I have been meaning to muse on pterosaurs, the Archaeopteryx and the hoatzin for a long time, but suddenly the subject has become topical again.
Today’s papers have a story along the lines of “Dinosaur the size of a giraffe could fly across continents” – I have linked to the Daily Telegraph version, which is as good as any, apart from the fact that it means pterosaur (Greek for “wing-lizard”), NOT dinosaur (Greek for “terrible-lizard”).
The new findings suggest that the ancient reptiles took flight by using the powerful muscles of their legs and arms to push off from the ground, effectively pole-vaulting over their wings.
This is completely different from the way birds take off, by just flapping wildly from a standing start if they are small, running to pick up speed and jumping into the air before flapping wildly if they are medium sized, or jumping off a high place if they are big (or in the case of swifts, have very short legs).
Dinosaurs (and pterosaurs) always interested me. My early education came mainly from Arthur Mee’s Children’s Encyclopedia in 10 volumes – a Victorian/Edwardian publication no doubt decades out of date before I even started reading it. It had a fascination with palaeontology and so did I.
I recall it took the various geological periods one by one, with wonderful illustrations of the natural scene of the time. It is in this way that I came to call all flying lizards pterodactyls and it took me a long time to realise it was more complicated than that.
The first fossil of a pterodactyl (Greek for “wing-finger”) was described by Italian scientist Cosimo Alessandro Collini in 1784 when he was curator of a museum in Bavaria, where the fossil had been found.
But he thought it was an aquatic creature and it was Frenchman George Cuvier who concluded it was a winged reptile and named it Ptero-Dactyle in 1809. It was Latinised to Pterodactylus by Constantine Samuel Rafinesque in 1815. This was the name of the genus and the particular species was called Pterodactylus antiquus.
The pterodactyls were of the late Jurassic or Tithonian, about 150 million years ago. Since they were first identified in fossils and I first read about them in Arthur Mee, the picture has become far more complicated.
I recall the illustrations showed pterodactyls with smooth, bald, round heads. So that when I then saw more contemporary illustrations of what were being called pteranodons (Greek for “wing-no teeth”) with head crests, I assumed the crests were what made the difference between a pterodactyl and a pteranodon.
Only now in researching this post do I find that the early pterodactyl fossils were mostly of young specimens, so showed no trace yet of a head crest. Hence the misleading old reconstructions and a confusion of species. Some pterodactyl fossils were the young of crested species later given a variety of different Latin names. See some imaginative reconstructions of pterodactyloids by Mineo Shiraishi.
The Rhamphorhynchus illustrated below was one of the few flying reptiles of the time that did lack a head crest and this is still believed to be so.
Returning to the pteranodon, this was a different genus from the European pterodactyls. Its fossils are from the later Cretaceous period (100 milion to 65 million years ago) and are found in present-day Kansas, Alabama, Nebraska, Wyoming and South Dakota.
Its first fossils were found by Othniel Charles Marsh in 1870, in the Smoky Hill Chalk deposits of western Kansas. Some early illustrations show the pteranodon wrongly with teeth and without a crest. But it is toothless, crested and today it is believed it moved around on all fours.
There is some debate over the feeding method of pterosaurs. Although skim-feeding over the sea, dipping the head in the water, is possible for some, others have a crest much too cumbersome so all they could do was snatch anything on the surface, or on land.
I can’t keep up, so I’ll digress…
Here’s a wonderful image of a giant pterosaur called Quetzalcoatlus northropi.
Doesn’t it remind you of the land striders in The Dark Crystal?
I didn’t read only Arthur Mee as a child. I also read lots of children’s annuals of an educational nature and I recall vividly one article titled “The bird that walks on its wings”. It was about the hoatzin, considered by some to be a bit of a relic of the first birds, because its young still have claws on their wings.
These claws are used to clamber around the trees in the young hoatzin’s Amazon habitat and prevent the little-uns dropping off.
They are rather clumsy birds, although beautiful in adult plumage. And happily they are not too threatened in the wild – the locals sometimes eat their eggs, but the meat is not much valued as it doesn’t taste very good – not surprising when the hoatzin’s alternate name is “stinkbird”.
The Latin name is Opisthocomus hoazin. Opisthocomus is Greek for “wearing long hair behind”, a reference to this pheasant-sized bird’s large crest.
Perhaps linking the hoatzin and the ancient winged lizards is good old Archaeopteryx (from the Greek “ancient-feather/wing”). Again this comes from the late Jurassic or Tithonian (150 million years ago).
The only fossils of Archaeopteryx have been found in the same area as the first Pterodactylus, in the Solnhofen limestone in Bavaria, southern Germany. This is no doubt because the rock here is famous for the great detail of the fossils it yields, enabling it to keep an outline of feathered wings.
Although the archaeopteryx was a contemporary of leather-winged pterosaurs, it is still generally believed by palaeontologists that birds are descendants of earlier small dinosaurs.