 Phylum: Chordata ("Cord" - named after the notochord):
 Chordates, or vertebrates, are among the most adaptable of animals, and are able to occupy almost any type of habitat on the planet, whether it be the deepest ocean trench or the highest mountain peak. They are distinguished from all invertebrate animals by the possession of a notochord (a dorsal supporting rod), which is replaced by the bony vertebral column in adults; a cartilaginous or bony endoskeleton; a dorsal hollow nerve cord (the spinal cord); and a series of gill pouches or slits, at least during development of the embryo (but which persist in adult cartilaginous [chondrichthyes] and bony [osteichthyes] fish), supported by a network of gill bars.
In respect to the local paleontology of Vancouver Island, the Chordates are further subdivided into the following six classes:
 Class: Chondrichthyes (Cartilaginous Fish):
The Cartilaginous Fish include all members of the sharks, skates, rays, and chimaeras. Together they form an ancient but highly developed group of aquatic and marine animals whose unique combination of well-developed sensory systems, powerful jaws and swimming musculature, and predaceous habits have made them a particularily successful group as well. There most distinguishing characteristic is their cartilaginous skeleton, which is presently considered to be a degenerative, rather than a primitive, feature, though in many other ways, such as in methods of reproduction and locomotion, they conform quite closely to those of the bony fish.
In respect to the local paleontology of Vancouver Island, the Chondrichthyes are further subdivided into the following two subclasses:
 Subclass: Holocephali (Chimaera Fish):
Known variously as the Rat-, Rabbit-, Spook-, and Ghostfish, the Holocephali (so named because their upper jaws are fused to their skulls) is an exclusively marine group that retains a curious mixture of features that are reminiscent of both the sharks and the bony fish. Instead of jaws lined with a series of sharp teeth, their jaws bear large flat plates, ideally suited to their diet of seaweed, molluscs, echinoderms, crustaceans, and small fish.
In respect to the local paleontology of Vancouver Island, the Holocephali are further subdivided into the following order:
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 Class: Osteichthyes (Bony Fish):
The Bony Fish includes all members of the Lungfish, and the Ray-finned and Lobe-finned fish. The group is adapted to all but the most inhospitable marine and aquatic habitats, and their streamlined shape, fins, and muscles are all superbly suited to locomotion through the water. Their skeletons are chiefly composed of bone, and their bodies are covered by scales, which serve as protection, and the animal breathes by absorbing oxygen from a stream of water propelled through a network of gills. Their wide range of body forms alone are indicative of their phenomenal diversity. Predaceous, swimming forms have trim, elongate bodies, powerful tail fins, and other advantages for swift pursuit; while sluggish, bottom-dwelling forms have flattened bodies for movement and concealment on the ocean floor. Various other body shapes express the amazing array of specializations for defense and attack, food-gathering, navigation, and reproduction.
In respect to the local paleontology of Vancouver Island, the Osteichthyes are further subdivided into the following two subclasses:
 Subclass: Actinopterygii (Ray-Finned Fish):
The Ray-finned Fish form a huge assemblage which includes all familiar forms of bony fish. Today they inhabit most aquatic and marine habitats, but their earliest fossils indicate an origin in Devonian freshwater streams and lakes. They have single dorsal and anal fins, paired pectoral and pelvic fins, their skeletons are either mostly or primarilly composed of bone, and their trunks and tails are encased in an armour of rhombic scales. But their most characteristic feature is the development of a series of stout spines that radiate out through, and support, each fin, especially in the pectoral, dorsal, and anal fins.
In respect to the local paleontology of Vancouver Island, the Actinopterygii are further subdivided into the following four orders:
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 Subclass: Sarcopterygii (Lobe-Finned Fish):
Although the Lobe-finned Fish are a conservative group, enjoying less diversification than have the other subclasses of bony fish, they are also the most important, at least in an evolutionary standpoint, because they are the ancestral stock from which the amphibians, and eventually all land-living vertebrates, evolved from. They include both marine and aquatic members, all possessing adaptations for breathing air and moving from one body of water to another: chief among them are nostrils that open into the mouth, lungs in addition to gills, and paired lobed fins to assist in movement.
