were awoken by the shaking, the quake has been felt as far away as southern Scotland.
In this country we are not immune from earthquakes, each year the BGS records around 200, but only about 10% are big enough to be felt by local residents. Fortunately, most of the quakes have epicentres which are offshore. The largest earthquake recorded in the British Isles took place in 1931. This quake had a local magnitude of 6.1, but fortunately it was centred on the Dogger Bank area of the North Sea. Even so, the quake and the aftershocks were powerful enough to cause structural damage to many buildings on the east coast of England.
The precise epicentre of the Market Rasen quake has been calculated to be latitude 53.419 degrees north and longitude 0.354 degrees west. It is understood to have taken place approximately 5,000 metres underground.
Earthquakes are monitored by the British Geological Survey, part of the Natural Environment Research Council (NERC). There is a network of 146 seismometer stations across the UK sending data to the head office based in Edinburgh four times per day. However, during times of earthquake activity data can be sent on demand and staff at the BGS can access data and analyse results from home. They are on call 24-hours a day, as scientists don’t know when a quake will strike.
Earthquakes of this magnitude occur approximately ever 30 years or so, in the world there are about 1,300 quakes of this magnitude or bigger each year. This latest quake is the biggest since 1984, when on the 19th July North Wales was struck by an earthquake that had a magnitude of 5.4. It too caused structural damage to many buildings with cities such as Liverpool 120 kilometres from the epicentre being affected.
None of the team members at Everything Dinosaur felt the quake (all sound asleep in our beds). However, one member of staff recalled the Manchester earthquakes that struck in the Autumn of 2002. A series of tremors were recorded with an epicentre in and around Manchester over a period of five weeks. The magnitude ranged from 1.1 to 3.9 ML (local magnitude). In total 106 tremors were recorded, the biggest of which (3.9 ML) hit on October 21st. Our colleague remembers particular incident very well, as he was travelling in a lift in an office block in the centre of Manchester at the time – very scary.
To read more about the work of the BGS and the latest on this mornings quake you can visit the BGS website.
A new study from a multi-national team of scientists provides evidence of the link between the explosion of early life forms and the oxidation of the deep oceans. The rise of oxygen levels within the ocean between 635 and 551 million years ago may have helped trigger the increase and rapid diversification of early lifeforms, leading ultimately to the “Cambrian Explosion”.
The “Cambrian Explosion” is a term used by scientists to describe the huge increase in life that occurred around 545 million years ago, at this stage of the history of life on Earth, all life was associated with marine environments. It was during the Cambrian that most of the major groups of animals that exist today evolved.
Soft bodied animals and the stromatolites (colonies of bacteria) were partly replaced and superseded by the evolution of organisms with hard parts such as exoskeletons and shells. The first forms of life that could be biomineralised evolved, this meant that the hard parts of their bodies could be preserved as fossils and thus this period of ancient history not only marks the increasing abundance and diversity of organisms but also marks the start of an enriched fossil record, providing palaeonotologists with more evolutionary evidence.
Complex organisms had been in existence prior to the beginning of the Palaeozoic, but the fossil record is extremely poor. Multi-cellular life forms have been recorded in rocks of approximately 600 million years of age, but these creatures seemed to have lacked any hard parts and as soft-bodied creatures, palaeontologists have only a few tantalising fossils to work with.
The rise in oxygen levels and the oxidation of deep oceans in the late Precambrian has been accepted for a number of years. However, it had been thought that the increase in photosynthetic bacteria such as cyanobacteria (formerly known as blue-green algae), assisted by other non-biological means such as the breakdown of water into hydrogen and oxygen by ultraviolet rays penetrating to the surface of the Earth through the ozone devoid atmosphere had led to the increase. Now, new research from scientists studying the geochemical structure of the Duoshantuo Formation in southern China reveals that life on Earth may have been influenced by two distinct pulses of oxygen. The first increase in oxygen predates the “Cambrian Explosion” by a significant amount of time but may have led to an increase in microscopic life forms. The second burst of oxygen aerating the oceans seemed to have occurred around 550 million years ago and in geological terms immediately pre-dates the increase in life during the early Cambrian.
