New Study into Fossilised Crocodile Poop Provides Evidence of Deinosuchus Diet

It was not just the tyrannosaurs and raptors that the unwary dinosaur herbivore had to look out for in the Late Cretaceous habitats of the southern and southwestern United States seventy million years ago.  In estuarine environments (where rivers meet the sea), there lurked a monster crocodile called Deinosuchus that would have quite happily tackled a duck-billed dinosaur or pachycephalosaur had one ventured too near.

Deinosuchus

That is the conclusion drawn by a team of U.S. based scientists following a study of ancient crocodile coprolite (fossilised poop).  The coprolite, some of which measures more than 13 cm long, has been assigned to the fearsome Late Cretaceous predator Deinosuchus and evidence from the study of such objects has helped scientists determine the diet of this huge reptile and where it lived.

Deinosuchus (Deinosuchus hatcheri) was a huge, crocodilian that lived in what was North America during the later stages of the Cretaceous period.  Although, no complete skeleton has been found, a number of fragmentary fossils and a nearly complete skull have been discovered.  Scientifically named in 1909, this huge reptile has been estimated to have reached lengths in excess of 10 metres and would have weighed perhaps as much as 2 tonnes.  A recent study has indicated that Deinosuchus (the name means “terrible crocodile”) may actually be  more closely related to modern alligators than crocodiles.

A Replica of a Hatching Deinosuchus

The Rebor Club Selection: Meta the hatchling Deinosuchus is about to leave its egg! It’s very keen to get to the safety of the water.

Picture credit: Everything Dinosaur

The picture (above) shows the Rebor limited-edition hatching Deinosuchus (Esturary variant).

To view the range of Rebor figures and models: Rebor Prehistoric Animal Figures.

Estimating the Size of Deinosuchus

It is difficult to provide an accurate estimate of the size of this particular ancient crocodile in the absence of more complete skeletal material.  Using ratio measurements of skull length compared to body size of modern crocodiles as a guide, an estimated size of between 10-12 metres can be obtained.

Professor David Schwimmer of Columbus State University and one of his students of palaeontology, Samantha Harrell; carried out a detailed analysis of the fossilised crocodile dung and bones that showed bite marks from crocodilians.  They have concluded that this fearsome beast preferred to live in shallow, estuarine environments and preyed mainly on sea turtles but would have also been capable of taking down a dinosaur or two.

Palaeontologist Professor Schwimmer (no relation to the actor who played Ross the palaeontologist in “Friends”) stated:

“We’re sure [Deinosuchus] ate a lot of sea turtles, but it’s evident it liked to prey on dinosaurs too.”

Professor Schwimmer and Harrell gave a combined presentation on the bite marks and the coprolites, at the March 13-16 Geological Society of America Northeastern/South-eastern annual meeting in Baltimore.  Additionally, the coprolite study is being published as “Coprolites of Deinosuchus and other Crocodylians from the Upper Cretaceous of Western Georgia, USA” in a special symposium volume of the New Mexico Museum of Natural History and Science Bulletin.

Bite Marks on Dinosaur Bones

The studies detail how bite marks on dinosaur bones discovered in various locations around the United States, and large fossilised dung droppings discovered near Columbus, Georgia (southern USA), have been linked to Deinosuchus.

The dung fossils are the first such documented samples from the Deinosuchus and help confirm that this giant, prehistoric crocodile preferred living in the marine shallows. Meanwhile, the separate bite mark findings reveal aspects of the creature’s eating habits.

In the spring of 2009, Professor Schwimmer asked Harrell to take command of a project as an independent study course to gather and analyse fossilised dung he had started to recover from a fossil hot spot along the banks of the Hannahatchee Creek in Stewart County, a major tributary of the Chattahoochee River, south of where the Piedmont meets the Coastal Plain.

Harrell explained coprolites are studied in order to convey information about the lifestyles of the dead and buried.  She discovered sand and lots of shell fragments, signifying that these crocodiles lived in a shallow, brackish, warm-water environment — likely near the mouth of a river where it opened to a sea with a sandy shoreline and an abundance of sea turtles for its diet.