In respect to the local paleontology of Vancouver Island, the Sarcopterygii are further subdivided into the following order:
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 Class: Reptilia (Reptiles):
The Reptiles were the first group of early tetrapods (four-legged, land-living vertebrates) to truly exploit dry land. These animals inherited a number of traits from their ancestors, the amphibians, which permitted them to live out of the water and breath air. These included the evolution of efficient limbs and posture, which serve to elevate and propel the animal when moving at high speed or over uneven ground, and of advanced circulatory and respiratory systems, which distribute oxygenated blood throughout the body.
But they are better characterized by a large number of adaptations that have permitted them a much reduced dependancy on water (when compared to the amphibians), chief among them the development of a layer of horny scales and an innovative reproductive strategy. The scales protected the animal both from desiccation and predators, but it was the evolution of internal fertilization and an egg covered by a protective leathery shell that made near unlimited colonization of the Late Paleozoic world a reality. This last structure eliminated the need for a swimming larval stage during the animal's development, and provided the growing embryo with oxygen, food, and water; removed nitrogen wastes; and insulated it against water-loss and from injury. However, their one major limitation was their metabolism. All reptiles, living and (presumably) extinct, require a constant source of heat; without it, their internal body temperatures match the external conditions. Though this strategy works fairly well for most environments (especially during the latter quarter of the Paleozoic and entire Mesozoic Eras), today it limits their expansion to the warmer climatic zones of the planet.
In respect to the local paleontology of Vancouver Island, the Reptilia are further subdivided into the following two subclasses:
 Subclass: Anapsida (Reptiles with no temporal opening):
The Anapsid Reptiles are best distinguished from all other reptile subclasses by the absence of an opening in the temporal region of the skull, behind and above the eye sockets. This is considered to be a primitive trait, in that it was possessed by the earliest known reptile and many of the Pennsylvanian, Permian, and Triassic reptile groups that evolved from it. In the past, this group included a host of forms from which the Diapsida and Synapsida (two other reptilian subclasses) eventually developed, but today they are represented only by the turtles and tortoises.
In respect to the local paleontology of Vancouver Island, the Anapsida are further subdivided into the following order:
 Order: Chelonia (Turtles and Tortoises):
This advanced group of primitive reptiles has traditionally been placed within the Anapsida (though this may soon change), based solely on the lack of any opening in the temporal region of the skull. However, this assignment may one day prove to have been an arbitrary one. Their general anatomy and behaviour (supposed and observed) is so distinct from that of other early anapsids that it seems more logical to have placed them in a subclass of their own. The entire skeleton of even the most primitive turtle is so altered that it reveals no clue as to the identity of its ancestor. In addition, there is no evidence for the prior existence of any temporal openings, which eliminates any chance of relationship to the Diapsida and Synapsida.
The Chelonia represent a conservative group of reptiles that have invaded many aquatic, marine, and terrestrial environments throughout the temperate, subtropical, and tropical regions of the planet. As the lifestyle of their earliest members became more and more amphibious, their bodies widened considerably while their limbs became quite paddlelike with a webbing of skin between each toe. A shell appeared on the back of the animal (called a carapace), which became fused to the ribs and to a covering of shell on the animal's stomach (plastron) at various points along its edge; it consisted of interlocking bone plates that formed in its skin and were covered by scales that greatly expanded into scutes. Teeth became progressively smaller, until they vanished altogether, their function being replaced by a horny beak.
The group is represented by the following families:
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 Subclass: Diapsida (Reptiles with two temporal openings):
As their name suggests, the skulls of these reptiles bear two temporal openings on each side of the skull. This development may be attributed to two major factors: the redistribution of stress on the skull when the animal is killing and/or feeding, and the concentration of muscle power over the limited surface area of the skull.
