Ichthyosaur

“ It is not improbable that in some cases this is the true explanation of the smaller skeletons within the larger ones, but it cannot be true of all, since wherever the small skeletons are identifiable they have been found to belong to the same species as the adult, and it would be absurd to suppose an ichthyosaur bent upon its prey would be at all likely to select as many as seven young animals, all of the same size and all of its own species. ”

“ It was named Ichthyosaurus (Gr. fish-lizard) by C. König in 1818 in allusion to its outward form, and is best known by nearly complete skeletons from the Lias of England and Germany. The large head is produced into a slender, pointed snout; and the jaws are provided with a row of conical teeth nearly uniform in size and deeply implanted in a continuous groove. The eye is enormous, and is surrounded by a ring of overlapping “sclerotic plates,” which would serve to protect the eye-ball during diving. ”

“ The latter animal had an extremely long neck and small head, with teeth like those of the crocodile, and paddles analogous to those of the Ichthyosaurus, but larger. It is supposed to have lived in shallow seas and estuaries, and to have breathed air like the Ichthyosaur and our modern cetacea. [6] Some of the reptiles above mentioned were of formidable dimensions. One specimen of Ichthyosaurus platydon, from the Lias at Lyme, now in the British Museum, must have belonged to an animal more than 24 feet in length; and there are species of Plesiosaurus which measure from 18 to 20 feet in length. ”

“ Probably our readers are already more or less familiar with the drawings of the fossilised remains of Ichthyosauri to be seen in almost every text-book of geology. (Fig. 3 is from Owen’s British Fossil Reptiles.) But we recommend all who take an interest in the world’s lost creations to pay a visit to the great Natural History Museum, at South Kensington. The fossil reptile gallery contains a magnificent series of Ichthyosauri, about thirty in number. ”

“ Reptiles of the Lias.—It is not, however, the fossil fish which form the most striking feature in the organic remains of the Lias; but the reptiles, which are extraordinary for their number, size, and structure. Among the most singular of these are several species of Ichthyosaurus and Plesiosaurus. The genus Ichthyosaurus, or fish-lizard, is not confined to this formation, but has been found in strata as high as the chalk-marl and gault of England, and as low as the muschelkalk of Germany, a formation which immediately succeeds the lias in the descending order. ”

“ This close approximation in the Ichthyosaurs to the form of the most strictly aquatic back-boned (vertebrate) animals of the existing creation is accompanied by an important modification of the surfaces forming the joints of the back-bone, each of which surfaces is hollow, leading to the inference that they were originally connected together by an elastic bag, or “capsule,” filled with fluid—a structure which prevails in the class of fishes, but not in any of the whale or porpoise tribe, nor in any, save a few of the very lowest and most fish-like, of the existing reptiles. ”

“ Buckland, “scarcely a single bone or scale has been removed from the place it occupied during life; which could not have happened had the uncovered bodies of these saurians been left, even for a few hours, exposed to putrefaction, and to the attacks of fishes and other smaller animals at the bottom of the sea.” [8] Not only are the skeletons of the Ichthyosaurs entire, but sometimes the contents of their stomachs still remain between their ribs, as before remarked, so that we can discover the particular species of fish on which they lived, and the form of their excrements. ”

“ Behind the Ichthyosaurus platyodon, is placed the restoration of the Ichthyosaurus tenuirostris, or Slender-snouted Fish-lizard. The most striking peculiarity of this species is the great length and slenderness of the jaw-bones, which, in combination with the large eye-sockets and flattened cranium, give to the entire skull a form which resembles that of a gigantic snipe or woodcock, with the bill armed with teeth. ”

“ And here is a cast of the pterodactyle and bones of the ichthyosaurus and the plesiosaurus, just as fresh as if it had been recently dug up in a churchyard. Thus, in the reptile class, there are no less than half of the orders which are absolutely extinct. If we turn to the 'Amphibia', there was one extinct order, the Labyrinthodonts, typified by the large salamander-like beast shown in this diagram.
No order of fishes is known to be extinct. Every fish that we find in the strata—to which I have been referring—can be identified and placed in one of the orders which exist at the present day. ”

