Pterodactylus - History

History

The animal now known as Pterodactylus was the first pterosaur ever to be identified. The first Pterodactylus specimen was described by the Italian scientist Cosimo Alessandro Collini in 1784, based on a fossil skeleton unearthed from the Solnhofen limestone of Bavaria. Collini was the curator of the "Naturalienkabinett", or nature cabinet (a precursor to the modern concept of the natural history museum), in the palace of Charles Theodore, Elector of Bavaria at Mannheim. The specimen had been given to the collection by Count Friedrich Ferdinand zu Pappenheim, probably around 1780, having been recovered from a lithographic limestone quarry in Eichstätt. Collini, however, did not conclude that the specimen was a flying animal. In fact, Collini could not fathom what kind of animal it might have been, rejecting affinities with the birds or the bats. He speculated that it may have been a sea creature, not for any anatomical reason, but because he thought the ocean depths were more likely to have housed unknown types of animals. The idea that pterosaurs were aquatic animals persisted among a minority of scientists as late as 1830, when the German zoologist Johann Georg Wagler published a text on "amphibians" which included an illustration of Pterodactylus using its wings as flippers. Wagler went so far as to classify Pterodactylus, along with other aquatic vertebrates (namely plesiosaurs, ichthyosaurs, and monotremes), in the class Gryphi, between birds and mammals.

It was the German/French scientist Johann Hermann who first stated that Pterodactylus used its long fourth finger to support a wing membrane. In March 1800, Hermann alerted the French scientist George Cuvier to the existence of Collini's fossil, believing that it had been captured by the occupying armies of Napoleon and sent to the French collections in Paris (and perhaps to Cuvier himself) as war booty; at the time special French political commissars systematically seized art treasures and objects of scientific interest. Hermann sent Cuvier a letter containing his own interpretation of the specimen (though he had not examined it personally), which he believed to be a mammal, including the first known life restoration of a pterosaur. Hermann restored the animal with wing membranes extending from the long fourth finger to the ankle and a covering of fur (neither wing membranes nor fur had been preserved in the specimen). Hermann also added a membrane between the neck and wrist, as is the condition in bats. Cuvier agreed with this interpretation, and at Hermann's suggestion, Cuvier became the first to publish these ideas in December 1800 in a very short description. Cuvier remarked, "" However, contrary to Hermann, Cuvier was convinced the animal was a reptile.

The specimen had not in fact been seized by the French. Rather, in 1802, following the death of Charles Theodore, it was brought to Munich, where Baron Johann Paul Carl von Moll had obtained a general exemption of confiscation for the Bavarian collections. Cuvier asked von Moll to study the fossil but was informed it could not be found. In 1809 Cuvier published a somewhat longer description, naming the animal, in which he refuted a hypothesis by Johann Friedrich Blumenbach that it would have been a shore bird.

Contrary to von Moll's report, the fossil was not missing; it was being studied by Samuel Thomas von Sömmerring, who gave a public lecture about it on 27 December 1810. In January 1811, von Sömmerring wrote a letter to Cuvier deploring the fact that he had only recently been informed of Cuvier's request for information. His lecture was published in 1812, and in it von Sömmerring named the species Ornithocephalus antiquus. The animal was described as being both a mammal, a bat, and a form in between mammals and birds, i.e. not intermediate in descent but in "affinity" or archetype. Cuvier disagreed, and the same year in his Ossemens fossiles provided a lengthy description in which he restated that the animal was a reptile. It was not until 1817 that a second specimen of Pterodactylus came to light, again from Solnhofen. This tiny specimen was that year described by von Soemmerring as Ornithocephalus brevirostris (for its short snout, now understood to be a juvenile character), and provided a restoration of the skeleton, the first one published for any pterosaur. This restoration was very inaccurate, von Soemmerring mistaking the long metacarpals for the bones of the lower arm, the lower arm for the humerus, this upper arm for the breast bone and this sternum again for the shoulder blades. Von Soemmerring did not change his opinion that these forms were bats and this "bat model" for interpreting pterosaurs would remain influential long after a consensus had been reached around 1860 that they were reptiles. The standard assumptions were that pterosaurs were quadrupedal, clumsy on the ground, furred, warmblooded and had a wing membrane reaching the ankle. Some of these elements have been confirmed, some refuted by modern research, while others remain disputed.

In 1998, the discovery of one specimen assigned to P. kochi shed light on the life appearance of Pterodactylus, as it preserved unique soft-tissue traits not present in previous fossil skeletons, including long, bristly pycnofibres (a fur-like body covering known only in pterosaurs) on the neck, details of an urpatagium (hind wing membrane between the legs and tail) that also stretched between the toes as webbing, and a pelican-like throat pouch. An additional specimen, studied using ultra-violet light, revealed even more information on the soft anatomy of Pterodactylus. This specimen (catelogue number JME SOS 4784) showed that like many other pterosaurs, Pterodactylus had a striated soft-tissue crest on the skull. Soft tissue impressions also showed unusually long, sharp, and recurved keratin sheaths on its claws. This specimen was also covered in hair-like pycnofibres, with unusually long pycnofibres covering the back of its neck. The remains of a small, hooked beak were preserved at the tips of the jaws between its upper and lower front teeth.