Since their earliest appearance in the Upper Pennsylvanian of Kansas, Diapsid reptiles have formed the largest and most progessive of all the reptile groups. Their membership has, throughout its long and glorious history, successfully invaded most aquatic, marine, terrestrial, and airborne habitats, and includes such honouraries as the crocodilians, ichthyosaurs, nothosaurs, plesiosaurs, placodonts (?), lizards and snakes, and a host of other groups; in addition to forming the root stock from which the Ornithosuchia (dinosaurs and pterosaurs) eventually evolved during the Triassic Period.
In respect to the local paleontology of Vancouver Island, the Diapsida are further subdivided into the following three orders:
 Order: Ichthyosauria (Dolphinlike Marine Reptiles):
Throughout the entirety of their long history, the Ichthyosaurs were the most highly specialized of all the various marine reptile groups, so it is not surprising that they also display the greatest change from the clumbsy, primitive animals that plied the Triassic shallows to the sleek, dolphinlike animals that hunted the Jurassic and Cretaceous depths.
Like the Chelonians (the turtles and tortoises), the earliest Ichthyosaurs give little clue as to the identity of their terrestrial ancestors, and it has only been recently that they have been reassigned to the Diapsida (as opposed to the now defunct Parapsida - also known as the Ichthyopterygia). These Triassic Ichthyosaurs, known from Spitsbergen, Japan, and China, were slender creatures whose tails were flattened, relatively straight, and lined with a narrow fin fold running above and below, like an eel's. The slender jaws were set with many cone-shaped teeth, superbly adapted to catching and devouring small fish and, later, belemnoids, squid, and octopods, whose remains are sometimes found preserved between the animal's ribs. They were obviously active predators, hunting by sight and, as some authors have speculated, perhaps even by rudimentary sonar, and their enormous eyes were strengthened by rings of bone and equipped to catch a maximum of light.
In time, the more advanced Ichthyosaurs developed a reversed heterocercal tail (a swimming organ not unlike that of the swiftest shark) in which the spine became downturned while the large, fleshy upper lobe enlarged. Modified for maximum speed (some estimates envision their submerged speed in excess of 40kmh [25mph]), it also provided them with an upward thrust, so critical in ambush attacks from below its prey. The spine also became designed for speed and flexibility. No longer were the individual vertebrae long and packed closely together, in the Jurassic and Cretaceous forms they were very short, highly excavated on both ends, and presumably spaced with large discs of cartilage between them. With such radical modifications in design came the addition of a muscular dorsal fin and the reduction of the animal's scales to just a few lining the forward edge of its pectoral and pelvic flippers. In addition, preserved pigment grains show that at least a few of them were dark along their backs, grading into white along their bellies. This helped to conceal them from their prey and whatever predators that shared their territory. Furthermore, a few Jurassic genera have been discovered with fossilized young either still intact within the abdominal cavity, or having just emerged.
The group is represented by the following families:
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 Order: Plesiosauria (Marine Reptiles):
The Plesiosaurs rank as perhaps the second most advanced of the various marine reptile groups, though, unlike the Ichthyosauria, they give adequate clues as to the identity of their ancestors: the amphibious, Triassic nothosaurs. And like the ichthyosaurs, it has only been recently that they too have been reassigned to the Diapsida (as opposed to the now defunct Euryapsida - also known as the Synaptosauria).
As a group, the Plesiosaurs became quite numerous and of worldwide extent during the Jurassic, but reached their zenith only during the Cretaceous Period, perhaps as a result of the decline of the ichthyosaurs (themselves a possible victim of the emergence of modern sharks). They are distinguished from their ancestors by the much greater size and similarity of their limbs, greatly expanded pectoral and pelvic girdles, and extremely massive stomach ribs (gastralia). These modifications resulted in a change in both the method and strength of propulsion, and it is currently thought that they sculled through the Mesozoic seas in much the same way as the sea lion rows its way through the modern Pacific Ocean. In addition, the strengthening of these elements also served to reinforce the entire trunk region against the increased stresses exerted upon it during rapid acceleration and maneuvering.