An international team of scientists from Virginia Tech, the University of Maryland, University of Nevada (Las Vegas) and the Chinese Academy of Sciences set out to test the relationship between the evolution of more complex and diverse life forms and environmental change. To do this the team needed to find sedimentary strata that pre-dates the Cambrian and a sequence of strata (stratigraphic column) that would show deposition and formation as a timeline, one that had not been altered or changed by other chemical or geological processes. Finding pristine Precambrian strata is a challenge in itself but such locations are known, one being the Doushantuo Formation in the Yangtze Gorges area, Guizhou Province, southern China. The strata consists of phosphate and dolomite sequences, laid down at the bottom of a sea. China at this time was made up of two separate and submerged continental sheets, that lay in shallow, warm tropical waters off the coast of the super-continent Gondwana. The first part of what was to become China, closest to Gondwana, straddled the Equator, the second part lay across the Tropic of Cancer.
By mapping the levels of oxygen at various levels in the stratigraphic column, the team could measure the amount of oxygen in the marine environment and then associate this with the biostratigraphic column (fossils used to date and correlate strata), this would provide evidence to support the increase in oxygen leading to a diversity and increase in lifeforms.
To calculate when there was enough oxygen to support animal life in the ocean, the researchers asked, “What kind of geochemical evidence would there be in the rock record?” said Shuhai Xiao, associate professor of geosciences at Virginia Tech.
Scientists hypothesized that there was a lot of dissolved organic carbon in the ocean when oxygen levels were low. If oxygen levels rose, some of this organic carbon would be oxidized into inorganic forms, some of which can be preserved as calcium carbonate (CaCO3 ) in the rock record. “We measured the carbon isotope signatures of organic and inorganic carbon in the ancient rocks to infer oxidation events,” said co-author Ganqing Jiang, assistant professor of geology at the University of Nevada at Las Vegas.
The stratigraphic column exposed during the construction of the dams in the Yangtze Gorges area represents a large slice of ancient geological history. The researchers carefully took samples from each strata of rock, the deeper the strata, then, unless the strata has been overturned, as can sometimes happen during mountain building processes for example, the older the rocks will be. This is an important geological principle it is called the “Law of Superposition”. Many hundreds of different samples were taken, representing marine deposits laid down during the Precambrian and early Cambrian.
The researchers cleaned and crushed the small samples to powder, which they reacted with acid to release carbon dioxide from carbonate minerals, and then burned the residue to get carbon dioxide from organic matter. “The carbon dioxide that is released was measured with mass spectrometers to gives us the isotopic signature of the carbonate and organic carbon that was present in the rock,” a researcher commented.
“The relative abundances of the carbon-12 and carbon-13 isotopes, which are stable and do not decay with time, provide a snapshot of the environmental processes taking place in the ocean at the different times recorded in the layers of rock”.
The stratigraphic pattern of carbon isotope abundances suggested to these researchers that the ocean, which largely lacked oxygen before animals arrived on the scene, was aerated by two discrete pulses of oxygen.
The first pulse that occured in the Precambrian seemed to have little impact on a large organic carbon reservoir in the deep ocean, but did spark changes in microscopic life. The second event, which occurred around 550 million years ago, immediately prior to the palaeontological event known as the “Cambrian Explosion”, resulted in the reduction of the organic carbon reservoir. This indicates that the ocean became fully oxidized just before the evolution and diversification of many of Earth’s earliest animals. Perhaps this dramatic increase in the level of available oxygen provided the fuel for the rapid burst of evolution. Certainly, scientists have speculated why all of our sudden around 545 million years ago evolution seems to have pressed the accelerator when for much of the Precambrian (Cryptozoic), evolution seemed to be progressing at a very slow pace. You could say that evolution, prior to the second pulse of oxygen had progressed at a snail’s pace but to be fair to the Gastropods (snails) these animals did not really get going until the early Cambrian.
The picture shows a field of view 0.15 millimetres in diameter of a beautifully preserved eukaryotes fossil from the Doushantuo formation (635-550 million years old). Eukaryotes are cells with their genetic material enclosed in a cell nucleus. Eukaryotes are believed to have first appeared in the fossil from strata dated to 2,100 million years ago, but evidence from molecular biology indicates that they may have been present earlier than this but left little or no fossil evidence.
“The Doushantuo Formation has a wonderful fossil record. It allows us to look at major fossil groups, when they appear and when they disappear, and to see a relationship between oxidation events and biological groups”, a researcher commented.
“This study supports the growing view that life and environment co-evolved through this tumultuous period of Earth history,” said geochemist Alan J. Kaufman, a co-author of the study from the University of Maryland.