Although it is difficult to be absolutely precise when assigning fossilised dung to a particular genus, in this case the size, shape and nature of the dung studied  does indicate a large crocodile and Deinosuchus is the only known genus of crocodile from this strata.

To view models of prehistoric crocodiles: Wild Safari Prehistoric World Models and Figures.

Canadian Worm Wiggles its Way to Pre-eminence

In the warm waters surrounding the Cambrian continent of Laurentia lived an array of bizarre creatures, early arthropods, brachiopods and our ancient vertebrate ancestors.  The Annelida (worms) were very well represented with a number of different families of segmented worms.  These survivors from the Precambrian continued to diversify and flourish and if you want to find the fossilised remains of a prehistoric worm, look no further than your average Canadian construction site.  That is exactly what one Canadian amateur fossil collector called “James” did, and he inadvertently helped the Royal Ottawa Museum (ROM) discover a fossil of a 480 million-year-old armoured worm.

The extremely rare fossil of an armoured worm, a fossil that predates the emergence of the dinosaurs by some 250 million years was found when a local fossil collector examined the spoil coming from the excavation of an underground car park for the World Exchange Plaza, a set of buildings that can be found in downtown Ottawa (Ontario State, Canada).  However, it was not until a similar find was made in Morocco that scientists from the ROM realised the significance of the fossil found on the construction site ten years earlier.

Armoured Worm

Lead author Jakob Vinther and colleague David Rudkin have published a detailed description of this fossil in January’s edition of the scientific journal “Palaeontology”.  This tiny fossil, (measuring 16 mm long), about the size of an adult man’s little finger nail represents the organism Plumulites canadensis, a member of the Machaeridian family.  The significance of the Canadian fossil was not recognised until similar material was recovered from ancient marine deposits found in North Africa.

In 1998, the local fossil fan, known as “James” approached the ROM and handed the bizarre fossil to museum staff.  It was not until the Moroccan material was discovered that researchers realised the importance of this ancient object.  Unfortunately, the original donor of the fossil cannot be traced.

This fossil and other recently discovered material helps to cement the evolutionary link between the ancient Machaeridia and Annelid worms.

Commenting on how rare this example was, Vinther stated:

“They are really hard to find complete, fewer than ten of these fossils are known to exist.  We just had these skeletons and we didn’t know what kind of animal was underneath these plates.  We didn’t even know that they were worms, actually.”

Pictures show the bizarre fossil found in the spoil of a Canadian construction site.  It superficially resembles the much larger Vendian organism Dickinsonia and seems to have a segmented body that has a mid-line of symmetry.  This creature probably lived on or in the sea floor.  It would have been a member of the epifauna.  Essentially vagrant it would have roamed around the soft sea bed on thin, spindly legs that emerged in parallel out of key body segments.  The strange carapace of bony plates that protected this creature was made from calcite.  It would have provided some protection against marauding cephalopods or arthropods.

The emergence of hard body parts, items such as shells and an exoskeleton is evidence of the “Cambrian Explosion” a period when life in the sea diversified rapidly and the first complex predator/prey relationships were established.

Body Armour

Commenting on the body armour of this creature, Yale University graduate, Vinther added:

“A number of animals started evolving a higher level of protection in this period of time.  These annelid worms, they did the same thing … that seems to correlate well with the appearance of cephalopods.”

The Machaeridia persisted for some 200 million years, finally going extinct towards the end of the Palaeozoic, but their ancestors are very much with us today and perform a number of essential roles in both marine and terrestrial eco-systems.

Strange Cambrian Fauna

Say hello to Cambrian wildlife.  Strange Cambrian fauna.

The picture (above) shows the Cambrian Toob by Safari Ltd a model set that highights the bizarre nature of Cambrian fauna.

Allan Donaldson, a retired Carleton University Professor of Geology, participated in an authorised dig at the construction site of the World Exchange Plaza.  He said he found the routine trilobites and shelled orthocones, but nothing spectacular like the Machaeridia this amateur found in the material removed from the spot.

“Good for him” Donaldson acknowledged.

It is hoped that all the publicity over this worm fossil will reach the ears of the local man who actually found this ancient relic of Late Cambrian marine life and he can come forward to take some of the credit for the discovery of the worm from pre-history.