For the most part the Plesiosaurs were marine reptiles adapted to life on the shallow continental slopes and open seas, though some forms are known to have frequented aquatic environments such as swamps, estuaries, and deep rivers. They were apparently active surface predators, diving infrequently, and dining mainly on fish, and the occassional belemnoid and octopod, swallowed whole or torn to shreds by the cagelike arrangement of their long, cone-shaped teeth.
The group is represented by the following families:
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 Order: Squamata (Lizards and Snakes):
Of all the fossil reptile groups found on Vancouver Island, only the Squamata survive to the present day. They are by far the most important of modern reptiles, both in terms of the number of species and their wide geographical distribution, and this success seems to lie with a combination of more effective hearing, jaw mechanics (expecially in the way the jaw-closing forces are applied), and locomotion. This permitted them an early advantage over the more primitive, lizardlike diapsid reptiles that had shared their late Paleozoic and Mesozoic worlds.
It would appear that the group is, in many respects, among the most highly specialized of the diapsid reptiles. Their skulls often lack the lower of the two temporal openings, and this is simply because of the extreme modification of this area of the skull to permit it great mobility with the lower jaw. In addition, several other skull bones have become markedly reduced or are absent, permitting enhanced mobility throughout the rest of the skull as well. This trend has been taken to the extreme in the snakes, which has enabled the Squamates as a whole to absorb the stresses of impact during capture of prey, and to allow the predator to engage prey that would otherwise be much too large for it to handle.
These modifications were the key to their evolutionary success. By the beginning of the Triassic Period they had already displaced their close relatives, invaded most terrestrial and a few marine and airborne habitats, and set the stage for the astonishing diversification of the Lacertilia (lizards) and Serpentes (snakes) before the close of the Cretaceous.
The group is represented by the following families:
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 Class: Ornithosuchia (Dinosaurs & Pterosaurs):
The Ornithosuchia is a provisional grouping of the Dinosauria and the Pterosauria, based on a suite of shared characters including a presumed metabolism that is advanced beyond the usual reptilian grade, but not as advanced as the avian or mammalian systems. This, along with an enhanced posture and mode of locomotion, are the primary characters that differentiate them from their immediate ancestors (the ornithosuchidae). The head of the femur (the upper leg bone) was turned inward and fitted into a deep, perforated socket (called the acetabulum); and the skull was lightened by the addition of an opening in front of each eye. These changes not only served to bring the legs directly under the body mass, thereby restricting leg movement to the fore and aft, but also permitted the trunk of the animal to balance more efficiently over its hips.
In respect to the local paleontology of Vancouver Island, the Ornithosuchia are further subdivided into the following two subclasses:
 Subclass: Dinosauria (Dinosaurs):
For 160 million years, from the Mid Triassic to the end of the Cretaceous, the Dinosauria completely dominated almost every terrestrial habitat on the planet. They were unquestionably the most successful group of vertebrate animals ever to have walked the earth, rivalling even the present dominion of the Cenozoic mammals in both diversity and distribution.
The transition from ornithosuchidae to the first true dinosaur probably occurred before the middle of the Triassic Period. It was not a large change, but instead was comprised of a series of small steps, involving, among others, minor refinements to the animal's hind limbs, pelvis, and skull. In addition, the pelvis was strengthened, and one or more extra vertebrae added, to provide a firmer attachment with the backbone.
