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PREHISTORIC CATS AND PREHISTORIC CAT-LIKE CREATURES Although we are familiar with cinema representations of sabre-toothed cats, only a handful of prehistoric big cats exceeded an average weights of 100 kilos and only four or five North American prehistoric big cats (not all are true cats) are in the 100+ kilos category. This means few were longer or taller at the shoulder than a modern leopard or jaguar. Many of the "bigger" prehistoric big cats were compact, muscular animals. Modern big cats are relatively long-legged and lithe in comparison. Although they are often called "big cats" many of the prehistoric species were not true cats, but were cat-like mammals. South America and Australia were both island continents and lacked placental mammals. The "lions" and "tigers" of those continents were lion-like marsupials, more closely related to kangaroos, wombats and their like. Theyare known as "cat analogues" as they resembled cats and filled the same ecological niche as cats. Another line of prehistoric cats were the Paleofelids ("ancient cats") that developed in parallel with the true cats and from a common ancestor, but which have left no modern descendants. Finally there are the prehistoric true cats, extinct relatives of modern cats. Why would evolution create creatures very similar in form to cats? It's an example of convergent evolution there are a limited number of solutions to environmental conditions hence animals that aren't closely related often independently evolve similar traits as they both adapt to similar environments and niches. The cat-like form has evolved at least three times: marsupial lions/tigers, Paleofelids and Neofelids. Sabre-toothed cat-like animals evolved separately four times in evolutionary history: Nimravids, Felids, Creodonts and the Thylacosmilids. The taxonomy (classification) of both living and extinct species changes frequently. As more fossil evidence comes to light, species are reclassified. Some are given their own species or genus while others are absorbed into an existing species or genus and their original classification is scrapped. Kingdom Phylum Class Order Superfamily Family Subfamily Subfamily Subfamily Subfamily Animalia Chordata Mammalia Carnivora Feliodea/Aeluroidea Felidae Acinonychinae Felinae Pantherinae Machairodontinae The animal kingdom Animals that have backbones Animals that suckle their young Animals that eat meat (Includes cats, hyenas, civets, mongooses) Modern cats Cheetah family Small cats Big cats (Tiger, Lion etc) Sabre-toothed cats (extinct)

Epoch Paleocene

Years 58 to 64 million years ago

Notes Began with extinction of dinosaurs. Emergence of early mammals.

Eocene

55.5 million to 38 million years ago

Emergence of first modern mammals. Epoch ended with a major extinction event. A relatively quiet time for mammalian evolution, few new faunas appeared. Recognisably modern mammals appeared. Modern mammals continue to diversify. Includes the ice ages. Recent era. Also called Alluvium epoch.

Oligocene

33.7 million to 23.8 million years ago

Miocene Pliocene Pleistocene Holocene

5 million to 24 million years ago 5 million to 1.8-1.6 million years ago 1.8-1.6 million to 10,000 years ago 10,000 radiocarbon years ago to present day

Other Definitions Marsupials Placentals Eutherians Taxon (plural: Taxa) Pouched mammals such as kangaroos and wombats. Mammals that carry their young to full term in an internal womb. Placental mammals. A creature's taxonomic classification.

Although there are references to animals being found in places far apart on the modern world map, the continents used to look very different. Some land masses that were once joined together have now split and drifted apart, others that were far apart have collided. Some land masses that are currently not joined to each other were joined by ancient land bridges when sea levels were much lower than they are today. EVOLUTION OF MODERN CATS (SUMMARY) Carnivorous mammals evolved from Miacids small pine marten-like insectivores that lived 60 million 55 million years ago. The miacids split into two lines: Miacidae and Viverravidae. Miacidae gave rise to Arctoidea/Canoidea group (bears and dogs) while Viverravidae gave rise to Aeluroidea/Feloidea group (cats, hyenas, civets, mongooses) around 48 million years ago. The Viverravidae also gave rise to a group called Nimravidae. The Nimravids were cat-like creatures that evolved in parallel with true cats; they are not part of true cat lineage and have left no living descendents. The first true cat to arise from Viverravidae was Proailurus (first cat") around 30 million years ago. The best-known species was P lemanensis, found in France. Proailurus was a small weasel-like cat with relatively short legs and a long body. It had one more premolar on each side of its bottom jaw than do modern cats. About 20 million years ago, Proailurus gave rise to Pseudaelurus. Pseudaelurus were Miocene ancestors of cats. Pseudaelurus lorteti was about the size of a large lynx while P validus was the size of a large lynx or small puma. Three other species of early cat are described as Pratifelis, Vishnufelis and Sivaelurus (S chinjienis).Pseudaelurus went on to split into two major groups: the Machairodontinae (true sabre-tooths) and Schizailurus (the ancestor of the modern day Felidae group).