The triggers for the oxidation events remain elusive, scientists are still not sure what set off these oxidizing events. Members of the research team have suggested that these two events recorded in marine sediments were probably related to oxygen in the atmosphere reacting with sediments on land as rocks are eroded away. The lack of biological activity on the land would have resulted in weathered rocks and soils on the continents releasing certain dissolved ions, such as sulphate, into rivers. These would then be transported to the sea where they might be used by bacteria to oxidize the organic carbon pool in the deep oceans.
This article has been adapted from materials published by Virginia Tech, USA. The full article entitled “Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation,” was written by Kathleen A. McFadden; Jing Huang and Xuelei Chu of the Institute of Geology and Geophysics, Chinese Academy of Sciences; Ganqing Jiang; Alan J. Kaufman; Chuanming Zhou and Xunlai Yuan of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences; and Shuhai Xiao.
It is due to be published in March.
This film was directed by David Fincher, whose only other film I have seen is Seven. It is based on the true story of the hunt for a serial killer who terrorised California in the late 1960’s and remained notorious and at large for many years. The Zodiac is not the central character in this story, the film portrays the obsession of individuals who set out to prove the identity of the killer. Specifically the film focuses on the preoccupation of a newspaper cartoonist and his desire to find the Zodiac, at the cost of his family and his job. I think this character is played by Jake Gyllenhaal, although for me it is Robert Downey Jr who steals most of the scenes with his portrayal of a drunken, hack and his fall from grace into despair and loneliness.
The crimes were committed when forensic science was in its infancy, there are few clues to go on and the lack of a co-ordinated police effort hampers the pursuit of the perpetrator. At various points in the film, you are given the impression that the net is closing in but each time the investigations lead you up a blind alley. To this end the film was a little frustrating, it lacked the clean, no fuss storyline of a CSI TV episode, but I guess that was the point. Real life crime is nothing like television and this film depicted the hunt for the killer with a degree of realism. The Californian police are not like Mounties – they don’t always get their man. The main detective on the case reminded me of Columbo, perhaps a deliberate attempt by the Director to contrast the police investigation in this movie with the more predictable denouement associated with the standard fayre on TV.
The film certainly had me interested, not fascinated but interested enough not to notice that the best part of 160 minutes had passed before the lights came up.
Overall, an OK way to spend an afternoon, but not enough dinosaurs for my liking.
Turn meal times into a Mesozoic adventure with the new range of children’s’ tableware from Everything Dinosaur. With plates, utensils, bowls and a cup including a matching vinyl coated placemat, this new range of dinnerware will have young dinosaur fans eager to take their place at the dinner table.
The design on this range depicts a number of prehistoric animals including a friendly looking Pteranodon, a turquoise Triceratops, a purple Stegosaurus and a hungry looking Tyrannosaurus rex, just what a young palaeontologist would expect to find on a dinner set designed with the Age of Reptiles in mind. Available as individual items, to enable Everything Dinosaur customers to be flexible with their purchasing, these items are also available as a set. The dinner set price has been discounted as an added incentive to encourage customers to purchase. Included in the tableware set is the hard-wearing, matching dinosaur placemat, so Mums and Dads have everything they need to turn meal times into a dinosaur adventure. The tough, robust tableware set is dishwasher safe and is suitable for young dinosaur fans from 12 months and upwards.
The table ware has been designed with little ones in mind, the plate is segmented to permit food items to be served separately if required, a good idea – parents and guardians can check what has been eaten. The sections also assist young children with their eating as the walls of each section can assist with them getting food onto the fork and spoon. Thought and attention has also gone into the design of the utensils and the cup. They are ideal for little hands to grasp. Even the bowl has been designed with care, its steep sides help prevent splashes.
Having proved popular on test, looks like the three geological periods of the Mesozoic – Triassic, Jurassic and the Cretaceous will have to renamed – breakfast, lunch and dinner!
For many palaeontologists discovering a perfectly preserved set of dinosaur footprints may mark a high point in their careers but for young Rhys Nichols of Scarborough finding dinosaur trackways is as easy as taking a walk along the beach.
Whilst walking with his father, on the beach at Burniston Rocks, north of the seaside resort of Scarborough on the North Yorkshire coast, Rhys noticed that part of cliff face had fallen away and it was here that he found the footprints. Rhys’ very proud father, Richard stated that “Rhys loves dinosaurs so for him to find something like that was wonderful. He was over the moon – I couldn’t get him away from it!