In respect to the local paleontology of Vancouver Island, the Dinosauria is further subdivided into the following order:
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 Subclass: Pterosauria (Pterosaurs):
Pterosaurs were the first of the vertebrates to claim mastery over the skies, if not by their somewhat primitive flight mechanics (in comparison to those of the birds), then at least by their high diversity and wide geographic distribution. Their earliest members are known from the Upper Triassic of northern Italy, and were already so advanced that, like the ichthyosaurs, they give little clue as to the identity of their ancestors. They evolved in considerable variety through the rest of the Mesozoic Era, gradually adapting to a large number of habitats and lifestyles, until suffering in the extinction at the close of the Cretaceous Period.
They are characterized by a skeleton that is highly specialized for flight, so much so that movement on the ground seems to have been a clumsy and very dangerous affair. Chief among these modifications was the transition of the forelimbs into a pair of membranous wings that were supported by a single, greatly enlarged fourth digit; an expanded region of the brain devoted to sight; and perhaps a hide of short, insulating hairs. All forms possessed short, stocky bodies; large, hollow wing bones filled with air sacks; and a wide breastbone (sternum) which furnished large attachment areas for the flight muscles. The early, Triassic forms were small (<1m [<3ft]) in length, with light, elongate skulls whose jaws were supplied with long, pointed teeth, well-suited to catching the animal's diet of insects and/or fish. But by the close of the Cretaceous Period, however, some Pterosaurs had become quite large (the largest animals to take to the skies, in fact), while others had developed a comblike seive for straining crustaceans and other invertebrates out of the water, or had lost their teeth altogether.
In respect to the local paleontology of Vancouver Island, the Pterosauria is further subdivided into the following order:
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 Class: Aves (Birds):
Of all the higher animals, no class of vertebrates is more graceful, melodious, or, many believe, more beautiful than the Birds. They are distributed over nearly the entire planet, ranging from forest to desert, from the highest mountain to the lowest plain, and on the surface of all the oceans. A few have been observed at the North Pole, and one, a skua, has even been seen at the South Pole. This global distribution is, in part, a result of the two major innovations introduced by them some 150 million years ago: an advanced, warm-blooded metabolism, superior even to that of the mammals, and sustained, powered flight.
The single most obvious feature which distinguishes them from all other animals is that they possess flight feathers, or insulating feathers that have been secondarily modified from flight feathers. If a living animal has either flight or insulating feathers, it is a bird, if it lacks these structures, it is something else. But this was not always true. Though some evidence exists to suggest that the earliest known bird (the Upper Jurassic Archaeopteryx, from Bavaria) inherited its warm-blooded metabolism from a small, as of yet unknown carnivorous dinosaur, there is mounting evidence to suggest that some dinosaurs (such as the Chinese Sinosauropteryx) may also have been covered, at least in part, by a coat of insulating featherlike structures. In addition to feathers, Birds are also characterized by the modification of the forelimbs into wings (although they may not necessarily be used for flight); the hindlimbs into walking, swimming, or perching appendages; and (in the Superorder Neognathae) the front of the skull and jaws into a horny, toothless beak.
In respect to the local paleontology of Vancouver Island, the Aves are further subdivided into the following subclass:
 Subclass: Neornithes (Modern Birds):
All Birds, other than Archaeopteryx, belong to the subclass Neornithes, and, for the most part, those found within the Cretaceous Period are confined to the Odontognathae, the Toothed Jaws. But, owing to the very delicate nature of most Bird fossils, and the relative lack of good Cretaceous specimens, one can rarely be certain if even a complete bone belongs to one of the other, rarer groups, or if it belongs to a new group altogether.
The three most conspicuous of the skeletal changes that differentiates the Neornithes from the Archaeornithes (whose sole member is presently Archaeopteryx) were the reduction of the tail to a short parson's nose (the pygostyle), the development of a large keeled sternum to increase the attachment area of the enlarged flight muscles, and the realignment of some of these muscles to increase the efficiency of the flight stroke.
The group is represented by the following families:
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 Class: Mammalia (Mammals):
Mammals, with their highly developed brains, senses, and numerous other ingenious adaptations, occupy almost every habitat on the Earth, and, with the possible exception of the insects, are presently overall the most biologically successful group in the entire animal kingdom.