The very early cats would have looked something like this modern day Fossa, a Madagascan mammal related to the Mongoose. This carnivore occupies a similar ecological niche to cats and preys on lemurs and rodents.

EARLY ANCESTORS OF THE CAT: PROAILURUS & PSEUDAELURUS Genus: Proailurus [Syn: Brachictis, Stenogale] Proailurus lemanensis ("Leman's Dawn Cat") Genus: Pseudaelurus [Syn: Ailuromachairodus, Sansanailurus, Schizailurus] P quadridentatus (P quadridenta) P lorteti P marshi P romieviens P intripedus [P sinclairi] P guangheensis P cuspidatus P turnauensis [P transitorius] P aeluroides P validus ?P stouti

Note: The names prefixed with "?" are questionable. They may result from misidentification of incomplete fossils. Taxonomists rarely agree over which species are separate and which are synonyms. For example, some members of Pseudaelurus have been classified as Metailurus (see the table for Machairodontinae).

18 million years ago, Schizailurus gave rise to the Felidae. The first of the modern Felids were the early cheetahs; now represented by Acinonyx (modern cheetah); true cheetahs are believed to have evolved around 7 million years ago. Some sources claim Miracinonyx (North American cheetahs) evolved only 4 million years ago from Acinonyx, but recent studies show Miracinonyx was probably ancestral to both cheetahs and puma and was intermediate in type between these two modern species. Around 12 million years ago, genus Felis appeared and eventually gave rise to many of our small cats. Two of the first modern Felis species were Felis lunensis (Martelli's cat, extinct), and Felis manul (Manul or Pallas's Cat, living). Extinct Felis species are: F attica, F bituminosa, F daggetti, F issiodorensis (Issoire Lynx), F lunensis and F vorohuensis. The ancestor of modern Felis species was F attica. Genus Panthera ("biting cats" or "roaring cats") genera evolved around 3 million years ago; there are a number of extinct species discussed later in this article. Genera Acinonyx, Felis and Panthera are all represented today and taxa of some modern species is regularly revised as more complete fossils of ancestral species are found, giving a clearer indication of who begat whom and when various lineages split. FAMILY THYLACOSMILIDAE: MARSUPIAL "SABRE-TOOTH TIGER"

The jaguar-sized Thylacosmilus ("pouched blade") was a large, predatory marsupial; part of a unique group of predators on the South American pampas; the borhyaenids. These appeared in the Miocene and ruled the South American forests and woodlands for some 30 million years, but have no known ancestor or descendant. Thylacosmilus was the most successful member of that family and was the ultimate mammalian predator of its day in Plio-Pleistocene South America, but when the continents of North America and South America joined, it lost out to the more highly developed and faster eutherian cats. Two species are described: T atrox and T lentis. Thylacosmilus atrox looked like a sabre-toothed cat, but is more closely related to kangaroos. As far as we know, Thylacosmilus was the only marsupial to have developed the sabre-toothed weapon. Like Smilodon, the eutherian sabre-tooth tiger, it had adapted to hunting mega-fauna. Thylacosmilus lacked incisor teeth, but had very long upper canine teeth that grew continually. These long stabbing teeth projected below the mouth-line. Strong neck and jaw muscles allowed the sabreteeth to be driven downward with a tremendous killing force. Its huge stabbing teeth were about 15 cm (6 inches) long (longer than those of Smilodon) and may have been used to slash the soft throat of its prey. The jaws were capable of a gape that left the teeth clear to do their work. These sabres grew continually throughout Thylacosmilus's life, much like the incisors of modern rodents. Unlike Smilodon (see later), it had no scabbard-like tooth-guards on its lower jaw though its skull had a deep flange on its lower jaw, forming a protective sheath for when the sabre teeth were not being used. Unlike modern cats, which tend to be sleek and long-legged, it appears to have been short-legged and heavily built, being about 1.2 metres (4 ft) long and weighing around 100 kilos. Its claws were not retractile. It probably preyed on large, slow-moving mammals and when the two continents joined, the highly specialised Thylacosmilus could not compete against the faster, sleeker eutherian big cats. South America has also had at least three species of cats whose body weights exceeded 300 kilos about

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