Experts have agreed that these fossil prints are a “great find”. The footprints are what is known as a trace fossil. Trace fossils preserve evidence of the activity of animals, such as their tracks; unlike many dinosaur fossil bones that may have been transported after death a long way from where the dinosaur originally lived, most trace fossils such as these prints are direct “in situ” evidence of the environment at the time and the place where the dinosaurs roamed.
The picture shows two beautifully preserved fossil footprints with the three toes of dinosaur seen clearly. The raised appearance of the fossil is typical of this sort of trace fossil. Footprint fossils can either be a depression-type fossil made by the weight of the animal or a cast of the “hole” made by the animal’s foot as it walked along. Sediments can fill the print up and it is these that are fossilised and the cast preserved giving the raised appearance. Mr Nichols measured the footprints estimating that they were around 21cm in diameter, other footprints have been found but they had been heavily eroded.
A number of fossilised dinosaur trackways have been found in the North Yorkshire area , much of the coast of the North East from Scarborough to near Redcar is comprised of exposed areas of delta mudstone and sandstone and thin coals that were laid down in the middle Jurassic approximately 160 million years ago. The rock strata where the prints have been found is well known for producing dinosaur trackways and isolated footprints, in fact geologists term this strata as the Burniston Footprint Bed. As blocks of silty sandstone fall onto the beach, split apart from the cliff face by erosion, these blocks frequently come to rest at the base of the cliff upside down revealing the finely detailed tracks of dinosaurs from the Jurassic period.
It is not known what actual species of dinosaur made the prints, as with most fossil trackways, unless the culprit is found fossilised at the end of the trackway, Ichnologists (scientists who specialise in studying tracks), can only speculate what sort of creature it was. Local museum staff have stated that this dinosaur may have been an Iguanodon. The three-toed prints are indicative of an Iguanodontidae, however, the mid Jurassic date is very early for such an animal, more normally associated with the early Cretaceous. Perhaps it could be a trackway made by a Dryosaur, these animals grew to lengths in excess of 3 metres, were relatively light and had a bi-pedal stance. Dryosaurs seem to have been relatively ubiquitous, with fossil being found in both the northern and southern hemispheres. Like many trackways the scientists may just have to resort to referring to these wonderfully, well preserved prints as belonging to an “in-determinant Ornithopod”.
This picture shows a close up of the footprint shown in the foreground in the picture with Rhys. The animal would have been walking from right to left as the page is viewed. The three-toes can clearly be seen, but there is little evidence of a claw mark, adding weight to the thought that this is the footprint of an Ornithopod. Based on comparisons with the fossils of Ornithopods such as the large amount of Iguanodontidae material available, it has been estimated that the dinosaur walking across the delta 160 million years ago would have been roughly the same size as young Rhys. It is not known whether the animal was a fully grown adult or juvenile. The pictures of the footprints indicate a bi-pedal stance, but as to what actual animal made these tracks, this will probably remain a mystery, unless of course Rhys happens to find another set of prints whilst beach-combing but this time with the fossils of the dinosaur which made them at the end of the track.
Here’s hoping… in the meantime well done to Rhys, palaeontology remains the only science where by going for a walk you can change the way the world views itself.
Chinese news sources have confirmed the announcement of the discovery of a new species of Sauropod (long-necked dinosaur) in eastern China. The partial, dis-articulated skeleton indicates a Titanosaur-like animal with an estimate height of 5 metres and an approximate length of 15 metres. The fossils were unearthed from Cretaceous period sediments at the foot of Hugong mountain, near to the large city of Dongyang in Zhejiang Province, eastern China.
The fossil was originally discovered in September 2007 and after a preliminary examination of the fossil bones by researchers from the Zhejiang Museum of Natural History aided by their Japanese colleagues, it has been declared a new species of dinosaur.
The deputy curator of Zhejiang Museum, Jin Xingsheng has made a statement describing the work carried out to date and claimed: ” It (the fossil) demonstrates many unique features, different from any identified dinosaur species. It will enrich the dinosaur family”.
This new dinosaur has yet to be formerly described and named, further research is currently being conducted and this will be subject to peer review. The fossils are being restored at the Dongyang museum and there are plans to put them on exhibit in late May or early June. The animal has not been named yet, but it has been muted that the name will reflect the fossil site’s close proximity to the large city of Dongyang. It is also likely that the Chinese scientists will reflect their own nomenclature framework when naming this new species, using a Chinese name rather than a standard Latinized approach. Western palaeontologists are bracing themselves, anticipating another very long genus name and one that will prove tricky to pronounce given the recent track record on dinosaur discoveries from China.