A covering of hair, at least on some part of the animal, or during some part of its life cycle, is the most obvious mammalian character, but they are also distinguished by other features of their anatomy that can only be supposed from their fossil record. The vast majority of Mammals (the Therians) nourish their young by means of a series of milk-secreting glands, a unique development in the animal world, and are themselves provided with a warm-blooded metabolism that is second only in efficiency to the birds. In addition, there is a suite of characters within the mammalian skull which serve to further differentiate them from their ancestors, the reptiles. Mammal teeth are generally much more complex than those of their reptilian counterparts, and the milk teeth are replaced by a permanent set of teeth as the animal matures. Furthermore, their jaw, except for their most primitive members, is composed of a single tooth-bearing bone (the dentary), and the attachment area for the neck vertebrae (of which there are usually only seven) are composed of two facets (the occipital condyles).
In respect to the local paleontology of Vancouver Island, the Mammalia are further subdivided into the following subclass:
 Subclass: Theria (Modern Mammals):
The Therian mammals are represented by all surviving mammalian orders except that of the egg-laying monotremes (primitive mammals like the duckbill platypus and the spiny anteater from Australia, Tasmania, and New Guinea); the marsupials and placentals. They are best distinguished by their capacity to nourish their young with milk produced from teats or mammary glands.
In respect to the local paleontology of Vancouver Island, the Theria is further subdivided into the following three orders:
 Order: Carnivora (Carnivores):
The flesh-eating mammals, order Carnivora, include the living dog, cat, bear, weasel, seal, and many other familiar families, and are among the few mammalian orders that have successfully invaded such a wide variety of aquatic, marine, and terrestrial habitats. They are all predators, their teeth are specially adapted for rending flesh, and the group is further divided into the Fissipedia (whose feet contain toes) and the Pinnipedia (whose limbs are modified into flippers).
The group is represented by the following families:
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 Order: Cetacea (Whales and Dolphins):
The Cetaceans are the most highly specialized of all the mammalian orders, both living and extinct, for exploiting a wide range of marine habitats. Today, after having evolved from a small, fish-eating mesonychid (a primitive group of carnivores, perhaps related to the forerunners of the order Carnivora) sometime during the Lower Eocene of the Mid East, they rank among the largest of the animals; hunt the seas for crustaceans, cephalopods, fish, and mammals; and range from pole to pole.
They are, therefore, characterized by a large suite of adaptations required for living in the ocean. These include anterior limbs that are modified into flippers, and progressive reduction of the posterior limbs. Some have a fleshy dorsal fin, and all have a tail that has been adapted into a horizontal device used for propulsion. The nostrils are invariably represented by a single or double blowhole on top of the head, and the covering of hair, so characteristic of mammals, has been reduced to a few whiskers that adorn the muzzle. The surviving Cetaceans are divided into the toothed (Odontoceti) and baleen (Mysticeti) whales.
The group is represented by the following families:
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 Order: Desmostylia (Extinct Marine Mammals):
Desmostylians represent a group of marine mammals that apparently evolved from a primitive member of the elephant group (the proboscideans), and whose fossils are today found in Paleocene and Neocene deposits of the Pacific Northwest, California, and Japan. Once confined to a collection of teeth that resembled those of the sea cow, the discovery of associated skeletal material demonstrates that they had a completely different body form. Apparently they were something akin to sea-going hippopotami, wading and swimming in the shallow waters, feeding on plants and bivalves that were exposed in the intertidal zone, and later on large amounts of marine algae.
The animal's body was short and stocky; with very heavy, elephantine limbs that ended in broad, somewhat specialized paddles. In addition, its skull demonstrates characters that are also very elephantine in nature. These include a long, mastodonlike skull with large canine tusks protruding outward from the front of the jaws, and it seems likely that these animals had a short, prehensile trunk or extended muscular upper lip.
The group is represented by the following families:
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