“ The presence of the undigested remains of vertebræ and other bones of animals of its own species in the coprolites of the Ichthyosaurus proves, as we have already had occasion to remark, that this great Saurian must have been a most voracious monster, since it habitually devoured not only fish, but individuals of its own race—the smaller becoming the prey of the larger. The structure of the jaw of the Ichthyosaurus leads us to believe that the animal swallowed its prey without dividing it. ”

“ Among these animals, the Ichthyosauri (Fish-Lizards) form one of the best-known and most prominent groups. They are chiefly found in the Lias, the lowest set of beds of the Jurassic deposits, and seem to have come in with the close of the Triassic epoch. It is greatly to be regretted that all that is known of the Triassic Reptiles antecedent to the Ichthyosauri still remains in the form of original papers, and is not yet embodied in text-books. ”

“ It is the most fearful of all antediluvian reptiles, the world-renowned Ichthyosaurus or Great Fish Lizard."
"And the other?"
"The other is a monstrous serpent, concealed under the hard vaulted shell of the turtle, the terrible enemy of its fearful rival, the Plesiosaurus, or Sea Crocodile."
Hans was quite right. The two monsters only disturbed the surface of the sea! At last have mortal eyes gazed upon two reptiles of the great primitive ocean! I saw the flaming red eyes of the Ichthyosaurus, each as big, or bigger than a man's head. ”

“ The ichthyosaurus was certainly a most unpleasant creature to meet alone in a narrow strait on a dark night; but if it comes to actual measurement, the very biggest ichthyosaurian skeleton ever unearthed does not exceed twenty-five feet from snout to tail. Now, this is an extremely decent size for a reptile, as reptiles go; for the crocodile and alligator, the two biggest existing lizards, seldom attain an extreme length of sixteen feet. ”

“ Lazily basking in the sun, when it condescends to shine, and resting his clumsy carcase on the ground that forms the shore near the said geological island at Sydenham, may be seen the old fish-lizard, or Ichthyosaurus, that forms the subject of the present chapter. He looks awkward on land, as if longing to get into his native element once more, and cleave its waters with his powerful tail-fin. His “flippers” seem too weak to enable him to crawl on land. ”

“ Naturalists are now pretty well agreed that the existence of the sea-serpent is a possibility; the celebrated Professor Agassiz said that if a naturalist had to sketch the outlines of an ichthyosaurus or plesiosaurus from the remains we have of them, he would make a drawing very similar to the sea-serpent as it has been described. The race is generally believed to be extinct, but he thought it probable that it would be the good-fortune of some person on the coast of Norway or North America to find a living representative of this type of reptile. ”

“ Though the Ichthyosaurs are undoubtedly marine animals, there is, however, reason to believe that they occasionally came on shore, as they possess a strong bony arch, supporting the fore-limbs, such as would permit of partial, if laborious, terrestrial progression. The head is of enormous size, with greatly prolonged jaws, holding numerous powerful conical teeth lodged in a common groove. ”

“ They have, as an order, so isolated a position, are so widely separated from all other reptiles in structure, that they have long been a puzzle to paleontologists. Like the whales and other cetaceans among mammals, we know the ichthyosaurs well in the plenitude of their power and the fulness of their development, but have yet only an imperfect knowledge of their earlier history, and none whatever of their earliest. However, as will be seen farther on, the recent discoveries by Merriam have shed much light on some of the stages of their evolution. ”

“ These have been discovered by Professor Marsh, in the Jurassic strata of the Rocky Mountains. They were eight or nine feet long, and in every other respect resembled Ichthyosaurs. As we have endeavoured to indicate in our illustration, the fish-lizards flourished in seas wherein animal, and doubtless vegetable life was very abundant. Any one who has collected fossils from the Lias of England will have found how full it is of beautiful organic remains, such as corals, mollusca, encrinites, sea-urchins, and other echinoids, fishes, etc. ”

