Rhamphorhynchus Falls Victim to Ganoid Fish

Scientists have frequently speculated how the likes of Rhamphorhynchus, a Late Jurassic, long-tailed pterosaur hunted fish.  A remarkable fossil find from lithographic limestone deposits of Solnhofen (Germany) may add weight to the theory that these pterosaurs skimmed the surface of the water, snatching fish from the sea with their spiky-toothed jaws.  There is certainly evidence in the fossil record to suggest that Rhamphorhynchus genera were piscivores (fish-eaters), however, this amazing fossil discovery also suggests that certain types of fish lurking in the anoxic (depleted of oxygen, thus aiding fossil preservation), waters of the lagoon were prepared to attack these flying reptiles and drag them to their doom.

Rhamphorhynchus

It seems that after a successful hunt, one unlucky pterosaur was grabbed by a predatory fish, a ganoid fish known as Aspidorhynchus acutirostris.  These two fish-eaters became tangled up, the pterosaur drowned and unable to shake the Rhamphorhynchus out of its mouth, the Jurassic fish also met its demise.

Pterosaur versus Ganoid Fish Preserved in the Fossil Record

Accidental fatal encounter between two Jurassic piscivores.

Picture credit: PloS One/Frey, Tischlinger.

The picture above shows the flying reptile with its wing trapped in the fine teeth of the predatory fish.  A number of fossils are known from the Solnhofen deposits were skull elements of ganoid fish are found in association with the remains of members of the Rhamphorhynchidae.  Since the jaws of the fish could not open very wide, and since no pterosaur remains have been found in the stomachs of fossilised fish of this genus, it can be assumed that flying reptiles were not a normal prey item for this predator.  Perhaps the water disturbance of a pterosaur skimming the surface water fishing attracted the attention of the larger fish, who inadvertently grabbed the Rhamphorhynchus as it flew passed.

Rhamphorhynchus is one of the best known of all the long-tailed pterosaurs.  Several species have been identified, the largest of which had a wingspan about the size of the height of a man (nearly six feet).  Fossils of the pterosaur  have been found in strata associated with coastal areas.  The teeth in the narrow jaws were long, pointed and interlocked when the jaws were closed indicating that this pterosaur was probably a hunter of fish, this new fossil discovery indicates that sometimes, inadvertently at least, Rhamphorhynchus became the hunted.

An Illustration of a Rhamphorhynchus

Flying low over the water – vulnerable to attack from below.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

For models and replicas of Rhamphorhynchus and other pterosaurs: Wild Safari Pterosaur and Dinosaur Models.

Evidently, the flight membrane of the reptile, jammed in the teeth of the fish.   Evidently, the fish could not swallow the pterosaur due to its size and bulky skeleton.  Furthermore, ganoid fishes like Aspidorhynchus have skulls with limited kinetic options such that they were not suitable to manipulate prey that exceeded the standard gape of the jaws.  So for the fish, it could not swallow its victim, nor could it free itself from the wing membrane.

The authors of the paper on this remarkable fossil find (paper published in the “Public Library of Science –  Biology”), suggest that the aktinofibrils of the tough and leathery wing membrane of the pterosaur got jammed between the densely packed teeth of the fish.  Like most extant fish Aspidorhynchus had no other possibility to get rid of its unwanted victim than trying to shake it loose or swimming rapidly and trying  spinning or twisting manoeuvres.   That the fish in fact tried to get rid of its unwanted meal by vigorous movements of its head is evidenced by the distortion of the left wing finger elements, while the remaining skeleton of the Rhamphorhynchus lies in natural articulation.  This is one Jurassic encounter that ended fatally for both participants.

Vertebrate skeletons from different creatures found together is exceedingly rare in the fossil record.  A number of fossils found at Solnhofen reveal this unfortunate relationship between Rhamphorhynchus and ganoid fish, but this specimen provides scientists with supporting evidence with regards to the feeding methods of the flying reptile.  Lodged in the throat of the pterosaur are the fossilised remains of a small Leptolepidid fish.  The pterosaur also has fish bones in its stomach.  The undigested state of the fish in the throat suggests that the Rhamphorhynchus was seized during or immediately after a successful hunt.

 Evidence of Rhamphorhynchus Hunting Fish

Rhamphorhynchus caught a fish.

Picture credit: PloS One/Frey, Tischlinger.

The picture shows a photograph (close up) of the jaws and throat of the Rhamphorhynchus (A), a line drawing showing the position of the small fish the pterosaur swallowed (B) and a close up of the tiny fish fossil viewed under filtered ultraviolet light which shows up greater detail than natural light (C).

In the PloS One journal the pictures are described, the straight vertebral column and the closed tail fin, which is orientated towards the mouth cavity suggests that the fish was not regurgitated during the agony of the pterosaur.  Furthermore the prey does not show any trace of digestion. A) photograph of the specimen WDC CSG 255 showing the position of the Leptolepides? in the throat of the flying reptile.  To the right hand side the skull of the ganoid fish predator visible.  B) line drawing of (A), C) close-up of Leptolepides? under filtered UV light: 1 caudal fin, 2 neural spines, 3 vertebral column.

To read more about the theory regarding how pterosaurs such as the Rhamphorhynchidae may have hunted: Pterosaur Feeding Habits – Could they Skim the Water for Fish?

Solnhofen deposits outcrop in an east-west belt north of Munich (Germany), they have produced some exquisite fossils, a record of the flora and fauna of a Jurassic lagoonal environment.  This remarkable fossil helps to add to our knowledge about vertebrate interactions that took place in that shallow water environment all those millions of years ago.

The scientific paper: “The Late Jurassic Pterosaur Rhamphorhynchus, a Frequent Victim of the Ganoid Fish Aspidorhynchus?” by Eberhard Frey and Helmut Tischlinger published in PLoS One.

