Our Archaeopteryx show has bedazzling fossils – the only Archaeopteryx skeleton in the New World, complete with clear impressions of feathers. Plus frog-mouthed pterodactyls, fast-swimming Sea Crocs, and slinky land lizards. Today we learn about the different types of Pterodactyls that have been found at Solnhofen.
The Jurassic Air Was Full of Wings!
The First ‘Dactyl Ever Discovered – 1784, Solnhofen
In that year, Cosimo Collini thoroughly scrutinized a perfect skeleton of a curious creature preserved in the Solnhofen lithographic stone.
Jaws: long, slender, with sharp teeth.
Arms: very long, with an extraordinary finger that could be stretched out and folded up.
Tail: very short.
Inner construction: bones hollow, like a bird’s.
Verdict: Not a bird, not a bat, but a new life form, never seen before.
More studies produced the name: “Wing-Finger,” Pterodactylus.
Solnhofen gave science a dozen more ‘dactyl species, some as large as a big seagull. Other Jurassic salt-water deposits produced specimens in England and France. Solnhofen still gave the best preserved ‘dactys. Some had the clear impression of the wing skin, connected to the single long finger on each hand.
Pterodactyl science has made a giant U-Turn in the last decades. Way back in the 1820’s, the best minds of paleontology were convinced that ‘dactyls walked and flew like bats. The Reverend William Buckland – “Mr. Jurassic” in England – drew up cartoons of Pterodactylus hanging onto cliffs like a bat, and fluttering over the Solnhofen lagoon with bat-style wings. His German colleagues agreed: in design of wings and hind feet, ‘dactyls were definitely batty.
Then came the New Wave of ‘dactyl research in the 1970’s. Young Ivy League scholars went “tsk, tsk….that silly old Buckland. He was wrong. Dactyls were really built like birds. All dactyls walked upright on their hind legs. They didn’t scuttle about in a bat manner.”
And so textbooks were revised. ‘Dactyls stood up and walked like Jurassic pigeons.
Footprints Back Buckland
But in 1980, a new set of evidence emerged – fossil tracks. If the New Wave was right, then ‘dactyl tracks should look like bird tracks. The left and right hind feet should have swung back and forth close together, and the hands should have been kept off the ground.
Surprise! Fossil tracks made by small dactyls and by big ‘dactyls showed hind feet that were held out sideways. And the hands were flat on the ground! “Dactyls walked like………BATS!
The case is closed. Hundreds of trackways and bio-mechanical studies of shoulder and hips say the same thing. ‘Dactyls moved on all fours when on the ground, like bats.
Pterodactylus was the commonest ‘dactyl at Solnhofen. No bigger than a tiny sand-piper, Pterodactylus had extra long arms and neck and a compact body with almost no tail.
The thin jaws could be used to snatch small fish. Or the snout might have been used to probe the sand flats, like a shore bird, searching for hidden worms and baby clams.
The long neck, arms and short tail are proof that Pterodactylus was a Jurassic cousin of the enormous ‘dactyls of the Cretaceous, including the Texas Quetzalcoatlus.
Rhamphorhynchus – The Devil-Tailed ‘Dactyl
Rhamphorhynchus was a flying Fish-Trap. The jaws carried long, sharp teeth that slanted forward, and the tips of the snout and lower jaw were pointed too. This ‘dactyl could dive down on the water and use its strong neck to throw the muzzle at fish and impale them.
The short arms made the wingstroke slower but more powerful than in Pterodactylus, so maximum speed was less but maneuverability was greater.
The long, bony tail was tipped with a vertical rudder of skin, reinforced by stiff fibers.
Long-tailed ‘dactyls went extinct in the Early Cretaceous and all the common ‘dactyl species of the Cretaceous were short-tailed relatives of Pterodactylus. Why did the long-tails die out? What gave the short-tails their superiority?
The final extinction of all ‘dactyls struck when the last dinosaurs died out 65 million years ago, at the very end of the Cretaceous.
Anurognathus – Frog-Mouthed Mini-‘Dactyl
Jewel of the Solnhofen Exhibit.
Rarest of the rare, with only two specimens known, is the famous “Frog-Mouthed ‘Dactyl,” Anurognathus.
The Frog-Mouth breaks all the ‘dactyl rules. It’s super-tiny, half the size of Pterodactylus and about as bulky as the average little brown bat that hovers over Texas meadows today. And unlike nearly all other ‘dactyls, the Frog-Mouth doesn’t have a long snout. Instead the mouth is short and very wide.
The Frog-Mouth design is what we’d expect from an aerial insect-hunter, a ‘dactyl that hunted the dragon-flies and beetles of the tropical Jurassic sky. The short tail and abbreviated wrist bones would make quick turns easy. The wide mouth would work like a bug-trap.
Anurognathus had the biggest eyes for it’s head size of any Solnhofen ‘dactyl. The acute visual system is a clue to unusual habits. Perhaps the Frog-Mouth was an insect-eater who flew in the darkness. More insects get airborne in the evening than during the daylight, so there would be more targets. And the eyes would have to be enlarged to detect prey in low-light environments.