“ The fossil which I venture to refer to the genus Ichthyosaurus is the symphysial part of a long slender mandible. The front end is wanting; and the rami have also been broken off just behind the symphysis. In its present mutilated state it measures 9 in. long, 1⋅2 transversely in front, and 2⋅1 at the posterior limit of the symphysis. Its outer surface is transversely gently convex, smooth, and finely wrinkled longitudinally. ”

“ Of no extinct reptile are the materials for a complete and exact restoration more abundant and satisfactory than of the Ichthyosaurus they plainly show that its general external figure must have been that of a huge predatory abdominal fish, with a longer tail, and a smaller tail-fin: scale-less, moreover, and covered by a smooth, or finely wrinkled skin analogous to that of the whale tribe. ”

“ Fossil remains now in the British Museum, and in the museum of the Geological Society, fully bear out the dimensions exhibited by the restoration of the animal as seen basking on the shore between the two specimens of Long-necked Plesiosaurs. The head of this species is relatively larger in proportion to the trunk, than in the Ichthyosaurus communis or Ichthyosaurus tenuirostris: the lower jaw is remarkably massive and powerful, and projects backwards beyond the joint, as far as it does in the crocodile. ”

“ The pelvis of amphibious or aquatic reptiles is also modified not a little. It lost all connection with the spinal column in the Mosasauria and later Ichthyosauria, but is firmly connected, as usual, in other water animals. The slender ilium of the mosasaurs, like that of the ichthyosaurs, lay loosely in the flesh with its upper end in apposition or ligamentously connected with the end of a transverse process or rib of a single vertebra. The narrow ischia and pubes meet in a symphysis, and there is a pubic foramen. ”

“ HERE were in the sea in very ancient times—long before the flood—two very large and wonderful reptiles. Of them we present striking illustrations. One of them has been named the Ichthyosaurus, which means Fish Reptile. Its head somewhat resembled that of the crocodile, except that the orbit was much larger, and had the nostril placed close to it, as in the whale, and not near the end of the snout. It had four paddles and a powerful tail, and was very active in its movements and a rapid swimmer.
The other huge reptile was the Plesiosaurus, the meaning of which is “Near to a Reptile.” ”

“ These animals which, in our days, rarely exceed a yard or so in length, attained in the Cretaceous period as much as twenty. The marine lizard, which we notice under the name of Mosasaurus, was then the scourge of the seas, playing the part of the Ichthyosauri of the Jurassic period; for, from the age of the Lias to that of the Chalk, the Ichthyosauri, the Plesiosauri, and the Teleosauri were, judging from their organisation, the tyrants of the waters. ”

“ As time passed, the sea serpents grew to such size that they became very sluggish and eventually perished because they did not have brains large enough to afford protection for their immense bodies. Their brains weighed less than two ounces notwithstanding the fact that these huge ichthyosaurs sometimes grew to be fifty feet long, the majority being over thirty-five feet in length. The marine crocodilians were also a reversion from the land type of reptile, but unlike the sea serpents, these animals always returned to the land to lay their eggs. ”

“ The Ichthyosaurs were much more fish-like or whale-like in form than the Plesiosaurs. "They were, indeed," says Sir E. Ray Lankester, "singularly like the porpoises and grampuses among living whales and stand in the same relation to land-living reptiles that the porpoises do to land-living mammals. Their fish-like appearance and fins are not primitive characters and do not indicate any closer blood relationship to fishes than that possessed by other reptiles. They are the offspring of four-legged terrestrial reptiles which have become specially modified and adapted to submarine life." ”

“ Blaineville in 1835 gave to the plesiosaurs an ordinal rank under the class Ichthyosauria, and even the astute Owen in 1839 united them with the ichthyosaurs as a suborder of his Enaliosauria, or “sea-saurians.” He called them Sauropterygia, or “reptile-finned,” and these terms, Enaliosauria, Ichthyopterygia, and Sauropterygia, have long persisted in works on natural history because of the prestige of Owen’s name. As we shall see later, the plesiosaurs are really of remote kinship to the ichthyosaurs, and there is no such natural group as the Enaliosauria. ”