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.

Dinosaur Tracks

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.

Studying Trace Fossils

A total of over 900 fossilised footprints from a variety of dinosaurs all dated from the 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.

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Two Dozen Species of Dinosaur

“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.

An Illustration of the Track Made by an Ornithopod Dinosaur

Picture credit: Everything Dinosaur

Photographs show 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.

To read an early article about dinosaur tracks discovered on the North Yorkshire coast: Dinosaur Tracks Found by Young Boy.

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.

Providing an Insight into Dinosaur Behaviour

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.

So far, Stanford has described and published Maryland’s first dinosaur track species (called an ichnospecies which translates to ‘trace species’). It consists of both front and back footprints of a hypsilophodontid dinosaur. He named the new dinosaur footprint type or species Hypsiloichnus marylandicus, meaning “trace of a hypsilophodontid dinosaur from Maryland.”

An overview of these, and other, finds was recently published in the journal Ichnos.

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.

Everything Dinosaur stocks a wide selection of dinosaur models including replicas of ornithopods and nodosaurids: Everything Dinosaur Models and Replicas.

Joint Chinese and Japanese Research Team announce new Sauropod Species

Chinese news sources have confirmed the announcement of the discovery of a new species of sauropod (long-necked dinosaur) in eastern China.  The partial, disarticulated 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.

New Dinosaur Species

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 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.

To read more about the discovery of Zhejiangosaurus:

New Dinosaur Species Announced in Eastern China.

This article has been compiled using a number of news sources including the Xinhua news agency.  Everything Dinosaur stocks a wide range of dinosaur models from the Chinese model maker PNSO: PNSO Dinosaur Models.

Giant Frog challenges Scientists over movement of Continents

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.

Frog and Toad Evolution

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 Study Fossil Bones

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.

Beelzebufo ampinga

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.

Beelzebufo – the Frog from Hell

Picture credit: Associated Press

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.

Wide Mouth and Powerful Jaws

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.

David Krause commented: “This frog, if it has the same habits as its living relatives in South America, was quite voracious.  It’s even conceivable that it could have taken down some hatchling dinosaurs.”

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.

A Relative of Extant Horned Frogs

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.

Scale Drawing of Beelzebufo Skeleton compared to Living Frogs

Big frog from the Mesozoic.

Picture credit: Journal of Proceedings of the National Academy of Sciences

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.

A Palaeontology Puzzle

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.

Evans says that when she first began to suspect the Madagascar fragments came from a frog related to South American Ceratophryinae, she was very cautious about the claim. “We knew it would be controversial,” she says. “There are people who believe everything on Madagascar today must have been there when it broke with Gondwanaland 160 million years ago.”

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.

Visti Everything Dinosaur’s website: Everything Dinosaur.