Aspidorhynchus

Name: Aspidorhynchus ‭(‬shield snout‭)‬.
Phonetic: Ass-pid-o-ryn-kus.
Named By: Agassiz‭ ‬-1843.
Classification: Chordata,‭ ‬Gnathostomata,‭ ‬Osteichthyes,‭ ‬Aspidorhynchiformes,‭ ‬Aspidorhynchidae.
Species: A.‭ ‬acutirostris,‭ ‬A.‭ ‬crassus,‭ ‬A.‭ ‬euodus,‭ ‬A.‭ ‬fisheri.
Diet: Carnivore.
Size: About‭ ‬60‭ ‬centimetres long.
Known locations: Europe including England,‭ ‬France and Germany.
Time period: Bathonian to Kimmeridgian of the Jurassic.
Fossil representation: Many individuals.

       In the simplest terms,‭ ‬Aspidorhynchus was very similar to the modern day gar‭ (‬a.k.a.‭ ‬garpike‭) ‬fish that inhabit Central and North America as well as the Caribbean,‭ ‬and are noted for being very successful predators.‭ ‬The body is very long and slender with fairly small fins for the size but a‭ ‬fairly‭ ‬well-developed tail.‭ ‬Together the body has a form‭ ‬suited to‭ ‬relying more upon sudden acceleration towards a prey target,‭ ‬closing the distance before it was able to respond to the threat.‭ ‬The snout is elongated and thin,‭ ‬though it remains uncertain as to why it was this form.‭ ‬It may have been an aid in striking at fish either with a direct thrust or a side to side slashing motion like a modern day sword fish.‭ ‬A slashing motion would probably not kill a fish outright,‭ ‬but could potentially stun of grievously wound one so that it could not swim away.

       One of the most fascinating discoveries involving Aspidorhynchus involves the pterosaur Rhamphorhynchus.‭ ‬With the description published in‭ ‬2012‭ ‬by Frey and Tschlinger,‭ ‬specimen WDC CSG‭ ‬255‭ ‬is a slab that contains the remains of a Rhamphorhynchus with two fish,‭ ‬Aspidorhynchus and Leptolepides.‭ ‬The Leptolepides was found within the throat of the Rhamphorhynchus.‭ ‬The left wing of the Rhamphorhynchus‭ ‬is pulled back in an unusual posture,‭ ‬and it seems that in life the membrane of the left wing was speared by the long snout of the Aspidorhynchus.‭
       The scenario is expected to have played out along the lines of a Rhamphorhynchus swooping in low to snatch a Leptolepides from the water.‭ ‬A roaming Aspidorhynchus then lunged towards the pterosaur,‭ ‬spearing its wing with the pointed snout.‭ ‬It is uncertain which creature the Aspidorhynchus was targeting,‭ ‬it may have actually been in the process of attacking the Leptolepides when Rhamphorhynchus just got in the way,‭ ‬or it may have even tried for Rhamphorhynchus as a target of opportunity.‭ ‬Either way it seems that with the pterosaurs wing wrapped around the fish’s snout the two sank down to a lower level of anoxic‭ (‬oxygen depleted‭) ‬water.‭ ‬Since pterosaurs couldn’t breathe underwater,‭ ‬the Rhamphorhynchus simply drowned,‭ ‬but the oxygen depleted water of the anoxic zone meant that the Aspidorhynchus would have suffocated and died before it could free itself from the pterosaurs wing membrane.‭ ‬The Leptolepides,‭ ‬still in the throat of the Rhamphorhynchus while this was happening would have had no chance of survival either.‭ ‬The same anoxic conditions that proved fatal to the Aspidorhynchus however were also responsible for the high level of preservation in the specimen.
       This is not the first example of a fish vs pterosaur interaction.‭ ‬An example of the fish genus Saurichthys has been found with the remains of the pterosaur Preondactylus arranged in a bolus‭ (‬a pellet of bones that would be spat out instead of digested‭) ‬found in close‭ ‬association to Saurichthys.‭ ‬It is uncertain however if this was a case of active predation or scavenging.

Further reading
-‭ ‬On some new genera and species of fossil fishes.‭ ‬-‭ ‬P.‭ ‬Egerton‭ ‬-‭ ‬1854.
-‭ ‬The Late Jurassic pterosaur Rhamphorhynchus,‭ ‬a frequent victim of the ganoid fish Aspidorhynchus‭? ‬-‭ ‬E.‭ ‬Frey‭ & ‬H.‭ ‬Tischlinger‭ ‬-‭ ‬2012.





----------------------------------------------------------------------------

Random favourites