Pterodactylus

“ About fifteen different kinds of Pterodactyles have been described from the Solenhofen Slate, mostly referred to the genus Pterodactylus, which comprises forms with a large head and long snout. Some have been placed in a genus (Ornithocephalus, or Ptenodracon) in which the head is relatively short. The majority of the species are relatively small. The skull in Ornithocephalus brevirostris is only 1 inch long, and the animal could not have stood more than 11⁄2 inches to its back standing on all fours, and but little over 21⁄2 inches standing as a biped, on the hind limbs. ”

“ The type of the genus Pterodactylus is the form originally described by Cuvier as Pterodactylus longirostris (p. 28) . It is also known as P. antiquus, that name having been given by a German naturalist after Cuvier had invented the genus, and before he had [Pg 168] named the species. There are some remarkable features in which Cuvier's animal is distinct from others which have been referred to the same genus. ”

“ And indeed the Pterodactylus crassirostris has a small tongue-shaped bone, probably belonging to the pelvis. The less important part of the skeleton, the tail, is formed precisely as in mammals, and is identical with that of the bats. Both the thigh and shin are mammalian, and only the foot retains the same number of parts as in reptiles. ”

“ In Pterodactylus dubius and P. grandipelvis and P. Kochi there are 5 or 6 vertebræ in the sacrum. In birds the sacral vertebræ vary from 5 to 22; in bats the number is from 5 to 6.
The short tails of Pterodactyles are more like those of mammals than birds; they include from 10 to 15 tail-vertebræ. In birds there are from 6 to 10 tail-vertebræ. Rhamphorhynchus has 38-40 tail-vertebræ, secured between thread-bones like those in the tail of rats.
The dorsal ribs are reptile-like. In herbivorous mammals and birds they are broader. A few species have the first pair of ribs large. ”

“ In the species Pterodactylus scolopaciceps the number of bones in the toes follows the formula two, three, three, four. In Pterodactylus micronyx the number is two, three, three, three. The terminal claws are much less developed than is usual with Birds; and there is a difference from Bats in the unequal length of the digits. Taken as a whole, the foot is perhaps more reptilian than avian, and in some genera is crocodilian.
The foot is the light foot of an active animal. Von Meyer thought that the hind legs were too slender to enable the animal to walk on land ”

“ It is a remarkable feature in these animals that the middle bones of the foot, termed instep bones or metatarsals, are usually close together, so that the toes diverge from a narrow breadth, as in P. longirostris, P. Kochi, and other forms; but there also appear to be splay-footed groups of Pterodactyles like the species which have been named P. elegans and P. micronyx, in which the metatarsus widens out so that the bones of the toes do not diverge, and that condition characterises the Ptenodracon (Pterodactylus brevirostris) , to which genus these species may possibly be referred. ”

“ B. Suborder Pterodactyloidea
Wing metacarpal, longer or but little shorter than forearm. Tail very short. No cervical ribs. Fifth toe more or less reduced.
Family Pterodactylidae. Nares and antorbital vacuity more or less coalescent. Teeth in anterior part of jaws. Anterior dorsal vertebrae not fused. All metacarpals articulating with carpus. Prepubes not band-like. Smaller.
Upper Jurassic. Pterodactylus Cuvier (Ornithocephalus Sommering, Diopecephalus Seeley, Cycnorhamphus Seeley, Pterodracon Lydekker) , Europe.
Family Ornithocheiridae. Skull more elongate. A supraoccipital crest. ”

“ As for the pterodactyl quoted in the last article, I have only to remark that this discussion arose purely from a consideration of what was the best type of flying apparatus nature had given man to study, and I claim that this prehistoric bird of geology does not come within this class. For if it is not fully established that this species had become extinct long before the appearance of man on the globe, it is at least certain that the man of that early day had not dreamt of flying and was presumably content if he could find other means to evade the pterodactyl's claw. ”