Pterosaur Bone Found Lodged in Velociraptor Body Cavity Suggests a Scavenged Meal

Scientists have published a paper detailing their studies into a very well preserved skeleton of a Velociraptor (Velociraptor mongoliensis) which reveals evidence of one of the last meals of this little Cretaceous carnivore.  The fossil was unearthed in the Gobi desert back in 1994, but a detailed, formal study has only just been completed and published in the scientific journal “Palaeogeography, Palaeoclimatology, and Palaeoecology”.

Last Meal of a Velociraptor

The fossil find, the first discovery of a pterosaur bone in the body cavity of a dinosaur, suggests that dromaeosaurs such as Velociraptor (V. mongoliensis), although active hunters, would have resorted to scavenging any available carcase that they could find.

An Illustration of Velociraptor mongoliensis

Did a juvenile Velociraptor have pterosaur as its last meal?

Picture credit: Everything Dinosaur

Velociraptor, made famous by its largely inaccurate portrayal in the Jurassic Park film trilogy, was a small, fast running, Late Cretaceous carnivore, perhaps as much as two metres long and standing a metre high.  It had a long, narrow snout, with jaws that were capable of opening very wide.  The jaws were lined with about eighty, small, sharp teeth.  Velociraptor had long, three-clawed hands but perhaps its most famous anatomical feature was the enlarged, sickle-shaped claw on the second toe.  Scientists remain unsure as to what this huge toe claw was used for.  It has been suggested that this claw, that could be held clear of the ground as the animal walked, may have acted like a grappling hook, helping this predator latch onto and cling to struggling prey.  Velociraptor mongoliensis is known from a number of superb fossil specimens including an amazing fossil of a Velociraptor preserved with a herbivorous Protoceratops apparently these dinosaurs perished whilst in combat.

The international research team included palaeontologists from University College (Dublin), the pterosaur bone inside the rib cage of the predator is an exciting discovery, this suggests that a flying reptile was one of the last things that this little dinosaur ate before it to met its demise.   The fossils suggest that this Velociraptor was a sub-adult, not yet fully grown perhaps weighing around 13 kilogrammes.  The bone fragment inside the body cavity, is highly pneumatised and the walls of the bone are very thin.  This suggests pterosaur, and given the fact that azhdarchid pterosaur remains have been found in strata dated to the same geological time period in that part of the Gobi desert, the research team have postulated that the bone is from a member of the Azhdarchidae group of flying reptiles.

The Rib Cage and the Pterosaur Bone

The last meal of a Velociraptor.

Picture credit: David Hone et al 2012

The black arrows in the picture point to the pterosaur remains found in the upper part of the rib cage, whilst the white arrow highlights evidence of a broken rib – evidence of a severe trauma in this dinosaur’s life.

The researchers have concluded that although Velociraptor was a fearsome predator, it would not have taken on a healthy full-sized pterosaur, an animal with a wingspan more than the length of the Velociraptor’s entire body.

David Hone, one of the co-authors of the scientific paper, based at University College Dublin’s School of Biology and Environmental Sciences stated:

“It would be difficult and probably even dangerous for the small theropod dinosaur to target a pterosaur with a wingspan of two metres or more, unless the pterosaur was already ill or injured.  So the pterosaur bone we’ve identified in the gut of the Velociraptor was most likely scavenged from a carcase rather than the result of a predatory kill.”

Velociraptor mongoliensis

A spokesperson from Everything Dinosaur commented:

“It is possible that this particular Velociraptor was part of a pack and given it’s sub-adult size, it may have been quite low in the pecking order.  Just like packs of hunting dogs in Africa today, low status animals may have had to wait their turn before being allowed to feast on a kill.  Perhaps the pterosaur had been attacked and killed by the pack and this individual had to be satisfied with a quickly gulped down bone as well as a few other scraps”.

Of course, such ideas can only be assertions, there is no evidence to suggest how the bone came to be in the body cavity of the Velociraptor, suffice to say it was ingested and using studies of the feeding behaviours of extant carnivores for comparison, it is likely that this Velociraptor was scavenging from the long, dead remains of a pterosaur.

To view articulated models of various dromaeosaurids: Beasts of the Mesozoic Articulated Dinosaurs.

A Close-Up of the Bone in the Rib Cage

The bone is highlighted in red

Picture credit: David Hone et al 2012 with additional annotation by Everything Dinosaur.

In the enlargement above we have highlighted the pterosaur bone in red, the scale bar provides a scale size for this illustration.

The discovery of such a large bone, approaching eight centimetres in length, nearly as long as the Velociraptor’s jaws, suggest that small dromaeosaurs were capable of consuming relatively large bones, something seen in crocodiles today.  Just like extant crocodilians, Velociraptor did not chew its food but swallowed it down as quick as it could – a good strategy for survival when at any minute a bigger predator may come along and bully you out of your meal.

The pterosaur bone, lodged in the rib cage, where the stomach would have been probably had not been swallowed for long, before the Velociraptor met its end.

Dr Hone added:

“The surface of the bone is smooth and in good condition, with no unusual traces of marks or deformation that could be attributed to digestive acids.  So it’s likely that the Velociraptor itself died not long after ingesting the bone”.

The rib cage itself provides an insight into the lives of Velociraptors.  The white arrow in the picture above points to a broken rib with signs of regrowth, suggesting that this dinosaur was injured or recovering from a traumatic injury at the time of its death.  Such evidence, known as pathology, shows that for this sub-adult Velociraptor, it must have taken a terrific knock at some point during its short life – but at least it lived to tell the tale – for a short while anyway.

To view a second article regarding evidence of Velociraptor scavenging behaviour: Velociraptors were Scavengers as well as Hunters.