For example, Zhejiang Province first come to prominence as far as Titanosaur remains are concerned in 1977 when the 22 metre long Jiangshanosaurus lixianensis was unearthed. This Titanosaur probably possessed some form of body armour and dates from approximately 125 million years ago early-mid Cretaceous (Aptian faunal stage).
In August 2007, scientists announced the identification of a new dinosaur species of armoured dinosaur which had been found near Lishui city in Zhejiang Province. This new species was named Zhejiangosaurus lishuiensis which roughly translates to “Zhejiang lizard of Lishui”. Zhejiangosaurus has been classified as a member of the Nodosauridae a group of armoured, herbivorous, bird-hipped dinosaurs. This animal has been named from a partial skeleton consisting of a preserved sacrum, part of the ischium, the pubis plus some vertebrae and front limb bones.
This article has been compiled using a number of news sources including the Xinhua news agency.
The picture shows a palaeontologist examining part of the matrix from which the new species of dinosaur was extracted.
The other day team members at Everything Dinosaur were asked by a Year 3 pupil during a dinosaur workshop in school, what was our favourite dinosaur? With over 1,100 genera to choose from there is certainly a wide choice, but after a little bit of discussion we choose Protoceratops. A large number of fossils of this horned dinosaur have been found, from very old, mature individuals down to babies and of course nests of eggs. With so much fossil material to study, Protoceratops is right up there as one of Everything Dinosaur’s favourites.
During this particular school visit we discussed with the Year 3 pupils Protoceratops and other horned dinosaurs, we then concluded our dinosaur work in schools on this occasion with a quick question and answer session with our palaeontologists. It seems that our visit and the dinosaur term topic in general was a big success.
Frogs are the most common type of amphibian alive today, with an estimated 5,500 separate species, making them the most diverse and successful clade of the Lissamphibians. They are known from all the continents except Antarctica but their fossil record is quite poor. Although very much extant, scientists still debate how many actual families make up the order containing frogs and toads – Anura. With discussion ongoing as to how to classify frogs and toads around today, it is no wonder that difficulties arise when trying to piece together the development and relationships between elements of Anura when you consider how sparse the fossil evidence is.
Now the discovery of a giant, Late Cretaceous frog from Madagascar that may be related to the horned frogs of South America, has opened up the debate once again over frog family ancestry and the break up of the super-continent Gondwanaland.
Frogs and toads are very specialised Lissamphibians with a body shape (morphology) unlike their living relatives and their ancient amphibian ancestors from the Palaeozoic. In comparison with other amphibian groups, they have dramatically reduced skeletons, lacking ribs, a tail, with a simple pelvic girdle and relatively few vertebrae. One of the earliest known frogs was also found in Madagascar, called Triadobatrachus; this animal dates back to the Triassic. Frogs and toads were probably relatively abundant during the Mesozoic but the lack of fossil evidence inhibits palaeontologists when it comes to working out Anura evolution. Fossil bones have been recorded from a number of Mesozoic sites but they are usually isolated fragments, ilia, humeri (limb bones) and the more robust skull elements such as the frontoparietals and squamosals – elements from the top and towards the rear of the skull respectively. Some upper jaws bones (maxillae) have also been located and it is the jaws and the partial skull elements that provide the greatest assistance to palaeontologists when they attempt to work out the relationships between extinct genera and species.
Researchers from New York’s Stony Brook University aided by a team from University College, London headed up by vertebrate morphologist and palaeontologist Susan Evans; have published their findings on this new species of Madagascan giant frog in the journal Proceedings of the National Academy of Sciences.
This discovery, led by David Krause of Stony Brook University may undermine current scientific thinking over the isolation of Madagascar that was believed to have taken place in the Cretaceous. Conventional theory states that by approximately 95 million years ago, the land mass that was to eventually form India and Madagascar had split away from Africa, part of the break up of Gondwanaland (Australia, New Zealand, Africa, Antarctica and South America). Over the next 30 million years or so a rising plume of hot magma forced its way through a fault rifting apart India and Madagascar. Madagascar was left an isolated island with its own distinct indigenous fauna and flora and India went northwards to collide with Asia.