“ Some were not larger than a sparrow; others about the size of a woodcock; yet others much larger, the largest of all having a spread of wing (or rather of the flying membranes) of twenty-five feet! It has been concluded that they could perch on trees, hang against perpendicular surfaces, such as the edge of a cliff, stand firmly on the ground, and probably crawl on all fours with wings folded. It may be well at once to point out that the Pterodactyl had no true wings like those of a bird, but a thin membrane similar to that of a bat, only differently supported ”

“ Cast of brain-cavity.
They are exhibited in Compartments a, b, c of the Table-case of Cabinet J. The letter F in a circle is placed against figured specimens.
History.
The Cambridge Pterodactyles first attain prominence in scientific literature in the year 1859. Professor Owen had figured (plate 32, fig. 6-8) fragments of bones in the Palæontographical Society's Monograph for 1851; the distal end of a large ulna (fig. 6) ; the shaft of a phalange of the wing-finger, probably the first (fig. 7) ; and the upper portion of the shaft of a small humerus showing part of the radial crest (fig. 8) . ”

“ Pterodactyles show singularly little variation in structure in their geological history. We chronicle the loss of the tail and loss of teeth. There is also the loss of the outermost wing digit from the hind foot as a supporter of the wing membrane. But the other variations are in the length of the metacarpus, or of the neck, or head. One of the fundamental laws of life necessitates that when an animal type ceases to adapt its organisation and modify its structures to suit the altered circumstances forced upon it by revolutions of the earth's surface its life's history becomes broken. ”

“ It would therefore follow—since birds and mammals are warm-blooded—that Pterodactyls were also. Such, at least, is the view of Professor H. G. Seeley, who says of the Cambridge specimens, "That they lived exclusively upon land and in air is improbable, considering the circumstances under which their remains are found. It is likely that they haunted the sea-shores, and, while sometimes rowing themselves over the water with their powerful wings, used the wing-membranes, as the bat does, to enclose their prey, and bring it to the mouth. ”

“ But no Pterodactyle has the head of the humerus convex from the radial to the ulnar sides, and the bird is distinctive in having the ulnar crest developed on the inferior side of the head: a faint approximation to a similar development is seen in Crocodile, but there is no trace of such a process in Pterodactyle. The distal end is more Bird-like than Lacertian in form, but is twisted to a greater angle with the proximal end than in birds.
Altogether the bone is distinctive. The points in which it is unlike birds and reptiles are those in which Birds and Lizards resemble each other ”

“ Far the most remarkable of these predecessors of the true birds were the pterodactyls whose bones we still find in our English cliffs at Lyme Regis and Whitby; creatures with a large reptilian head, fierce jaws set with sharp-pointed teeth, and fore-arms prolonged into a great projecting finger so as to support a membranous wing or fold of skin, somewhat analogous to that of the bats. The pterodactyls do not stand anywhere in the regular line of descent toward the true birds ”

“ It is scarcely possible to distinguish the remains of the toothed and toothless skeletons except in the dentary character of the jaws. There is no evidence that the toothless types ever possessed a tooth of any sort. They were first found in fragments in England in the Cambridge Greensand, but were afterwards met with in great abundance in the Chalk of Kansas, where the same animals were named Pteranodon. A jaw so entirely bird-like suggests that the digestive organs of Pterodactyles may in such toothless forms at least have been characterised by a gizzard, which is so distinctive of Birds. ”

“ The forelimbs are always a pair of wings, the fifth digit or “little” finger being enormously elongated for the support of a smooth flying membrane (seen in specimens from the lithographic stone of Bavaria) . The wings are thus constructed on the same plan as those of a bat, but instead of four fingers, only one is elongated to bear the membrane. The hind-limbs are comparatively feeble, and must have been of very little use for walking.
The remains of pterodactyles are found chiefly in marine deposits, so that these reptiles must have frequented the coastlines. ”

“ The tail is always so short as to be inappreciable. Many of the specimens are fragmentary, and the characters of the group are not easily determined without careful comparisons and measurements. The bones of the [Pg 166] fore limb and wing finger are less stout than in the Rhamphorhynchus type, while the femur is generally a little longer than the humerus, and the wing finger is short in comparison with its condition in Rhamphorhynchus. These short-tailed Pterodactyles give the impression of being active little animals, having very much the aspect of birds, upon four legs or two. ”

“ It is the first flash of light on a dark problem, and its brilliance of inference has never been equalled. Its effects were seen when Prince Charles Bonaparte, the eminent ornithologist, in Italy, suggested for the group the name Ornithosauria; when the profound anatomist de Blainville, in France, placed the short-tailed animal in a class between Reptiles and Birds named Pterodactylia; and Andreas Wagner, of Munich, who had more Pterodactyles to judge from [Pg 31] than his predecessors, saw in the fossil animal a saurian in transition to a bird. ”

“ Most anatomists will probably agreee in considering that many features of the skeleton of pterodactyls, such for example as its remarkable pneumaticity are due to modifications for flight, but the author considers that Pterodactyls and Birds form two parallel groups which may be regarded as ancient divergent forks of the same branch of animal life. But whether we accept all Professor Seeley's deductions or not we may safely accept his facts and we are indebted to him for having placed so much information within our reach and for having given it in so readable a form. ”

“ But even then there are undoubtedly Dinosaurs belonging to that period, so that the question of relationship would resolve itself into a common origin, not a derivation of birds from Dinosaurs." Of the relation between birds and Pterosaurians, particularly Pterodactyles—and Prof. Newton has conclusively shown most interesting resemblances — Mr. Beddard considers the main difficulty "in the way of comparing Pterodacytles and birds is in the fact that both can fly, and that each has acquired the power of flight by a different method. ”

“ Papers were communicated to the Cambridge Philosophical Society on February 17, 1868, on indications of Mammalian affinities in Pterodactyles in the pelvis and femur, and February 22, 1869, on the bird-like characters of the brain and metatarsus in the Pterodactyls from the Cambridge Greensand. The other references to Cambridge specimens are in a paper "On the literature of English Pterodactyles" in the Annals and Magazine of Natural History for Feb. ”

“ The extinct Pterodactyles hold a relation to Birds in the scheme of life not unlike that which Monotremata hold to other Mammals. Both are remarkable for the variety of their affinities and resemblances to Reptiles. The Ornithosauria have long passed away; the Monotremes are nearing extinction. Both appear to be supplanted by parallel groups which were their contemporaries. Birds now fill the earth in a way that Flying Reptiles never surpassed; but their flight is made in a different manner, and the wing is extended to support the animal in the air, chiefly by appendages to the skin. ”

“ One of these sketches shows us such a creature hungrily inspecting a pool where Crinoids, with their long stems, large, closely-coiled Chambered Shells, and Brachiopods, the Oysters and Clams of those days, offer him a tempting repast. Here and there a Pterodactyl, the curious winged reptile of the later middle periods, stretches its long neck from the water, and birds also begin to make their appearance.
After these come the Tertiary periods: the Eocene first, where the landscape is already broken up by hills and mountains, clothed with a varied vegetation of comparatively modern character. ”

“ In the accompanying figure is given a restoration of Pteranodon, one of these most highly specialized pterodactyls, based upon skeletons from the Cretaceous chalk of western Kansas. As in all restorations of extinct animals which departed widely from any now in existence, entire truthfulness of expression and appearance can not be expected. A more or less close approximation to the living picture is, however, assured from a complete knowledge of the skeleton and the impression in the rocks of form and of membranes, which have been preserved with the bones of allied forms. ”

“ The points in which it is distinct from birds are that the bone is not produced proximally beyond the glenoid cavity for the humerus, which, instead of being lateral as in birds, and looking outward, in Pterodactyles forms the proximal-termination of the bone. The sternal articulation is proportionally much shorter transversely in Pterodactyles, terminating in a convex margin which rounds up into the thin outer margin, as in the immature coracoid of the common Cock. It is bow-shaped in front instead of being straight, and is commonly longer than in birds. ”