The fossilised bones of Beelzebufo ampinga, a frog the size of a partially deflated beach ball and tipping the scales at around 4 kilogrammes, making it the largest frog found to date, resemble the bones of the extant frog group – the Ceratophyrinae. The Ceratophyrinae, termed the “horned frogs” as many members of this family have soft extensions of skin growing out from the upper eyelid, which resemble little horns; are associated with South America. Study of the fossils have indicated that this ancient animal is not related to any of the frog species living on Madagascar today. If Madagascar was very much an isolated island when Beelzebufo was hopping around, then how do scientists explain a member of the Ceratophyrinae group on an island thousands of miles away from their ancestral home of the South Americas.
The diagram above shows an artist’s impression of Beelzebufo, with a modern frog and a pencil for scale. Although only partial elements of the skeleton have been recovered Krause and his team estimate that this animal was 40 cm long and would have weighed as much as a large domestic cat.
The most characteristic feature of the Ceratophyrinae is not their horned eyelids (some members of the group do not possess this feature), but their large heads, huge mouths and blunt snouts. They are voracious and unfussy hunters, lying half submerged in mud waiting for any unsuspecting small animal to wander by. Basically, anything that can fit into their mouths is on the menu, mice, frogs, snakes, fish and such like.
Beelzebufo had a very wide mouth and powerful jaws, plus teeth. The skull material recovered has ridges and groves on it; perhaps indicating that this animal had bony armour or a protective head shield.
The name Beelzebufo is a derivative of the Greek word for Devil and bufo is the Latin for toad. The “Devil Toad” would be an apt title for a frog capable of swallowing whole baby dinosaurs.
Krause and his team began finding fragments of abnormally large frog bones whilst studying the late Cretaceous sediments of the Mahajganga basin in north-western Madagascar in 1993. Amongst the various dinosaur and crocodilian fossils a total of 60 fossil frog bone fragments were located during a number of expeditions to the area by the New York team. The unusually large frog bones were sent to the University College, London for specialist Susan Evans to examine. The London researchers were not able to piece together a complete skeleton but they had enough of the skull elements to make a diagnosis and interpret Beelzebufo as a relative of the horned frogs group.
The giveaway clinching evidence was the skull material indicating a “short, fat skull with a huge mouth”, says Evans.
The drawing depicts the skeleton of Beelzebufo ampinga (A) compared to the largest extant member of the south American Ceratophyrs (B) and the largest frog species found on Madagascar today (C). The skeletal material in white represents bones found, those parts of Beelzebufo skeleton in grey are a scientific impression as to what the remainder of the skeleton would have looked like.
The link to South America raises a palaeontology puzzle. Standard theory for how the continents drifted apart show what is now Madagascar would have been long separated by ocean from the Americas during Beelzebufo’s time. Frogs with their soft permeable skins cannot survive long in salt water, so reaching Madagascar by swimming can be ruled out.
Krause contends that the giant frog provides evidence for competing theories that some bridge still connected the land masses that late in time, perhaps via Antarctica that was much warmer than today. Perhaps Gondwanaland stayed together for longer than scientists currently think, could India/Madagascar have been linked to South America by an Antarctica land bridge as recently as the late Cretaceous.
Blair Hedges, a biologist at Pennsylvania State University in University Park, agrees that Beelzebufo is an important find. “The new fossil frog, besides being large and odd-shaped, is quite unexpected because of its apparent relationship with South American species,” he says.
But he says he isn’t yet convinced that the new find is related to the South American frogs. Molecular clock data suggests that these frogs split from a common ancestor more recently than 66 million years ago, he says. “Based on molecular evidence of frog relationships, the specific resemblance to some living wide-mouthed frogs is more likely from [evolutionary] convergence than actual relationship.” Convergent evolution, where unrelated species occupying similar niches tend to look the same, is common in frogs, he says.
Even if they are related, he adds, this doesn’t mean that the frogs necessarily had to walk on land from one location to another before Gondwana split. “Any organism, including a frog, can raft on dead vegetation,” he says.
Flood events and tropical storms can wash relatively large pieces of vegetation out to sea, some of these “rafts” get washed up on foreign shores. A number of animals migrate between islands today under these circumstances.
Susan Evans and her team remain convinced that Beelzebufo is a relative of the horned frogs of the Americas and refutes the convergence evolution theory. “It is the same family. I have no doubt of that,” she says.
It seems that this large, voracious frog – a trouble maker back in the Mesozoic, eating anything that could fit in its mouth, is going to be causing just as much trouble in scientific circles here in the Holocene.